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Sample records for light quarks radiate

  1. Radiative decays of heavy and light mesons in a quark triangle approach

    NASA Astrophysics Data System (ADS)

    Jones, N. R.; Liu, Dongsheng

    1996-06-01

    The radiative meson decays V-->Pγ and P-->γγ are analyzed using the quark triangle diagram. Experimental data yield well determined estimates of the universal quark-antiquark-meson couplings g'Vqq¯ and g'Pqq¯ for the light meson sector. Also predictions for the ratios of neutral to charged heavy meson decay coupling constants are given and await experimental confirmation.

  2. Energy loss for heavy quarks in relation to light partons: is radiative energy loss for heavy quarks anomalous?

    PubMed

    Lacey, Roy A; Wei, R; Ajitanand, N N; Alexander, J M; Gong, X; Jia, J; Mawi, A; Mohapatra, S; Reynolds, D; Salnikov, S; Taranenko, A

    2009-10-02

    The scaling properties of jet-suppression measurements are compared for nonphotonic electrons (e+/-) and neutral pions (pi(0)) in Au+Au collisions at sqrt[S(NN)]=200 GeV. For a broad range of transverse momenta and collision centralities, the comparison is consistent with jet quenching dominated by radiative energy loss for both heavy and light partons. Less quenching is indicated for heavy quarks via e+/-; this gives an independent estimate of the transport coefficient q that agrees with its magnitude obtained from quenching of light partons via pi(0)'s.

  3. Decay constants and radiative decays of heavy mesons in light-front quark model

    SciTech Connect

    Choi, Ho-Meoyng

    2007-04-01

    We investigate the magnetic dipole decays V{yields}P{gamma} of various heavy-flavored mesons such as (D,D*,D{sub s},D{sub s}*,{eta}{sub c},J/{psi}) and (B,B*,B{sub s},B{sub s}*,{eta}{sub b},{upsilon}) using the light-front quark model constrained by the variational principle for the QCD-motivated effective Hamiltonian. The momentum dependent form factors F{sub VP}(q{sup 2}) for V{yields}P{gamma}* decays are obtained in the q{sup +}=0 frame and then analytically continued to the timelike region by changing q{sub perpendicular} to iq{sub perpendicular} in the form factors. The coupling constant g{sub VP{gamma}} for real photon case is then obtained in the limit as q{sup 2}{yields}0, i.e. g{sub VP{gamma}}=F{sub VP}(q{sup 2}=0). The weak decay constants of heavy pseudoscalar and vector mesons are also calculated. Our numerical results for the decay constants and radiative decay widths for the heavy-flavored mesons are overall in good agreement with the available experimental data as well as other theoretical model calculations.

  4. Exclusive radiative Higgs decays as probes of light-quark Yukawa couplings

    NASA Astrophysics Data System (ADS)

    König, Matthias; Neubert, Matthias

    2015-08-01

    We present a detailed analysis of the rare exclusive Higgs boson decays into a single vector meson and a photon and investigate the possibility of using these processes to probe the light-quark Yukawa couplings. We work with an effective Lagrangian with modified Higgs couplings to account for possible new-physics effects in a model-independent way. The h → Vγ decay rate is governed by the destructive interference of two amplitudes, one of which involves the Higgs coupling to the quark anti-quark pair inside the vector meson. We derive this amplitude at next-to-leading order in α s using QCD factorization, including the resummation of large logarithmic corrections and accounting for the effects of flavor mixing. The high factorization scale μ ˜ m h ensures that our results are rather insensitive to the hadronic parameters characterizing the light-cone distribution amplitude of the vector meson. The second amplitude arises from the loop-induced effective hγγ * and hγZ * couplings, where the off-shell gauge boson converts into the vector meson. We devise a strategy to eliminate theoretical uncertainties related to this amplitude to almost arbitrary precision. This opens up the possibility to probe for modifications of the c- and b-quark Yukawa couplings and modifications of the s-quark Yukawa coupling in the high-luminosity LHC run. In particular, we show that measurements of the ratios Br( h → Υ( nS) γ)/Br( h → γγ) and can provide complementary information on the real and imaginary parts of the b-quark Yukawa coupling. More accurate measurements would be possible at a future 100 TeV proton-proton collider.

  5. Quark-antiquark states and their radiative transitions in terms of the spectral integral equation: Light mesons

    NASA Astrophysics Data System (ADS)

    Anisovich, V. V.; Dakhno, L. G.; Matveev, M. A.; Nikonov, V. A.; Sarantsev, A. V.

    2007-03-01

    We continue the investigation of mesons in terms of the spectral integral equation initiated before for the bbar b and cbar c systems; we consider the light-quark (u, d, s) mesons with masses M ≤ 3 GeV. The calculations have been performed for the mesons lying on linear trajectories in the (n, M 2) planes, where n is the radial quantum number. Our consideration relates to the qbar q states with one component in the flavor space, with the quark and antiquark masses equal to each other, such as π(0-+), ρ(1--), ω(1--), ϕ(1--), a 0(0++), a 1(1++), a 2(2++), b 1(1+-), f 2(2++), π 2(2-+), ρ 3(3--), ω 3(3--), ϕ 3(3--), π 4(4-+) at n ≤ 6. We obtained the wave functions and mass values of mesons lying on these trajectories. The corresponding trajectories are linear, in agreement with data. We have calculated the two-photon decays π, a 0(980), a 2(1320), f 2(1285), f 2(1525) and radiative transitions ρ, ω → γπ, which agree qualitatively with the experiment. On this basis, we extract the singular part of the interaction amplitude, which corresponds to the so-called “confinement interaction.” The description of the data requires the presence of the strong t-channel singularities for both scalar and vector exchanges.

  6. Differences between heavy and light quarks.

    SciTech Connect

    Maris, P.; Roberts, C. D.

    1997-11-10

    The quark Dyson-Schwinger equation shows that there are distinct differences between light and heavy quarks. The dynamical mass function of the light quarks is characterized by a sharp increase below 1 GeV, whereas the mass function of the heavy quarks is approximately constant in this infrared region. As a consequence, the heavy meson masses increase linearly with the current quark masses, whereas the light pseudoscalar meson masses are proportional to the square root of the current quark masses.

  7. Spectroscopy of light and heavy quarks

    SciTech Connect

    Cooper, S.

    1986-11-01

    New results on various controversial light mesons are reviewed, including the glueball candidates f/sub 2/(1720) and eta(1460), the 1/sup + +/-0/sup - +/ mass ''coincidences'' f/sub 1/(1285)-eta(1275) and f/sub 1/(1420)-eta(1420), as well as evidence for the X(3100)..--> lambda..anti p+n..pi.. and the rho(1480)..-->..phi ..pi.., which have quantum numbers not allowed for q anti q. The ..gamma gamma -->..VV effects move out of the threshold region with data on ..gamma gamma --> omega..rho. Statistically weak data on GAMMA/sub ..gamma gamma../eta/sub c/ and the search for heavy quark P/sub 1/ states are presented. GAMMA/sub ee/, B/sub ..mu mu../, and GAMMA/sub tot/ for the UPSILON(1S), UPSILON(2S), and UPSILON(3S) are updated using new data and a consistent treatment of the radiative corrections for GAMMA/sub ee/. New data on the mass splittings of the chi/sub b/(2P) compare favorably with the scalar confinement model, which may however have new trouble. 150 refs., 43 figs.

  8. Radiatively generated hierarchy of lepton and quark masses

    NASA Astrophysics Data System (ADS)

    Hernández, A. E. Cárcamo; Kovalenko, Sergey; Schmidt, Ivan

    2017-02-01

    We propose a model for radiatively generating the hierarchy of the Standard Model (SM) fermion masses: tree-level top quark mass; 1-loop bottom, charm, tau and muon masses; 2-loop masses for the light up, down and strange quarks as well as for the electron; and 4-loop masses for the light active neutrinos. Our model is based on a softlybroken S 3 × Z 2 discrete symmetry. Its scalar sector consists only of one SM Higgs doublet and three electrically neutral SM-singlet scalars. We do not need to invoke either electrically charged scalar fields, or an extra SU2 L scalar doublet, or the spontaneous breaking of the discrete group, which are typical for other radiative models in the literature. The model features a viable scalar dark matter candidate.

  9. Light quark Yukawa couplings from Higgs kinematics

    DOE PAGES

    Soreq, Yotam; Zhu, Hua Xing; Zupan, Jure

    2016-12-13

    We show that the normalized Higgs production pT and yh distributions are sensitive probes of Higgs couplings to light quarks. For up and/or down quark Yukawa couplings comparable to the SM b quark Yukawa themore » $$\\bar{u}u$$ or $$\\bar{d}d$$ fusion production of the Higgs could lead to appreciable softer pT distribution than in the SM. The rapidity distribution, on the other hand, becomes more forward. Here, we find that, owing partially to a downward fluctuation, one can derive competitive bounds on the two couplings using ATLAS measurements of normalized pT distribution at 8TeV. With 300 fb-1 at 13TeV LHC one could establish flavor non-universality of the Yukawa couplings in the down sector.« less

  10. Light quark Yukawa couplings from Higgs kinematics

    NASA Astrophysics Data System (ADS)

    Soreq, Yotam; Zhu, Hua Xing; Zupan, Jure

    2016-12-01

    We show that the normalized Higgs production p T and y h distributions are sensitive probes of Higgs couplings to light quarks. For up and/or down quark Yukawa couplings comparable to the SM b quark Yukawa the ūu or overline{d}d fusion production of the Higgs could lead to appreciable softer p T distribution than in the SM. The rapidity distribution, on the other hand, becomes more forward. We find that, owing partially to a downward fluctuation, one can derive competitive bounds on the two couplings using ATLAS measurements of normalized p T distribution at 8 TeV. With 300 fb-1 at 13 TeV LHC one could establish flavor non-universality of the Yukawa couplings in the down sector.

  11. Light quark Yukawa couplings from Higgs kinematics

    SciTech Connect

    Soreq, Yotam; Zhu, Hua Xing; Zupan, Jure

    2016-12-13

    We show that the normalized Higgs production pT and yh distributions are sensitive probes of Higgs couplings to light quarks. For up and/or down quark Yukawa couplings comparable to the SM b quark Yukawa the $\\bar{u}u$ or $\\bar{d}d$ fusion production of the Higgs could lead to appreciable softer pT distribution than in the SM. The rapidity distribution, on the other hand, becomes more forward. Here, we find that, owing partially to a downward fluctuation, one can derive competitive bounds on the two couplings using ATLAS measurements of normalized pT distribution at 8TeV. With 300 fb-1 at 13TeV LHC one could establish flavor non-universality of the Yukawa couplings in the down sector.

  12. Radiative corrections to the Dalitz plot of semileptonic decays of neutral baryons with light or charm quarks

    SciTech Connect

    Martinez, A.; Garcia, A. ); Tun, D.M. )

    1993-05-01

    In this paper we obtain an expression for the Dalitz plot of semileptonic decays of neutral baryons including radiative corrections up to order [alpha][ital q]/[pi][ital M][sub 1] ([ital q] is the four-momentum transfer and [ital M][sub 1] is the mass of the decaying baryon). The model dependence of the radiative corrections is kept in a general form which is suitable for a model-independent experimental analysis. The bremsstrahlung contribution is given in two ways. The first one leaves the triple integration over the photon variables to be performed numerically and the second one is completely analytic. Our result is suitable for high-statistics decays of ordinary baryons as well as for medium-statistics decays of charm baryons.

  13. Addendum to Radiative corrections to the Dalitz plot of semileptonic decays of neutral baryons with light or charm quarks''

    SciTech Connect

    Martinez, A.; Tun, D.M.; Garcia, A.; Sanchez-Colon, G. Coordinacion de Dinamica Orbital, Telecomunicaciones de Mexico, Av. de las Telecomunicaciones s/n, C.P. 09300, Mexico, Distrito Federal Departamento de Fisica, Centro de Investigacion y de Estudios Avanzados del Instituto Politecnico Nacional, Apartado Postal 14-740, C.P. 07000, Mexico, Distrito Federal )

    1994-08-01

    We show that the radiative corrections containing terms up to order [alpha][ital q]/[pi][ital M][sub 1] for unpolarized semileptonic decays of baryons with positron emission can be obtained by simply reversing the sign of the axial-vector form factors in the corresponding final expressions of such decays with electron emission. This rule is valid regardless of the final kinematical variables chosen and of the particular Lorentz frame in which the final results are required.

  14. Diquark and light four-quark states

    SciTech Connect

    Zhang Ailin; Huang Tao; Steele, Tom G.

    2007-08-01

    Four-quark states with different internal clusters are discussed within the constituent quark model. It is pointed out that the diquark concept is not meaningful in the construction of a tetraquark interpolating current in the QCD sum-rule approach, and hence existing sum-rule studies of four-quark states are incomplete. An updated QCD sum-rule determination of the properties of diquark clusters is then used as input for the constituent quark model to obtain the masses of light 0{sup ++} tetraquark states (i.e. a bound state of two diquark clusters). The results support the identification of {sigma}(600), f{sub 0}(980), and a{sub 0}(980) as the 0{sup ++} light tetraquark states, and seem to be inconsistent with the tetraquark state interpretation of the new BES observations of the near-threshold pp enhancements, X(1835) and X(1812), with the possible exception that X(1576) may be an exotic first orbital excitation of f{sub 0}(980) or a{sub 0}(980)

  15. Diquark and light four-quark states

    NASA Astrophysics Data System (ADS)

    Zhang, Ailin; Huang, Tao; Steele, Tom G.

    2007-08-01

    Four-quark states with different internal clusters are discussed within the constituent quark model. It is pointed out that the diquark concept is not meaningful in the construction of a tetraquark interpolating current in the QCD sum-rule approach, and hence existing sum-rule studies of four-quark states are incomplete. An updated QCD sum-rule determination of the properties of diquark clusters is then used as input for the constituent quark model to obtain the masses of light 0++ tetraquark states (i.e. a bound state of two diquark clusters). The results support the identification of σ(600), f0(980), and a0(980) as the 0++ light tetraquark states, and seem to be inconsistent with the tetraquark state interpretation of the new BES observations of the near-threshold pp¯ enhancements, X(1835) and X(1812), with the possible exception that X(1576) may be an exotic first orbital excitation of f0(980) or a0(980).

  16. Light Four-Quark States and New Observations by BES

    NASA Astrophysics Data System (ADS)

    Zhang, A.; Huang, T.; Steele, T.

    Four-quark states are discussed within the constituent quark model.Incompleteness of existed studies of four-quark state with QCD sum rule is analyzed. The masses of diquark cluster were determined by QCD sum rules, and light four-quark states masses were obtained in terms of the diquark. The four-quark state possibility of the newly observed near-threshold pbar p enhancement, X(1835), X(1812) and X(1576) by BES is discussed.

  17. Heavy quarks and interjet radiation

    NASA Astrophysics Data System (ADS)

    Sung, Ilmo

    In the first part of this thesis, we show how properties of Quantum Chromodynamics (QCD) can be used directly or indirectly to discover physics beyond the standard model (BSM) in collider experiments. We introduce new methods to determine the color SU(3) gauge content of BSM resonances from new physics signals by investigating the pattern of soft gluon radiation into specified regions of a detector. We use energy flow, treated by perturbative QCD and factorization, as a tool to analyze properties of new physics. This approach allows the analytical prediction of the distribution of soft gluon radiation into a rapidity region of a detector, reflecting the standard model gauge content of heavy resonances. The results, in general, predict more radiation for singlet than for octet resonances. Especially, for spin-1 resonance production, we show a quite large difference in radiation into a rapidity gap region from color singlet and octet resonances. We also introduce the use of the collinear enhancement in perturbative QCD amplitudes to distinguish products of highly-boosted massive particle decay from QCD jets whose collinear structure is described by a factorized jet function. At the LHC, events with highly-boosted massive particles such as top, W, Z and Higgs may be a key ingredient for the discovery of new physics. In many decay channels, these particles would be identified as high-pt jets, and any such signal of definite mass must be disentangled from a large background of QCD jets. We discover that this background far exceeds such signals, and relying solely on jet mass as a way to reject QCD background from signal would probably not suffice in most case. To solve this problem, we find that jets from QCD are characterized by different patterns of intrajet energy flow compared to highly-boosted heavy particle decays. Based on this observation, we introduce several event shapes that could be used to disentangle signals from backgrounds. In the second part of this

  18. Light quark simulations with FLIC fermions

    SciTech Connect

    J.M. Zanotti; D.B. Leinweber; W. Melnitchouk; A.G. Williams; J.B. Zhang

    2002-06-01

    Hadron masses are calculated in quenched lattice QCD in order to probe the scaling behavior of a novel fat-link clover fermion action in which only the irrelevant operators of the fermion action are constructed using APE-smeared links. Light quark masses corresponding to an m{sub pi}/m{sub p} ratio of 0.35 are considered to assess the exceptional configuration problem of clover-fermion actions. This Fat-Link Irrelevant Clover (FLIC) fermion action provides scaling which is superior to mean-field improvement and offers advantages over nonperturbative improvement, including reduced exceptional configurations.

  19. Transverse momentum dependent quark and gluon distributions of light nuclei

    NASA Astrophysics Data System (ADS)

    Nematollahi, H.; Yazdanpanah, M. M.

    2017-07-01

    We investigate the unpolarized transverse momentum dependent (TMD) structure of light nuclei in the modified chiral quark exchange model (QEM), for the first time. To this end, we calculate the TMD quark and gluon distributions inside the bound state nucleons of the light nuclei based on the modified chiral quark model (χ {{QM}}) in which the TMD bare quark distributions of the bounded nucleons are needed. In order to compute these bare distributions, we first obtain the bare quark momentum densities using the QEM and then calculate the TMD bare distributions applying a theoretical method in which the light-cone variables are used. Finally, considering the nucleon structure of helium, tritium and deuteron nuclei, we obtain their TMD quark and gluon densities at low Q 2 scale. It is shown that our results have appropriate properties that are expected for the TMD distribution functions.

  20. D(S) spectrum and leptonic decays with Fermilab heavy quarks and improved staggered light quarks

    SciTech Connect

    Massimo Di Pierro et al.

    2004-03-12

    We present preliminary results for the D{sub s} meson spectrum and decay constants in unquenched lattice QCD. Simulations are carried out with 2 + 1 dynamical quarks using gauge configurations generated by the MILC collaboration. We use the ''asqtad'' a{sup 2} improved staggered action for the light quarks, and the clover heavy quark action with the Fermilab interpretation. We compare our spectrum results with the newly discovered 0{sup +} and 1{sup +} states in the D{sub s} system.

  1. Radiative corrections to top-quark decay

    NASA Astrophysics Data System (ADS)

    Eilam, G.; Mendel, R. R.; Migneron, R.; Soni, A.

    1991-06-01

    We calculate all radiative corrections to one-loop order for the main decay of the top quark, t-->b+W, in the standard model, retaining exact dependence on all masses. For mt=150 GeV and MH=100 GeV we find a -2.9% (-6.9%) correction with a very weak dependence on the Higgs-boson mass, in renormalization schemes that use α, GF, and MZ (GF, MW, and MZ) as input parameters. Out of the above results, -8.5% is due to QCD. The mt and MH dependence is given up to 300 and 1000 GeV, respectively. The inadequacy of a leading mt calculation is pointed out.

  2. QCD thermodynamics with light quarks and glueball spectra with dynamical quarks

    SciTech Connect

    Sinclair, D.K.

    1989-11-01

    Simulations of Lattice QCD with 4 flavors of light staggered quarks (m = .025) were performed on a 12{sup 3} {times} 4 lattice, confirming the first order nature of the transition. Lattice QCD with a light isodoublet of staggered quarks (m = .0125), and a heavier singlet (m = .25) was studied, also on a 12{sup 3} {times} 4 lattice. The order of the transition was less clear. Improved glueball wavefunctions have been used to study glueball spectra in theories incorporating dynamical quarks. 10 refs., 3 figs.

  3. A radiative model of quark masses with binary tetrahedral symmetry

    NASA Astrophysics Data System (ADS)

    Natale, Alexander

    2017-01-01

    A radiative model of quark and lepton masses utilizing the binary tetrahedral (T‧) flavor symmetry, or horizontal symmetry, is proposed which produces the first two generation of quark masses through their interactions with vector-like quarks that carry charges under an additional U (1). By softly-breaking the T‧ to a residual Z4 through the vector-like quark masses, a CKM mixing angle close to the Cabibbo angle is produced. In order to generate the cobimaximal neutrino oscillation pattern (θ13 ≠ 0 ,θ23 = π / 4 ,δCP = ± π / 2) and protect the horizontal symmetry from arbitrary corrections in the lepton sector, there are automatically two stabilizing symmetries in the dark sector. Several benchmark cases where the correct relic density is achieved in a multi-component DM scenario, as well as the potential collider signatures of the vector-like quarks are discussed.

  4. A model of radiatively induced quark and lepton mass model

    NASA Astrophysics Data System (ADS)

    Nomura, Takaaki

    2017-07-01

    We discuss a radiatively induced quark and lepton mass model in the rst and second generation introducing extra U(1) gauge symmetry, discrete Z 2 symmetry, vector-like fermions and exotic scalar elds. Then we analyze the allowed parameter regions which simultaneously satisfy the constraints of FCNCs for the quark sector and of LFVs including μ - e conversion, observed quark mass and mixing, and the lepton mass and mixing. In addition, the typical value for the (g - 2) μ in our model is presented. We also show extension of the model in which Majorana type neutrino masses are generated at the two loop level.

  5. Light Higgs and vector-like quarks without prejudice

    NASA Astrophysics Data System (ADS)

    Fajfer, Svjetlana; Greljo, Admir; Kamenik, Jernej F.; Mustać, Ivana

    2013-07-01

    Light vector-like quarks with non-renormalizable couplings to the Higgs are a common feature of models trying to address the electroweak (EW) hierarchy problem by treating the Higgs as a pseudo-goldstone boson of a global (approximate) symmetry. We systematically investigate the implications of the leading dimension five operators on Higgs phenomenology in presence of dynamical up- and down-type weak singlet as well as weak doublet vector-like quarks. After taking into account constraints from precision EW and flavour observables we show that contrary to the renormalizable models, significant modifications of Higgs properties are still possible and could shed light on the role of vector-like quarks in solutions to the EW hierarchy problem. We also briefly discuss implications of higher dimensional operators for direct vector-like quark searches at the LHC.

  6. Role of heavy quarks in light hadron fragmentation

    NASA Astrophysics Data System (ADS)

    Epele, Manuel; García Canal, Carlos; Sassot, R.

    2016-08-01

    We investigate the role of heavy quarks in the production of light flavored hadrons and in the determination of the corresponding nonperturbative hadronization probabilities. We define a general mass variable flavor number scheme for fragmentation functions that accounts for heavy quark mass effects, and perform a global QCD analysis to an up-to-date data set including very precise Belle and BABAR results. We show that the mass dependent picture provides a much more accurate and consistent description of the data.

  7. Light-quark masses from unquenched lattice QCD

    SciTech Connect

    Ishikawa, T.; Aoki, S.; Fukugita, M.; Hashimoto, S.; Kaneko, T.; Yamada, N.; Ishikawa, K-I.; Okawa, M.; Ishizuka, N.; Kuramashi, Y.; Taniguchi, Y.; Ukawa, A.; Yoshie, T.; Iwasaki, Y.; Kanaya, K.; Tsutsui, N.

    2008-07-01

    We calculate the light meson spectrum and the light quark masses by lattice QCD simulation, treating all light quarks dynamically and employing the Iwasaki gluon action and the nonperturbatively O(a)-improved Wilson quark action. The calculations are made at the squared lattice spacings at an equal distance a{sup 2}{approx_equal}0.005, 0.01, and 0.015 fm{sup 2}, and the continuum limit is taken assuming an O(a{sup 2}) discretization error. The light meson spectrum is consistent with experiment. The up, down, and strange quark masses in the MS scheme at 2 GeV are m=(m{sub u}+m{sub d})/2=3.55{sub -0.28}{sup +0.65} MeV and m{sub s}=90.1{sub -6.1}{sup +17.2} MeV where the error includes statistical and all systematic errors added in quadrature. These values contain the previous estimates obtained with the dynamical u and d quarks within the error.

  8. Mass of heavy-light mesons in a constituent quark picture with partially restored chiral symmetry

    NASA Astrophysics Data System (ADS)

    Park, Aaron; Gubler, Philipp; Harada, Masayasu; Lee, Su Houng; Nonaka, Chiho; Park, Woosung

    2016-03-01

    We probe effects of the partial chiral symmetry restoration to the mass of heavy-light mesons in a constituent quark model by changing the constituent quark mass of the light quark. Due to the competing effect between the quark mass and the linearly rising potential, whose contribution to the energy increases as the quark mass decreases, the heavy-light meson mass has a minimum value near the constituent quark mass typically used in the vacuum. Hence, the meson mass increases as one decreases the constituent quark mass consistent with recent QCD sum rule analyses, which show an increasing D meson mass as the chiral order parameter decreases.

  9. LIGHT QUARK MASSES: A STATUS REPORT AT DPF 2000

    SciTech Connect

    R. GUPTA; K. MALTMAN

    2000-12-01

    A summary of the extraction of light quark masses from both QCD sumrules and lattice QCD simulations is presented. The focus is on providing a careful statement of the potential weaknesses in each calculation, and on integrating the work of different collaborations to provide a coherent picture.

  10. Multiplicity difference between heavy- and light-quark jets revisited

    NASA Astrophysics Data System (ADS)

    Dokshitzer, Yu L.; Fabbri, F.; Khoze, V. A.; Ochs, W.

    2006-02-01

    The perturbative QCD approach to multiparticle production predicts a characteristic suppression of particle multiplicity in a heavy-quark jet as compared to a light-quark jet. In the modified leading logarithmic approximation (MLLA) the multiplicity difference δ_{Qell} between heavy- and light-quark jets is derived in terms of a few other experimentally measured quantities. The earlier prediction for b-quarks needs revision in the light of new experimental results and the improvement in the understanding of the experimental data. We now find δ_{bell} = 4.4±0.4. The updated MLLA results on δ_{bell} and δ_{cell} are compared with the present data from e + e - annihilation. Their expected energy independence is confirmed within the energy range between 29 and 200 GeV; the absolute values are now in better agreement with experiment than in the previous analysis, and the remaining difference can be attributed largely to next-to-MLLA contributions, an important subset of which are identified and evaluated.

  11. Momentum-transfer contributions to the radiative corrections of the Dalitz plot of semileptonic decays of charged baryons with light or charm quarks

    SciTech Connect

    Tun, D.M.; Juarez W., S.R. ); Garcia, A. )

    1991-12-01

    We obtain an expression for the Dalitz plot of semileptonic decays of charged baryons, including radiative corrections with all the terms of the order {alpha} times the momentum transfer. The model dependence of the radiative corrections is kept in a general form which is suitable for model-independent experimental analysis. The bremsstrahlung contribution is given in two ways. The first one leaves the triple integration over the photon variables to be performed numerically and the second one is completely analytic. Our result is suitable for high-statistics decays of ordinary baryons as well as for medium-statistics decays of charm baryons.

  12. Hadron production in light and heavy, quark and antiquark jets

    SciTech Connect

    Baird, K.G.; SLD Collaboration

    1996-08-01

    The authors review four hadronization studies performed by the SLD experiment at SLAC, involving separation of light (Z{sup 0} {r_arrow} u{anti u}, d{anti d}, s{anti s}), c, and b flavors using precision vertexing, and separation of q- and {anti q}-jets using the highly polarized SLC electron beam. They measured the differences between the average charged multiplicities in Z{sup 0} {r_arrow} light, {r_arrow} c{anti c}, and {r_arrow}b{anti b} events, and found that the results were consistent with predictions of perturbative QCD. Next, they measured {pi}/{Kappa}/p/{Kappa}{sup 0}/{Lambda}{sup 0} production in light events for the first time, and compared with production in c- and b-flavor events. They then examined particle production differences in light quark and antiquark hemispheres, and observed more high momentum baryons and K{sup {minus}}`s than antibaryons and K{sup +}`s in quark hemispheres, consistent with the leading particle hypothesis. Lastly, they performed a search for jet handedness in light q- and {anti q}-jets. Assuming Standard Model values of quark polarization in Z{sup 0} decays, they have set an improved upper limit on the analyzing power of the handedness method.

  13. Threshold pion photoproduction in a light-cone quark model

    NASA Astrophysics Data System (ADS)

    Konen, W.; Drechsel, D.

    1991-07-01

    The instantaneous and seagull graphs are calculated for pion photoproduction in a relativistic light-cone model of the nucleon. In both pseudoscalar and pseudovector coupling we find the ratios A (-): A (0): A (+) = 1: ( {-1}/{2}μ):( {-9}/{5}μ) in the nonrelativistic limit. These results correspond to the sum of seagull and Z-graph in the nonrelativistic quark model. In pseudovector coupling also the numerical results for realistic-model parameters are close to those values.

  14. Multiplicity Difference Between Heavy and Light Quark Jets

    NASA Astrophysics Data System (ADS)

    Fabbri, Fabrizio

    2007-11-01

    A peculiar prediction of perturbative QCD, with the assumption of Local Parton Hadron Duality, is that the difference in mean hadron multiplicity between heavy and light quark initiated events in e+e- annihilation, δQℓ, is energy independent. In the Modified Leading Logarithmic Approximation (MLLA), the numerical value of the constant is derived in terms of a few experimentally measurable quantities. While the energy independence of δQℓ has been succesfully verified experimentally for b-quarks up to the highest LEP2 energy, the numerical prediction originally published in 1992, δ MLLAbl = 5.5 ± 0.8, clearly overestimates the experimental results. In this work, done in collaboration with Yuri L. Dokshitzer, Valery A. Khoze and Wolfgang Ochs, we show that the original MLLA prediction needs a revision, in the light of new experimental results and the improvement in the understanding of the experimental data. We now find δ MLLAbl = 4.4 ± 0.4, in better agreement with experiment, and we show that the remaining difference can be attributed largely to next-to-MLLA contributions, an important subset of which are identified and evaluated. The situation for charmed quarks is also reviewed.

  15. Multiplicity Difference between Heavy and Light Quark Jets Revisited

    NASA Astrophysics Data System (ADS)

    Fabbri, Fabrizio

    2006-04-01

    A peculiar prediction of perturbative QCD, obtained within the Local Parton Hadron Duality (LPHD) framework, is that the multiplicity difference δQl between heavy and light quark jets produced in e+e- annihilation is energy independent. In the Modified Leading Logarithmic Approximation (MLLA) the corresponding constant is derived in terms of a few experimentally measurable quantities. While the energy independence of δQl has been succesfully verified experimentally for b-quarks up to the highest LEP2 energy, its numerical prediction (δblMLLA = 5.5 ± 0.8) overestimates the experimental results. The work presented in this talk, done in collaboration with Yuri L. Dokshitzer, Valery A. Khoze and Wolfgang Ochs, shows that in the light of new experimental results and the improvement in the understanding of the experimental data, this prediction needs indeed a revision. We now find δbl = 4.4 ± 0.4, in better agreement with experiment, and we shaw that the remaining difference can be attributed largely to next-to-MLLA contributions, an important subset of which are identified and evaluated. The situation with charmed quarks is also reviewed.

  16. Radiative leptonic Bc decay in the relativistic independent quark model

    NASA Astrophysics Data System (ADS)

    Barik, N.; Naimuddin, Sk.; Dash, P. C.; Kar, Susmita

    2008-12-01

    The radiative leptonic decay Bc-→μ-ν¯μγ is analyzed in its leading order in a relativistic independent quark model based on a confining potential in an equally mixed scalar-vector harmonic form. The branching ratio for this decay in the vanishing lepton mass limit is obtained as Br(Bc→μνμγ)=6.83×10-5, which includes the contributions of the internal bremsstrahlung and structure-dependent diagrams at the level of the quark constituents. The contributions of the bremsstrahlung and the structure-dependent diagrams, as well as their additive interference parts, are compared and found to be of the same order of magnitude. Finally, the predicted photon energy spectrum is observed here to be almost symmetrical about the peak value of the photon energy at Ẽγ≃(MBc)/(4), which may be quite accessible experimentally at LHC in near future.

  17. Radiative light dark matter

    NASA Astrophysics Data System (ADS)

    Dedes, A.; Karamitros, D.; Pilaftsis, A.

    2017-06-01

    We present a Peccei-Quinn (PQ)-symmetric two-Higgs doublet model that naturally predicts a fermionic singlet dark matter in the mass range 10 keV-1 GeV. The origin of the smallness of the mass of this light singlet fermion arises predominantly at the one-loop level, upon soft or spontaneous breakdown of the PQ symmetry via a complex scalar field in a fashion similar to the so-called Dine-Fischler-Sredniki-Zhitnitsky axion model. The mass generation of this fermionic radiative light dark matter (RLDM) requires the existence of two heavy vectorlike SU(2) isodoublets, which are not charged under the PQ symmetry. We show how the RLDM can be produced via the freeze-in mechanism, thus accounting for the missing matter in the Universe. Finally, we briefly discuss possible theoretical and phenomenological implications of the RLDM model for the strong C P problem and the CERN Large Hadron Collider (LHC).

  18. Azimuthal spin asymmetries in light-cone constituent quark models

    SciTech Connect

    Boffi, S.; Pasquini, B.; Efremov, A. V.; Schweitzer, P.

    2009-05-01

    We present results for all leading-twist azimuthal spin asymmetries in semi-inclusive lepton-nucleon deep-inelastic scattering due to T-even transverse-momentum dependent parton distribution functions on the basis of a light-cone constituent quark model. Attention is paid to discuss the range of applicability of the model, especially with regard to the scale dependence of the observables and the transverse-momentum dependence of the distributions. We find good agreement with available experimental data and present predictions to be further tested by future CLAS, COMPASS, and HERMES data.

  19. Up quark mass in lattice QCD with three light dynamical quarks and implications for strong CP invariance.

    PubMed

    Nelson, Daniel R; Fleming, George T; Kilcup, Gregory W

    2003-01-17

    A standing mystery in the standard model is the unnatural smallness of the strong CP violating phase. A massless up quark has long been proposed as one potential solution. A lattice calculation of the constants of the chiral Lagrangian essential for the determination of the up quark mass, 2alpha(8)-alpha(5), is presented. We find 2alpha(8)-alpha(5)=0.29+/-0.18, which corresponds to m(u)/m(d)=0.410+/-0.036. This is the first such calculation using a physical number of dynamical light quarks, N(f)=3.

  20. Radiative seesaw-type mechanism of fermion masses and non-trivial quark mixing

    NASA Astrophysics Data System (ADS)

    Arbeláez, Carolina; Hernández, A. E. Cárcamo; Kovalenko, Sergey; Schmidt, Ivan

    2017-06-01

    We propose a predictive inert two-Higgs doublet model, where the standard model (SM) symmetry is extended by S3⊗ Z2⊗ Z_{12} and the field content is enlarged by extra scalar fields, charged exotic fermions and two heavy right-handed Majorana neutrinos. The charged exotic fermions generate a non-trivial quark mixing and provide one-loop-level masses for the first- and second-generation charged fermions. The masses of the light active neutrinos are generated from a one-loop-level radiative seesaw mechanism. Our model successfully explains the observed SM fermion mass and mixing pattern.

  1. Light-cone distribution amplitudes for heavy-quark hadrons

    NASA Astrophysics Data System (ADS)

    Bell, Guido; Feldmann, Thorsten; Wang, Yu-Ming; Yip, Matthew W. Y.

    2013-11-01

    We construct parametrizations of light-cone distribution amplitudes (LCDAs) for B-mesons and Λ b -baryons that obey various theoretical constraints, and which are simple to use in factorization theorems relevant for phenomenological applications in heavy-flavour physics. In particular, we find the eigenfunctions of the Lange-Neubert renormalization kernel, which allow for a systematic implementation of renormalization-group evolution effects for both B-meson and Λ b -baryon decays. We also present a new strategy to construct LCDA models from momentum-space projectors, which can be used to implement Wandzura-Wilczek-like relations, and which allow for a comparison with theoretical approaches that go beyond the collinear limit for the light-quark momenta in energetic heavy-hadron decays.

  2. Nucleon parton distributions in a light-front quark model

    NASA Astrophysics Data System (ADS)

    Gutsche, Thomas; Lyubovitskij, Valery E.; Schmidt, Ivan

    2017-02-01

    Continuing our analysis of parton distributions in the nucleon, we extend our light-front quark model in order to obtain both the helicity-independent and the helicity-dependent parton distributions, analytically matching the results of global fits at the initial scale μ ˜ 1 GeV; they also contain the correct Dokshitzer-Gribov-Lipatov-Altarelli-Parisi evolution. We also calculate the transverse parton, Wigner and Husimi distributions from a unified point of view, using our light-front wave functions and expressing them in terms of the parton distributions q_v(x) and δ q_v(x). Our results are very relevant for the current and future program of the COMPASS experiment at SPS (CERN).

  3. Parton distribution in pseudoscalar mesons with a light-front constituent quark model

    NASA Astrophysics Data System (ADS)

    de Melo, J. P. B. C.; Ahmed, Isthiaq; Tsushima, Kazuo

    2016-05-01

    We compute the distribution amplitudes of the pion and kaon in the light-front constituent quark model with the symmetric quark-bound state vertex function [1, 2, 3]. In the calculation we explicitly include the flavor-SU(3) symmetry breaking effect in terms of the constituent quark masses of the up (down) and strange quarks. To calculate the kaon parton distribution functions (PDFs), we use both the conditions in the light-cone wave function, i.e., when s ¯ quark is on-shell, and when u quark is on-shell, and make a comparison between them. The kaon PDFs calculated in the two different conditions clearly show asymmetric behaviour due to the flavor SU(3)-symmetry breaking implemented by the quark masses [4, 5].

  4. Quarks

    NASA Astrophysics Data System (ADS)

    Gell-Mann, M.

    In these lectures I want to speak about at least two interpretations of the concept of quarks for hadrons and the possible relations between them. First I want to talk about quarks as "constituent quarks". These were used especially by G. Zweig (1964) who referred to them as aces. One has a sort of a simple model by which one gets elementary results about the low-lying bound and resonant states of mesons and baryons, and certain crude symmetry properties of these states, by saying that the hadrons act as if they were made up of subunits, the constituent quarks q. These quarks are arranged in an isotopic spin doublet u, d and an isotopic spin singlet s, which has the same charge as d and acts as if it had a slightly higher mass…

  5. Hadronic physics of q anti q light quark mesons, quark molecules and glueballs

    SciTech Connect

    Lindenbaum, S.J.

    1980-10-01

    A brief introduction reviews the development of QCD and defines quark molecules and glueballs. This review is concerned primarily with u, d, and s quarks, which provide practically all of the cross section connected with hadronic interactions. The following topics form the bulk of the paper: status of quark model classification for conventional u, d, s quark meson states; status of multiquark or quark molecule state predictions and experiments; glueballs and how to find them; and the OZI rule in decay and production and how glueballs might affect it. 17 figures, 1 table. (RWR)

  6. Heavy-heavy and heavy-light quarks interactions generated by QCD vacuum

    NASA Astrophysics Data System (ADS)

    Musakhanov, Mirzayusuf

    2017-03-01

    The QCD vacuum is populated by instantons that correspond to the tunneling processes in the vacuum. This mechanism creates the strong vacuum gluon fields. As result, the QCD vacuum instantons induce very strong interactions between light quarks, initially almost massless. Such a strong interactions bring a large dynamical mass M of the light quarks and bound them to produce almost massless pions in accordance with the spontaneous breaking of the chiral symmetry (SBCS). On the other hand, the QCD vacuum instantons also interact with heavy quarks and responsible for the generation of the heavy-heavy and heavy-light quarks interactions, with a traces of the SBCS. If we take the average instanton size \\bar ρ = 0.33 fm, and the average inter-instanton distance \\bar R = 1 fm we obtain the dynamical light quark mass to be M = 365 MeV and the instanton media contribution to the heavy quark mass ΔM=70 MeV. These factors define the coupling between heavy-light and heavy-heavy quarks induced by the QCD vacuum instantons. We consider first the instanton effects on the heavy-heavy quarks potential, including its spin-dependent part. We also discuss those effects on the masses of the charmonia and their hyperfine mass splittings. At the second part we discuss the interaction between a heavy and light quarks generated by instantons and it's effects.

  7. Three-quark light-cone amplitudes of the proton and quark orbital-motion-dependent observables

    NASA Astrophysics Data System (ADS)

    Ji, Xiangdong; Ma, Jian-Ping; Yuan, Feng

    2003-03-01

    We study the three-quark light-cone amplitudes of the proton including quarks' transverse momenta. We classify these amplitudes using a newly-developed method in which light-cone wave functions are constructed from a class of light-cone matrix elements. We derive the constraints on the amplitudes from parity and time-reversal symmetries. We use the amplitudes to calculate the physical observables which vanish when the quark orbital angular momentum is absent. These include transverse-momentum dependent parton distributions Δ qT( x, k⊥), qT( x, k⊥), δq( x, k⊥), and δqL( x, k⊥), twist-three parton distributions gT( x) and hL( x), helicity-flip generalized parton distributions E( x, ξ=0, Q2) and its associates, and the Pauli form factor F2( Q2).

  8. Light-light and heavy-light mesons in the model of QCD string with quarks at the ends

    NASA Astrophysics Data System (ADS)

    Nefediev, A. V.

    2002-06-01

    The variational einbein field method is applied to the model of the QCD string with quarks at the ends for the case of light-light and heavy-light mesons. Special attention is payed to the proper string dynamics. The correct string slope of the Regge trajectories is reproduced for light-light states which comes out from the picture of rotating string. Masses of several low-lying orbitally and radially excited states in the D, Ds, B, and Bs meson spectra are calculated and a good agreement with the experimental data as well as with recent lattice calculations is found. The role of the string correction to the interquark interaction is discussed at the example of the identification of D*' (2637) state recently claimed by DELPHI Collaboration. For the heavy-light mesons the standard constants used in Heavy Quark Effective Theory are extracted and compared to the results of other approaches.

  9. Light-by-Light Hadronic Corrections to the Muon G-2 Problem Within the Nonlocal Chiral Quark Model

    NASA Astrophysics Data System (ADS)

    Dorokhov, A. E.; Radzhabov, A. E.; Zhevlakov, A. S.

    2017-03-01

    Results of calculation of the light-by-light contribution from the lightest neutral pseudoscalar and scalar mesons and the dynamical quark loop to the muon anomalous magnetic moment are discussed in the framework of the nonlocal SU(3) × SU(3) chiral quark model. The model is based on four-quark interaction of the Nambu-Jona-Lasinio type and Kobayashi-Maskawa-`t Hooft six-quark interaction. The full kinematic dependence of vertices with off-shell mesons and photons in intermediate states in the light-by-light scattering amplitude is taken into account. All calculations are elaborated in explicitly gauge-invariant manner. These results complete calculations of all hadronic light-by-light scattering contributions to aμ in the leading order in the 1/Nc expansion. The final result does not allow the discrepancy between the experiment and the Standard Model to be explained.

  10. Four-quark and hybrid mixing in the light-quark vector sector

    NASA Astrophysics Data System (ADS)

    Donnachie, A.; Kalashnikova, Yu. S.

    1993-12-01

    The data on e + e - annihilation are shown to be incompatible with an interpretation of the observed vector mesons asqbar q excitations. It is necessary to consider mixing with somenon - qbar q system. Two specific models are considered: either four-quark states or hybrid states mixing with the conventional quark-antiquark excitations. Both models are compatible with the present e + e - annihilation data. It is possible to incorporate the 1.3 GeV J PC =1-- state seen by LASS in the ππ channel in the four-quark model, but this is not possible with the hybrid model.

  11. Glueballs, Hybrids, Baryons and Pentaquarks: Hadron05 summary on light-quark spectroscopy

    SciTech Connect

    Klempt, Eberhard

    2006-02-11

    Results on light-quark spectroscopy presented at Hadron05 are reviewed. Particular emphasis is given to the status of pentaquarks and of glueballs and exotic mesons. Experiments are proposed to decide on open issues.

  12. Light colored scalars and the up quarks phenomenology

    NASA Astrophysics Data System (ADS)

    Fajfer, Svjetlana; Doršner, Ilja; Kamenik, Jernej F.; Košnik, Nejc

    2010-12-01

    A colored weak singlet scalar can accommodate the 2 σ disagreement of the measured forward-backward asymmetry from the Standard model prediction in the tt¯ production at the Tevatron. Such colored scalars appear in a class of grand unified theories. Their couplings to up quarks can be fully constrained using D-D oscillation observables, as well as di-jet and single top production measurements at the Tevatron. After making predictions for the flavour changing neutral current transitions in the charm and top quark sectors, we discuss the impact of these constraints on the texture of the up-quark mass matrix within a class of grand unified models.

  13. Light hadron spectroscopy in two-flavor QCD with small sea quark masses

    SciTech Connect

    Namekawa, Y.; Aoki, S.; Iwasaki, Y.; Kanaya, K.; Fukugita, M.; Ishikawa, K.-I.; Ishizuka, N.; Ukawa, A.; Yoshie, T.; Kaneko, T.; Kuramashi, Y.; Lesk, V. I.; Umeda, T.; Okawa, M.

    2004-10-01

    We extend the study of the light hadron spectrum and the quark mass in two-flavor QCD to smaller sea quark mass, corresponding to m{sub PS}/m{sub V}=0.60-0.35. Numerical simulations are carried out using the RG-improved gauge action and the meanfield-improved clover quark action at {beta}=1.8 (a=0.2 fm from {rho} meson mass). We observe that the light hadron spectrum for small sea quark mass does not follow the expectation from chiral extrapolations with quadratic functions made from the region of m{sub PS}/m{sub V}=0.80-0.55. Whereas fits with either polynomial or continuum chiral perturbation theory (ChPT) fail, the Wilson ChPT (WChPT) that includes a{sup 2} effects associated with explicit chiral symmetry breaking successfully fits the whole data: In particular, WChPT correctly predicts the light quark mass spectrum from simulations for medium heavy quark mass, such as m{sub PS}/m{sub V} > or approx. 0.5. Reanalyzing the previous data with the use of WChPT, we find the mean up and down quark mass being smaller than the previous result from quadratic chiral extrapolation by approximately 10%, m{sub ud}{sup MS-bar}({mu}=2 GeV)=3.11(17) [MeV] in the continuum limit.

  14. Constraining Light-Quark Yukawa Couplings from Higgs Distributions.

    PubMed

    Bishara, Fady; Haisch, Ulrich; Monni, Pier Francesco; Re, Emanuele

    2017-03-24

    We propose a novel strategy to constrain the bottom and charm Yukawa couplings by exploiting Large Hadron Collider (LHC) measurements of transverse momentum distributions in Higgs production. Our method does not rely on the reconstruction of exclusive final states or heavy-flavor tagging. Compared to other proposals, it leads to an enhanced sensitivity to the Yukawa couplings due to distortions of the differential Higgs spectra from emissions which either probe quark loops or are associated with quark-initiated production. We derive constraints using data from LHC run I, and we explore the prospects of our method at future LHC runs. Finally, we comment on the possibility of bounding the strange Yukawa coupling.

  15. Constraining Light-Quark Yukawa Couplings from Higgs Distributions

    NASA Astrophysics Data System (ADS)

    Bishara, Fady; Haisch, Ulrich; Monni, Pier Francesco; Re, Emanuele

    2017-03-01

    We propose a novel strategy to constrain the bottom and charm Yukawa couplings by exploiting Large Hadron Collider (LHC) measurements of transverse momentum distributions in Higgs production. Our method does not rely on the reconstruction of exclusive final states or heavy-flavor tagging. Compared to other proposals, it leads to an enhanced sensitivity to the Yukawa couplings due to distortions of the differential Higgs spectra from emissions which either probe quark loops or are associated with quark-initiated production. We derive constraints using data from LHC run I, and we explore the prospects of our method at future LHC runs. Finally, we comment on the possibility of bounding the strange Yukawa coupling.

  16. Light bending in radiation background

    SciTech Connect

    Kim, Jin Young; Lee, Taekoon E-mail: tlee@kunsan.ac.kr

    2014-01-01

    We consider the velocity shift of light in presence of radiation emitted by a black body. Within geometric optics formalism we calculate the bending angle of a light ray when there is a gradient in the energy density. We model the bending for two simplified cases. The bending angle is proportional to the inverse square power of the impact parameter (∝1/b{sup 2}) when the dilution of energy density is spherically symmetric. The bending angle is inversely proportional to the impact parameter (∝1/b) when the energy density dilutes cylindrically. Assuming that a neutron star is an isothermal black body, we estimate the order of magnitude for such bending angle and compare it with the bending angle by magnetic field.

  17. Some aspects of quark fragmentation: comparison of heavy (c) and light quarks (u,d,s)

    SciTech Connect

    Derrick, M.

    1984-01-01

    The data that the author presents come from the first two years of operation of the High Resolution Spectrometer (HRS) at PEP, and correspond to an integrated luminosity of 106 +- 5 pb/sup -1/ (20 pb/sup -1/ from the first year and 86 pb/sup -1/ from the second year's running). Since the quark-meson transitions may have a particularly simple form at the values of the momentum fraction Z = 2p/sub meson//..sqrt..s, we emphasize this aspect of the data, and show how a sample of e/sup +/e/sup -/ ..-->.. (u anti u, d anti d, s anti s) events can be selected. The characteristics of these events are compared to e/sup +/e/sup -/ ..-->.. c anti c selected by a D* tag.

  18. Lattice investigation of nucleon structure at light quark masses

    SciTech Connect

    Zanotti, James M.

    2010-07-27

    Lattice simulations of hadronic structure are now reaching a level where they are able to not only complement, but also provide guidance to current and forthcoming experimental programmes at, e.g. Jefferson Lab, COMPASS/CERN and FAIR/GSI. By considering new simulations at low quark masses and on large volumes, we review the recent progress that has been made in this exciting area by the QCDSF/UKQCD collaboration. In particular, results obtained close to the physical point for several quantities, including electromagnetic form factors and moments of ordinary parton distribution functions, show some indication of approaching their phenomenological values.

  19. B -meson decay constants from 2+1 -flavor lattice QCD with domain-wall light quarks and relativistic heavy quarks

    DOE PAGES

    Christ, Norman H.; Flynn, Jonathan M.; Izubuchi, Taku; ...

    2015-03-10

    We calculate the B-meson decay constants fB, fBs, and their ratio in unquenched lattice QCD using domain-wall light quarks and relativistic b quarks. We use gauge-field ensembles generated by the RBC and UKQCD collaborations using the domain-wall fermion action and Iwasaki gauge action with three flavors of light dynamical quarks. We analyze data at two lattice spacings of a ≈ 0.11, 0.086 fm with unitary pion masses as light as Mπ ≈ 290 MeV; this enables us to control the extrapolation to the physical light-quark masses and continuum. For the b quarks we use the anisotropic clover action with themore » relativistic heavy-quark interpretation, such that discretization errors from the heavy-quark action are of the same size as from the light-quark sector. We renormalize the lattice heavy-light axial-vector current using a mostly nonperturbative method in which we compute the bulk of the matching factor nonperturbatively, with a small correction, that is close to unity, in lattice perturbation theory. We also improve the lattice heavy-light current through O(αsa). We extrapolate our results to the physical light-quark masses and continuum using SU(2) heavy-meson chiral perturbation theory, and provide a complete systematic error budget. We obtain fB0 = 199.5(12.6) MeV, fB+=195.6(14.9) MeV, fBs=235.4(12.2) MeV, fBs/fB0=1.197(50), and fBs/fB+=1.223(71), where the errors are statistical and total systematic added in quadrature. Finally, these results are in good agreement with other published results and provide an important independent cross-check of other three-flavor determinations of B-meson decay constants using staggered light quarks.« less

  20. B-meson decay constants from 2+1-flavor lattice QCD with domain-wall light quarks and relativistic heavy quarks

    SciTech Connect

    Christ, Norman H.; Flynn, Jonathan M.; Izubuchi, Taku; Kawanai, Taichi; Lehner, Christoph; Soni, Amarjit; Van de Water, Ruth S.; Witzel, Oliver

    2015-03-10

    We calculate the B-meson decay constants fB, fBs, and their ratio in unquenched lattice QCD using domain-wall light quarks and relativistic b-quarks. We use gauge-field ensembles generated by the RBC and UKQCD collaborations using the domain-wall fermion action and Iwasaki gauge action with three flavors of light dynamical quarks. We analyze data at two lattice spacings of a ≈ 0.11, 0.086 fm with unitary pion masses as light as Mπ ≈ 290 MeV; this enables us to control the extrapolation to the physical light-quark masses and continuum. For the b-quarks we use the anisotropic clover action with the relativistic heavy-quark interpretation, such that discretization errors from the heavy-quark action are of the same size as from the light-quark sector. We renormalize the lattice heavy-light axial-vector current using a mostly nonperturbative method in which we compute the bulk of the matching factor nonperturbatively, with a small correction, that is close to unity, in lattice perturbation theory. We also improve the lattice heavy-light current through O(αsa). We extrapolate our results to the physical light-quark masses and continuum using SU(2) heavy-meson chiral perturbation theory, and provide a complete systematic error budget. We obtain fB0 = 196.2(15.7) MeV, fB+ = 195.4(15.8) MeV, fBs = 235.4(12.2) MeV, fBs/fB0 = 1.193(59), and fBs/fB+ = 1.220(82), where the errors are statistical and total systematic added in quadrature. In addition, these results are in good agreement with other published results and provide an important independent cross check of other three-flavor determinations of B-meson decay constants using staggered light quarks.

  1. Energy density of light quark jet using AdS/CFT

    NASA Astrophysics Data System (ADS)

    Morad, R.; Horowitz, W. A.

    2017-01-01

    We study the energy loss rate of light quarks via the AdS/CFT correspondence in both a static and an expanding plasma. Unlike heavy quarks, light quark energy loss in AdS/CFT is surprisingly dependent on both the string initial conditions and the very definition of the jet itself in the gravity theory. We aim to more closely match the string initial conditions to those expected from perturbative quantum chromodyanics (pQCD)-the theory known to describe the physics of high-momentum particles at early times in heavy ion collisions-by computing the energy-momentum tensor associated with the propagation of the classical string solution. The jet energy-momentum tensor in a strongly-coupled calculation can be found by a superposition of contributions from a collection of point particles whose paths approximate the evolution of the string world-sheet. My results show that some times after creation the pair of quark-anti quark, the energy density is not time dependent. This means that the corresponding jet does not lose energy and the associated nuclear modification factor would be one as expected. Also, the results reveal the virtuality dependency of energy density distribution over space. As expected, the energy of a more virtual jet is spread over wider angles.

  2. Orbital structure of quarks inside the nucleon in the light-cone diquark model

    SciTech Connect

    Lu Zhun; Schmidt, Ivan

    2010-11-01

    We study the orbital angular momentum structure of the quarks inside the proton. By employing the light-cone diquark model and the overlap representation formalism, we calculate the chiral-even generalized parton distribution functions H{sub q}(x,{xi},{Delta}{sup 2}), H-tilde{sub q}(x,{xi},{Delta}{sup 2}), and E{sub q}(x,{xi},{Delta}{sup 2}) at zero skewedness for q=u and d quarks. In our model, E{sub u} and E{sub d} have opposite sign with similar size. Those generalized parton distribution functions are applied to calculate the orbital angular momentum distributions, showing that L{sub u}(x) is positive, while L{sub d}(x) is consistent with zero compared with L{sub u}(x). We introduce the impact parameter dependence of the quark orbital angular momentum distribution. It describes the position space distribution of the quark orbital angular momentum at given x. We found that the impact parameter dependence of the quark orbital angular momentum distribution is axially symmetric in the light-cone diquark model.

  3. Light-Quark Baryon Spectroscopy from ANL-Osaka Dynamical Coupled-Channels Analysis

    NASA Astrophysics Data System (ADS)

    Kamano, Hiroyuki

    We review our recent efforts for determining resonance parameters associated with light-quark baryons (N*,Δ *,Λ *,Σ *) through comprehensive analyses of various meson production reactions off the nucleon within the ANL-Osaka dynamical coupled-channels approach.

  4. Lattice measurement of BB_s with a chiral light quark action

    NASA Astrophysics Data System (ADS)

    Blossier, B.

    2007-12-01

    The computation on the lattice of the bag parameter BB_s associated to the B-B¯ mixing amplitude in the Standard Model is presented. The estimation has been made by combining the static limit of HQET and the Neuberger light quark action which preserves the chiral symmetry on the lattice. We find BBMS¯stat(m)=0.92(3).

  5. Isgur-Wise function within a modified heavy-light chiral quark model

    SciTech Connect

    Eeg, Jan O.; Kumericki, Kresimir

    2010-04-01

    We consider the Isgur-Wise function {xi}({omega}) within a new modified version of a heavy-light chiral quark model. While early versions of such models gave an absolute value of the slope that was too small, namely {xi}{sup '}(1){approx_equal}-0.4 to -0.3, we show how extended version(s) may lead to values around -1, in better agreement with recent measurements. This is obtained by introducing a new mass parameter in the heavy-quark propagator. We also shortly comment on the consequences for the decay modes B{yields}DD.

  6. Phenomenology of enhanced light quark Yukawa couplings and the W±h charge asymmetry

    NASA Astrophysics Data System (ADS)

    Yu, Felix

    2017-02-01

    I propose the measurement of the W ± h charge asymmetry as a consistency test for the Standard Model (SM) Higgs, which is sensitive to enhanced Yukawa couplings of the first and second generation quarks. I present a collider analysis for the charge asymmetry in the same-sign lepton final state, pp → W ± h → ( ℓ ± ν) ( ℓ ± νjj), aimed at discovery significance for the SM W ± h production mode in each charge channel with 300 fb-1 of 14 TeV LHC data. Using this decay mode, I estimate the statistical precision on the charge asymmetry should reach 0.4% with 3 ab-1 luminosity, enabling a strong consistency test of the SM Higgs hypothesis. I also discuss direct and indirect constraints on light quark Yukawa couplings from direct and indirect probes of the Higgs width as well as Tevatron and Large Hadron Collider Higgs data. While the main effect from enhanced light quark Yukawa couplings is a rapid increase in the total Higgs width, such effects could be mitigated in a global fit to Higgs couplings, leaving the W ± h charge asymmetry as a novel signature to test directly the Higgs couplings to light quarks.

  7. Radiative decays of double heavy baryons in a relativistic constituent three-quark model including hyperfine mixing effects

    SciTech Connect

    Branz, Tanja; Faessler, Amand; Gutsche, Thomas; Lyubovitskij, Valery E.; Oexl, Bettina; Ivanov, Mikhail A.; Koerner, Juergen G.

    2010-06-01

    We study flavor-conserving radiative decays of double-heavy baryons using a manifestly Lorentz covariant constituent three-quark model. Decay rates are calculated and compared to each other in the full theory, keeping masses finite, and also in the heavy quark limit. We discuss in some detail hyperfine mixing effects.

  8. Boosted event topologies from TeV scale light quark composite partners

    NASA Astrophysics Data System (ADS)

    Backović, Mihailo; Flacke, Thomas; Kim, Jeong Han; Lee, Seung J.

    2015-04-01

    We propose a new search strategy for quark partners which decay into a boosted Higgs and a light quark. As an example, we consider phenomenologically viable right handed up-type quark partners of mass ˜ 1 TeV in composite pseudo-Nambu-Goldstone-boson Higgs models within the context of flavorful naturalness. Our results show that S/B > 1 and signal significance of ˜ 7σ is achievable at TeV LHC with 35 fb-1 of integrated luminosity, sufficient to claim discovery of a new particle. A combination of a multi-dimensional boosted Higgs tagging technique, kinematics of pair produced heavy objects and b-tagging serves to efficiently diminish the large QCD backgrounds while maintaining adequate levels of signal efficiency. We present the analysis in the context of effective field theory, such that our results can be applied to any future search for pair produced vector-like quarks with decay modes to Higgs and a light jet.

  9. Enhanced Higgs associated production with a top quark pair in the NMSSM with light singlets

    NASA Astrophysics Data System (ADS)

    Badziak, Marcin; Wagner, Carlos E. M.

    2017-02-01

    Precision measurements of the 125 GeV Higgs resonance recently discovered at the LHC have determined that its properties are similar to the ones of the Standard Model (SM) Higgs boson. However, the current uncertainties in the determination of the Higgs boson couplings leave room for significant deviations from the SM expectations. In fact, if one assumes no correlation between the top-quark and gluon couplings to the Higgs, the current global fit to the Higgs data lead to central values of the Higgs couplings to the bottom-quark and the top-quark that are about 2 σ away from the SM predictions. In a previous work, we showed that such a scenario could be realized in the Next to Minimal Supersymmetric extension of the SM (NMSSM), for heavy singlets and light MSSM-like Higgs bosons and scalar top quarks, but for couplings that ruined the perturbative consistency of the theory up to the GUT scale. In this work we show that a perturbative consistent scenario, for somewhat heavier stops, may be obtained in the presence of light singlets. An interesting bonus of this scenario is the possibility of explaining an excess of events observed in CP-even Higgs searches at LEP2.

  10. Perterbative O(asa) matching in static heavy and domain-wall light quark system

    SciTech Connect

    Ishikawa,T.

    2008-07-14

    We discuss the perturbative O(a{sub s}a) matching in the static heavy and domain-wall light quark system. The gluon action is the Iwasaki action and the link smearing is performed in the static heavy action. The chiral symmetry of the light quark realized by using the domain-wall fermion formulation does not prohibit the mixing of the operators at O(a). The application of O(a) improvement to the actual data shows that the B meson decay constant f{sub B}, the matrix elements M{sub B} and the B parameter B{sub B} have non-negligible effects, while the effect on the SU(3) breaking ratio {zeta} is small.

  11. Sivers and Boer-Mulders functions in Light-Cone Quark Models

    SciTech Connect

    Pasquini, Barbara; Yuan, Feng

    2010-01-29

    Results for the naive-time-reversal-odd quark distributions in a light-cone quark model are presented. The final-state interaction effects are generated via single-gluon exchange mechanism. The formalism of light-cone wave functions is used to derive general expressions in terms of overlap of wave-function amplitudes describing the different orbital angular momentum components of the nucleon. In particular, the model predictions show a dominant contribution from S- and P-wave interference in the Sivers function and a significant contribution also from the interference of P and D waves in the Boer-Mulders function. The favourable comparison with existing phenomenological parametrizations motivates further applications to describe azimuthal asymmetries in hadronic reactions.

  12. Exclusive Rare B ( s, c) Decays in Light-Front Quark Model

    NASA Astrophysics Data System (ADS)

    Choi, Ho-Meoyng

    2013-03-01

    We investigate the exclusive rare {B_sto (K,η^{(')})(ν_{ell}bar{ν_{ell}}, ell^+ell^-)} and {B_cto D_{(s)}(ν_{ell}bar{ν_{ell}}, ell^+ell^-)} ( ℓ = e, μ, τ) decays within the standard model and the light-front quark model constrained by the variational principle for the QCD motivated effective Hamiltonian. The branching ratios and the longitudinal lepton polarization asymmetries are calculated and compared with other theoretical model predictions.

  13. Light-Quark Baryon Spectroscopy within ANL-Osaka Dynamical Coupled-Channels Approach

    NASA Astrophysics Data System (ADS)

    Kamano, Hiroyuki

    2016-10-01

    Recent results on the study of light-quark baryons with the ANL-Osaka dynamical coupled-channels (DCC) approach are presented, which contain the N^* and Δ ^* spectroscopy via the analysis of π N and γ N reactions and the Λ ^* and Σ ^* spectroscopy via the analysis of K^- p reactions. A recent application of our DCC approach to neutrino-nucleon reactions in the resonance region is also presented.

  14. Flavor SU(3) properties of beauty tetraquark states with three different light quarks

    NASA Astrophysics Data System (ADS)

    He, Xiao-Gang; Ko, Pyungwon

    2016-10-01

    Beauty tetraquark states X (b bar q‧q″ q bar) composed of b bar su d bar , b bar ds u bar , and b bar ud s bar , are unique that all the four valence quarks are different. Although the claim of existence of the first two states by D0 was not confirmed by data from LHCb, the possibility of such states still generated a lot of interests and should be pursued further. Non-observation of X (b bar q‧q″ q bar) states by LHCb may be just due to a still lower production rate than the limit of LHCb or at some different mass ranges. In this work we use light quark SU (3) flavor symmetry as guideline to classify symmetry properties of beauty tetraquark states. The multiplets which contain states with three different light quarks must be one of 6 bar or 15 of SU (3) representations. We study possible decays of such a tetraquark state into a B meson and a light pseudoscalar octet meson by constructing a leading order chiral Lagrangian, and also provide search strategies to determine whether a given tetraquark state of this type belongs to 6 bar or 15. If X (b bar q‧q″ q bar) belongs to 15, there are new doubly charged tetraquark states b bar uu d bar and b bar uu s bar .

  15. Investigation of light baryons in a three-body quark model

    NASA Astrophysics Data System (ADS)

    Aslanzadeh, M.; Rajabi, A. A.

    2017-02-01

    We present a three-body quark model based on hypercentral approach for investigating the internal structure of light baryons. The analytically obtained energy eigenvalues and eigenfunctions of the three-body problem have been used in the calculations of the mass spectrum of light baryons and electromagnetic elastic form factors of nucleon. The magnetic moments and charge radii of nucleon have also been calculated. We have compared the evaluated observables with experimental data and it has been shown that the present model provides a good description of the observed resonances.

  16. Searching the Inclusive Lepton + Photon + Missing E(T) + b-quark Signature for Radiative Top Quark Decay and Non-Standard-Model Processes

    SciTech Connect

    Aaltonen, T.; Adelman, Jahred A.; Akimoto, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, Dante E.; Anastassov, A.; Annovi, Alberto; Antos, Jaroslav; Apollinari, G.; Apresyan, A.; /Purdue U. /Waseda U.

    2009-06-01

    In a search for new phenomena in a signature suppressed in the standard model of elementary particles (SM), we compare the inclusive production of events containing a lepton ({ell}), a photon ({gamma}), significant transverse momentum imbalance (E{sub T}), and a jet identified as containing a b-quark, to SM predictions. The search uses data produced in proton-antiproton collisions at {radical}s = 1.96 TeV corresponding to 1.9 fb{sup -1} of integrated luminosity taken with the CDF detector at the Fermilab Tevatron. We find 28 {ell}{gamma}bE{sub T} events versus an expectation of 31.0{sub -3.5}{sup +4.1} events. If we further require events to contain at least three jets and large total transverse energy, simulations predict that the largest SM source is top-quark pair production with an additional radiated photon, t{bar t} + {gamma}. In the data we observe 16 t{bar t}{gamma} candidate events versus an expectation from non-top-quark SM sources of 11.2{sub -2.1}{sup +2.3}. Assuming the difference between the observed number and the predicted non-top-quark total is due to SM top quark production, we estimate the t{bar t} cross section to be 0.15 {+-} 0.08 pb.

  17. Search for a heavy particle decaying to a top quark and a light quark in pp ¯ collisions at √s=1.96 TeV.

    PubMed

    Aaltonen, T; Adelman, J; Alvarez González, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Arisawa, T; Artikov, A; Asaadi, J; Ashmanskas, W; Auerbach, B; Aurisano, A; Azfar, F; Badgett, W; Bae, T; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Barria, P; Bartos, P; Bauce, M; Bedeschi, F; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Bhatti, A; Bisello, D; Bizjak, I; Bland, K R; Blumenfeld, B; Bocci, A; Bodek, A; Bortoletto, D; Boudreau, J; Boveia, A; Brigliadori, L; Bromberg, C; Brucken, E; Budagov, J; Budd, H S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Calamba, A; Calancha, C; Camarda, S; Campanelli, M; Campbell, M; Canelli, F; Carls, B; Carlsmith, D; Carosi, R; Carrillo, S; Carron, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavaliere, V; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, K; Chokheli, D; Chung, W H; Chung, Y S; Ciocci, M A; Clark, A; Clarke, C; Compostella, G; Convery, M E; Conway, J; Corbo, M; Cordelli, M; Cox, C A; Cox, D J; Crescioli, F; Cuevas, J; Culbertson, R; Dagenhart, D; d'Ascenzo, N; Datta, M; de Barbaro, P; Dell'Orso, M; Demortier, L; Deninno, M; Devoto, F; d'Errico, M; Di Canto, A; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Donati, S; Dong, P; Dorigo, M; Dorigo, T; Ebina, K; Elagin, A; Eppig, A; Erbacher, R; Errede, S; Ershaidat, N; Eusebi, R; Farrington, S; Feindt, M; Fernandez, J P; Field, R; Flanagan, G; Forrest, R; Frank, M J; Franklin, M; Freeman, J C; Funakoshi, Y; Furic, I; Gallinaro, M; Garcia, J E; Garfinkel, A F; Garosi, P; Gerberich, H; Gerchtein, E; Giagu, S; Giakoumopoulou, V; Giannetti, P; Gibson, K; Ginsburg, C M; Giokaris, N; Giromini, P; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldin, D; Goldschmidt, N; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Grinstein, S; Grosso-Pilcher, C; Group, R C; Guimaraes da Costa, J; Hahn, S R; Halkiadakis, E; Hamaguchi, A; Han, J Y; Happacher, F; Hara, K; Hare, D; Hare, M; Harr, R F; Hatakeyama, K; Hays, C; Heck, M; Heinrich, J; Herndon, M; Hewamanage, S; Hocker, A; Hopkins, W; Horn, D; Hou, S; Hughes, R E; Hurwitz, M; Husemann, U; Hussain, N; Hussein, M; Huston, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jang, D; Jayatilaka, B; Jeon, E J; Jindariani, S; Jones, M; Joo, K K; Jun, S Y; Junk, T R; Kamon, T; Karchin, P E; Kasmi, A; Kato, Y; Ketchum, W; Keung, J; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kim, Y J; Kimura, N; Kirby, M; Klimenko, S; Knoepfel, K; Kondo, K; Kong, D J; Konigsberg, J; Kotwal, A V; Kreps, M; Kroll, J; Krop, D; Kruse, M; Krutelyov, V; Kuhr, T; Kurata, M; Kwang, S; Laasanen, A T; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lecompte, T; Lee, E; Lee, H S; Lee, J S; Lee, S W; Leo, S; Leone, S; Lewis, J D; Limosani, A; Lin, C-J; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, C; Liu, H; Liu, Q; Liu, T; Lockwitz, S; Loginov, A; Lucchesi, D; Lueck, J; Lujan, P; Lukens, P; Lungu, G; Lys, J; Lysak, R; Madrak, R; Maeshima, K; Maestro, P; Malik, S; Manca, G; Manousakis-Katsikakis, A; Margaroli, F; Marino, C; Martínez, M; Mastrandrea, P; Matera, K; Mattson, M E; Mazzacane, A; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Mesropian, C; Miao, T; Mietlicki, D; Mitra, A; Miyake, H; Moed, S; Moggi, N; Mondragon, M N; Moon, C S; Moore, R; Morello, M J; Morlock, J; Movilla Fernandez, P; Mukherjee, A; Muller, Th; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Naganoma, J; Nakano, I; Napier, A; Nett, J; Neu, C; Neubauer, M S; Nielsen, J; Nodulman, L; Noh, S Y; Norniella, O; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Ortolan, L; Pagan Griso, S; Pagliarone, C; Palencia, E; Papadimitriou, V; Paramonov, A A; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Pianori, E; Pilot, J; Pitts, K; Plager, C; Pondrom, L; Poprocki, S; Potamianos, K; Prokoshin, F; Pranko, A; Ptohos, F; Punzi, G; Rahaman, A; Ramakrishnan, V; Ranjan, N; Rao, K; Redondo, I; Renton, P; Rescigno, M; Riddick, T; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rodriguez, T; Rogers, E; Rolli, S; Roser, R; Ruffini, F; Ruiz, A; Russ, J; Rusu, V; Safonov, A; Sakumoto, W K; Sakurai, Y; Santi, L; Sato, K; Saveliev, V; Savoy-Navarro, A; Schlabach, P; Schmidt, A; Schmidt, E E; Schwarz, T; Scodellaro, L; Scribano, A; Scuri, F; Seidel, S; Seiya, Y; Semenov, A; Sforza, F; Shalhout, S Z; Shears, T; Shepard, P F; Shimojima, M; Shochet, M; Shreyber-Tecker, I; Simonenko, A; Sinervo, P; Sliwa, K; Smith, J R; Snider, F D; Soha, A; Sorin, V; Song, H; Squillacioti, P; Stancari, M; St Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Strycker, G L; Sudo, Y; Sukhanov, A; Suslov, I; Takemasa, K; Takeuchi, Y; Tang, J; Tecchio, M; Teng, P K; Thom, J; Thome, J; Thompson, G A; Thomson, E; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Totaro, P; Trovato, M; Ukegawa, F; Uozumi, S; Varganov, A; Vázquez, F; Velev, G; Vellidis, C; Vidal, M; Vila, I; Vilar, R; Vizán, J; Vogel, M; Volpi, G; Wagner, P; Wagner, R L; Wakisaka, T; Wallny, R; Wang, S M; Warburton, A; Waters, D; Wester, W C; Whiteson, D; Wicklund, A B; Wicklund, E; Wilbur, S; Wick, F; Williams, H H; Wilson, J S; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, H; Wright, T; Wu, X; Wu, Z; Yamamoto, K; Yamato, D; Yang, T; Yang, U K; Yang, Y C; Yao, W-M; Yeh, G P; Yi, K; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanetti, A; Zeng, Y; Zhou, C; Zucchelli, S

    2012-05-25

    We present a search for a new heavy particle X produced in association with a top quark, pp[over ¯]→t(X→t[over ¯]q) or pp[over ¯]→t[over ¯](X[over ¯]→tq[over ¯]), where q stands for up quarks and down quarks. Such a particle may explain the recent anomalous measurements of top-quark forward-backward asymmetry. If the light-flavor quark (q) is reconstructed as a jet (j), this gives a t[over ¯]+j or t+j resonance in tt[over ¯]+jet events, a previously unexplored experimental signature. In a sample of events with exactly one lepton, missing transverse momentum and at least five jets, corresponding to an integrated luminosity of 8.7 fb(-1) collected by the CDF II detector, we find the data to be consistent with the standard model. We set cross-section upper limits on the production (pp[over ¯]→Xt or X[over ¯]t[over ¯]) at 95% confidence level from 0.61 pb to 0.02 pb for X masses ranging from 200 GeV/c(2) to 800 GeV/c(2), respectively.

  18. On quark-antiquark approximation in light front QCD with zero gluon modes

    SciTech Connect

    Zubov, Roman; Prokhvatilov, Evgeni

    2016-01-22

    We consider a transition to the light front Hamiltonian from theories quantized on spacelike planes approaching to the light front. In this approach we preserve the dynamics of zero mode present in the theories near the light front. We make the limit transition differently for zero and nonzero modes. This leads to the appearance of some phenomenological parameter which can be used to describe vacuum effects. Also we use a lattice gauge invariant regularization in transverse coordinate space. As an illustration of our scheme we consider the quark-antiquark bound states problem in 2+1 dimensions. We construct basis states in the light front Fock space and provide detailed computations of the Hamiltonian matrix in this basis. These steps allow us to construct the matrix eigenvalue equation. In conclusion we discuss the nuances of obtained results.

  19. Thermodynamics of lattice QCD with 2 light dynamical (staggered) quark flavours on a 16 sup 3 times 8 lattice

    SciTech Connect

    Gottlieb, S.; Krasnitz, A. . Dept. of Physics); Heller, U.M.; Kennedy, A.D. . Supercomputer Computations Research Inst.); Kogut, J.B. . Dept. of Physics); Liu, W. ); Renken, R.L. (University of Central F

    1991-01-01

    Lattice QCD with 2 light staggered quark flavours is being simulated on a 16{sup 3} {times} 8 lattice to study the transition from hadronic matter to a quark gluon plasma. We have completed runs at m{sub q} = 0.0125 and are extending this to m{sub q} = 0.00625. We also examine the addition of a non-dynamical strange'' quark. Thermodynamic order parameters are being measured across the transition and further into the plasma phase, as are various screening lengths. No evidence for a first order transition is seen, and we estimate the transition temperature to be {Tc} = 143(7)MeV.

  20. Thermodynamics of lattice QCD with 2 light dynamical (staggered) quark flavours on a 16{sup 3} {times} 8 lattice

    SciTech Connect

    Gottlieb, S.; Krasnitz, A.; Heller, U.M.; Kennedy, A.D.; Kogut, J.B.; Liu, W.; Renken, R.L.; Sinclair, D.K.; Sugar, R.L.; Toussaint, D.; Wang, K.C.

    1991-12-31

    Lattice QCD with 2 light staggered quark flavours is being simulated on a 16{sup 3} {times} 8 lattice to study the transition from hadronic matter to a quark gluon plasma. We have completed runs at m{sub q} = 0.0125 and are extending this to m{sub q} = 0.00625. We also examine the addition of a non-dynamical ``strange`` quark. Thermodynamic order parameters are being measured across the transition and further into the plasma phase, as are various screening lengths. No evidence for a first order transition is seen, and we estimate the transition temperature to be {Tc} = 143(7)MeV.

  1. K-->pipi amplitudes from lattice QCD with a light charm quark.

    PubMed

    Giusti, L; Hernández, P; Laine, M; Pena, C; Wennekers, J; Wittig, H

    2007-02-23

    We compute the leading-order low-energy constants of the DeltaS=1 effective weak Hamiltonian in the quenched approximation of QCD with up, down, strange, and charm quarks degenerate and light. They are extracted by comparing the predictions of finite-volume chiral perturbation theory with lattice QCD computations of suitable correlation functions carried out with quark masses ranging from a few MeV up to half of the physical strange mass. We observe a DeltaI=1/2 enhancement in this corner of the parameter space of the theory. Although matching with the experimental result is not observed for the DeltaI=1/2 amplitude, our computation suggests large QCD contributions to the physical DeltaI=1/2 rule in the GIM limit, and represents the first step to quantify the role of the charm-quark mass in K-->pipi amplitudes. The use of fermions with an exact chiral symmetry is an essential ingredient in our computation.

  2. CHIRAL LIMIT AND LIGHT QUARK MASSES IN 2+1 FLAVOR DOMAIN WALL QCD.

    SciTech Connect

    SCHOLZ,E.; LIN, M.

    2007-07-30

    We present results for meson masses and decay constants measured on 24{sup 3} x 64 lattices using the domain wall fermion formulation with an extension of the fifth dimension of L{sub s} = 16 for N{sub f} 2 + 1 dynamical quark flavors. The lightest dynamical meson mass in our set-up is around 331MeV. while partially quenched mesons reach masses as low as 250MeV. The applicability of SU(3) x SU(3) and SU(2) x SU(2) (partially quenched) chiral perturbation theory will be compared and we quote values for the low-energy constants from both approaches. We will extract the average light quark and strange quark masses and use a non-perturbative renormalization technique (RI/MOM) to quote their physical values. The pion and kaon decay constants are determined at those values from our chiral fits and their ratio is used to obtain the CKM-matrix element |V{sub us}|. The results presented here include statistical errors only.

  3. Dependence on the quark masses of elastic phase shifts and light resonances within standard and unitarized ChPT

    SciTech Connect

    Nebreda, J.; Pelaez, J. R.

    2011-10-24

    We study the dependence of the {pi}{pi} scattering phase shifts on the light quark mass in both standard and unitarized SU(2) Chiral Perturbation Theory (ChPT) to one and two loops. We then use unitarized SU(3) ChPT to study the elastic f{sub 0}(600),{kappa}(800), {rho}(770) and K{sup *}(892) resonances. The quark masses are varied up to values of interest for lattice studies. We find a very soft dependence on the light quark mass of the {pi}{pi} phase shifts at one loop and lightly stronger at two loops and a good agreement with lattice results. The SU(3) analysis shows that the properties of the {rho}(770) and K{sup *}(892) depend smoothly on the quark mass whereas the scalar resonances present a non-analyticity at high quark masses. We also confirm the lattice assumption of quark mass independence of the vector two-meson coupling that, however, is violated for scalars.

  4. Recent results in light-quark meson spectroscopy from Fermilab experiment E-760

    SciTech Connect

    Hasan, M.A.; Bharadwaj, V.; Church, M.; Hahn, A.; Hasan, M.A.; Hsueh, S.; Marsh, W.; Peoples, J. Jr.; Pordes, S.; Rapidis, P.

    1994-09-01

    Fermilab experiment E-760 light-quark meson spectroscopy data for proton-antiproton annihilation to 3{pi}{sup 0}, 2{pi}{sup 0}{eta}, {pi}{sup 0}2{eta}, and 3{eta} in-flight have confirmed the 1500 MeV state at rest seen previously at CERN. Structures above this energy are complex, and preliminary results of amplitude analysis, in progress, for extracting spin quantum numbers show the possibility of nearly degenerate states for some of these structures. 9 refs., 6 figs., 3 tabs.

  5. Searching the inclusive ℓγE̸T+b-quark signature for radiative top quark decay and non-standard-model processes

    NASA Astrophysics Data System (ADS)

    Aaltonen, T.; Adelman, J.; Akimoto, T.; Álvarez González, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Apresyan, A.; Arisawa, T.; Artikov, A.; Ashmanskas, W.; Attal, A.; Aurisano, A.; Azfar, F.; Badgett, W.; Barbaro-Galtieri, A.; Barnes, V. E.; Barnett, B. A.; Barria, P.; Bartsch, V.; Bauer, G.; Beauchemin, P.-H.; Bedeschi, F.; Beecher, D.; Behari, S.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Beretvas, A.; Beringer, J.; Bhatti, A.; Binkley, M.; Bisello, D.; Bizjak, I.; Blair, R. E.; Blocker, C.; Blumenfeld, B.; Bocci, A.; Bodek, A.; Boisvert, V.; Bolla, G.; Bortoletto, D.; Boudreau, J.; Boveia, A.; Brau, B.; Bridgeman, A.; Brigliadori, L.; Bromberg, C.; Brubaker, E.; Budagov, J.; Budd, H. S.; Budd, S.; Burke, S.; Burkett, K.; Busetto, G.; Bussey, P.; Buzatu, A.; Byrum, K. L.; Cabrera, S.; Calancha, C.; Campanelli, M.; Campbell, M.; Canelli, F.; Canepa, A.; Carls, B.; Carlsmith, D.; Carosi, R.; Carrillo, S.; Carron, S.; Casal, B.; Casarsa, M.; Castro, A.; Catastini, P.; Cauz, D.; Cavaliere, V.; Cavalli-Sforza, M.; Cerri, A.; Cerrito, L.; Chang, S. H.; Chen, Y. C.; Chertok, M.; Chiarelli, G.; Chlachidze, G.; Chlebana, F.; Cho, K.; Chokheli, D.; Chou, J. P.; Choudalakis, G.; Chuang, S. H.; Chung, K.; Chung, W. H.; Chung, Y. S.; Chwalek, T.; Ciobanu, C. I.; Ciocci, M. A.; Clark, A.; Clark, D.; Compostella, G.; Convery, M. E.; Conway, J.; Cordelli, M.; Cortiana, G.; Cox, C. A.; Cox, D. J.; Crescioli, F.; Cuenca Almenar, C.; Cuevas, J.; Culbertson, R.; Cully, J. C.; Dagenhart, D.; Datta, M.; Davies, T.; de Barbaro, P.; de Cecco, S.; Deisher, A.; de Lorenzo, G.; Dell'Orso, M.; Deluca, C.; Demortier, L.; Deng, J.; Deninno, M.; Derwent, P. F.; di Canto, A.; di Giovanni, G. P.; Dionisi, C.; di Ruzza, B.; Dittmann, J. R.; D'Onofrio, M.; Donati, S.; Dong, P.; Donini, J.; Dorigo, T.; Dube, S.; Efron, J.; Elagin, A.; Erbacher, R.; Errede, D.; Errede, S.; Eusebi, R.; Fang, H. C.; Farrington, S.; Fedorko, W. T.; Feild, R. G.; Feindt, M.; Fernandez, J. P.; Ferrazza, C.; Field, R.; Flanagan, G.; Forrest, R.; Frank, M. J.; Franklin, M.; Freeman, J. C.; Frisch, H. J.; Furic, I.; Gallinaro, M.; Galyardt, J.; Garberson, F.; Garcia, J. E.; Garfinkel, A. F.; Garosi, P.; Genser, K.; Gerberich, H.; Gerdes, D.; Gessler, A.; Giagu, S.; Giakoumopoulou, V.; Giannetti, P.; Gibson, K.; Gimmell, J. L.; Ginsburg, C. M.; Giokaris, N.; Giordani, M.; Giromini, P.; Giunta, M.; Giurgiu, G.; Glagolev, V.; Glenzinski, D.; Gold, M.; Goldschmidt, N.; Golossanov, A.; Gomez, G.; Gomez-Ceballos, G.; Goncharov, M.; González, O.; Gorelov, I.; Goshaw, A. T.; Goulianos, K.; Gresele, A.; Grinstein, S.; Grosso-Pilcher, C.; Group, R. C.; Grundler, U.; Guimaraes da Costa, J.; Gunay-Unalan, Z.; Haber, C.; Hahn, K.; Hahn, S. R.; Halkiadakis, E.; Han, B.-Y.; Han, J. Y.; Happacher, F.; Hara, K.; Hare, D.; Hare, M.; Harper, S.; Harr, R. F.; Harris, R. M.; Hartz, M.; Hatakeyama, K.; Hays, C.; Heck, M.; Heijboer, A.; Heinrich, J.; Henderson, C.; Herndon, M.; Heuser, J.; Hewamanage, S.; Hidas, D.; Hill, C. S.; Hirschbuehl, D.; Hocker, A.; Hou, S.; Houlden, M.; Hsu, S.-C.; Huffman, B. T.; Hughes, R. E.; Husemann, U.; Hussein, M.; Huston, J.; Incandela, J.; Introzzi, G.; Iori, M.; Ivanov, A.; James, E.; Jang, D.; Jayatilaka, B.; Jeon, E. J.; Jha, M. K.; Jindariani, S.; Johnson, W.; Jones, M.; Joo, K. K.; Jun, S. Y.; Jung, J. E.; Junk, T. R.; Kamon, T.; Kar, D.; Karchin, P. E.; Kato, Y.; Kephart, R.; Ketchum, W.; Keung, J.; Khotilovich, V.; Kilminster, B.; Kim, D. H.; Kim, H. S.; Kim, H. W.; Kim, J. E.; Kim, M. J.; Kim, S. B.; Kim, S. H.; Kim, Y. K.; Kimura, N.; Kirsch, L.; Klimenko, S.; Knuteson, B.; Ko, B. R.; Kondo, K.; Kong, D. J.; Konigsberg, J.; Korytov, A.; Kotwal, A. V.; Kreps, M.; Kroll, J.; Krop, D.; Krumnack, N.; Kruse, M.; Krutelyov, V.; Kubo, T.; Kuhr, T.; Kulkarni, N. P.; Kurata, M.; Kwang, S.; Laasanen, A. T.; Lami, S.; Lammel, S.; Lancaster, M.; Lander, R. L.; Lannon, K.; Lath, A.; Latino, G.; Lazzizzera, I.; Lecompte, T.; Lee, E.; Lee, H. S.; Lee, S. W.; Leone, S.; Lewis, J. D.; Lin, C.-S.; Linacre, J.; Lindgren, M.; Lipeles, E.; Lister, A.; Litvintsev, D. O.; Liu, C.; Liu, T.; Lockyer, N. S.; Loginov, A.; Loreti, M.; Lovas, L.; Lucchesi, D.; Luci, C.; Lueck, J.; Lujan, P.; Lukens, P.; Lungu, G.; Lyons, L.; Lys, J.; Lysak, R.; MacQueen, D.; Madrak, R.; Maeshima, K.; Makhoul, K.; Maki, T.; Maksimovic, P.; Malde, S.; Malik, S.; Manca, G.; Manousakis-Katsikakis, A.; Margaroli, F.; Marino, C.; Marino, C. P.; Martin, A.; Martin, V.; Martínez, M.; Martínez-Ballarín, R.; Maruyama, T.; Mastrandrea, P.; Masubuchi, T.; Mathis, M.; Mattson, M. E.; Mazzanti, P.; McFarland, K. S.; McIntyre, P.; McNulty, R.; Mehta, A.; Mehtala, P.; Menzione, A.; Merkel, P.; Mesropian, C.; Miao, T.; Miladinovic, N.; Miller, R.; Mills, C.; Milnik, M.; Mitra, A.; Mitselmakher, G.; Miyake, H.; Moggi, N.; Moon, C. S.; Moore, R.; Morello, M. J.; Morlock, J.; Movilla Fernandez, P.; Mülmenstädt, J.; Mukherjee, A.; Muller, Th.; Mumford, R.; Murat, P.; Mussini, M.; Nachtman, J.; Nagai, Y.; Nagano, A.; Naganoma, J.; Nakamura, K.; Nakano, I.; Napier, A.; Necula, V.; Nett, J.; Neu, C.; Neubauer, M. S.; Neubauer, S.; Nielsen, J.; Nodulman, L.; Norman, M.; Norniella, O.; Nurse, E.; Oakes, L.; Oh, S. H.; Oh, Y. D.; Oksuzian, I.; Okusawa, T.; Orava, R.; Osterberg, K.; Pagan Griso, S.; Palencia, E.; Papadimitriou, V.; Papaikonomou, A.; Paramonov, A. A.; Parks, B.; Pashapour, S.; Patrick, J.; Pauletta, G.; Paulini, M.; Paus, C.; Peiffer, T.; Pellett, D. E.; Penzo, A.; Phillips, T. J.; Piacentino, G.; Pianori, E.; Pinera, L.; Pitts, K.; Plager, C.; Pondrom, L.; Poukhov, O.; Pounder, N.; Prakoshyn, F.; Pronko, A.; Proudfoot, J.; Ptohos, F.; Pueschel, E.; Punzi, G.; Pursley, J.; Rademacker, J.; Rahaman, A.; Ramakrishnan, V.; Ranjan, N.; Redondo, I.; Renton, P.; Renz, M.; Rescigno, M.; Richter, S.; Rimondi, F.; Ristori, L.; Robson, A.; Rodrigo, T.; Rodriguez, T.; Rogers, E.; Rolli, S.; Roser, R.; Rossi, M.; Rossin, R.; Roy, P.; Ruiz, A.; Russ, J.; Rusu, V.; Rutherford, B.; Saarikko, H.; Safonov, A.; Sakumoto, W. K.; Saltó, O.; Santi, L.; Sarkar, S.; Sartori, L.; Sato, K.; Savoy-Navarro, A.; Schlabach, P.; Schmidt, A.; Schmidt, E. E.; Schmidt, M. A.; Schmidt, M. P.; Schmitt, M.; Schwarz, T.; Scodellaro, L.; Scribano, A.; Scuri, F.; Sedov, A.; Seidel, S.; Seiya, Y.; Semenov, A.; Sexton-Kennedy, L.; Sforza, F.; Sfyrla, A.; Shalhout, S. Z.; Shears, T.; Shepard, P. F.; Shimojima, M.; Shiraishi, S.; Shochet, M.; Shon, Y.; Shreyber, I.; Sinervo, P.; Sisakyan, A.; Slaughter, A. J.; Slaunwhite, J.; Sliwa, K.; Smith, J. R.; Snider, F. D.; Snihur, R.; Soha, A.; Somalwar, S.; Sorin, V.; Spreitzer, T.; Squillacioti, P.; Stanitzki, M.; St. Denis, R.; Stelzer, B.; Stelzer-Chilton, O.; Stentz, D.; Strologas, J.; Strycker, G. L.; Suh, J. S.; Sukhanov, A.; Suslov, I.; Suzuki, T.; Taffard, A.; Takashima, R.; Takeuchi, Y.; Tanaka, R.; Tecchio, M.; Teng, P. K.; Terashi, K.; Thom, J.; Thompson, A. S.; Thompson, G. A.; Thomson, E.; Tipton, P.; Ttito-Guzmán, P.; Tkaczyk, S.; Toback, D.; Tokar, S.; Tollefson, K.; Tomura, T.; Tonelli, D.; Torre, S.; Torretta, D.; Totaro, P.; Tourneur, S.; Trovato, M.; Tsai, S.-Y.; Tu, Y.; Turini, N.; Ukegawa, F.; Vallecorsa, S.; van Remortel, N.; Varganov, A.; Vataga, E.; Vázquez, F.; Velev, G.; Vellidis, C.; Vidal, M.; Vidal, R.; Vila, I.; Vilar, R.; Vine, T.; Vogel, M.; Volobouev, I.; Volpi, G.; Wagner, P.; Wagner, R. G.; Wagner, R. L.; Wagner, W.; Wagner-Kuhr, J.; Wakisaka, T.; Wallny, R.; Wang, S. M.; Warburton, A.; Waters, D.; Weinberger, M.; Weinelt, J.; Wester, W. C., III; Whitehouse, B.; Whiteson, D.; Wicklund, A. B.; Wicklund, E.; Wilbur, S.; Williams, G.; Williams, H. H.; Wilson, P.; Winer, B. L.; Wittich, P.; Wolbers, S.; Wolfe, C.; Wright, T.; Wu, X.; Würthwein, F.; Xie, S.; Yagil, A.; Yamamoto, K.; Yamaoka, J.; Yang, U. K.; Yang, Y. C.; Yao, W. M.; Yeh, G. P.; Yi, K.; Yoh, J.; Yorita, K.; Yoshida, T.; Yu, G. B.; Yu, I.; Yu, S. S.; Yun, J. C.; Zanello, L.; Zanetti, A.; Zhang, X.; Zheng, Y.; Zucchelli, S.

    2009-07-01

    We compare the inclusive production of events containing a lepton (ℓ), a photon (γ), significant transverse momentum imbalance (E̸T), and a jet identified as containing a b-quark, to SM predictions. The search uses data produced in proton-antiproton collisions at s=1.96TeV corresponding to 1.9fb-1 of integrated luminosity taken with the CDF detector. We find 28 ℓγbE̸T events versus an expectation of 31.0-3.5+4.1 events. If we further require events to contain at least three jets and large total transverse energy, the largest SM source is radiative top-quark pair production, t tmacr +γ. In the data we observe 16 t tmacr γ candidate events versus an expectation from SM sources of 11.2-2.1+2.3. Assuming the difference between the observed number and the predicted non-top-quark total of 6.8-2.0+2.2 is due to SM top-quark production, we estimate the t tmacr γ cross section to be 0.15±0.08pb.

  6. QCD analysis of light charged Higgs production through polarized top quark decay in two different frames

    NASA Astrophysics Data System (ADS)

    Nejad, S. Mohammad Moosavi; Abbaspour, S.

    2017-03-01

    Light and heavy charged Higgs bosons are predicted by many models with an extended Higgs sector such as the two-Higgs-doublet model (2HDM). Searches for the charged Higgs bosons have been done by the ATLAS and the CMS experiments at the Large Hadron Collider (LHC) in proton-proton collision. However, a definitive search of charged Higgs bosons still has to be carried out by the LHC experiments. The experimental observation of charged Higgs bosons would indicate physics beyond the Standard Model. In the present work we study the O({α}_s) correction to the energy spectrum of the inclusive bottom-flavored mesons ( X b ) in polarized top quark decays into a light charged Higgs boson ( m H+ < m t ) and a massless bottom quark followed by the hadronization process b → X b in the type-I 2HDM, i.e. t(↑) → H + b → H + X b + Jet. This spin-dependent energy distribution is studied in two different helicity coordinate systems. This study could be considered as a new channel to indirect search for the charged Higgs bosons. To present our phenomenological predictions, we restrict ourselves to the constraints on the m H+ - tan β parameter space determined by the recent results of the CMS and the ATLAS collaborations.

  7. Extracting the Light Quark Mass Ratio m{sub u}/m{sub d} from Bottomonia Transitions

    SciTech Connect

    Guo Fengkun; Hanhart, Christoph; Meissner, Ulf-G.

    2010-10-15

    We propose a new method to extract the light quark mass ratio m{sub u}/m{sub d} using the {Upsilon}(4S){yields}h{sub b{pi}}{sup 0}({eta}) bottomonia transitions. The decay amplitudes are dominated by the light quark mass differences, and the corrections from other effects are rather small, allowing for a precise extraction. We also discuss how to reduce the theoretical uncertainty with the help of future experiments. As a by-product, we show that the decay {Upsilon}(4S){yields}h{sub b{eta}} is expected to be a nice channel for searching for the h{sub b} state.

  8. Radiative backwarming in white-light flares

    NASA Technical Reports Server (NTRS)

    Machado, Marcos E.; Emslie, A. Gordon; Avrett, Eugene H.

    1989-01-01

    Consideration is given to empirical atmospheric structures that are consistent with enhanced white-light continuum emission in solar flares. Results are presented from calculations of radiative transfer in lines and continua in empirical white-light flare model atmospheres, showing that flares with strong emission in the Balmer lines and continuum must show increases at longer wavelengths due to H(-) emission from overheated photospheric levels, which the Paschen continuum contribution in the same wavelength range is neglible. Also, plausible heating mechanisms that can lead to white-light flare emission are examined.

  9. Light Quark Fragmentation and a Measurement of A{sub s} at the SLD

    SciTech Connect

    Staengle, Hermann

    1999-04-19

    We have studied the fragmentation process in Z{sup 0} {yields} light-flavor (u{bar u}, d{bar d}, s{bar s}) events by measuring the differential cross sections for the production of the identified hadrons {pi}{sup {+-}}, K{sup {+-}}, p/{bar p}, K{sub s}{sup 0}, {Lambda}{sup 0}/{bar {Lambda}}{sup 0}, K*{sup 0}/{bar K}*{sup 0} and {phi}, and by performing a preliminary study of correlations in rapidity between pairs of identified {pi}{sup {+-}}, K{sup {+-}}, and p/{bar p}. Short range charge correlations are observed between all combinations of these three hadron species. A strong long range correlation is observed between all combinations of these three hadron species. A strong long range correlation is observed for high-momentum charged kaon pairs, and weaker {pi}{sup +}{pi}{sup -}, {pi}{sup +}K{sup -} and pK{sup -} correlations are observed. The SLC beam polarization is used to tag the quark hemisphere in each event, allowing the first study of rapidities signed such that positive rapidity is along the quark rather than antiquark direction. Distributions of signed rapidities and of ordered differences between signed rapidities provide new insights into leading particle production and several new tests of fragmentation models. We have used these correlation studies to perform a preliminary direct measurement of the parity violating coupling of the Z{sup 0} to strange quarks, A{sub s}. Our result is: A{sub s} = 0.82 {+-} 0.10(stat.) {+-} 0.08(syst.)(preliminary).

  10. Preliminary measurement of the charged multiplicities in b, c and light quark events from Z{sup 0} decays

    SciTech Connect

    1996-06-01

    Average charged multiplicities have been measured separately in b, c and light quark (u, d, s) events from Z{sup 0} decays measured in the SLD experiment. Impact parameters of charged tracks were used to select enriched samples of b and light quark events, and reconstructed charmed mesons were used to select c quark events. We measured the charged multiplicities: {anti n}{sub uds} = 20.21 {+-} 0.10 (stat.) {+-} 0.17 (syst.), {anti n}{sub c} = 21.28 {+-} 0.46 (stat.){sub -0.33}{sup +0.38} (syst.) and {anti n}{sub b} = 23.14 {+-} 0.10 (stat.){sub -0.34}{sup +0.35} (syst.), from which we derived the differences between the total average charged multiplicities of c or b quark events and light quark events: {Delta}{anti n}{sub c} = 1.07 {+-} 0.47 (stat.){sub -0.30}{sup +0.36} (syst.) and {Delta}{anti n}{sub b} = 2.93 {+-} 0.14 (stat.){sub -0.29}{sup +0.30} (syst.). We compared these measurements with those at lower center-of-mass energies and with perturbative QCD predictions. These combined results are in agreement with the QCD expectations and disfavor the hypothesis of flavor-independent fragmentation.

  11. Scalar K{pi} form factor and light-quark masses

    SciTech Connect

    Jamin, Matthias; Oller, Jose Antonio; Pich, Antonio

    2006-10-01

    Recent experimental improvements on K-decay data allow for a precise extraction of the strangeness-changing scalar K{pi} form factor and the related strange scalar spectral function. On the basis of this scalar as well as the corresponding pseudoscalar spectral function, the strange quark mass is determined to be m{sub s}(2 GeV)=92{+-}9 MeV. Further taking into account chiral perturbation theory mass ratios, the light up and down quark masses turn out to be m{sub u}(2 GeV)=2.7{+-}0.4 MeV as well as m{sub d}(2 GeV)=4.8{+-}0.5 MeV. As a by-product, we also find a value for the Cabibbo angle |V{sub us}|=0.2236(29) and the ratio of meson decay constants F{sub K}/F{sub {pi}}=1.203(16). Performing a global average of the strange mass by including extractions from other channels as well as lattice QCD results yields m{sub s}(2 GeV)=94{+-}6 MeV.

  12. Quark-Diquark Systematics of Baryons and the SU(6) Symmetry for Light States

    NASA Astrophysics Data System (ADS)

    Anisovich, A. V.; Anisovich, V. V.; Matveev, M. A.; Nikonov, V. A.; Sarantsev, A. V.; Vulfs, T. O.

    We continue our attempts to systematize baryons, which are composed of light quarks (q = u, d), as quark-diquark systems. The notion of two diquarks is used: (i) D11, with the spin SD = 1 and isospin ID = 1 and (ii) D00, with SD = 0 and ID = 0. Here we try to resolve the problem of the low-lying Δ ((5)/(2)-) states: in the last experiments the lightest state is observed at ≳2200 MeV, not at 1900-2000 MeV as it has been stated 20 years ago. We are looking for different systematization variants with the forbidden low-lying Δ ((5)/(2)-) states in the mass region ≲2000 MeV. We see that the inclusion of the SU(6) constraints on qD11 states with angular momentum L = 1 results in a shift of the lightest Δ ((5)/(2)-) isobar to 2300 MeV. The scheme with the SU(6) constraints for low-lying qD11 and qD00 states (with L = 0, 1) is presented in detail.

  13. Hadron spectrum, quark masses, and decay constants from light overlap fermions on large lattices

    SciTech Connect

    Galletly, D.; Horsley, R.; Guertler, M.; Perlt, H.; Schiller, A.; Rakow, P. E. L.; Schierholz, G.; Streuer, T.

    2007-04-01

    We present results from a simulation of quenched overlap fermions with Luescher-Weisz gauge field action on lattices up to 24{sup 3}48 and for pion masses down to {approx_equal}250 MeV. Among the quantities we study are the pion, rho, and nucleon masses; the light and strange quark masses; and the pion decay constant. The renormalization of the scalar and axial vector currents is done nonperturbatively in the RI-MOM scheme. The simulations are performed at two different lattice spacings, a{approx_equal}0.1 fm and {approx_equal}0.15 fm, and on two different physical volumes, to test the scaling properties of our action and to study finite volume effects. We compare our results with the predictions of chiral perturbation theory and compute several of its low-energy constants. The pion mass is computed in sectors of fixed topology as well.

  14. The light stop quark with small stop-neutralino difference in the MSSM

    SciTech Connect

    Milstene, C.; Carena, Marcela S.; Freitas, A.; Finch, A.; Sopczak, A.; Kluge, Hannelies

    2005-12-01

    The MSSM can explain electro-weak symmetry breaking if one scalar top quark (stop) is light. In addition, in this framework, the neutralino is a good dark matter candidate and for small stop-neutralino mass differences dm{sub i} = 30 GeV, co-annihilation plays an important role to match the results from WMAP and SDSS for the relic density in the universe. In this scenario, the stops mainly decays into charm and neutralino, making its discovery difficult at hadron colliders due to background and trigger limitations. They present results for the discovery reach of the ILC for a DM candidate as low as 0(5 GeV) based on a realistic experimental simulation. Moreover, the stop parameters could be measured with high precision.

  15. Viability of carbon-based life as a function of the light quark mass.

    PubMed

    Epelbaum, Evgeny; Krebs, Hermann; Lähde, Timo A; Lee, Dean; Meissner, Ulf-G

    2013-03-15

    The Hoyle state plays a crucial role in the helium burning of stars that have reached the red giant stage. The close proximity of this state to the triple-alpha threshold is needed for the production of carbon, oxygen, and other elements necessary for life. We investigate whether this life-essential condition is robust or delicately fine-tuned by measuring its dependence on the fundamental constants of nature, specifically the light quark mass and the strength of the electromagnetic interaction. We show that there exist strong correlations between the alpha-particle binding energy and the various energies relevant to the triple-alpha process. We derive limits on the variation of these fundamental parameters from the requirement that sufficient amounts of carbon and oxygen be generated in stars. We also discuss the implications of our results for an anthropic view of the Universe.

  16. Non-degenerate light quark masses from 2+1f lattice QCD+QED

    SciTech Connect

    Drury, Shane; Blum, Thomas; Hayakawa, Masashi; Izubuchi, Taku; Sachrajda, Chris; Zhou, Ran

    2014-01-01

    We report on a calculation of the effects of isospin breaking in Lattice QCD+QED. This involves using Chiral Perturbation Theory with Electromagnetic corrections to find the renormalized, non-degenerate, light quark masses. The calculations are carried out on QCD ensembles generated by the RBC and UKQCD collaborations using Domain Wall Fermions and the Iwasaki and Iwasaki+DSDR Gauge Actions with unitary pion masses down to 170 MeV. Non-compact QED is treated in the quenched approximation. The simulations use a $32^3$ lattice size with $a^{-1}=2.28(3)$ GeV (Iwasaki) and 1.37(1) (Iwasaki+DSDR). This builds on previous work from the RBC/UKQCD collaboration with lattice spacing $a^{-1}=1.78(4)$ GeV.

  17. Cosmic ultraviolet background radiation and zodiacal light

    NASA Technical Reports Server (NTRS)

    Tennyson, P. D.; Henry, R. C.; Feldman, P. D.; Hartig, G. F.

    1988-01-01

    Spectroscopic measurements of the diffuse cosmic UV background in the 1700-2850-A range are presented. In agreement with previous results, the data have resulted in the detection at high Galactic latitude of an intensity of 300 + or - 100 photons/sq cm s sr A at 1800 A without correction for starlight or airglow, a similar intensity over the 1900-2500-A range after correction for measured airglow, and a similar intensity over the 2500-2800-A range after correction for zodiacal light. It is suggested that this radiation may originate partly in line radiation from a Galactic halo and partly from extragalactic sources, perhaps the integrated light of distant galaxies.

  18. Quark mass dependence of light resonances and phase shifts in elastic {pi}{pi} and {pi}K scattering

    SciTech Connect

    Nebreda, J.; Pelaez, J. R.

    2010-12-28

    We study the light quark mass dependence of the {pi}{pi} scattering phase shifts in standard one and two-loop SU(2) Chiral Perturbation Theory (ChPT). We then repeat the study with unitarized ChPT and, furthermore, we extend the analysis to SU(3) and generate the elastic f{sub 0}(600),{kappa}(800), {rho}(770) and K*(892) resonances from unitarization. The quark masses are varied up to values of interest for lattice studies. We find that the SU(2){pi}{pi} phase shifts both in standard and unitarized ChPT depend very softly on the pion mass and that our results are in fair agreement with lattice results in the I = 2, J = 0 channel. In the SU(3) amplitudes, the mass and width of the {rho}(770) and K*(892) present an analogous and smooth quark mass dependence. In contrast, both scalars present a similar non-analyticity at high quark masses. We also confirm the lattice assumption of independence of the vector two-meson coupling on the quark mass, that is, nevertheless, violated for scalars.

  19. Search for pair production of a new heavy quark that decays into a W boson and a light quark in pp collisions at s=8 TeV with the ATLAS detector

    DOE PAGES

    Aad, G.; Abbott, B.; Abdallah, J.; ...

    2015-12-22

    In this study, a search is presented for pair production of a new heavy quark (Q) that decays into a W boson and a light quark (q) in the final state where one W boson decays leptonically (to an electron or muon plus a neutrino) and the other W boson decays hadronically. The analysis is performed using an integrated luminosity of 20.3 fb–1 of pp collisions at √s = 8 TeV collected by the ATLAS detector at the LHC. No evidence of QQ¯ production is observed. New chiral quarks with masses below 690 GeV are excluded at 95% confidence level,more » assuming BR(Q → Wq)=1. Results are also interpreted in the context of vectorlike quark models, resulting in the limits on the mass of a vectorlike quark in the two-dimensional plane of BR(Q → Wq) versus BR(Q → Hq).« less

  20. Constraining in-medium heavy-quark energy-loss mechanisms via angular correlations between heavy and light mesons

    NASA Astrophysics Data System (ADS)

    Rohrmoser, M.; Gossiaux, P.-B.; Gousset, T.; Aichelin, J.

    2017-01-01

    Two-particle correlations obtained from parton showers that pass the hot and dense medium of the quark gluon plasma (QGP) can be used as an alternative observable, in addition to the combination of the nuclear modification factor RAA and the elliptic flow v 2, to study the mechanisms of in-medium heavy quark energy-loss. In particular, angular correlations represent a promising tool to distinguish between energy loss due to collisional and radiative interactions of jet and medium particles. To this end, parton cascades were created in Monte-Carlo simulations, where individual particles can undergo both parton splitting as well as an effective jet-medium interaction. A first model simulates the effects of induced radiations on parton cascades. Its consequences on angular correlations of partons within jets were studied in detail, with particular focus on angular broadening. The results can be compared to a second model that effectively describes elastic scatterings of jet and medium particles.

  1. Light-quark and gluon jet discrimination in [Formula: see text] collisions at [Formula: see text] with the ATLAS detector.

    PubMed

    Aad, G; Abbott, B; Abdallah, J; Abdel Khalek, S; Abdinov, O; Aben, R; Abi, B; Abolins, M; AbouZeid, O S; Abramowicz, H; Abreu, H; Abreu, R; Abulaiti, Y; Acharya, B S; Adamczyk, L; Adams, D L; Adelman, J; Adomeit, S; Adye, T; Agatonovic-Jovin, T; Aguilar-Saavedra, J A; Agustoni, M; Ahlen, S P; Ahmad, A; Ahmadov, F; Aielli, G; Åkesson, T P A; Akimoto, G; Akimov, A V; Albert, J; Albrand, S; Alconada Verzini, M J; Aleksa, M; Aleksandrov, I N; Alexa, C; Alexander, G; Alexandre, G; Alexopoulos, T; Alhroob, M; Alimonti, G; Alio, L; Alison, J; Allbrooke, B M M; Allison, L J; Allport, P P; Allwood-Spiers, S E; Almond, J; Aloisio, A; Alonso, A; Alonso, F; Alpigiani, C; Altheimer, A; Alvarez Gonzalez, B; Alviggi, M G; Amako, K; Amaral Coutinho, Y; Amelung, C; Amidei, D; Amor Dos Santos, S P; Amorim, A; Amoroso, S; Amram, N; Amundsen, G; Anastopoulos, C; Ancu, L S; Andari, N; Andeen, T; Anders, C F; Anders, G; Anderson, K J; Andreazza, A; Andrei, V; Anduaga, X S; Angelidakis, S; Angelozzi, I; 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Thun, R P; Tian, F; Tibbetts, M J; Tikhomirov, V O; Tikhonov, Yu A; Timoshenko, S; Tiouchichine, E; Tipton, P; Tisserant, S; Todorov, T; Todorova-Nova, S; Toggerson, B; Tojo, J; Tokár, S; Tokushuku, K; Tollefson, K; Tomlinson, L; Tomoto, M; Tompkins, L; Toms, K; Topilin, N D; Torrence, E; Torres, H; Torró Pastor, E; Toth, J; Touchard, F; Tovey, D R; Tran, H L; Trefzger, T; Tremblet, L; Tricoli, A; Trigger, I M; Trincaz-Duvoid, S; Tripiana, M F; Triplett, N; Trischuk, W; Trocmé, B; Troncon, C; Trottier-McDonald, M; Trovatelli, M; True, P; Trzebinski, M; Trzupek, A; Tsarouchas, C; Tseng, J C-L; Tsiareshka, P V; Tsionou, D; Tsipolitis, G; Tsirintanis, N; Tsiskaridze, S; Tsiskaridze, V; Tskhadadze, E G; Tsukerman, I I; Tsulaia, V; Tsuno, S; Tsybychev, D; Tudorache, A; Tudorache, V; Tuna, A N; Tupputi, S A; Turchikhin, S; Turecek, D; Turk Cakir, I; Turra, R; Tuts, P M; Tykhonov, A; Tylmad, M; Tyndel, M; Uchida, K; Ueda, I; Ueno, R; Ughetto, M; Ugland, M; Uhlenbrock, M; Ukegawa, F; Unal, G; 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Zaidan, R; Zaitsev, A M; Zaman, A; Zambito, S; Zanello, L; Zanzi, D; Zaytsev, A; Zeitnitz, C; Zeman, M; Zemla, A; Zengel, K; Zenin, O; Ženiš, T; Zerwas, D; Zevi Della Porta, G; Zhang, D; Zhang, F; Zhang, H; Zhang, J; Zhang, L; Zhang, X; Zhang, Z; Zhao, Z; Zhemchugov, A; Zhong, J; Zhou, B; Zhou, L; Zhou, N; Zhu, C G; Zhu, H; Zhu, J; Zhu, Y; Zhuang, X; Zibell, A; Zieminska, D; Zimine, N I; Zimmermann, C; Zimmermann, R; Zimmermann, S; Zimmermann, S; Zinonos, Z; Ziolkowski, M; Zobernig, G; Zoccoli, A; Zur Nedden, M; Zurzolo, G; Zutshi, V; Zwalinski, L

    A likelihood-based discriminant for the identification of quark- and gluon-initiated jets is built and validated using 4.7 fb[Formula: see text] of proton-proton collision data at [Formula: see text] [Formula: see text] collected with the ATLAS detector at the LHC. Data samples with enriched quark or gluon content are used in the construction and validation of templates of jet properties that are the input to the likelihood-based discriminant. The discriminating power of the jet tagger is established in both data and Monte Carlo samples within a systematic uncertainty of [Formula: see text] 10-20 %. In data, light-quark jets can be tagged with an efficiency of [Formula: see text] while achieving a gluon-jet mis-tag rate of [Formula: see text] in a [Formula: see text] range between [Formula: see text] and [Formula: see text] for jets in the acceptance of the tracker. The rejection of gluon-jets found in the data is significantly below what is attainable using a Pythia 6 Monte Carlo simulation, where gluon-jet mis-tag rates of 10 % can be reached for a 50 % selection efficiency of light-quark jets using the same jet properties.

  2. Excited and exotic charmonium, D s and D meson spectra for two light quark masses from lattice QCD

    NASA Astrophysics Data System (ADS)

    Cheung, Gavin K. C.; O'Hara, Cian; Moir, Graham; Peardon, Michael; Ryan, Sinéad M.; Thomas, Christopher E.; Tims, David

    2016-12-01

    We present highly-excited charmonium, D s and D meson spectra from dynamical lattice QCD calculations with light quarks corresponding to M π ˜ 240 MeV and compare these to previous results with M π ˜ 400 MeV. Utilising the distillation framework, large bases of carefully constructed interpolating operators and a variational procedure, we extract and reliably identify the continuum spin of an extensive set of excited mesons. These include states with exotic quantum numbers which, along with a number with non-exotic quantum numbers, we identify as having excited gluonic degrees of freedom and interpret as hybrid mesons. Comparing the spectra at the two different M π , we find only a mild light-quark mass dependence and no change in the overall pattern of states.

  3. Electroexcitation of the Δ(1232)32+ and Δ(1600)32+ in a light-front relativistic quark model

    DOE PAGES

    Aznauryan, Inna G.; Burkert, Volker D.

    2015-09-30

    Here, the magnetic-dipole form factor and the ratios REM and RSM for the γ* N → Δ(1232)3/2+ transition are predicted within light-front relativistic quark model up to photon virtuality Q2=12 GeV2. Furthermore, we predict the helicity amplitudes of the γ* N → Δ(1600)3/2+ transition assuming the Δ(1600)3/2+ is the first radial excitation of the ground state Delta(1232)3/2+.

  4. Scalar correlator at [symbol: see text](alpha(s)4), Higgs boson decay into bottom quarks, and bounds on the light-quark masses.

    PubMed

    Baikov, P A; Chetyrkin, K G; Kühn, J H

    2006-01-13

    We compute, for the first time, the absorptive part of the massless correlator of two quark scalar currents in five loops. As physical applications, we consider the [symbol: see text](alpha(s)4) corrections to the decay rate of the standard model Higgs boson into quarks, as well as the constraints on the strange quark mass following from QCD sum rules.

  5. Observability of quarks

    SciTech Connect

    Bjorken, J.D.

    1985-12-01

    Even if stable hadrons with fractional charge do not exist, most of the criteria of observability used for ordinary elementary particles apply in principle to quarks as well. This is especially true in a simplified world containing only hadrons made of top quarks and gluons. In the real world containing light quarks, essential complications do occur, but most of the conclusions survive.

  6. Determination of the b-quark Mass and Nonperturbative parameters in Semileptonic and Radiative Penguin Decays at BaBar

    SciTech Connect

    Tackmann, Kerstin; collaboration, for the BABAR

    2008-01-23

    Knowing the mass of the b-quark is essential to the study of the structure and decays of B mesons as well as to future tests of the Higgs mechanism of mass generation. We present recent preliminary measurements of the b-quark mass and related nonperturbative parameters from moments of kinematic distributions in charmed and charmless semileptonic and radiative penguin B decays. Their determination from charmless semileptonic B decays is the first measurement in this mode. The data were collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -}-collider at the Stanford Linear Accelerator Center at a center-of-momentum energy of 10:58 GeV.

  7. Quark-novae Occurring in Massive Binaries : A Universal Energy Source in Superluminous Supernovae with Double-peaked Light Curves

    NASA Astrophysics Data System (ADS)

    Ouyed, Rachid; Leahy, Denis; Koning, Nico

    2016-02-01

    A quark-nova (QN; the sudden transition from a neutron star into a quark star), which occurs in the second common envelope (CE) phase of a massive binary, gives excellent fits to superluminous, hydrogen-poor, supernovae (SLSNe) with double-peaked light curves, including DES13S2cmm, SN 2006oz, and LSQ14bdq (http://www.quarknova.ca/LCGallery.html). In our model, the H envelope of the less massive companion is ejected during the first CE phase, while the QN occurs deep inside the second, He-rich, CE phase after the CE has expanded in size to a radius of a few tens to a few thousands of solar radii; this yields the first peak in our model. The ensuing merging of the quark star with the CO core leads to black hole formation and accretion, explaining the second long-lasting peak. We study a sample of eight SLSNe Ic with double-humped light curves. Our model provides good fits to all of these, with a universal explosive energy of 2 × 1052 erg (which is the kinetic energy of the QN ejecta) for the first hump. The late-time emissions seen in iPTF13ehe and LSQ14bdq are fit with a shock interaction between the outgoing He-rich (i.e., second) CE and the previously ejected H-rich (i.e., first) CE.

  8. QUARK-NOVAE OCCURRING IN MASSIVE BINARIES: A UNIVERSAL ENERGY SOURCE IN SUPERLUMINOUS SUPERNOVAE WITH DOUBLE-PEAKED LIGHT CURVES

    SciTech Connect

    Ouyed, Rachid; Leahy, Denis; Koning, Nico

    2016-02-10

    A quark-nova (QN; the sudden transition from a neutron star into a quark star), which occurs in the second common envelope (CE) phase of a massive binary, gives excellent fits to superluminous, hydrogen-poor, supernovae (SLSNe) with double-peaked light curves, including DES13S2cmm, SN 2006oz, and LSQ14bdq (http://www.quarknova.ca/LCGallery.html). In our model, the H envelope of the less massive companion is ejected during the first CE phase, while the QN occurs deep inside the second, He-rich, CE phase after the CE has expanded in size to a radius of a few tens to a few thousands of solar radii; this yields the first peak in our model. The ensuing merging of the quark star with the CO core leads to black hole formation and accretion, explaining the second long-lasting peak. We study a sample of eight SLSNe Ic with double-humped light curves. Our model provides good fits to all of these, with a universal explosive energy of 2 × 10{sup 52} erg (which is the kinetic energy of the QN ejecta) for the first hump. The late-time emissions seen in iPTF13ehe and LSQ14bdq are fit with a shock interaction between the outgoing He-rich (i.e., second) CE and the previously ejected H-rich (i.e., first) CE.

  9. Strong decays of heavy-light mesons in a chiral quark model

    NASA Astrophysics Data System (ADS)

    Zhong, Xian-Hui; Zhao, Qiang

    2008-07-01

    We carry out a systematic study of the heavy-light meson strong decays in a chiral quark model. For the S-wave vectors [D*(2007), D*±(2010)], P-wave scalars [D0*(2400), B0*(5730)], and tensors [D2*(2460), Ds2*(2573)], we obtain results in good agreement with the experimental data. For the axial vectors D1(2420) and D1'(2430), a state mixing scheme between 1P11 and 1P13 is favored with a mixing angle ϕ≃-(55±5)°, which is consistent with previous theoretical predictions. The same mixing scheme also applies to Ds1(2460) and Ds1(2536) that accounts for the narrow width of the Ds1(2536) and its dominant decay into D*K. For B1(5725) and B1'(5732), such a mixing explains well the decay width of the former but leads to an even broader B1'(5732). Predictions for the strange-bottom axial vectors are also made. For the undetermined meson D*(2640), we find that they fit well in the radially excited state 2S13 according to its decay mode. The newly observed DsJ*(2860) strongly favors the D-wave excited state 1D33. For DsJ*(2632) and DsJ*(2690), we find they are difficult to fit in any Ds excitations in that mass region, if the experimental data are accurate. Theoretical predictions for decay modes of those unobserved states as multiplets of 2S and 1D waves are also presented, which should be useful for the further experimental search for those states.

  10. Charmed and light pseudoscalar meson decay constants from four-flavor lattice QCD with physical light quarks

    SciTech Connect

    Bazavov, A.; Bernard, C.; Komijani, J.; Bouchard, C. M.; DeTar, C.; Foley, J.; Levkova, L.; Du, D.; Laiho, J.; El-Khadra, A. X.; Freeland, E. D.; Gámiz, E.; Gottlieb, Steven; Heller, U. M.; Kim, J.; Toussaint, D.; Kronfeld, A. S.; Mackenzie, P. B.; Simone, J. N.; Van de Water, R. S.; Zhou, R.; Neil, E. T.; Sugar, R.

    2014-10-30

    We compute the leptonic decay constants fD+, fDs, and fK+ and the quark-mass ratios mc/ms and ms/ml in unquenched lattice QCD using the experimentally determined value of fπ+ for normalization. We use the MILC highly improved staggered quark ensembles with four dynamical quark flavors—up, down, strange, and charm—and with both physical and unphysical values of the light sea-quark masses. The use of physical pions removes the need for a chiral extrapolation, thereby eliminating a significant source of uncertainty in previous calculations. Four different lattice spacings ranging from a0.06 to 0.15 fm are included in the analysis to control the extrapolation to the

  11. Measurement of the rate of charm quark pairs produced by radiated gluons in hadronic Z decay

    NASA Astrophysics Data System (ADS)

    Park, Hyangkyu

    1998-11-01

    We have measured the probability of gluon splitting to charm quark pairs using 1.7 million hadronic Z decays collected in 1994 and 1995 at the L3 detector. Although this process, gluon splitting to charm quark pairs, is one of the basic processes in QCD, it has not been well understood both theoretically and experimentally. Furthermore, the limited knowledge of this process is one of the biggest sources of error in the measurement of the fraction of Z decays to bottom quark pairs (Rb). For this measurement, we have applied two methods to events with a three-jet event topology. One method. relies on tagging charm hadrons by identifying a lepton in the lowest energy jet. Another method uses a neural network technique for identifying events containing gluon splitting into charm quark pairs. Though the first method provides a simple way to tag a charm quark, it is limited by statistics. The second method improves the statistical accuracy by utilizing the entire hadronic event sample. Combining both methods, we measure the average number of gluons splitting into charm quark pairs per hadronic event to be overlinenoverlineg-->coverlinecoverline =(2.22+/-0.18+/-0.44) %. We performed a combined fit with this result and other existing measurements of overlinenoverlineg-->coverlinecoverline at LEP experiments. The result allows a stringent test of various QCD models and reduces the single biggest source of systematic error in the measurement of Rb.

  12. One-loop operator matching in the static heavy and domain-wall light quark system with O(a) improvement

    SciTech Connect

    Ishikawa, T.; Aoki, Y.; Flynn, J.; Izubuchi, T.; Loktik, O.

    2011-05-09

    We discuss perturbative O(g{sup 2} a) matching with static heavy quarks and domain-wall light quarks for lattice operators relevant to B-meson decays and B{sup 0} - {bar B}{sup 0} mixing. The chiral symmetry of the light domain-wall quarks does not prohibit operator mixing at O(a) for these operators. The O(a) corrections to physical quantities are non-negligible and must be included to obtain high-precision simulation results for CKM physics. We provide results using plaquette, Symanzik, Iwasaki and DBW2 gluon actions and applying APE, HYP1 and HYP2 link-smearing for the static quark action.

  13. Nucleon scalar and tensor charges from lattice QCD with light Wilson quarks

    NASA Astrophysics Data System (ADS)

    Green, J. R.; Negele, J. W.; Pochinsky, A. V.; Syritsyn, S. N.; Engelhardt, M.; Krieg, S.

    2012-12-01

    We present 2+1 flavor lattice QCD calculations of the nucleon scalar and tensor charges. Using the BMW clover-improved Wilson action with pion masses between 149 and 356 MeV and three source-sink separations between 0.9 and 1.4 fm, we achieve good control over excited-state contamination and extrapolation to the physical pion mass. As a consistency check, we also present results from calculations using unitary domain wall fermions with pion masses between 297 and 403 MeV, and using domain wall valence quarks and staggered sea quarks with pion masses between 293 and 597 MeV.

  14. Search for Dimuon Decays of a Light Scalar Boson in Radiative Transitions Y -> gamma A^0

    SciTech Connect

    Aubert, B.

    2009-06-02

    We search for evidence of a light scalar boson in the radiative decays of the {Upsilon}(2S) and {Upsilon}(3S) resonances: {Upsilon}(2S, 3S) {yields} {gamma}A{sup 0}, A{sup 0} {yields} {mu}{sup +}{mu}{sup -}. Such a particle appears in extensions of the Standaard Model, where a light CP-odd Higgs boson naturally couples strongly to b-quarks. We find no evidence for such processes in the mass range 0.212 {<=} m{sub A{sup 0}} {<=} 9.3 GeV in the samples of 99 x 10{sup 6} {Upsilon}(2S) and 122 x 10{sup 6} {Upsilon}(3S) decays collected by the BABAR detector at the PEP-II B-factory and set stringent upper limits on the effective coupling of the b quark to the A{sup 0}. We also limit the dimuon branching fraction of the {eta}{sub b} meson: {Beta}({eta}{sub b} {yields} {mu}{sup +}{mu}{sup -}) < 0.9% at 90% confidence level.

  15. Search for a heavy particle decaying to a top quark and a light quark in $p\\bar{p}$ collisions at $\\sqrt{s}=1.96$ TeV

    SciTech Connect

    Aaltonen, T.; Adelman, J.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J.A.; Arisawa, T.; /Waseda U. /Dubna, JINR

    2012-03-01

    We present a search for a new heavy particle M produced in association with a top quark, p{bar p} {yields} t(M {yields} {bar t}q) or p{bar p} {yields} {bar t}({bar M} {yields} t{bar q}), where q stands for up quarks and down quarks. Such a particle may explain the recent anomalous measurements of top-quark forward-backward asymmetry. If the light-flavor quark (q) is reconstructed as a jet (j), this gives a {bar t}+j or t+j resonance in t{bar t}+jet events, a previously unexplored experimental signature. In a sample of events with exactly one lepton, missing transverse momentum and at least five jets, corresponding to an integrated luminosity of 8.7 fb{sup -1} collected by the CDF II detector, we find the data to be consistent with the standard model. We set cross-section upper limits on the production (p{bar p} {yields} Mt or {bar M} {bar t}) at 95% confidence level from 0.61 pb to 0.02 pb for M masses ranging from 200 GeV/c{sup 2} to 800 GeV/c{sup 2}, respectively.

  16. Search for Pair Production of Light Scalar Top Quarks in pp¯ Collisions at √(s)=1.8 TeV

    NASA Astrophysics Data System (ADS)

    Abazov, V. M.; Abbott, B.; Abdesselam, A.; Abolins, M.; Abramov, V.; Acharya, B. S.; Adams, D. L.; Adams, M.; Ahmed, S. N.; Alexeev, G. D.; Alton, A.; Alves, G. A.; Arnoud, Y.; Avila, C.; Babintsev, V. V.; Babukhadia, L.; Bacon, T. C.; Baden, A.; Baffioni, S.; Baldin, B.; Balm, P. W.; Banerjee, S.; Barberis, E.; Baringer, P.; Barreto, J.; Bartlett, J. F.; Bassler, U.; Bauer, D.; Bean, A.; Beaudette, F.; Begel, M.; Belyaev, A.; Beri, S. B.; Bernardi, G.; Bertram, I.; Besson, A.; Beuselinck, R.; Bezzubov, V. A.; Bhat, P. C.; Bhatnagar, V.; Bhattacharjee, M.; Blazey, G.; Blekman, F.; Blessing, S.; Boehnlein, A.; Bojko, N. I.; Bolton, T. A.; Borcherding, F.; Bos, K.; Bose, T.; Brandt, A.; Briskin, G.; Brock, R.; Brooijmans, G.; Bross, A.; Buchholz, D.; Buehler, M.; Buescher, V.; Burtovoi, V. S.; Butler, J. M.; Canelli, F.; Carvalho, W.; Casey, D.; Castilla-Valdez, H.; Chakraborty, D.; Chan, K. M.; Chekulaev, S. V.; Cho, D. K.; Choi, S.; Chopra, S.; Claes, D.; Clark, A. R.; Connolly, B.; Cooper, W. E.; Coppage, D.; Crã©Pã©-Renaudin, S.; Cummings, M. A.; Cutts, D.; da Motta, H.; Davis, G. A.; de, K.; de Jong, S. J.; Demarteau, M.; Demina, R.; Demine, P.; Denisov, D.; Denisov, S. P.; Desai, S.; Diehl, H. T.; Diesburg, M.; Doulas, S.; Dudko, L. V.; Duflot, L.; Dugad, S. R.; Duperrin, A.; Dyshkant, A.; Edmunds, D.; Ellison, J.; Eltzroth, J. T.; Elvira, V. D.; Engelmann, R.; Eno, S.; Ermolov, P.; Eroshin, O. V.; Estrada, J.; Evans, H.; Evdokimov, V. N.; Ferbel, T.; Filthaut, F.; Fisk, H. E.; Fortner, M.; Fox, H.; Fu, S.; Fuess, S.; Gallas, E.; Galyaev, A. N.; Gao, M.; Gavrilov, V.; Genik, R. J., II; Genser, K.; Gerber, C. E.; Gershtein, Y.; Ginther, G.; Gómez, B.; Goncharov, P. I.; Gounder, K.; Goussiou, A.; Grannis, P. D.; Greenlee, H.; Greenwood, Z. D.; Grinstein, S.; Groer, L.; Grünendahl, S.; Gurzhiev, S. N.; Gutierrez, G.; Gutierrez, P.; Hadley, N. J.; Haggerty, H.; Hagopian, S.; Hagopian, V.; Hall, R. E.; Han, C.; Hansen, S.; Hauptman, J. M.; Hebert, C.; Hedin, D.; Heinmiller, J. M.; Heinson, A. P.; Heintz, U.; Hildreth, M. D.; Hirosky, R.; Hobbs, J. D.; Hoeneisen, B.; Huang, J.; Huang, Y.; Iashvili, I.; Illingworth, R.; Ito, A. S.; Jaffré, M.; Jain, S.; Jesik, R.; Johns, K.; Johnson, M.; Jonckheere, A.; Jöstlein, H.; Juste, A.; Kahl, W.; Kahn, S.; Kajfasz, E.; Kalinin, A. M.; Karmanov, D.; Karmgard, D.; Kehoe, R.; Kesisoglou, S.; Khanov, A.; Kharchilava, A.; Klima, B.; Kohli, J. M.; Kostritskiy, A. V.; Kotcher, J.; Kothari, B.; Kozelov, A. V.; Kozlovsky, E. A.; Krane, J.; Krishnaswamy, M. R.; Krivkova, P.; Krzywdzinski, S.; Kubantsev, M.; Kuleshov, S.; Kulik, Y.; Kunori, S.; Kupco, A.; Kuznetsov, V. E.; Landsberg, G.; Lee, W. M.; Leflat, A.; Lehner, F.; Leonidopoulos, C.; Li, J.; Li, Q. Z.; Lima, J. G.; Lincoln, D.; Linn, S. L.; Linnemann, J.; Lipton, R.; Lucotte, A.; Lueking, L.; Lundstedt, C.; Luo, C.; Maciel, A. K.; Madaras, R. J.; Malyshev, V. L.; Manankov, V.; Mao, H. S.; Marshall, T.; Martin, M. I.; Mattingly, S. E.; Mayorov, A. A.; McCarthy, R.; McMahon, T.; Melanson, H. L.; Melnitchouk, A.; Merkin, M.; Merritt, K. W.; Miao, C.; Miettinen, H.; Mihalcea, D.; Mokhov, N.; Mondal, N. K.; Montgomery, H. E.; Moore, R. W.; Mutaf, Y. D.; Nagy, E.; Narain, M.; Narasimham, V. S.; Naumann, N. A.; Neal, H. A.; Negret, J. P.; Nelson, S.; Nomerotski, A.; Nunnemann, T.; O'Neil, D.; Oguri, V.; Oshima, N.; Padley, P.; Papageorgiou, K.; Parashar, N.; Partridge, R.; Parua, N.; Patwa, A.; Peters, O.; Pétroff, P.; Piegaia, R.; Pope, B. G.; Prosper, H. B.; Protopopescu, S.; Przybycien, M. B.; Qian, J.; Rajagopalan, S.; Rapidis, P. A.; Reay, N. W.; Reucroft, S.; Ridel, M.; Rijssenbeek, M.; Rizatdinova, F.; Rockwell, T.; Royon, C.; Rubinov, P.; Ruchti, R.; Sabirov, B. M.; Sajot, G.; Santoro, A.; Sawyer, L.; Schamberger, R. D.; Schellman, H.; Schwartzman, A.; Shabalina, E.; Shivpuri, R. K.; Shpakov, D.; Shupe, M.; Sidwell, R. A.; Simak, V.; Sirotenko, V.; Slattery, P.; Smith, R. P.; Snow, G. R.; Snow, J.; Snyder, S.; Solomon, J.; Song, Y.; Sorín, V.; Sosebee, M.; Sotnikova, N.; Soustruznik, K.; Souza, M.; Stanton, N. R.; Steinbrück, G.; Stoker, D.; Stolin, V.; Stone, A.; Stoyanova, D. A.; Strang, M. A.; Strauss, M.; Strovink, M.; Stutte, L.; Sznajder, A.; Talby, M.; Taylor, W.; Tentindo-Repond, S.; Trippe, T. G.; Turcot, A. S.; Tuts, P. M.; van Kooten, R.; Vaniev, V.; Varelas, N.; Villeneuve-Seguier, F.; Volkov, A. A.; Vorobiev, A. P.; Wahl, H. D.; Wang, Z.-M.; Warchol, J.; Watts, G.; Wayne, M.; Weerts, H.; White, A.; Whiteson, D.; Wijngaarden, D. A.; Willis, S.; Wimpenny, S. J.; Womersley, J.; Wood, D. R.; Xu, Q.; Yamada, R.; Yasuda, T.; Yatsunenko, Y. A.; Yip, K.; Yu, J.; Zanabria, M.; Zhang, X.; Zhou, B.; Zhou, Z.; Zielinski, M.; Zieminska, D.; Zieminski, A.; Zutshi, V.; Zverev, E. G.; Zylberstejn, A.

    2004-06-01

    Using 85.2±3.6 pb-1 of pp¯ collisions collected at √(s)=1.8 TeV with the D0 detector at Fermilab’s Tevatron Collider, we present the results of a search for direct pair production of scalar top quarks (t˜), the supersymmetric partners of the top quark. We examined events containing two or more jets and missing transverse energy, the signature of light scalar top quark decays to charm quarks and neutralinos. After selections, we observe 27 events while expecting 31.1±6.4 events from known standard model processes. Comparing these results to next-to-leading-order production cross sections, we exclude a significant region of t˜ and neutralino phase space. In particular, we exclude the t˜ mass mt˜<122 GeV/c2 for a neutralino mass of 45 GeV/c2.

  17. Dual Superconducting Model of QCD and the Spectra of Heavy and Heavy- Light Quark Systems

    NASA Astrophysics Data System (ADS)

    Fulcher, Lp

    1997-04-01

    The dual superconducting model of QCD provides a natural explanation of quark confinement as a Meissner effect, where the magnetic condensate present in the vacuum attempts to exclude the colour electric flux lines produced by the quark sources. The essential physics of this model is incorporated in an approach developed by Baker, Ball and Zachariasen(M. Baker, J. Ball and F. Zachariasen, Phys. Rev. D51), 1968(1995)., where the field equations are used to eliminate the Higgs field and the dual gluon fields and thus to express the interaction between a quark and an antiquark as an effective potential. Considering the spin averages of upsilon, charmonium and heavy-flavor states allows one to focus on the central potential and the leading relativistic corrections to it. The challenge is to account for the properties of these systems with the same set of potential parameters. Some important progress in this direction will be described. The spinless Salpeter equation is used to consider the effects of relativistic kinematics(L. Fulcher, Phys. Rev. D50), 447(1994)..

  18. Detail of window treatment, suspended radiators, and fluorescent lights, prop ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of window treatment, suspended radiators, and fluorescent lights, prop shop. View to east. - San Bernardino Valley College, Auditorium, 701 South Mount Vernon Avenue, San Bernardino, San Bernardino County, CA

  19. Heavy quark masses

    NASA Technical Reports Server (NTRS)

    Testa, Massimo

    1990-01-01

    In the large quark mass limit, an argument which identifies the mass of the heavy-light pseudoscalar or scalar bound state with the renormalized mass of the heavy quark is given. The following equation is discussed: m(sub Q) = m(sub B), where m(sub Q) and m(sub B) are respectively the mass of the heavy quark and the mass of the pseudoscalar bound state.

  20. Flashes of light-radiation therapy to the brain.

    PubMed

    Blumenthal, Deborah T; Corn, Benjamin W; Shtraus, Natan

    2015-08-01

    We present a series of three patients who received therapeutic external beam radiation to the brain and experienced a phenomenon of the sensation of flashes of bright or blue light, simultaneous with radiation delivery. We relate this benign phenomenon to low-dose exposure to the eye fields and postulate that the occurrence is underreported in this treated population.

  1. Precise MS light-quark masses from lattice QCD in the regularization invariant symmetric momentum-subtraction scheme

    SciTech Connect

    Gorbahn, Martin; Jaeger, Sebastian

    2010-12-01

    We compute the conversion factors needed to obtain the MS and renormalization-group-invariant (RGI) up, down, and strange quark masses at next-to-next-to-leading order from the corresponding parameters renormalized in the recently proposed RI/SMOM and RI/SMOM{sub {gamma}{sub {mu}} }renormalization schemes. This is important for obtaining the MS masses with the best possible precision from numerical lattice QCD simulations, because the customary RI{sup (')}/MOM scheme is afflicted with large irreducible uncertainties both on the lattice and in perturbation theory. We find that the smallness of the known one-loop matching coefficients is accompanied by even smaller two-loop contributions. From a study of residual scale dependences, we estimate the resulting perturbative uncertainty on the light-quark masses to be about 2% in the RI/SMOM scheme and about 3% in the RI/SMOM{sub {gamma}{sub {mu}} }scheme. Our conversion factors are given in fully analytic form, for general covariant gauge and renormalization point. We provide expressions for the associated anomalous dimensions.

  2. Nucleon Resonance Electrocouplings from Light-Front Quark Models at {\\varvec{Q}}^2 up to 12 GeV^2

    NASA Astrophysics Data System (ADS)

    Obukhovsky, Igor T.; Faessler, Amand; Gutsche, Thomas; Lyubovitskij, Valery E.

    2016-11-01

    A relativistic light-front quark model is used to describe both the elastic nucleon and nucleon-Roper transition form factors in a large Q^2 range, up to 35 GeV^2 for the elastic and up to 12 GeV^2 for the resonance case. Relativistic three-quark configurations satisfying the Pauli exclusion principle on the light-front are used for the derivation of the current matrix elements. The Roper resonance is considered as a mixed state of a three-quark core configuration and a molecular N+σ hadron component. Based on this ansatz we obtain a realistic description of both processes, elastic and inelastic, in the sector of positive parity and show that existing experimental data are indicative of a composite structure of the Roper resonance. A useful generalization of this technique is suggested for description of negative parity nucleon resonances 1/2^-, 3/2^-, 5/2^-.

  3. Review of meson spectroscopy: quark states and glueballs

    SciTech Connect

    Chanowitz, M.S.

    1981-11-01

    A group of three lectures on hadron spectroscopy are presented. Topics covered include: light L = 0 mesons, light L = 1 mesons, antiquark antiquark quark quark exotics, a catalogue of higher quark antiquark excitations, heavy quarkonium, and glueballs. (GHT)

  4. Flavor Changing Neutral Coupling Mediated Radiative Top Quark Decays at Next-to-Leading Order in QCD

    SciTech Connect

    Drobnak, Jure; Kamenik, Jernej F.; Fajfer, Svjetlana

    2010-06-25

    We compute the branching ratios for the rare top quark decays t{yields}c{gamma} and t{yields}cZ mediated by effective flavor changing neutral couplings at next-to-leading order in QCD, including the effects due to operator mixing. After resumming contributions of the order of [{alpha}{sub s}log({Lambda}/m{sub t})]{sup n}, where {Lambda} is the scale at which the effective operators are generated, using renormalization group methods, we compute finite matrix element corrections and study the effects of experimental kinematic cuts on the extracted branching ratios. We find that the t{yields}c{gamma} decay can also be used to probe the effective operators mediating t{yields}cg processes, since the latter can naturally contribute 10% or more to the radiative decay. Conversely, any experimental signal of t{yields}cg would indicate a natural lower bound on t{yields}cZ, {gamma}.

  5. Two-loop matching factors for light quark masses and three-loop mass anomalous dimensions in the RI/SMOM schemes

    SciTech Connect

    Sturm, C.; Almeida, L.

    2010-04-26

    Light quark masses can be determined through lattice simulations in regularization invariant momentum-subtraction (RI/MOM) schemes. Subsequently, matching factors, computed in continuum perturbation theory, are used in order to convert these quark masses from a RI/MOM scheme to the {ovr MS} scheme. We calculate the two-loop corrections in QCD to these matching factors as well as the three-loop mass anomalous dimensions for the RI/SMOM and RI/SMOM{sub {gamma}{mu}} schemes. These two schemes are characterized by a symmetric subtraction point. Providing the conversion factors in the two different schemes allows for a better understanding of the systematic uncertainties. The two-loop expansion coefficients of the matching factors for both schemes turn out to be small compared to the traditional RI/MOM schemes. For n{sub f} = 3 quark flavors they are about 0.6%-0.7% and 2%, respectively, of the leading order result at scales of about 2 GeV. Therefore, they will allow for a significant reduction of the systematic uncertainty of light quark mass determinations obtained through this approach. The determination of these matching factors requires the computation of amputated Green's functions with the insertions of quark bilinear operators. As a by-product of our calculation we also provide the corresponding results for the tensor operator.

  6. Two-loop matching factors for light quark masses and three-loop mass anomalous dimensions in the regularization invariant symmetric momentum-subtraction schemes

    SciTech Connect

    Almeida, Leandro G.; Sturm, Christian

    2010-09-01

    Light quark masses can be determined through lattice simulations in regularization invariant momentum-subtraction (RI/MOM) schemes. Subsequently, matching factors, computed in continuum perturbation theory, are used in order to convert these quark masses from a RI/MOM scheme to the MS scheme. We calculate the two-loop corrections in QCD to these matching factors as well as the three-loop mass anomalous dimensions for the RI/SMOM and RI/SMOM{sub {gamma}{sub {mu}} }schemes. These two schemes are characterized by a symmetric subtraction point. Providing the conversion factors in the two different schemes allows for a better understanding of the systematic uncertainties. The two-loop expansion coefficients of the matching factors for both schemes turn out to be small compared to the traditional RI/MOM schemes. For n{sub f}=3 quark flavors they are about 0.6%-0.7% and 2%, respectively, of the leading order result at scales of about 2 GeV. Therefore, they will allow for a significant reduction of the systematic uncertainty of light quark mass determinations obtained through this approach. The determination of these matching factors requires the computation of amputated Green's functions with the insertions of quark bilinear operators. As a by-product of our calculation we also provide the corresponding results for the tensor operator.

  7. Radiation properties of Turkish light source facility TURKAY

    NASA Astrophysics Data System (ADS)

    Nergiz, Zafer

    2015-09-01

    The synchrotron light source TURKAY, which is one of the sub-project of Turkish Accelerator Center (TAC), has been supported by Ministry of Development of Turkey since 2006. The facility is designed to generate synchrotron radiation (SR) in range 0.01-60 keV from a 3 GeV storage ring with a beam emittance of 0.51 nm rad. Synchrotron radiation will be produced from the bending magnets and insertion devices in the storage ring. In this paper design studies for possible devices to produce synchrotron radiation and radiation properties of these devices with TURKAY storage ring parameters are presented.

  8. Electroexcitation of nucleon resonances of the [70,1-] multiplet in a light-front relativistic quark model

    DOE PAGES

    Aznauryan, I. G.; Burkert, V. D.

    2017-06-13

    We utilize the light-front relativistic quark model to predict the 3q core contribution to the electroexcitation of nucleon resonances of the [70,1–] multiplet on the proton and neutron at Q2 < 5 GeV2. The investigation is motivated by new experimental data from continuous electron beam accelerator facility large acceptance spectrometer on meson electroproduction for a wide range of the hadronic invariant mass including the full third nucleon resonance region up to √s = 1.8 GeV. For the states N(1520)3/2–, N(1535)1/2–, and N(1675)5/2–, experimental results on the electroexcitation amplitudes on the proton are available for a wide range of Q2. Lastly,more » this allowed us also to quantify the expected meson-baryon contributions to these amplitudes as a function of Q2.« less

  9. Electroexcitation of nucleon resonances of the [70 ,1-] multiplet in a light-front relativistic quark model

    NASA Astrophysics Data System (ADS)

    Aznauryan, I. G.; Burkert, V. D.

    2017-06-01

    We utilize the light-front relativistic quark model to predict the 3 q core contribution to the electroexcitation of nucleon resonances of the [70 ,1-] multiplet on the proton and neutron at Q2<5 GeV2 . The investigation is motivated by new experimental data from continuous electron beam accelerator facility large acceptance spectrometer on meson electroproduction for a wide range of the hadronic invariant mass including the full third nucleon resonance region up to √{s }=1.8 GeV. For the states N (1520 ) 3/2-,N (1535 ) 1/2- , and N (1675 ) 5/2- , experimental results on the electroexcitation amplitudes on the proton are available for a wide range of Q2. This allowed us also to quantify the expected meson-baryon contributions to these amplitudes as a function of Q2.

  10. Branching fractions of semileptonic D and D_s decays from the covariant light-front quark model

    NASA Astrophysics Data System (ADS)

    Cheng, Hai-Yang; Kang, Xian-Wei

    2017-09-01

    Based on the predictions of the relevant form factors from the covariant light-front quark model, we show the branching fractions for the D (D_s) → (P, S, V, A) ℓ ν _ℓ (ℓ =e or μ ) decays, where P denotes the pseudoscalar meson, S the scalar meson with a mass above 1 GeV, V the vector meson and A the axial-vector one. Comparison with the available experimental results are made, and we find an excellent agreement. The predictions for other decay modes can be tested in a charm factory, e.g., the BESIII detector. The future measurements will definitely further enrich our knowledge of the hadronic transition form factors as well as the inner structure of the even-parity mesons ( S and A).

  11. Two-particle twist-3 distribution amplitudes of the pion and kaon in the light-front quark model

    NASA Astrophysics Data System (ADS)

    Choi, Ho-Meoyng; Ji, Chueng-Ryong

    2017-03-01

    We investigate the two-particle twist-3 distribution amplitudes (DAs) of the pseudoscalar mesons, in particular pseudoscalar [ϕ3;M P(x ) ] and pseudotensor [ϕ3;M σ(x ) ] DAs of the pion and kaon, in the light-front quark model based on the variational principle. We find that the behavior of the conformal symmetry in each meson distribution amplitude depends on the chiral-limit characteristics of the light-front trial wave function taken in the variational principle. We specifically take the two different light-front trial wave functions, Gaussian vs power-law type, and discuss their characteristics of the conformal symmetry in the chiral symmetry limit as well as their resulting degree of the conformal symmetry breaking in ϕ3;M P(x ) and ϕ3;M σ(x ) depending on the trial wave function taken in the computation. We present numerical results of transverse moments, Gegenbauer moments and ξ -moments and compare them with other available model estimates. The SU(3) flavor-symmetry breaking effect is also quantified with the numerical computation.

  12. Wigner Distributions of Quarks for Different Polarizations

    NASA Astrophysics Data System (ADS)

    More, Jai; Mukherjee, Asmita; Nair, Sreeraj

    2017-03-01

    We calculate quark Wigner distributions using the light-front wave functions in a dressed quark model. In this model, a proton target is replaced by a simplified spin-1/2 state, namely a quark dressed with a gluon. We calculate the Wigner distributions for different polarization configuration of quark and the target state in this model.

  13. Producing terahertz coherent synchrotron radiation at the Hefei Light Source

    NASA Astrophysics Data System (ADS)

    Xu, De-Rong; Xu, Hong-Liang; Shao, Yan

    2015-07-01

    This paper theoretically proves that an electron storage ring can generate coherent radiation in the THz region using a quick kicker magnet and an AC sextupole magnet. When the vertical chromaticity is modulated by the AC sextupole magnet, the vertical beam collective motion excited by the kicker produces a wavy spatial structure after a number of longitudinal oscillation periods. The radiation spectral distribution was calculated from the wavy bunch parameters at the Hefei Light Source (HLS). When the electron energy is reduced to 400 MeV, extremely strong coherent synchrotron radiation (CSR) at 0.115 THz should be produced. Supported by National Natural Science Foundation of China (11375176)

  14. Revisiting scalar quark hidden sector in light of 750-GeV diphoton resonance

    NASA Astrophysics Data System (ADS)

    Chiang, Cheng-Wei; Ibe, Masahiro; Yanagida, Tsutomu T.

    2016-05-01

    We revisit the model of a CP -even singlet scalar resonance proposed in arXiv:1507.02483 , where the resonance appears as the lightest composite state made of scalar quarks participating in hidden strong dynamics. We show that the model can consistently explain the excess of diphoton events with an invariant mass around 750 GeV reported by both the ATLAS and CMS experiments. We also discuss the nature of the charged composite states in the TeV range which accompany to the neutral scalar. Due to inseparability of the dynamical scale and the mass of the resonance, the model also predicts signatures associated with the hidden dynamics such as leptons, jets along with multiple photons at future collider experiments. We also associate the TeV-scale dynamics behind the resonance with an explanation of dark matter.

  15. Light neutrino masses and mixing angles in SO(10) from the flavor structure of quarks, and the solar neutrino problem

    NASA Astrophysics Data System (ADS)

    Kang, Kyungsik; Shin, Michael

    1987-02-01

    The light neutrino masses and their mixing angles are investigated in a class of SO(10) models with the GRSY seesaw mechanism. The models are motivated by a recent proposal on the structure of the Yukawa couplings postulated from the observed K-M angles and the strong-CP problem. The scale of the seesaw mechanism is found to be bounded from above by the invisible axion scale, leading to a lower bound on the light neutrino masses. The main results are: 0.18eV<=mv3<=100eV, mv1/mv2=O(mu/mc), and mv2/mv3=O((mc/mt)(√mumc/mt)) for the non-hierarchical structure of the right-handed neutrino mass matrix (MN), and mv2/mv3=O(mc/mt) for the hierarchical structure of MN, θeμ≅√me/mμ+exp(iηl')O(√mu/mc), θμt≅√mμ/mt-exp(iη2)O(√mc/mt), and θe/mtθμt, where η1' and η2 are some phases. With present experimental constraints on the mixing angles, νμ-ντ and νe-νμ oscillations may be observable in the next generation of experiments. Regarding the solution to the solar neutrino problem with the MSW amplification mechanism, we find that the relevant neutrino oscillation in the sun should be in the νe-νμ channel, instead of the νe-νt channel which the ``naive seesaw'' model at the GUT scale predicts. Moreover, we also find that, for the structure of MN similar to those of quarks, the existence of a light fourth generation neutrino is inevitable, if the cosmological mass density bound is to be saturated by the light neutrino masses and the solar neutrino problem is solved by the MSW mechanism.

  16. Extraction of light quark masses from sum rule analyses of axial vector and vector current Ward identities

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Tanmoy; Gupta, Rajan; Maltman, Kim

    1998-05-01

    In light of recent lattice results for the light quark masses ms and mu+md, we reexamine the use of sum rules in the extraction of these quantities, and discuss a number of potential problems with existing analyses. The most important issue is that of the overall normalization of the hadronic spectral functions relevant to the sum rule analyses. We explain why previous treatments, which fix this normalization by assuming complete resonance dominance of the continuum threshold region, can potentially overestimate the resonance contributions to spectral integrals by factors as large as ~5. We propose an alternate method of normalization based on an understanding of the role of resonances in chiral perturbation theory which avoids this problem. The second important uncertainty we consider relates to the physical content of the assumed location s0 of the onset of duality with perturbative QCD. We find that the extracted quark masses depend very sensitively on this parameter. We show that the assumption of duality imposes very severe constraints on the shape of the relevant spectral function in the dual region and present rigorous lower bounds for mu+md as a function of s0 based on a combination of these constraints and the requirement of positivity of ρ5(s). In the extractions of ms, we find that the conventional choice of the value of s0 is not physical. For a more reasonable choice of s0, we are not able to find a solution that is stable with respect to variations of the Borel transform parameter. This problem can, unfortunately, be overcome only if the hadronic spectral function is determined up to significantly larger values of s than is currently possible. Finally, we also estimate the error associated with the convergence of perturbative QCD expressions used in the sum rule analyses. Our conclusion is that, taking all of these issues into account, the resulting sum rule estimates for both mu+md and ms could easily have uncertainties as large as a factor of 2

  17. Radiative transport theory for light propagation in luminescent media.

    PubMed

    Sahin, Derya; Ilan, Boaz

    2013-05-01

    We propose a generalization of radiative transport theory to account for light propagation in luminescent random media. This theory accounts accurately for the multiple absorption and reemission of light at different wavelengths and for anisotropic luminescence. To test this theory, we apply it to model light propagation in luminescent solar concentrators (LSCs). The source-iteration method is used in two spatial dimensions for LSCs based on semiconductor quantum dots and aligned nanorods. The LSC performance is studied in detail, including its dependence on particle concentration and the anisotropy of the luminescence. The computational results using this theory are compared with Monte Carlo simulations of photon transport and found to agree qualitatively. The proposed approach offers a deterministic methodology, which can be advantageous for analytic and computational modeling. This approach has potential for more efficient and cost-effective LSCs, as well as in other applications involving luminescent radiation.

  18. Effects of ultraviolet radiation, visible light, and infrared radiation on erythema and pigmentation: a review.

    PubMed

    Sklar, Lindsay R; Almutawa, Fahad; Lim, Henry W; Hamzavi, Iltefat

    2013-01-01

    The effects of ultraviolet radiation, visible light, and infrared radiation on cutaneous erythema, immediate pigment darkening, persistent pigment darkening, and delayed tanning are affected by a variety of factors. Some of these factors include the depth of cutaneous penetration of the specific wavelength, the individual skin type, and the absorption spectra of the different chromophores in the skin. UVB is an effective spectrum to induce erythema, which is followed by delayed tanning. UVA induces immediate pigment darkening, persistent pigment darkening, and delayed tanning. At high doses, UVA (primarily UVA2) can also induce erythema in individuals with skin types I-II. Visible light has been shown to induce erythema and a tanning response in dark skin, but not in fair skinned individuals. Infrared radiation produces erythema, which is probably a thermal effect. In this article we reviewed the available literature on the effects of ultraviolet radiation, visible light, and infrared radiation on the skin in regards to erythema and pigmentation. Much remains to be learned on the cutaneous effects of visible light and infrared radiation.

  19. Decays of heavy vector mesons in the quark confinement model

    NASA Astrophysics Data System (ADS)

    Ivanov, M. A.; Valit, Yu. M.

    1995-12-01

    We analyze the radiative and hadronic decays of vector heavy mesons within the relativistic quark model with confined light quarks. The only adjustable parameters in this approach are the values of constituent masses of heavy quarks ( M c and M b). We adjust them using the available experimental data from CLEO and ARGUS-collaborations for the D *→ Dγ and D *→ Dπ branching ratios. It is found that the value of M c varies approximately in the interval 1.3 GeV< M c<1.65 GeV. We give the predictions for the absolute values of decay widths and compare our results with those obtained in other approaches. Also we consider the heavy quark limit M Q→∞ with E=M H-MQ=const for the decay amplitudes.

  20. Long-distance transmission of light in a scintillator-based radiation detector

    DOEpatents

    Dowell, Jonathan L.; Talbott, Dale V.; Hehlen, Markus P.

    2017-07-11

    Scintillator-based radiation detectors capable of transmitting light indicating the presence of radiation for long distances are disclosed herein. A radiation detector can include a scintillator layer and a light-guide layer. The scintillator layer is configured to produce light upon receiving incident radiation. The light-guide layer is configured to receive light produced by the scintillator layer and either propagate the received light through the radiation detector or absorb the received light and emit light, through fluorescence, that is propagated through the radiation detector. A radiation detector can also include an outer layer partially surrounding the scintillator layer and light-guide layer. The index of refraction of the light-guide layer can be greater than the index of refraction of adjacent layers.

  1. Entropy of radiation: the unseen side of light.

    PubMed

    Delgado-Bonal, Alfonso

    2017-05-10

    Despite the fact that 2015 was the international year of light, no mention was made of the fact that radiation contains entropy as well as energy, with different spectral distributions. Whereas the energy function has been vastly studied, the radiation entropy distribution has not been analysed at the same speed. The Mode of the energy distribution is well known -Wien's law- and Planck's law has been analytically integrated recently, but no similar advances have been made for the entropy. This paper focuses on the characterization of the entropy of radiation distribution from an statistical perspective, obtaining a Wien's like law for the Mode and integrating the entropy for the Median and the Mean in polylogarithms, and calculating the Variance, Skewness and Kurtosis of the function. Once these features are known, the increasing importance of radiation entropy analysis is evidenced in three different interdisciplinary applications: defining and determining the second law Photosynthetically Active Radiation (PAR) region efficiency, measuring the entropy production in the Earth's atmosphere, and showing how human vision evolution was driven by the entropy content in radiation.

  2. Runaway quarks

    SciTech Connect

    Gurarie, V.

    1995-08-01

    When heavy nuclei collide, a quark-gluon plasma is formed. The plasma is subject to a strong electric field due to the charge of the colliding nuclei. The electric field can influence the behavior of the quark-gluon plasma. In particular, we might observe an increased number of quarks moving in the direction of that field, as we do in the standard electron-ion plasma. In this paper we show that this phenomenon, called the runaway quarks, does not exist.

  3. Lighting system with optical fibers based on enery of solar radiation

    NASA Astrophysics Data System (ADS)

    Zajkowski, Maciej

    2003-04-01

    This paper presents concepts of lighting systems using artifial light and natural solar radiation in illuminating rooms; it shortly exhibits systems for obtaining energy of solar radiation with the use of concentrators and heliostats following the Sun in its movement.

  4. Spectrum of second-harmonic radiation generated from incoherent light

    SciTech Connect

    Stabinis, A.; Pyragaite, V.; Tamosauskas, G.; Piskarskas, A.

    2011-10-15

    We report on the development of the theory of second-harmonic generation by an incoherent pump with broad angular and frequency spectra. We show that spatial as well as temporal walk-off effects in a nonlinear crystal result in angular dispersion of the second-harmonic radiation. We demonstrate that the acceptance angle in second-harmonic generation by incoherent light is caused by the width of the pump angular spectrum and the resulting angular dispersion of second-harmonic radiation but does not depend on crystal length. In this case the frequency spectrum of second-harmonic radiation is determined by its angular dispersion and the pump angular spectrum. The theory is supported by an experiment in which a LiIO{sub 3} crystal was pumped by a tungsten halogen lamp.

  5. Applications of Cherenkov Light Emission for Dosimetry in Radiation Therapy

    NASA Astrophysics Data System (ADS)

    Glaser, Adam Kenneth

    Since its discovery in the 1930's, the Cherenkov effect has been paramount in the development of high-energy physics research. It results in light emission from charged particles traveling faster than the local speed of light in a dielectric medium. The ability of this emitted light to describe a charged particle's trajectory, energy, velocity, and mass has allowed scientists to study subatomic particles, detect neutrinos, and explore the properties of interstellar matter. However, only recently has the phenomenon been considered in the practical context of medical physics and radiation therapy dosimetry, where Cherenkov light is induced by clinical x-ray photon, electron, and proton beams. To investigate the relationship between this phenomenon and dose deposition, a Monte Carlo plug-in was developed within the Geant4 architecture for medically-oriented simulations (GAMOS) to simulate radiation-induced optical emission in biological media. Using this simulation framework, it was determined that Cherenkov light emission may be well suited for radiation dosimetry of clinically used x-ray photon beams. To advance this application, several novel techniques were implemented to realize the maximum potential of the signal, such as time-gating for maximizing the signal to noise ratio (SNR) and Cherenkov-excited fluorescence for generating isotropic light release in water. Proof of concept experiments were conducted in water tanks to demonstrate the feasibility of the proposed method for two-dimensional (2D) projection imaging, three-dimensional (3D) parallel beam tomography, large field of view 3D cone beam tomography, and video-rate dynamic imaging of treatment plans for a number of common radiotherapy applications. The proposed dosimetry method was found to have a number of unique advantages, including but not limited to its non-invasive nature, water-equivalence, speed, high-resolution, ability to provide full 3D data, and potential to yield data in-vivo. Based on

  6. Non-contact pumping of light emitters via non-radiative energy transfer

    DOEpatents

    Klimov, Victor I.; Achermann, Marc

    2010-01-05

    A light emitting device is disclosed including a primary light source having a defined emission photon energy output, and, a light emitting material situated near to said primary light source, said light emitting material having an absorption onset equal to or less in photon energy than the emission photon energy output of the primary light source whereby non-radiative energy transfer from said primary light source to said light emitting material can occur yielding light emission from said light emitting material.

  7. Nucleon quark distributions in a covariant quark-diquark model

    SciTech Connect

    Ian Cloet; W. Bentz; Anthony Thomas

    2005-04-01

    Spin-dependent and spin-independent quark light-cone momentum distributions and structure functions are calculated for the nucleon. We utilize a modified Nambu-Jona-Lasinio model in which confinement is simulated by eliminating unphysical thresholds for nucleon decay into quarks. The nucleon bound state is obtained by solving the Faddeev equation in the quark-diquark approximation, where both scalar and axial-vector diquarks channels are included. We find excellent agreement between our model results and empirical data.

  8. Effects of a dressed quark-gluon vertex in vector heavy-light mesons and theory average of the Bc* meson mass

    NASA Astrophysics Data System (ADS)

    Gómez-Rocha, M.; Hilger, T.; Krassnigg, A.

    2016-04-01

    We extend earlier investigations of heavy-light pseudoscalar mesons to the vector case, using a simple model in the context of the Dyson-Schwinger-Bethe-Salpeter approach. We investigate the effects of a dressed quark-gluon vertex in a systematic fashion and illustrate and attempt to quantify corrections beyond the phenomenologically very useful and successful rainbow-ladder truncation. In particular we investigate the dressed quark-photon vertex in such a setup and make a prediction for the experimentally as yet unknown mass of the Bc* , which we obtain at 6.334 GeV well in line with predictions from other approaches. Furthermore, we combine a comprehensive set of results from the theoretical literature. The theoretical average for the mass of the Bc* meson is 6.336 ±0.002 GeV .

  9. Radiation force and torque of light-sheets

    NASA Astrophysics Data System (ADS)

    Mitri, F. G.

    2017-06-01

    The aim of this work is to provide exact analytical closed-form expressions for the longitudinal and transverse optical radiation force and axial spin torque components, for a 2D surface cross-section with arbitrary shape in the field of light-sheet beams of arbitrary wavefront. Generalized partial-wave series expressions for the longitudinal and transverse optical radiation forces and torque are derived based on the multipole expansion in cylindrical wave functions, stemming from series expansions for the incident and scattered electromagnetic fields. The incident light-sheet wavefields are expressed using generalized series involving the beam-shape coefficients (BSCs), and the scattered fields are given in terms of series involving the scattering coefficients of the object. Numerical illustrative examples on a dielectric absorptive circular cylindrical cross-section are provided for different wavefronts, ranging from plane waves, as well as non-paraxial scalar Airy and Gaussian light-sheet beams. The BSCs are derived based on the angular spectrum decomposition method, which provides adequate means to evaluate the radiation force and torque components when the cylinder cross-section is centered on the beam, or shifted off-axially with respect to the incident axis of wave propagation. In essence, the present theoretical analysis provides a complete formalism in the framework of the generalized Lorenz-Mie theory in 2D based upon exact closed-form series expressions to compute the optical force and torque components induced by 2D light-sheets of arbitrary wavefronts, illuminating a scatterer with an arbitrary geometrical cross-section (in 2D). Possible applications are in particle transport and rotation.

  10. Measurement of Radiation - Light Field Congruence using a Photodiode Array

    NASA Astrophysics Data System (ADS)

    Balderson, Michael J.

    Improved treatment techniques in radiation therapy provide incentive to reduce treatment margins, thereby increasing the necessity for more accurate geometrical setup of the linear accelerator and accompanying components. In this thesis, we describe the development of a novel device that enables precise and automated measurement of radiation-light field congruence of medical linear accelerators for the purpose of improving setup accuracy, and standardizing repeated quality control activities. The device consists of a silicon photodiode array, an evaluation board, a data acquisition card, and a laptop. Using the device, we show that the radiation-light field congruence for both 6 and 15 MV beams is within 2 mm on a Varian Clinac 21 EX medical linear accelerator. Because measurements are automated, ambiguities resulting from observer variability are removed, greatly improving the reproducibility of measurements over time and across observers. We expect the device to be useful in providing consistent measurements on linear accelerators used for stereotactic radiosurgery, during the commissioning of new linear accelerators, and as an alternative to film or other commercially available devices for performing monthly or annual quality control checks.

  11. Light-emitting diodes as a radiation source for plants

    NASA Technical Reports Server (NTRS)

    Bula, R. J.; Morrow, R. C.; Tibbitts, T. W.; Barta, D. J.; Ignatius, R. W.; Martin, T. S.

    1991-01-01

    Development of a more effective radiation source for use in plant-growing facilities would be of significant benefit for both research and commercial crop production applications. An array of light-emitting diodes (LEDs) that produce red radiation, supplemented with a photosynthetic photon flux (PPF) of 30 micromoles s-1 m-2 in the 400- to 500-nm spectral range from blue fluorescent lamps, was used effectively as a radiation source for growing plants. Growth of lettuce (Lactuca sativa L. Grand Rapids') plants maintained under the LED irradiation system at a total PPF of 325 micromoles s-1 m-2 for 21 days was equivalent to that reported in the literature for plants grown for the same time under cool-white fluorescent and incandescent radiation sources. Characteristics of the plants, such as leaf shape, color, and texture, were not different from those found with plants grown under cool-white fluorescent lamps. Estimations of the electrical energy conversion efficiency of a LED system for plant irradiation suggest that it may be as much as twice that published for fluorescent systems.

  12. Polarization characteristics of radiation in both 'light' and conventional undulators

    NASA Astrophysics Data System (ADS)

    Potylitsyn, A. P.; Kolchuzhkin, A. M.; Strokov, S. A.

    2017-07-01

    As a rule, an intensity spectrum of undulator radiation (UR) is calculated by using the classical approach, even for electron energy higher than 10 GeV. Such a spectrum is determined by an electron trajectory in an undulator while neglecting radiation loss. Using Planck's law, the UR photon spectrum can be calculated from the obtained intensity spectrum, for both linear and nonlinear regimes. The electron radiation process in a field of strong electromagnetic waves is considered within the quantum electrodynamics framework, using the Compton scattering process or radiation in a 'light' undulator. A comparison was made of the results from using these two approaches, for UR spectra generated by 250-GeV electrons in an undulator with a 11.5-mm period; this comparison shows that they coincide with high accuracy. The characteristics of the collimated UR beam (i.e. spectrum and circular polarization) were simulated while taking into account the discrete process of photon emission along an electron trajectory in both undulator types. Both spectral photon distributions and polarization dependence on photon energy are 'smoothed', in comparison to that expected for a long undulator-the latter of which considers the ILC positron source (ILC Technical Design Report).

  13. Light-emitting diodes as a radiation source for plants

    NASA Technical Reports Server (NTRS)

    Bula, R. J.; Morrow, R. C.; Tibbitts, T. W.; Barta, D. J.; Ignatius, R. W.; Martin, T. S.

    1991-01-01

    Development of a more effective radiation source for use in plant-growing facilities would be of significant benefit for both research and commercial crop production applications. An array of light-emitting diodes (LEDs) that produce red radiation, supplemented with a photosynthetic photon flux (PPF) of 30 micromoles s-1 m-2 in the 400- to 500-nm spectral range from blue fluorescent lamps, was used effectively as a radiation source for growing plants. Growth of lettuce (Lactuca sativa L. Grand Rapids') plants maintained under the LED irradiation system at a total PPF of 325 micromoles s-1 m-2 for 21 days was equivalent to that reported in the literature for plants grown for the same time under cool-white fluorescent and incandescent radiation sources. Characteristics of the plants, such as leaf shape, color, and texture, were not different from those found with plants grown under cool-white fluorescent lamps. Estimations of the electrical energy conversion efficiency of a LED system for plant irradiation suggest that it may be as much as twice that published for fluorescent systems.

  14. Controlling radiation fields in siemans designed light water reactors

    SciTech Connect

    Riess, R.; Marchl, T.

    1995-03-01

    An essential item for the control of radiation fields is the minimization of the use of satellites in the reactor systems of Light Water Reactors (LWRs). A short description of the qualification of Co-replacement materials will be followed by an illustration of the locations where these materials were implemented in Siemens designed LWRs. Especially experiences in PWRs show the immense influence of reduction of cobalt sources on dose rate buildup. The corrosion and the fatique and wear behavior of the replacement materials has not created concern up to now. A second tool to keep occupational radiation doses at a low level in PWRs is the use of the modified B/Li-chemistry. This is practized in Siemens designed plants by keeping the Li level at a max. value of 2 ppm until it reaches a pH (at 300{degrees}C) of {approximately}7.4. This pH is kept constant until the end of the cycle. The substitution of cobalt base alloys and thus the removal of the Co-59 sources from the system had the largest impact on the radiation levels. Nonetheless, the effectiveness of the coolant chemistry should not be neglected either. Several years of successful operation of PWRs with the replacement materials resulted in an occupational radiation exposure which is below 0.5 man-Sievert/plant and year.

  15. Instrumentation for remote sensing solar radiation from light aircraft.

    PubMed

    Howard, J A; Barton, I J

    1973-10-01

    The paper outlines the instrumentation needed to study, from a light aircraft, the solar radiation reflected by ground surfaces and the incoming solar radiation. A global shortwave radiometer was mounted on the roof of the aircraft and a specially designed mount was used to support a downward pointing 70-mm aerial camera, a downward pointing narrow-beam pyranometer, and, sometimes, a downward pointing global shortwave pyranometer. Calibration factors were determined for the three pyranometers by comparison with a standard Angstrom compensation pyrheliometer. Results have indicated trends in the albedos of major plant communities and have shown that the calculated albedo values vary according to whether the downward pointing instrument is narrow-beam or global. Comparisons were also made with albedos measured on the ground.

  16. Manipulating particles with light: radiation and gradient forces

    NASA Astrophysics Data System (ADS)

    Bradshaw, David S.; Andrews, David L.

    2017-05-01

    The manipulation of matter with electromagnetic radiation is a capacity that has been known for over a century. However, the prominence of such optical effects only grew rapidly following the invention of optical tweezers in the 1980s. While both the original theory and the early trapping techniques are based on the radiation force, optical tweezing uses the gradient force. This paper aims to differentiate between these two clearly distinct types of optical forces, which are sometimes confused in the literature. We also discuss three completely separate forms of optical torque that can be applied to a particle, also due to an electromagnetic field. These involve the transfer of either spin or orbital angular momentum from the beam to the particle, depending on the character of the light, or the often overlooked alignment effect that can act on a cylindrical particle due to a gradient force.

  17. Material selection for acoustic radiators that are light and stiff.

    PubMed

    Porter, S P; Markley, D C; Van Tol, D J; Meyer, R J

    2011-01-01

    The headmass is a key element in tonpilz transducer design. As an acoustic radiator, a successful headmass must be built from a material that is both light and stiff. To assess the suitability of ceramics for this application, the authors used the mechanical properties of candidate materials to perform a theoretical comparison based on the flexural behavior of square plates. Although not a comprehensive metric for identifying the best headmass materials, the headmass flexure may be usefully employed as a first-level selection criteria. A software routine based on thin plate and thick plate theory was created to evaluate the flexural behavior in candidate materials.

  18. Light hadron spectra in the constituent quark model with the Kobayashi-Kondo-Maskawa-'t Hooft effective U {sub A} (1) symmetry breaking interaction

    SciTech Connect

    Dmitrasinovic, V. . E-mail: dmitrasin@yahoo.com; Toki, H.

    2006-02-15

    We make a critical comparison of several versions of instanton-induced interactions present in the literature, all based on ITEP group's extension to three colours and flavours of 't Hooft's effective lagrangian, with the predictions of the phenomenological Kobayashi-Kondo-Maskawa (KKM) chiral quark lagrangian. We analyze the effects of all versions of the effective U {sub A} (1) symmetry breaking interactions on light hadron spectra in the non-relativistic constituent quark model. We show that the KKMT force, when used as a residual hyperfine interaction reproduces the correct ordering of pseudoscalar and vector mesons even without explicitly taking chiral symmetry into account. Moreover, the nucleon spectra are also correctly reproduced, only the Roper resonance remains too high, albeit lower than usual, at 1660 MeV. The latter's lower than expected mass is not due to a small excitation energy, as in the Glozman-Riska (GR) model, but to a combination of colour, flavour, and spatial wave function properties that enhance the relevant matrix elements. The KKMT interaction explicitly depends on flavour and spin of the quarks, but unlike the GR flavour-spin one it has a firm footing in QCD. In the process we provide several technical advances, in particular we show the first explicit derivation of the three-body Fierz transformation and apply it to the KKM interaction. We also discuss the ambiguities associated with the colour degree of freedom.

  19. Reconfigurable Array of Radiating Elements (RARE) controlled by light

    NASA Technical Reports Server (NTRS)

    Sadovnik, Lev

    1994-01-01

    The parameters of a silicon - dielectric - metal microstrip line were compared with those of a metal - dielectric - metal microstrip line from an actual FLAPS antenna. The proposed structure has higher losses; this is caused by the electrical conductivity of the illuminated silicon electrode being lower than is the case with a line using a copper top electrode. However, the value of these conductive losses is on the same order as the radiative losses in the microstrip line used in FLAPS antenna. These results point to the feasibility of using the proposed type of a microstrip line in a light-controlled reconfigurable MMW antenna with reasonable energy losses and with a reasonable light flux.

  20. In vitro influence of light radiation on hair steroid concentrations.

    PubMed

    Grass, Juliane; Miller, Robert; Carlitz, Esther H D; Patrovsky, Fabian; Gao, Wei; Kirschbaum, Clemens; Stalder, Tobias

    2016-11-01

    Hair cortisol concentrations (hairF) are considered to be relatively robust to various confounding influences. However, a potentially important covariate factor that has received little attention in this context is hair exposure to ultraviolet/sunlight radiation. We conducted a detailed experimental investigation to examine the effects of light exposure on hair cortisol. In study I, a hydrocortisone-containing solution was subjected to short-term artificial light irradiation for 1, 3, 5, 10, 15, or 30min to evaluate the stability of cortisol molecules due to radiant energy. In study II, hair samples (N=12) were subjected to single short-term artificial light irradiation for 0, 1, or 5h to examine light-induced effects in the hair matrix. In study III, hair samples (N=25) were subjected to long-term naturalistic sunlight radiation over a period of two months (during summer) with daily exposure times of 0, 1, 3, or 6h, respectively. Besides cortisol, studies II & III also examined concentrations of cortisone (hairE), dehydroepiandrosterone (hairDHEA) and progesterone (hairP) in hair, quantified using LC-MS/MS technology. Results across the three studies consistently revealed effects of light irradiation on hair steroid concentrations: Longer light exposure resulted in a decrease of dissolved hydrocortisone (study I) as well as of hairF and hairE (studies II and III). Conversely, hairDHEA and hairP increased with longer natural sunlight exposure times (study III), while this effect was not observed for short-term artificial light irradiation (study II). Combined, our findings imply sunlight exposure as a potential confound in hair steroid research. Given the experimental character of this investigation, the magnitude of this effect under real-life testing conditions is difficult to estimate. To support future investigation into this, we designed a 'sunlight-exposure' questionnaire to share with the research community. The assessment and statistical accounting for

  1. Surface reconstruction from structured-light images for radiation therapy

    NASA Astrophysics Data System (ADS)

    Peshko, Olesya; Anand, Christopher K.; Terlaky, Tamás

    2005-09-01

    To design and deliver proper radiation treatment for cancer patients, knowledge of the body's surface in the affected area is required. Currently, surface information is obtained by using a manually operated tracer. The drawbacks of this contact method include slow operation, and errors in repositioning the patient in an x-ray machine. Utilization of MRI or CT is also possible but expensive. We propose a non-contact, quick, inexpensive method to reconstruct the surface. In our non-contact method, a mask with transparent circular coloured spots and a black background, and an incoherent light source are used to create structured-light images. Colour coding is necessary to establish the correspondence between the projected and the observed patterns, which is essential for surface reconstruction. The deformed light pattern is photographed by an offset camera and analyzed. First, noise reduction is performed because images are noisy due to the low-light conditions and low sensitivity of an off-the-shelf camera. Then, pattern elements (light elliptical spots) are found in the image. We use an inverse polynomial to model the intensity of a light spot, which results in a non-convex, least-squares optimization problem. Next, spots are assigned to a grid according to their colours and location, and errors are corrected using the relative position of the spots. Finally, spatial coordinates of the surface points are computed and surface reconstruction is performed. The described algorithms are implemented as a MATLAB package, which converts the acquired images into a three-dimensional surface. The developed system is inexpensive, and it can easily be mounted on an x-ray machine. The software package can run on any standard PC.

  2. Effect of the magnetic field on the photon radiation from quark-gluon plasma in heavy ion collisions

    NASA Astrophysics Data System (ADS)

    Zakharov, B. G.

    2016-11-01

    We develop a formalism for the photon emission from the quark-gluon plasma with an external electromagnetic field. We then use it to investigate the effect of the magnetic field on the photon emission from the quark-gluon plasma created in AA collisions. We find that even for a very optimistic assumption on the magnitude of the magnetic field generated in AA collisions its effect on the photon emission rate is practically negligible. For this reason the magnetic field cannot generate a significant azimuthal asymmetry in the photon spectrum.

  3. Verification of light & radiation field coincidence quality assurance for radiation therapy by using a-Se based DR system

    NASA Astrophysics Data System (ADS)

    Kim, Jin-Young; Park, Eun-Tae; Choi, Yun-Seon; Cho, Heung-Lae; Ahn, Ki-Jung; Park, Sung-Kwang; Kim, Ji-Na; Suh, Tae-Suk; Kim, Jin-Seon; Hong, Ju-Yeon; Park, Jeong-Eun; Kim, Kyo-Tae; Oh, Kyung-Min; Kim, Hyunjung; Jo, Sun-Mi; Oh, Won-Yong; Jin, Seong-Jin; Cho, Woong

    2015-04-01

    Currently, the American Association of Physicists in Medicine (AAPM) recommends measuring the surface field size once a week by using an analog film in order to verify light and radiation field coincidence in the Quality Assurance (QA) of radiotherapy. However, the use of the film does not allow for a quantitative method of evaluation, and measuring the light field with radiation field detectors in a 2D array is difficult. Therefore, we used an amorphous-Se (a-Se) digital radiation detection system to measure the light and radiation fields simultaneously for a quantitative QA system, and the feasibility of using such a system was confirmed by ensuring the coincidence of the light and the radiation field measurements. The characteristics of the analog film and the a-Se digital radiation detection system were compared by delivering to each doses of 100, 10 monitor units(MU) of radiation at a rate of 400 MU/min to a radiation field 100 × 100 mm2 in size from a 100 cm source-surface distance (SSD). A 0.5 mm to 0.6 mm difference was measured in the X-axis, and a 0.3 mm difference was measured in the Y-axis. The difference in the measurements of the coincidence of light and the radiation field was less than 0.3 mm, which is relatively insignificant. These results indicate that the use of an a-Se digital radiation detection system is adequate for quality assurance of radiotherapy using light and radiation field coincidence. In addition, the experiment is considered to have provided valuable results in that the a-Se based digital radiation detection system enables simple and accurate QA for clinical radiation therapy by assessing the coincidence in the alignment of the light and the radiation fields.

  4. Naive time-reversal odd phenomena in semi-inclusive deep-inelastic scattering from light-cone constituent quark models

    SciTech Connect

    Barbara Pasquini, Peter Schweitzer

    2011-06-01

    We present results for leading-twist azimuthal asymmetries in semi-inclusive lepton-nucleon deep-inelastic scattering due to naively time-reversal odd transverse-momentum dependent parton distribution functions from the light-cone constituent quark model. We carefully discuss the range of applicability of the model, especially with regard to positivity constraints and evolution effects. We find good agreement with available experimental data from COMPASS and HERMES, and present predictions to be tested in forthcoming experiments at Jefferson Lab.

  5. Recovery of radiation-damaged plastic light-guide materials

    NASA Astrophysics Data System (ADS)

    Jahan, M. S.; Stovall, J. C.; Ermer, D. R.; Cooke, D. W.; Bennett, B. L.

    1993-01-01

    Radiation damage and subsequent recovery of PMMA-based and amorphous fluoropolymer (Teflon-AF) light guides (LG) were studied using uv-visible absorption, ESR, and thermally stimulated luminescence (TSL) techniques. No appreciable decay of the γ-ray-induced 420-nm band of the PMMA-based LG was observed in air at room temperature (RT) within a week after irradiation, while it was found to be annealable by isothermal heating at temperatures varying between 40 and 100°C or by heating in a microwave oven. Emission of light was also observed during the isothermal annealing of the LG. X- and γ-irradiated Teflon-AF showed a broad absorption band spreading from 200 to 350 nm with no observable degradation of its optical clarity. In conjunction with ESR measurements the uv absorption was attributed to the radiation-induced peroxy radicals formed at the polytetrafluoroethylene (PTFE) site of the main copolymer chain. The recovery of the Teflon-AF was obtained in a few days by post-irradiation storage in air at room temperature. However, a rapid recovery could be obtained by heating at higher temperatures (RT≤T≤95°C) as suggested by TSL result.

  6. Blue Light and Ultraviolet Radiation Exposure from Infant Phototherapy Equipment.

    PubMed

    Pinto, Iole; Bogi, Andrea; Picciolo, Francesco; Stacchini, Nicola; Buonocore, Giuseppe; Bellieni, Carlo V

    2015-01-01

    Phototherapy is the use of light for reducing the concentration of bilirubin in the body of infants. Although it has become a mainstay since its introduction in 1958, a better understanding of the efficacy and safety of phototherapy applications seems to be necessary for improved clinical practices and outcomes. This study was initiated to evaluate workers' exposure to Optical Radiation from different types of phototherapy devices in clinical use in Italy. During infant phototherapy the staff monitors babies periodically for around 10 min every hour, and fixation of the phototherapy beam light frequently occurs: almost all operators work within 30 cm of the phototherapy source during monitoring procedures, with most of them commonly working at ≤25 cm from the direct or reflected radiation beam. The results of this study suggest that there is a great variability in the spectral emission of equipments investigated, depending on the types of lamps used and some phototherapy equipment exposes operators to blue light photochemical retinal hazard. Some of the equipment investigated presents relevant spectral emission also in the UVA region. Taking into account that the exposure to UV in childhood has been established as an important contributing factor for melanoma risk in adults and considering the high susceptibility to UV-induced skin damage of the newborn, related to his pigmentary traits, the UV exposure of the infant during phototherapy should be "as low as reasonably achievable," considering that it is unnecessary to the therapy. It is recommended that special safety training be provided for the affected employees: in particular, protective eyewear can be necessary during newborn assistance activities carried out in proximity of some sources. The engineering design of phototherapy equipment can be optimized. Specific requirements for photobiological safety of lamps used in the phototherapy equipment should be defined in the safety product standard for such

  7. LIGHT SCATTERING: Observation of multiple scattering of laser radiation from a light-induced jet of microparticles in suspension

    NASA Astrophysics Data System (ADS)

    Kondrat'ev, Andrei V.

    2004-06-01

    Variation in the correlation function of light multiply scattered by a random medium was observed with increasing the incident beam power. The light-induced motion of microparticles in suspension, caused by a high-power laser radiation, serves as an additional factor in the decorrelation of the scattered light. The experimental data are in good agreement with the results of theoretical analysis.

  8. Search for doubly-heavy dibaryons in a quark model

    NASA Astrophysics Data System (ADS)

    Vijande, J.; Valcarce, A.; Richard, J.-M.; Sorba, P.

    2016-08-01

    We study the stability of hexaquark systems containing two heavy quarks and four light quarks within a simple quark model. No bound or metastable state is found. The reason stems from a delicate interplay between chromoelectric and chromomagnetic effects. Our calculation also provides information about anticharmed pentaquarks that are seemingly unbound in simple quark models.

  9. Effect of blue light radiation on curcumin-induced cell death of breast cancer cells

    NASA Astrophysics Data System (ADS)

    Zeng, X. B.; Leung, A. W. N.; Xia, X. S.; Yu, H. P.; Bai, D. Q.; Xiang, J. Y.; Jiang, Y.; Xu, C. S.

    2010-06-01

    In the present study, we have successfully set up a novel blue light source with the power density of 9 mW/cm2 and the wavelength of 435.8 nm and then the novel light source was used to investigate the effect of light radiation on curcumin-induced cell death. The cytotoxicity was investigated 24 h after the treatment of curcumin and blue light radiation together using MTT reduction assay. Nuclear chromatin was observed using a fluorescent microscopy with Hoechst33258 staining. The results showed blue light radiation could significantly enhance the cytotoxicity of curcumin on the MCF-7 cells and apoptosis induction. These findings demonstrated that blue light radiation could enhance curcumin-induced cell death of breast cancer cells, suggesting light radiation may be an efficient enhancer of curcumin in the management of breast cancer.

  10. The Stanford Synchrotron Radiation Laboratory, 20 years of synchrotron light

    SciTech Connect

    Cantwell, K.

    1993-08-01

    The Stanford Synchrotron Radiation Laboratory (SSRL) is now operating as a fully dedicated light source with low emittance electron optics, delivering high brightness photon beams to 25 experimental stations six to seven months per year. On October 1, 1993 SSRL became a Division of the Stanford Linear Accelerator Center, rather than an Independent Laboratory of Stanford University, so that high energy physics and synchrotron radiation now function under a single DOE contract. The SSRL division of SLAC has responsibility for operating, maintaining and improving the SPEAR accelerator complex, which includes the storage ring and a 3 GeV injector. SSRL has thirteen x-ray stations and twelve VUV/Soft x-ray stations serving its 600 users. Recently opened to users is a new spherical grating monochromator (SGM) and a multiundulator beam line. Circularly polarized capabilities are being exploited on a second SGM line. New YB{sub 66} crystals installed in a vacuum double-crystal monochromator line have sparked new interest for Al and Mg edge studies. One of the most heavily subscribed stations is the rotation camera, which has been recently enhanced with a MAR imaging plate detector system for protein crystallography on a multipole wiggler. Under construction is a new wiggler-based structural molecular biology beam line with experimental stations for crystallography, small angle scattering and x-ray absorption spectroscopy. Plans for new developments include wiggler beam lines and associated facilities specialized for environmental research and materials processing.

  11. Light scattering of ultrafine silica particles by VUV synchrotron radiation.

    PubMed

    Shu, Jinian; Wilson, Kevin R; Arrowsmith, Alan N; Ahmed, Musahid; Leone, Stephen R

    2005-06-01

    Vacuum ultraviolet (VUV) light scattering from ultrafine silica particles is studied with an aerosol instrument recently established at the Advanced Light Source (ALS) in Berkeley. Silica particles, size-selected by a differential mobility analyzer, are introduced into vacuum through a set of aerodynamic lenses to form a particle beam. The scattered photons from the crossing area of the VUV synchrotron beam and particle beam are detected with a rotatable VUV photon detector. The angular distributions of scattered photons (ADSP) originating from 70, 100, 200 nm diameter silica particles are measured with 145.9 and 118.1 nm synchrotron radiation. These angular distributions show strong forward scattering. The measured ADSPs are consistent with simulation of Mie scattering. The refractive indices of silica particles, 2.6 + 1.1i and 1.6 + 0.0001i for 118.1 and 145.9 nm, respectively, are obtained by fitting the measured ADSPs; the least average percentage deviations are 18% and 6%, respectively. The scattered fluxes at widely different wavelengths (visible versus VUV) also exhibit clear size sensitivity. Under comparable experimental conditions of photon fluxes and detection efficiencies, limits of particle size detection of 70 and 250 nm are obtained, respectively, when using 118.1 and 532 nm illumination. As anticipated, VUV scattering is a more sensitive probe for ultrafine particles, which will find application in detection of these ubiquitous species beyond the confines of a laboratory.

  12. Detecting heavy quarks

    SciTech Connect

    Benenson, G.; Chau, L.L.; Ludlam, T.; Paige, F.E.; Platner, E.D.; Protopopescu, S.D.; Rehak, P.

    1983-01-01

    In this exercise we examine the performance of a detector specifically configured to tag heavy quark (HQ) jets through direct observations of D-meson decays with a high resolution vertex detector. To optimize the performance of such a detector, we assume the small diamond beam crossing configuration as described in the 1978 ISABELLE proposal, giving a luminosity of 10/sup 32/ cm/sup -2/ sec/sup -1/. Because of the very large backgrounds from light quark (LQ) jets, most triggering schemes at this luminosity require high P/sub perpendicular to/ leptons and inevitably give missing neutrinos. If alternative triggering schemes could be found, then one can hope to find and calculate the mass of objects decaying to heavy quarks. A scheme using the high resolution detector will also be discussed in detail. The study was carried out with events generated by the ISAJET Monte Carlo and a computer simulation of the described detector system. (WHK)

  13. Sound radiation from a water-filled pipe, radiation into light fluid.

    PubMed

    Liu, Bilong; Pan, Jie; Li, Xiaodong; Tian, Jing

    2002-12-01

    This paper is concerned with the sound radiation from a water-filled exhaust pipe. The pipe opening and a plate attached to it form a vibrating surface for this radiation. Fluid-structural coupling between the pipe and enclosed fluid is included in the system modeling, but light fluid assumption is used for sound radiation into the space above the vibrating surface. In this paper, a numerical study on the n = 0 mode in the pipe shows that the wave types associated with this mode have different characteristics in two regions of the nondimensional frequency omega. In the first region of 0radiation from the pipe opening and the attached plate. This paper also demonstrates the effect of these waves and their coupling in the water-filled pipe and across the plate and pipe boundary on the radiated sound pressure. Experimental results obtained in a semi-anechoic room are used to partially validate the theoretical and numerical predictions.

  14. The use of computed radiography plates to determine light and radiation field coincidence

    SciTech Connect

    Kerns, James R.; Anand, Aman

    2013-11-15

    Purpose: Photo-stimulable phosphor computed radiography (CR) has characteristics that allow the output to be manipulated by both radiation and optical light. The authors have developed a method that uses these characteristics to carry out radiation field and light field coincidence quality assurance on linear accelerators.Methods: CR detectors from Kodak were used outside their cassettes to measure both radiation and light field edges from a Varian linear accelerator. The CR detector was first exposed to a radiation field and then to a slightly smaller light field. The light impinged on the detector's latent image, removing to an extent the portion exposed to the light field. The detector was then digitally scanned. A MATLAB-based algorithm was developed to automatically analyze the images and determine the edges of the light and radiation fields, the vector between the field centers, and the crosshair center. Radiographic film was also used as a control to confirm the radiation field size.Results: Analysis showed a high degree of repeatability with the proposed method. Results between the proposed method and radiographic film showed excellent agreement of the radiation field. The effect of varying monitor units and light exposure time was tested and found to be very small. Radiation and light field sizes were determined with an uncertainty of less than 1 mm, and light and crosshair centers were determined within 0.1 mm.Conclusions: A new method was developed to digitally determine the radiation and light field size using CR photo-stimulable phosphor plates. The method is quick and reproducible, allowing for the streamlined and robust assessment of light and radiation field coincidence, with no observer interpretation needed.

  15. Radial Correlations Between Two Quarks

    NASA Astrophysics Data System (ADS)

    Green, A. M.; Koponen, J.; Pennanen, P.; Michael, C.

    2002-04-01

    In nuclear many-body problems the short-range correlation between two nucleons is well described by the corresponding correlation in the two-body problem. Therefore, as a first step in any attempt at an analogous description of many-quark systems, it is necessary to know the two-quark correlation. With this in mind, we study the light quark distribution in a heavy-light meson with a static heavy quark. The charge and matter radial distributions of these heavy-light mesons are measured on a lattice with a light quark mass about that of the strange quark. Both distributions can be well fitted upto r ≈ 0.7 fm with the exponential form wi2 (r), where Wi(r) = A exp(-r/ri). For the charge(c) and matter(m) distributions rc ≈ 0.32(2)fm and rm ≈ 0.24(2)fm. We also discuss the normalisation of the total charge (defined to be unity in the continuum limit) and matter integrated over all space, finding 1.30(5) and 0.4(1) respectively for a lattice spacing ≈ 0.17 fm.

  16. Search for Dimuon Decays of a Light Scalar in Radiative Transitions Y(3S) -> gamma A0

    SciTech Connect

    Aubert, B

    2009-06-02

    The fundamental nature of mass is one of the greatest mysteries in physics. The Higgs mechanism is a theoretically appealing way to account for the different masses of elementary particles and implies the existence of a new, yet unseen particle, the Higgs boson. We search for evidence of a light scalar (e.g. a Higgs boson) in the radiative decays of the narrow {Upsilon}(3S) resonance: {Upsilon}(3S) {yields} {gamma}A{sup 0}, A{sup 0} {yields} {mu}{sup +}{mu}{sup -}. Such an object appears in extensions of the Standard Model, where a light CP-odd Higgs boson naturally couples strongly to b-quarks. We find no evidence for such processes in a sample of 122 x 10{sup 6} {Upsilon}(3S) decays collected by the BABAR collaboration at the PEP-II B-factory, and set 90% C.L. upper limits on the branching fraction product {Beta}({Upsilon}(3S) {yields} {gamma}A{sup 0}) x {Beta}(A{sup 0} {yields} {mu}{sup +}{mu}{sup -}) at (0.25 - 5.2) x 10{sup -6} in the mass range 0.212 {<=} m{sub A{sup 0}} {<=} 9.3 GeV. We also set a limit on the dimuon branching fraction of the {eta}{sub b} meson {Beta}({eta}{sub b} {yields} {mu}{sup +}{mu}{sup -}) < 0.8% at 90% C.L. The results are preliminary.

  17. Hydrogen and helium excitation by EUV radiation for the production of white-light flares

    NASA Technical Reports Server (NTRS)

    Poland, A. I.; Milkey, R. W.; Thompson, W. T.

    1988-01-01

    Non-LTE radiative transfer calculations for hydrogen and helium in a simple model atmosphere are used to demonstrate that EUV radiation cannot be the main energy source for white-light flares. The opacities in the Lyman continuum and the helium I and II continua are found to be much larger than the enhanced opacity in the visible hydrogen continuum. It is shown that the EUV radiation is absorbed before it can have a significant effect on the visible light continuum.

  18. Spectroscopy of diffuse light in dust clouds. Scattered light and the solar neighbourhood radiation field

    NASA Astrophysics Data System (ADS)

    Lehtinen, K.; Mattila, K.

    2013-01-01

    Context. The optical surface brightness of dark nebulae is mainly due to scattering of integrated starlight by classical dust grains. It contains information on the impinging interstellar radiation field, cloud structure, and grain scattering properties. We have obtained spectra of the scattered light from 3500 to 9000 Å in two globules, the Thumbprint Nebula and DC 303.8-14.2. Aims. We use observations of the scattered light to study the impinging integrated starlight spectrum as well as the scattered Hα and other line emissions from all over the sky. We search also for the presence of other than scattered light in the two globules. Methods. We obtained long-slit spectra encompassing the whole globule plus adjacent sky in a one-slit setting, thus enabling efficient elimination of airglow and other foreground sky components. We calculated synthetic integrated starlight spectra for the solar neighbourhood using HIPPARCOS-based stellar distributions and the spectral library of Pickles. Results. Spectra are presented separately for the bright rims and dark cores of the globules. The continuum spectral energy distributions and absorption line spectra can be well modelled with the synthetic integrated starlight spectra. Emission lines of Hα +[N II], Hβ, and [S II] are detected and are interpreted in terms of scattered light plus an in situ warm ionized medium component behind the globules. We detected an excess of emission over the wavelength range 5200-8000 Å in DC 303.8-14.2 but the nature of this emission remains open. Based on observations collected at the European Southern Observatory, Chile, under programme ESO No. 073.C-0239(A). Appendix A is available in electronic form at http://www.aanda.org.

  19. Physics of the Charm Quark

    SciTech Connect

    Carrillo Moreno, Salvador; Vazquez Valencia, Elsa Fabiola

    2006-09-25

    This is a brief summary about the development of the charm quark physics in the area of experimental physics. The summary is centered in what is done by mexican physicists, particularly in the E791 and the FOCUS Experiment at FERMILAB. FOCUS (or E831) was designed to detect states of matter combining one or more charm quarks with light quarks (strange, up, down). The experiment created 10 times as many such particles as in previous experiments and investigated several topics on charm physics including high precision studies of charm semileptonic decays, studies of hadronic charm decays (branching ratios and Daltiz analyses), lifetime measurements of all charm particles, searches for mixing, CP/CPT violation, rare and forbidden decays, spectroscopy of excited charm mesons and baryons, charm production asymmetry measurements, light quark diffractive studies, QCD studies using charm pair events and searches for and upper limits on: charm pentaquarks, double charm baryons, DSJ(2632)

  20. Search for pair production of a new heavy quark that decays into a W boson and a light quark in pp collisions at s=8TeV with the ATLAS detector

    SciTech Connect

    Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Aben, R.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Abreu, R.; Abulaiti, Y.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Adelman, J.; Adomeit, S.; Adye, T.; Affolder, A. A.; Agatonovic-Jovin, T.; Agricola, J.; Aguilar-Saavedra, J. A.; Ahlen, S. P.; Ahmadov, F.; Aielli, G.; Akerstedt, H.; Åkesson, T. P. A.; Akimov, A. V.; Alberghi, G. L.; Albert, J.; Albrand, S.; Alconada Verzini, M. J.; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexopoulos, T.; Alhroob, M.; Alimonti, G.; Alio, L.; Alison, J.; Alkire, S. P.; Allbrooke, B. M. M.; Allport, P. P.; Aloisio, A.; Alonso, A.; Alonso, F.; Alpigiani, C.; Altheimer, A.; Alvarez Gonzalez, B.; Álvarez Piqueras, D.; Alviggi, M. G.; Amadio, B. T.; Amako, K.; Amaral Coutinho, Y.; Amelung, C.; Amidei, D.; Amor Dos Santos, S. P.; Amorim, A.; Amoroso, S.; Amram, N.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anders, J. K.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Angelidakis, S.; Angelozzi, I.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Aperio Bella, L.; Arabidze, G.; Arai, Y.; Araque, J. P.; Arce, A. T. H.; Arduh, F. A.; Arguin, J-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnold, H.; Arratia, M.; Arslan, O.; Artamonov, A.; Artoni, G.; Asai, S.; Asbah, N.; Ashkenazi, A.; Åsman, B.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Augsten, K.; Aurousseau, M.; Avolio, G.; Axen, B.; Ayoub, M. K.; Azuelos, G.; Baak, M. A.; Baas, A. E.; Baca, M. J.; Bacci, C.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Bagiacchi, P.; Bagnaia, P.; Bai, Y.; Bain, T.; Baines, J. T.; Baker, O. K.; Baldin, E. M.; Balek, P.; Balestri, T.; Balli, F.; Balunas, W. K.; Banas, E.; Banerjee, Sw.; Bannoura, A. A. E.; Barak, L.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnes, S. L.; Barnett, B. M.; Barnett, R. M.; Barnovska, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Bartoldus, R.; Barton, A. E.; Bartos, P.; Basalaev, A.; Bassalat, A.; Basye, A.; Bates, R. L.; Batista, S. J.; Batley, J. R.; Battaglia, M.; Bauce, M.; Bauer, F.; Bawa, H. S.; Beacham, J. B.; Beattie, M. D.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, M.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bednyakov, V. A.; Bee, C. P.; Beemster, L. J.; Beermann, T. A.; Begel, M.; Behr, J. K.; Belanger-Champagne, C.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Bender, M.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Benhar Noccioli, E.; Benitez Garcia, J. A.; Benjamin, D. P.; Bensinger, J. R.; Bentvelsen, S.; Beresford, L.; Beretta, M.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Beringer, J.; Bernard, C.; Bernard, N. R.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Berta, P.; Bertella, C.; Bertoli, G.; Bertolucci, F.; Bertsche, C.; Bertsche, D.; Besana, M. I.; Besjes, G. J.; Bessidskaia Bylund, O.; Bessner, M.; Besson, N.; Betancourt, C.; Bethke, S.; Bevan, A. J.; Bhimji, W.; Bianchi, R. M.; Bianchini, L.; Bianco, M.; Biebel, O.; Biedermann, D.; Bieniek, S. P.; Biesuz, N. V.; Biglietti, M.; Bilbao De Mendizabal, J.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biondi, S.; Bjergaard, D. M.; Black, C. W.; Black, J. E.; Black, K. M.; Blackburn, D.; Blair, R. E.; Blanchard, J. -B.; Blanco, J. E.; Blazek, T.; Bloch, I.; Blocker, C.; Blum, W.; Blumenschein, U.; Blunier, S.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. S.; Bocci, A.; Bock, C.; Boehler, M.; Bogaerts, J. A.; Bogavac, D.; Bogdanchikov, A. G.; Bohm, C.; Boisvert, V.; Bold, T.; Boldea, V.; Boldyrev, A. S.; Bomben, M.; Bona, M.; Boonekamp, M.; Borisov, A.; Borissov, G.; Borroni, S.; Bortfeldt, J.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boudreau, J.; Bouffard, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; Boutle, S. K.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozic, I.; Bracinik, J.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Breaden Madden, W. D.; Brendlinger, K.; Brennan, A. J.; Brenner, L.; Brenner, R.; Bressler, S.; Bristow, K.; Bristow, T. M.; Britton, D.; Britzger, D.; Brochu, F. M.; Brock, I.; Brock, R.; Bronner, J.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brosamer, J.; Brost, E.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Bruni, A.; Bruni, G.; Bruschi, M.; Bruscino, N.; Bryngemark, L.; Buanes, T.; Buat, Q.; Buchholz, P.; Buckley, A. G.; Buda, S. I.; Budagov, I. A.; Buehrer, F.; Bugge, L.; Bugge, M. K.; Bulekov, O.; Bullock, D.; Burckhart, H.; Burdin, S.; Burgard, C. D.; Burghgrave, B.; Burke, S.; Burmeister, I.; Busato, E.; Büscher, D.; Büscher, V.; Bussey, P.; Butler, J. M.; Butt, A. I.; Buttar, C. M.; Butterworth, J. M.; Butti, P.; Buttinger, W.; Buzatu, A.; Buzykaev, A. R.; Cabrera Urbán, S.; Caforio, D.; Cairo, V. M.; Cakir, O.; Calace, N.; Calafiura, P.; Calandri, A.; Calderini, G.; Calfayan, P.; Caloba, L. P.; Calvet, D.; Calvet, S.; Camacho Toro, R.; Camarda, S.; Camarri, P.; Cameron, D.; Caminal Armadans, R.; Campana, S.; Campanelli, M.; Campoverde, A.; Canale, V.; Canepa, A.; Cano Bret, M.; Cantero, J.; Cantrill, R.; Cao, T.; Capeans Garrido, M. D. M.; Caprini, I.; Caprini, M.; Capua, M.; Caputo, R.; Carbone, R. M.; Cardarelli, R.; Cardillo, F.; Carli, T.; Carlino, G.; Carminati, L.; Caron, S.; Carquin, E.; Carrillo-Montoya, G. D.; Carter, J. R.; Carvalho, J.; Casadei, D.; Casado, M. P.; Casolino, M.; Castaneda-Miranda, E.; Castelli, A.; Castillo Gimenez, V.; Castro, N. F.; Catastini, P.; Catinaccio, A.; Catmore, J. R.; Cattai, A.; Caudron, J.; Cavaliere, V.; Cavalli, D.; Cavalli-Sforza, M.; Cavasinni, V.; Ceradini, F.; Cerio, B. C.; Cerny, K.; Cerqueira, A. S.; Cerri, A.; Cerrito, L.; Cerutti, F.; Cerv, M.; Cervelli, A.; Cetin, S. A.; Chafaq, A.; Chakraborty, D.; Chalupkova, I.; Chang, P.; Chapman, J. D.; Charlton, D. G.; Chau, C. C.; Chavez Barajas, C. A.; Cheatham, S.; Chegwidden, A.; Chekanov, S.; Chekulaev, S. V.; Chelkov, G. A.; Chelstowska, M. A.; Chen, C.; Chen, H.; Chen, K.; Chen, L.; Chen, S.; Chen, S.; Chen, X.; Chen, Y.; Cheng, H. C.; Cheng, Y.; Cheplakov, A.; Cheremushkina, E.; Cherkaoui El Moursli, R.; Chernyatin, V.; Cheu, E.; Chevalier, L.; Chiarella, V.; Chiarelli, G.; Chiodini, G.; Chisholm, A. S.; Chislett, R. T.; Chitan, A.; Chizhov, M. V.; Choi, K.; Chouridou, S.; Chow, B. K. B.; Christodoulou, V.; Chromek-Burckhart, D.; Chudoba, J.; Chuinard, A. J.; Chwastowski, J. J.; Chytka, L.; Ciapetti, G.; Ciftci, A. K.; Cinca, D.; Cindro, V.; Cioara, I. A.; Ciocio, A.; Cirotto, F.; Citron, Z. H.; Ciubancan, M.; Clark, A.; Clark, B. L.; Clark, P. J.; Clarke, R. N.; Clement, C.; Coadou, Y.; Cobal, M.; Coccaro, A.; Cochran, J.; Coffey, L.; Cogan, J. G.; Colasurdo, L.; Cole, B.; Cole, S.; Colijn, A. P.; Collot, J.; Colombo, T.; Compostella, G.; Conde Muiño, P.; Coniavitis, E.; Connell, S. H.; Connelly, I. A.; Consorti, V.; Constantinescu, S.; Conta, C.; Conti, G.; Conventi, F.; Cooke, M.; Cooper, B. D.; Cooper-Sarkar, A. M.; Cornelissen, T.; Corradi, M.; Corriveau, F.; Corso-Radu, A.; Cortes-Gonzalez, A.; Cortiana, G.; Costa, G.; Costa, M. J.; Costanzo, D.; Côté, D.; Cottin, G.; Cowan, G.; Cox, B. E.; Cranmer, K.; Cree, G.; Crépé-Renaudin, S.; Crescioli, F.; Cribbs, W. A.; Crispin Ortuzar, M.; Cristinziani, M.; Croft, V.; Crosetti, G.; Cuhadar Donszelmann, T.; Cummings, J.; Curatolo, M.; Cúth, J.; Cuthbert, C.; Czirr, H.; Czodrowski, P.; D’Auria, S.; D’Onofrio, M.; Da Cunha Sargedas De Sousa, M. J.; Da Via, C.; Dabrowski, W.; Dafinca, A.; Dai, T.; Dale, O.; Dallaire, F.; Dallapiccola, C.; Dam, M.; Dandoy, J. R.; Dang, N. P.; Daniells, A. C.; Danninger, M.; Dano Hoffmann, M.; Dao, V.; Darbo, G.; Darmora, S.; Dassoulas, J.; Dattagupta, A.; Davey, W.; David, C.; Davidek, T.; Davies, E.; Davies, M.; Davison, P.; Davygora, Y.; Dawe, E.; Dawson, I.; Daya-Ishmukhametova, R. K.; De, K.; de Asmundis, R.; De Benedetti, A.; De Castro, S.; De Cecco, S.; De Groot, N.; de Jong, P.; De la Torre, H.; De Lorenzi, F.; De Pedis, D.; De Salvo, A.; De Sanctis, U.; De Santo, A.; De Vivie De Regie, J. B.; Dearnaley, W. J.; Debbe, R.; Debenedetti, C.; Dedovich, D. V.; Deigaard, I.; Del Peso, J.; Del Prete, T.; Delgove, D.; Deliot, F.; Delitzsch, C. M.; Deliyergiyev, M.; Dell’Acqua, A.; Dell’Asta, L.; Dell’Orso, M.; Della Pietra, M.; della Volpe, D.; Delmastro, M.; Delsart, P. A.; Deluca, C.; DeMarco, D. A.; Demers, S.; Demichev, M.; Demilly, A.; Denisov, S. P.; Derendarz, D.; Derkaoui, J. E.; Derue, F.; Dervan, P.; Desch, K.; Deterre, C.; Dette, K.; Deviveiros, P. O.; Dewhurst, A.; Dhaliwal, S.; Di Ciaccio, A.; Di Ciaccio, L.; Di Domenico, A.; Di Donato, C.; Di Girolamo, A.; Di Girolamo, B.; Di Mattia, A.; Di Micco, B.; Di Nardo, R.; Di Simone, A.; Di Sipio, R.; Di Valentino, D.; Diaconu, C.; Diamond, M.; Dias, F. A.; Diaz, M. A.; Diehl, E. B.; Dietrich, J.; Diglio, S.; Dimitrievska, A.; Dingfelder, J.; Dita, P.; Dita, S.; Dittus, F.; Djama, F.; Djobava, T.; Djuvsland, J. I.; do Vale, M. A. B.; Dobos, D.; Dobre, M.; Doglioni, C.; Dohmae, T.; Dolejsi, J.; Dolezal, Z.; Dolgoshein, B. A.; Donadelli, M.; Donati, S.; Dondero, P.; Donini, J.; Dopke, J.; Doria, A.; Dova, M. T.; Doyle, A. T.; Drechsler, E.; Dris, M.; Dubreuil, E.; Duchovni, E.; Duckeck, G.; Ducu, O. A.; Duda, D.; Dudarev, A.; Duflot, L.; Duguid, L.; Dührssen, M.; Dunford, M.; Duran Yildiz, H.; Düren, M.; Durglishvili, A.; Duschinger, D.; Dutta, B.; Dyndal, M.; Eckardt, C.; Ecker, K. M.; Edgar, R. C.; Edson, W.; Edwards, N. C.; Ehrenfeld, W.; Eifert, T.; Eigen, G.; Einsweiler, K.; Ekelof, T.; El Kacimi, M.; Ellert, M.; Elles, S.; Ellinghaus, F.; Elliot, A. A.; Ellis, N.; Elmsheuser, J.; Elsing, M.; Emeliyanov, D.; Enari, Y.; Endner, O. C.; Endo, M.; Erdmann, J.; Ereditato, A.; Ernis, G.; Ernst, J.; Ernst, M.; Errede, S.; Ertel, E.; Escalier, M.; Esch, H.; Escobar, C.; Esposito, B.; Etienvre, A. I.; Etzion, E.; Evans, H.; Ezhilov, A.; Fabbri, L.; Facini, G.; Fakhrutdinov, R. M.; Falciano, S.; Falla, R. J.; Faltova, J.; Fang, Y.; Fanti, M.; Farbin, A.; Farilla, A.; Farooque, T.; Farrell, S.; Farrington, S. M.; Farthouat, P.; Fassi, F.; Fassnacht, P.; Fassouliotis, D.; Faucci Giannelli, M.; Favareto, A.; Fayard, L.; Fedin, O. L.; Fedorko, W.; Feigl, S.; Feligioni, L.; Feng, C.; Feng, E. J.; Feng, H.; Fenyuk, A. B.; Feremenga, L.; Fernandez Martinez, P.; Fernandez Perez, S.; Ferrando, J.; Ferrari, A.; Ferrari, P.; Ferrari, R.; Ferreira de Lima, D. 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A.; Parodi, F.; Parsons, J. A.; Parzefall, U.; Pasqualucci, E.; Passaggio, S.; Pastore, F.; Pastore, Fr.; Pásztor, G.; Pataraia, S.; Patel, N. D.; Pater, J. R.; Pauly, T.; Pearce, J.; Pearson, B.; Pedersen, L. E.; Pedersen, M.; Pedraza Lopez, S.; Pedro, R.; Peleganchuk, S. V.; Pelikan, D.; Penc, O.; Peng, C.; Peng, H.; Penning, B.; Penwell, J.; Perepelitsa, D. V.; Perez Codina, E.; Pérez García-Estañ, M. T.; Perini, L.; Pernegger, H.; Perrella, S.; Peschke, R.; Peshekhonov, V. D.; Peters, K.; Peters, R. F. Y.; Petersen, B. A.; Petersen, T. C.; Petit, E.; Petridis, A.; Petridou, C.; Petroff, P.; Petrolo, E.; Petrucci, F.; Pettersson, N. E.; Pezoa, R.; Phillips, P. W.; Piacquadio, G.; Pianori, E.; Picazio, A.; Piccaro, E.; Piccinini, M.; Pickering, M. A.; Piegaia, R.; Pignotti, D. T.; Pilcher, J. E.; Pilkington, A. D.; Pin, A. W. J.; Pina, J.; Pinamonti, M.; Pinfold, J. L.; Pingel, A.; Pires, S.; Pirumov, H.; Pitt, M.; Pizio, C.; Plazak, L.; Pleier, M. -A.; Pleskot, V.; Plotnikova, E.; Plucinski, P.; Pluth, D.; Poettgen, R.; Poggioli, L.; Pohl, D.; Polesello, G.; Poley, A.; Policicchio, A.; Polifka, R.; Polini, A.; Pollard, C. S.; Polychronakos, V.; Pommès, K.; Pontecorvo, L.; Pope, B. G.; Popeneciu, G. A.; Popovic, D. S.; Poppleton, A.; Pospisil, S.; Potamianos, K.; Potrap, I. N.; Potter, C. J.; Potter, C. T.; Poulard, G.; Poveda, J.; Pozdnyakov, V.; Pralavorio, P.; Pranko, A.; Prasad, S.; Prell, S.; Price, D.; Price, L. E.; Primavera, M.; Prince, S.; Proissl, M.; Prokofiev, K.; Prokoshin, F.; Protopapadaki, E.; Protopopescu, S.; Proudfoot, J.; Przybycien, M.; Ptacek, E.; Puddu, D.; Pueschel, E.; Puldon, D.; Purohit, M.; Puzo, P.; Qian, J.; Qin, G.; Qin, Y.; Quadt, A.; Quarrie, D. R.; Quayle, W. B.; Queitsch-Maitland, M.; Quilty, D.; Raddum, S.; Radeka, V.; Radescu, V.; Radhakrishnan, S. K.; Radloff, P.; Rados, P.; Ragusa, F.; Rahal, G.; Rajagopalan, S.; Rammensee, M.; Rangel-Smith, C.; Rauscher, F.; Rave, S.; Ravenscroft, T.; Raymond, M.; Read, A. L.; Readioff, N. P.; Rebuzzi, D. M.; Redelbach, A.; Redlinger, G.; Reece, R.; Reeves, K.; Rehnisch, L.; Reichert, J.; Reisin, H.; Rembser, C.; Ren, H.; Renaud, A.; Rescigno, M.; Resconi, S.; Rezanova, O. L.; Reznicek, P.; Rezvani, R.; Richter, R.; Richter, S.; Richter-Was, E.; Ricken, O.; Ridel, M.; Rieck, P.; Riegel, C. J.; Rieger, J.; Rifki, O.; Rijssenbeek, M.; Rimoldi, A.; Rinaldi, L.; Ristić, B.; Ritsch, E.; Riu, I.; Rizatdinova, F.; Rizvi, E.; Robertson, S. H.; Robichaud-Veronneau, A.; Robinson, D.; Robinson, J. E. M.; Robson, A.; Roda, C.; Roe, S.; Røhne, O.; Rolli, S.; Romaniouk, A.; Romano, M.; Romano Saez, S. M.; Romero Adam, E.; Rompotis, N.; Ronzani, M.; Roos, L.; Ros, E.; Rosati, S.; Rosbach, K.; Rose, P.; Rosendahl, P. L.; Rosenthal, O.; Rossetti, V.; Rossi, E.; Rossi, L. P.; Rosten, J. H. N.; Rosten, R.; Rotaru, M.; Roth, I.; Rothberg, J.; Rousseau, D.; Royon, C. R.; Rozanov, A.; Rozen, Y.; Ruan, X.; Rubbo, F.; Rubinskiy, I.; Rud, V. I.; Rudolph, C.; Rudolph, M. S.; Rühr, F.; Ruiz-Martinez, A.; Rurikova, Z.; Rusakovich, N. A.; Ruschke, A.; Russell, H. L.; Rutherfoord, J. P.; Ruthmann, N.; Ryabov, Y. F.; Rybar, M.; Rybkin, G.; Ryder, N. C.; Saavedra, A. F.; Sabato, G.; Sacerdoti, S.; Saddique, A.; Sadrozinski, H. F-W.; Sadykov, R.; Safai Tehrani, F.; Saha, P.; Sahinsoy, M.; Saimpert, M.; Saito, T.; Sakamoto, H.; Sakurai, Y.; Salamanna, G.; Salamon, A.; Salazar Loyola, J. E.; Saleem, M.; Salek, D.; Sales De Bruin, P. H.; Salihagic, D.; Salnikov, A.; Salt, J.; Salvatore, D.; Salvatore, F.; Salvucci, A.; Salzburger, A.; Sammel, D.; Sampsonidis, D.; Sanchez, A.; Sánchez, J.; Sanchez Martinez, V.; Sandaker, H.; Sandbach, R. L.; Sander, H. G.; Sanders, M. P.; Sandhoff, M.; Sandoval, C.; Sandstroem, R.; Sankey, D. P. C.; Sannino, M.; Sansoni, A.; Santoni, C.; Santonico, R.; Santos, H.; Santoyo Castillo, I.; Sapp, K.; Sapronov, A.; Saraiva, J. G.; Sarrazin, B.; Sasaki, O.; Sasaki, Y.; Sato, K.; Sauvage, G.; Sauvan, E.; Savage, G.; Savard, P.; Sawyer, C.; Sawyer, L.; Saxon, J.; Sbarra, C.; Sbrizzi, A.; Scanlon, T.; Scannicchio, D. A.; Scarcella, M.; Scarfone, V.; Schaarschmidt, J.; Schacht, P.; Schaefer, D.; Schaefer, R.; Schaeffer, J.; Schaepe, S.; Schaetzel, S.; Schäfer, U.; Schaffer, A. C.; Schaile, D.; Schamberger, R. D.; Scharf, V.; Schegelsky, V. A.; Scheirich, D.; Schernau, M.; Schiavi, C.; Schillo, C.; Schioppa, M.; Schlenker, S.; Schmieden, K.; Schmitt, C.; Schmitt, S.; Schmitt, S.; Schneider, B.; Schnellbach, Y. J.; Schnoor, U.; Schoeffel, L.; Schoening, A.; Schoenrock, B. D.; Schopf, E.; Schorlemmer, A. L. S.; Schott, M.; Schouten, D.; Schovancova, J.; Schramm, S.; Schreyer, M.; Schuh, N.; Schultens, M. J.; Schultz-Coulon, H. -C.; Schulz, H.; Schumacher, M.; Schumm, B. A.; Schune, Ph.; Schwanenberger, C.; Schwartzman, A.; Schwarz, T. A.; Schwegler, Ph.; Schweiger, H.; Schwemling, Ph.; Schwienhorst, R.; Schwindling, J.; Schwindt, T.; Sciacca, F. G.; Scifo, E.; Sciolla, G.; Scuri, F.; Scutti, F.; Searcy, J.; Sedov, G.; Sedykh, E.; Seema, P.; Seidel, S. C.; Seiden, A.; Seifert, F.; Seixas, J. M.; Sekhniaidze, G.; Sekhon, K.; Sekula, S. J.; Seliverstov, D. M.; Semprini-Cesari, N.; Serfon, C.; Serin, L.; Serkin, L.; Serre, T.; Sessa, M.; Seuster, R.; Severini, H.; Sfiligoj, T.; Sforza, F.; Sfyrla, A.; Shabalina, E.; Shamim, M.; Shan, L. Y.; Shang, R.; Shank, J. T.; Shapiro, M.; Shatalov, P. B.; Shaw, K.; Shaw, S. M.; Shcherbakova, A.; Shehu, C. Y.; Sherwood, P.; Shi, L.; Shimizu, S.; Shimmin, C. O.; Shimojima, M.; Shiyakova, M.; Shmeleva, A.; Shoaleh Saadi, D.; Shochet, M. J.; Shojaii, S.; Shrestha, S.; Shulga, E.; Shupe, M. A.; Shushkevich, S.; Sicho, P.; Sidebo, P. E.; Sidiropoulou, O.; Sidorov, D.; Sidoti, A.; Siegert, F.; Sijacki, Dj.; Silva, J.; Silver, Y.; Silverstein, S. B.; Simak, V.; Simard, O.; Simic, Lj.; Simion, S.; Simioni, E.; Simmons, B.; Simon, D.; Sinervo, P.; Sinev, N. B.; Sioli, M.; Siragusa, G.; Sisakyan, A. N.; Sivoklokov, S. Yu.; Sjölin, J.; Sjursen, T. B.; Skinner, M. B.; Skottowe, H. P.; Skubic, P.; Slater, M.; Slavicek, T.; Slawinska, M.; Sliwa, K.; Smakhtin, V.; Smart, B. H.; Smestad, L.; Smirnov, S. Yu.; Smirnov, Y.; Smirnova, L. N.; Smirnova, O.; Smith, M. N. K.; Smith, R. W.; Smizanska, M.; Smolek, K.; Snesarev, A. A.; Snidero, G.; Snyder, S.; Sobie, R.; Socher, F.; Soffer, A.; Soh, D. A.; Sokhrannyi, G.; Solans, C. A.; Solar, M.; Solc, J.; Soldatov, E. Yu.; Soldevila, U.; Solodkov, A. A.; Soloshenko, A.; Solovyanov, O. V.; Solovyev, V.; Sommer, P.; Song, H. Y.; Soni, N.; Sood, A.; Sopczak, A.; Sopko, B.; Sopko, V.; Sorin, V.; Sosa, D.; Sosebee, M.; Sotiropoulou, C. L.; Soualah, R.; Soukharev, A. M.; South, D.; Sowden, B. C.; Spagnolo, S.; Spalla, M.; Spangenberg, M.; Spanò, F.; Spearman, W. R.; Sperlich, D.; Spettel, F.; Spighi, R.; Spigo, G.; Spiller, L. A.; Spousta, M.; St. Denis, R. D.; Stabile, A.; Staerz, S.; Stahlman, J.; Stamen, R.; Stamm, S.; Stanecka, E.; Stanescu, C.; Stanescu-Bellu, M.; Stanitzki, M. M.; Stapnes, S.; Starchenko, E. A.; Stark, J.; Staroba, P.; Starovoitov, P.; Staszewski, R.; Steinberg, P.; Stelzer, B.; Stelzer, H. J.; Stelzer-Chilton, O.; Stenzel, H.; Stewart, G. A.; Stillings, J. A.; Stockton, M. C.; Stoebe, M.; Stoicea, G.; Stolte, P.; Stonjek, S.; Stradling, A. R.; Straessner, A.; Stramaglia, M. E.; Strandberg, J.; Strandberg, S.; Strandlie, A.; Strauss, E.; Strauss, M.; Strizenec, P.; Ströhmer, R.; Strom, D. M.; Stroynowski, R.; Strubig, A.; Stucci, S. A.; Stugu, B.; Styles, N. A.; Su, D.; Su, J.; Subramaniam, R.; Succurro, A.; Sugaya, Y.; Suk, M.; Sulin, V. V.; Sultansoy, S.; Sumida, T.; Sun, S.; Sun, X.; Sundermann, J. E.; Suruliz, K.; Susinno, G.; Sutton, M. R.; Suzuki, S.; Svatos, M.; Swiatlowski, M.; Sykora, I.; Sykora, T.; Ta, D.; Taccini, C.; Tackmann, K.; Taenzer, J.; Taffard, A.; Tafirout, R.; Taiblum, N.; Takai, H.; Takashima, R.; Takeda, H.; Takeshita, T.; Takubo, Y.; Talby, M.; Talyshev, A. A.; Tam, J. Y. C.; Tan, K. G.; Tanaka, J.; Tanaka, R.; Tanaka, S.; Tannenwald, B. B.; Tannoury, N.; Tapia Araya, S.; Tapprogge, S.; Tarem, S.; Tarrade, F.; Tartarelli, G. F.; Tas, P.; Tasevsky, M.; Tashiro, T.; Tassi, E.; Tavares Delgado, A.; Tayalati, Y.; Taylor, F. E.; Taylor, G. N.; Taylor, P. T. E.; Taylor, W.; Teischinger, F. A.; Teixeira Dias Castanheira, M.; Teixeira-Dias, P.; Temming, K. K.; Temple, D.; Ten Kate, H.; Teng, P. K.; Teoh, J. J.; Tepel, F.; Terada, S.; Terashi, K.; Terron, J.; Terzo, S.; Testa, M.; Teuscher, R. J.; Theveneaux-Pelzer, T.; Thomas, J. P.; Thomas-Wilsker, J.; Thompson, E. N.; Thompson, P. D.; Thompson, R. J.; Thompson, A. S.; Thomsen, L. A.; Thomson, E.; Thomson, M.; Thun, R. P.; Tibbetts, M. J.; Ticse Torres, R. E.; Tikhomirov, V. O.; Tikhonov, Yu. A.; Timoshenko, S.; Tiouchichine, E.; Tipton, P.; Tisserant, S.; Todome, K.; Todorov, T.; Todorova-Nova, S.; Tojo, J.; Tokár, S.; Tokushuku, K.; Tollefson, K.; Tolley, E.; Tomlinson, L.; Tomoto, M.; Tompkins, L.; Toms, K.; Torrence, E.; Torres, H.; Torró Pastor, E.; Toth, J.; Touchard, F.; Tovey, D. R.; Trefzger, T.; Tremblet, L.; Tricoli, A.; Trigger, I. M.; Trincaz-Duvoid, S.; Tripiana, M. F.; Trischuk, W.; Trocmé, B.; Troncon, C.; Trottier-McDonald, M.; Trovatelli, M.; Truong, L.; Trzebinski, M.; Trzupek, A.; Tsarouchas, C.; Tseng, J. C-L.; Tsiareshka, P. V.; Tsionou, D.; Tsipolitis, G.; Tsirintanis, N.; Tsiskaridze, S.; Tsiskaridze, V.; Tskhadadze, E. G.; Tsukerman, I. I.; Tsulaia, V.; Tsuno, S.; Tsybychev, D.; Tudorache, A.; Tudorache, V.; Tuna, A. N.; Tupputi, S. A.; Turchikhin, S.; Turecek, D.; Turra, R.; Turvey, A. J.; Tuts, P. M.; Tykhonov, A.; Tylmad, M.; Tyndel, M.; Ueda, I.; Ueno, R.; Ughetto, M.; Ugland, M.; Ukegawa, F.; Unal, G.; Undrus, A.; Unel, G.; Ungaro, F. C.; Unno, Y.; Unverdorben, C.; Urban, J.; Urquijo, P.; Urrejola, P.; Usai, G.; Usanova, A.; Vacavant, L.; Vacek, V.; Vachon, B.; Valderanis, C.; Valencic, N.; Valentinetti, S.; Valero, A.; Valery, L.; Valkar, S.; Vallecorsa, S.; Valls Ferrer, J. A.; Van Den Wollenberg, W.; Van Der Deijl, P. C.; van der Geer, R.; van der Graaf, H.; van Eldik, N.; van Gemmeren, P.; Van Nieuwkoop, J.; van Vulpen, I.; van Woerden, M. C.; Vanadia, M.; Vandelli, W.; Vanguri, R.; Vaniachine, A.; Vannucci, F.; Vardanyan, G.; Vari, R.; Varnes, E. W.; Varol, T.; Varouchas, D.; Vartapetian, A.; Varvell, K. E.; Vazeille, F.; Vazquez Schroeder, T.; Veatch, J.; Veloce, L. M.; Veloso, F.; Velz, T.; Veneziano, S.; Ventura, A.; Ventura, D.; Venturi, M.; Venturi, N.; Venturini, A.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J. C.; Vest, A.; Vetterli, M. C.; Viazlo, O.; Vichou, I.; Vickey, T.; Vickey Boeriu, O. E.; Viehhauser, G. H. A.; Viel, S.; Vigne, R.; Villa, M.; Villaplana Perez, M.; Vilucchi, E.; Vincter, M. G.; Vinogradov, V. B.; Vivarelli, I.; Vives Vaque, F.; Vlachos, S.; Vladoiu, D.; Vlasak, M.; Vogel, M.; Vokac, P.; Volpi, G.; Volpi, M.; von der Schmitt, H.; von Radziewski, H.; von Toerne, E.; Vorobel, V.; Vorobev, K.; Vos, M.; Voss, R.; Vossebeld, J. H.; Vranjes, N.; Vranjes Milosavljevic, M.; Vrba, V.; Vreeswijk, M.; Vuillermet, R.; Vukotic, I.; Vykydal, Z.; Wagner, P.; Wagner, W.; Wahlberg, H.; Wahrmund, S.; Wakabayashi, J.; Walder, J.; Walker, R.; Walkowiak, W.; Wang, C.; Wang, F.; Wang, H.; Wang, H.; Wang, J.; Wang, J.; Wang, K.; Wang, R.; Wang, S. M.; Wang, T.; Wang, T.; Wang, X.; Wanotayaroj, C.; Warburton, A.; Ward, C. P.; Wardrope, D. R.; Washbrook, A.; Wasicki, C.; Watkins, P. M.; Watson, A. T.; Watson, I. J.; Watson, M. F.; Watts, G.; Watts, S.; Waugh, B. M.; Webb, S.; Weber, M. S.; Weber, S. W.; Webster, J. S.; Weidberg, A. R.; Weinert, B.; Weingarten, J.; Weiser, C.; Weits, H.; Wells, P. S.; Wenaus, T.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M.; Werner, P.; Wessels, M.; Wetter, J.; Whalen, K.; Wharton, A. M.; White, A.; White, M. J.; White, R.; White, S.; Whiteson, D.; Wickens, F. J.; Wiedenmann, W.; Wielers, M.; Wienemann, P.; Wiglesworth, C.; Wiik-Fuchs, L. A. M.; Wildauer, A.; Wilkens, H. G.; Williams, H. H.; Williams, S.; Willis, C.; Willocq, S.; Wilson, A.; Wilson, J. A.; Wingerter-Seez, I.; Winklmeier, F.; Winter, B. T.; Wittgen, M.; Wittkowski, J.; Wollstadt, S. J.; Wolter, M. W.; Wolters, H.; Wosiek, B. K.; Wotschack, J.; Woudstra, M. J.; Wozniak, K. W.; Wu, M.; Wu, M.; Wu, S. L.; Wu, X.; Wu, Y.; Wyatt, T. R.; Wynne, B. M.; Xella, S.; Xu, D.; Xu, L.; Yabsley, B.; Yacoob, S.; Yakabe, R.; Yamada, M.; Yamaguchi, D.; Yamaguchi, Y.; Yamamoto, A.; Yamamoto, S.; Yamanaka, T.; Yamauchi, K.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, H.; Yang, Y.; Yao, W-M.; Yap, Y. C.; Yasu, Y.; Yatsenko, E.; Yau Wong, K. H.; Ye, J.; Ye, S.; Yeletskikh, I.; Yen, A. L.; Yildirim, E.; Yorita, K.; Yoshida, R.; Yoshihara, K.; Young, C.; Young, C. J. S.; Youssef, S.; Yu, D. R.; Yu, J.; Yu, J. M.; Yu, J.; Yuan, L.; Yuen, S. P. Y.; Yurkewicz, A.; Yusuff, I.; Zabinski, B.; Zaidan, R.; Zaitsev, A. M.; Zalieckas, J.; Zaman, A.; Zambito, S.; Zanello, L.; Zanzi, D.; Zeitnitz, C.; Zeman, M.; Zemla, A.; Zeng, Q.; Zengel, K.; Zenin, O.; Ženiš, T.; Zerwas, D.; Zhang, D.; Zhang, F.; Zhang, G.; Zhang, H.; Zhang, J.; Zhang, L.; Zhang, R.; Zhang, X.; Zhang, Z.; Zhao, X.; Zhao, Y.; Zhao, Z.; Zhemchugov, A.; Zhong, J.; Zhou, B.; Zhou, C.; Zhou, L.; Zhou, L.; Zhou, M.; Zhou, N.; Zhu, C. G.; Zhu, H.; Zhu, J.; Zhu, Y.; Zhuang, X.; Zhukov, K.; Zibell, A.; Zieminska, D.; Zimine, N. I.; Zimmermann, C.; Zimmermann, S.; Zinonos, Z.; Zinser, M.; Ziolkowski, M.; Živković, L.; Zobernig, G.; Zoccoli, A.; zur Nedden, M.; Zurzolo, G.; Zwalinski, L.

    2015-12-22

    We present a search for pair production of a new heavy quark ( Q ) that decays into a W boson and a light quark (q) in the final state where one W boson decays leptonically (to an electron or muon plus a neutrino) and the other W boson decays hadronically. The analysis is performed using an integrated luminosity of 20.3 fb-1 of pp collisions at $\\sqrt{s}$ = 8 TeV collected by the ATLAS detector at the LHC. No evidence of $Q\\overline{Q}$ production is observed. New chiral quarks with masses below 690 GeV are excluded at 95% confidence level, assuming BR ( Q → W q ) = 1 . Results are also interpreted in the context of vectorlike quark models, resulting in the limits on the mass of a vectorlike quark in the two-dimensional plane of BR ( Q → W q ) versus BR ( Q → H q ) .

  1. Tracking down hyper-boosted top quarks

    SciTech Connect

    Larkoski, Andrew J.; Maltoni, Fabio; Selvaggi, Michele

    2015-06-05

    The identification of hadronically decaying heavy states, such as vector bosons, the Higgs, or the top quark, produced with large transverse boosts has been and will continue to be a central focus of the jet physics program at the Large Hadron Collider (LHC). At a future hadron collider working at an order-of-magnitude larger energy than the LHC, these heavy states would be easily produced with transverse boosts of several TeV. At these energies, their decay products will be separated by angular scales comparable to individual calorimeter cells, making the current jet substructure identification techniques for hadronic decay modes not directly employable. In addition, at the high energy and luminosity projected at a future hadron collider, there will be numerous sources for contamination including initial- and final-state radiation, underlying event, or pile-up which must be mitigated. We propose a simple strategy to tag such "hyper-boosted" objects that defines jets with radii that scale inversely proportional to their transverse boost and combines the standard calorimetric information with charged track-based observables. By means of a fast detector simulation, we apply it to top quark identification and demonstrate that our method efficiently discriminates hadronically decaying top quarks from light QCD jets up to transverse boosts of 20 TeV. Lastly, our results open the way to tagging heavy objects with energies in the multi-TeV range at present and future hadron colliders.

  2. Tracking down hyper-boosted top quarks

    NASA Astrophysics Data System (ADS)

    Larkoski, Andrew J.; Maltoni, Fabio; Selvaggi, Michele

    2015-06-01

    The identification of hadronically decaying heavy states, such as vector bosons, the Higgs, or the top quark, produced with large transverse boosts has been and will continue to be a central focus of the jet physics program at the Large Hadron Collider (LHC). At a future hadron collider working at an order-of-magnitude larger energy than the LHC, these heavy states would be easily produced with transverse boosts of several TeV. At these energies, their decay products will be separated by angular scales comparable to individual calorimeter cells, making the current jet substructure identification techniques for hadronic decay modes not directly employable. In addition, at the high energy and luminosity projected at a future hadron collider, there will be numerous sources for contamination including initial- and final-state radiation, underlying event, or pile-up which must be mitigated. We propose a simple strategy to tag such "hyper-boosted" objects that defines jets with radii that scale inversely proportional to their transverse boost and combines the standard calorimetric information with charged track-based observables. By means of a fast detector simulation, we apply it to top quark identification and demonstrate that our method efficiently discriminates hadronically decaying top quarks from light QCD jets up to transverse boosts of 20 TeV. Our results open the way to tagging heavy objects with energies in the multi-TeV range at present and future hadron colliders.

  3. Tracking down hyper-boosted top quarks

    DOE PAGES

    Larkoski, Andrew J.; Maltoni, Fabio; Selvaggi, Michele

    2015-06-05

    The identification of hadronically decaying heavy states, such as vector bosons, the Higgs, or the top quark, produced with large transverse boosts has been and will continue to be a central focus of the jet physics program at the Large Hadron Collider (LHC). At a future hadron collider working at an order-of-magnitude larger energy than the LHC, these heavy states would be easily produced with transverse boosts of several TeV. At these energies, their decay products will be separated by angular scales comparable to individual calorimeter cells, making the current jet substructure identification techniques for hadronic decay modes not directlymore » employable. In addition, at the high energy and luminosity projected at a future hadron collider, there will be numerous sources for contamination including initial- and final-state radiation, underlying event, or pile-up which must be mitigated. We propose a simple strategy to tag such "hyper-boosted" objects that defines jets with radii that scale inversely proportional to their transverse boost and combines the standard calorimetric information with charged track-based observables. By means of a fast detector simulation, we apply it to top quark identification and demonstrate that our method efficiently discriminates hadronically decaying top quarks from light QCD jets up to transverse boosts of 20 TeV. Lastly, our results open the way to tagging heavy objects with energies in the multi-TeV range at present and future hadron colliders.« less

  4. Heavy quark production and spectroscopy

    SciTech Connect

    Appel, J.A.

    1993-11-01

    This review covers many new experimental results on heavy flavor production and spectroscopy. It also shows some of the increasingly improved theoretical understanding of results in light of basic perturbative QCD and heavy quark symmetry. At the same time, there are some remaining discrepancies among experiments as well as significant missing information on some of the anticipated lowest lying heavy quark states. Most interesting, perhaps, are some clearly measured production effects awaiting full explanation.

  5. Image Gently, Step Lightly: promoting radiation safety in pediatric interventional radiology.

    PubMed

    Sidhu, Manrita; Goske, Marilyn J; Connolly, Bairbre; Racadio, John; Yoshizumi, Terry T; Strauss, Keith J; Coley, Brian D; Utley, Tara

    2010-10-01

    The Image Gently, Step Lightly campaign is an education and awareness campaign focusing on radiation safety in pediatric interventional radiology. To promote radiation safety by standardizing workflow and encouraging team responsibility, the campaign Website includes a procedural checklist that the medical team may use to review radiation safety steps before each pediatric interventional procedure. Use of this checklist can be an effective tool in the ongoing effort to maximize radiation safety during interventional procedures.

  6. Violet light causes photodegradation of wood beyond the zone affected by ultraviolet radiation

    Treesearch

    Yutaka Kataoka; Makoto Kiguchi; R. Sam Williams; Philip D. Evans

    2007-01-01

    The limited penetration of wood by light explains why the weathering of wood exposed outdoors is a surface phenomenon. Wood is rapidly degraded by short-wave-length UV radiation, but the penetration of light into wood is positively correlated with its wavelength. Hence, subsurface degradation is likely to be caused by longer-wavelength light that still has sufficient...

  7. Residual monomer in a composite resin after light-curing with different sources, light intensities and spectra of radiation.

    PubMed

    Filipov, Ivan A; Vladimirov, Stoyan B

    2006-01-01

    The purpose of this study was to investigate the amount of residual monomer in a composite resin after light-curing with different sources, light intensities and spectra of radiation. The resin specimens (4 mm in diameter; 2 mm thick) (n=5) were inserted in Plexglass matrixes and light-cured with a halogen lamp, LED and PAC units for 40, 40 and 5 s, respectively. The polymerized specimens were ground and 25 mg of each specimen were immersed in 8 mL 96% ethanol for 24 h to extract the residual monomer. The amount of residual monomer was determined by the standard straight line method. The light spectrum of the different LCUs was shot and processed through researches of the absorbation of the standard solutions at a level of lambda=275 nm and their extracts. Data were analyzed statistically by variational dispersion analysis and Tukey-Kramer test at 5% significance level. It was observed that, the halogen lamp produced the smallest amount of monomer under sufficient light intensity. The spectrum of light radiation of PAC was within the limits of 450- 490 nm and was of extremely high intensity. This imposes the use of short-limited light impulses, but also might lead to deterioration quality of polymerization. The LED unit had the best spectral radiation. An increase of light intensity was proved necessary.

  8. Properties of Doubly Heavy Baryons in the Relativistic Quark Model

    SciTech Connect

    Ebert, D.; Faustov, R.N.; Galkin, V.O.; Martynenko, A.P.

    2005-05-01

    Mass spectra and semileptonic decay rates of baryons consisting of two heavy (b or c) and one light quark are calculated in the framework of the relativistic quark model. The doubly heavy baryons are treated in the quark-diquark approximation. The ground and excited states of both the diquark and quark-diquark bound systems are considered. The quark-diquark potential is constructed. The light quark is treated completely relativistically, while the expansion in the inverse heavy-quark mass is used. The weak transition amplitudes of heavy diquarks bb and bc going, respectively, to bc and cc are explicitly expressed through the overlap integrals of the diquark wave functions in the whole accessible kinematic range. The relativistic baryon wave functions of the quark-diquark bound system are used for the calculation of the decay matrix elements, the Isgur-Wise function, and decay rates in the heavy-quark limit.

  9. Leptonic-decay-constant ratio f(K+)/f(π+) from lattice QCD with physical light quarks.

    PubMed

    Bazavov, A; Bernard, C; DeTar, C; Foley, J; Freeman, W; Gottlieb, Steven; Heller, U M; Hetrick, J E; Kim, J; Laiho, J; Levkova, L; Lightman, M; Osborn, J; Qiu, S; Sugar, R L; Toussaint, D; Van de Water, R S; Zhou, R

    2013-04-26

    A calculation of the ratio of leptonic decay constants f(K+)/f(π+) makes possible a precise determination of the ratio of Cabibbo-Kobayashi-Maskawa (CKM) matrix elements |V(us)|/|V(ud)| in the standard model, and places a stringent constraint on the scale of new physics that would lead to deviations from unitarity in the first row of the CKM matrix. We compute f(K+)/f(π+) numerically in unquenched lattice QCD using gauge-field ensembles recently generated that include four flavors of dynamical quarks: up, down, strange, and charm. We analyze data at four lattice spacings a ≈ 0.06, 0.09, 0.12, and 0.15 fm with simulated pion masses down to the physical value 135 MeV. We obtain f(K+)/f(π+) = 1.1947(26)(37), where the errors are statistical and total systematic, respectively. This is our first physics result from our N(f) = 2+1+1 ensembles, and the first calculation of f(K+)/f(π+) from lattice-QCD simulations at the physical point. Our result is the most precise lattice-QCD determination of f(K+)/f(π+), with an error comparable to the current world average. When combined with experimental measurements of the leptonic branching fractions, it leads to a precise determination of |V(us)|/|V(ud)| = 0.2309(9)(4) where the errors are theoretical and experimental, respectively.

  10. Light scattering apparatus and method for determining radiation exposure to plastic detectors

    DOEpatents

    Hermes, Robert E.

    2002-01-01

    An improved system and method of analyzing cumulative radiation exposure registered as pits on track etch foils of radiation dosimeters. The light scattering apparatus and method of the present invention increases the speed of analysis while it also provides the ability to analyze exposure levels beyond that which may be properly measured with conventional techniques. Dosimeters often contain small plastic sheets that register accumulated damage when exposed to a radiation source. When the plastic sheet from the dosimeter is chemically etched, a track etch foil is produced wherein pits or holes are created in the plastic. The number of these pits, or holes, per unit of area (pit density) correspond to the amount of cumulative radiation exposure which is being optically measured by the apparatus. To measure the cumulative radiation exposure of a track etch foil a high intensity collimated beam is passed through foil such that the pits and holes within the track etch foil cause a portion of the impinging light beam to become scattered upon exit. The scattered light is focused with a lens, while the primary collimated light beam (unscattered light) is blocked. The scattered light is focused by the lens onto an optical detector capable of registering the optical power of the scattered light which corresponds to the cumulative radiation to which the track etch foil has been exposed.

  11. A study on computation optimization method for three-dimension scene light field radiation simulation in visible light band

    NASA Astrophysics Data System (ADS)

    Li, Ligang; Ni, Wei; Ma, Xiaoshan; Yang, Zhen; Meng, Xin; Shen, Feifei

    2016-10-01

    The simulation of high accuracy three-dimension (3D) scene optical field radiation distribution can provide the input for camera design, optimization of key parameters and testing of various imaging models. It can benefit for reducing the strong coupling between the imaging models and scene simulation. However, the simulation computation is extremely large and the non-optimization computing method can't performed efficiently. Therefore, a study was carried out from the algorithm optimization and using high-performance platform to accelerate the operation speed. On the one hand, the visibility of scene was pre-computed which include the visibility from the light source to each facet in scene and the visibility between facets. The bounding box accelerate algorithm was adopted which can avoid a lot of time-consuming computation of occlusion in the light field radiation simulation process. On the other hand, since the 3D scene light field radiation simulation was obtained by a large number of light approximation, the algorithms can be divided blocks and processed parallelly. The GPU parallel framework was adopted to realize the simulation model of light field radiation in visible band. Finally, experiments were performed. The result shown the proposed method was more efficient and effective compared with the non-optimization method.

  12. Estimate of Radiative decay of the heavy-light systems

    NASA Astrophysics Data System (ADS)

    Matsuki, T.; Morii, T.; Seo, K.

    We propose a method how to calculate decay amplitudes of the heavy-light mesons associated with one photon or one chiral light hadron, using our semi-relativistic model, which succeeds in predicting and/or reproducing recently discovered all the heavy-light mesons, i.e., D/Ds /B/Bs including the so-called DsJ . We also obtain the relativistic expression for the decay amplitudes by Lorentz-boosting the the rest-frame wave functions.

  13. Masses of constituent quarks confined in open bottom hadrons

    NASA Astrophysics Data System (ADS)

    Borka Jovanović, V.; Borka, D.; Jovanović, P.; Milošević, J.; Ignjatović, S. R.

    2014-12-01

    We apply color-spin and flavor-spin quark-quark interactions to the meson and baryon constituent quarks, and calculate constituent quark masses, as well as the coupling constants of these interactions. The main goal of this paper was to determine constituent quark masses from light and open bottom hadron masses, using the fitting method we have developed and clustering of hadron groups. We use color-spin Fermi-Breit (FB) and flavor-spin Glozman-Riska (GR) hyperfine interaction (HFI) to determine constituent quark masses (especially b quark mass). Another aim was to discern between the FB and GR HFI because our previous findings had indicated that both interactions were satisfactory. Our improved fitting procedure of constituent quark masses showed that on average color-spin (FB) HFI yields better fits. The method also shows the way how the constituent quark masses and the strength of the interaction constants appear in different hadron environments.

  14. Radiation of Electron in the Field of Plane Light Wave

    SciTech Connect

    Zelinsky, A.; Drebot, I.V.; Grigorev, Yu.N.; Zvonareva, O.D.; Tatchyn, R.; /SLAC

    2006-02-24

    Results of integration of a Lorentz equation for a relativistic electron moving in the field of running, plane, linear polarized electromagnetic wave are presented in the paper. It is shown that electron velocities in the field of the wave are almost periodic functions of time. For calculations of angular spectrum of electron radiation intensity expansion of the electromagnetic field in a wave zone into generalized Fourier series was used. Expressions for the radiation intensity spectrum are presented in the paper. Derived results are illustrated for electron and laser beam parameters of NSC KIPT X-ray generator NESTOR. It is shown that for low intensity of the interacting electromagnetic wave the results of energy and angular spectrum calculations in the frame of classical electrodynamics completely coincide with calculation results produced using quantum electrodynamics. Simultaneously, derived expressions give possibilities to investigate dependence of energy and angular Compton radiation spectrum on phase of interaction and the interacting wave intensity.

  15. Physics of the nucleon sea quark distributions

    SciTech Connect

    Vogt, R.

    2000-03-10

    Sea quark distributions in the nucleon have naively been expected to be generated perturbatively by gluon splitting. In this case, there is no reason for the light quark and anti-quark sea distributions to be different. No asymmetries in the strange or heavy quark sea distributions are predicted in the improved parton model. However,recent experiments have called these naive expectations into question. A violation of the Gottfried sum rule has been measured in several experiments, suggesting that (bar u) < (bar d) in the proton. Additionally, other measurements, while not definitive, show that there may be an asymmetry in the strange and anti-strange quark sea distributions. These effects may require nonperturbative explanations. In this review we first discuss the perturbative aspects of the sea quark distributions. We then describe the experiments that could point to nonperturbative contributions to the nucleon sea. Current phenomenological models that could explain some of these effects are reviewed.

  16. HUNTING THE QUARK GLUON PLASMA.

    SciTech Connect

    LUDLAM, T.; ARONSON, S.

    2005-04-11

    The U.S. Department of Energy's Relativistic Heavy Ion Collider (RHIC) construction project was completed at BNL in 1999, with the first data-taking runs in the summer of 2000. Since then the early measurements at RHIC have yielded a wealth of data, from four independent detectors, each with its international collaboration of scientists: BRAHMS, PHENIX, PHOBOS, and STAR [1]. For the first time, collisions of heavy nuclei have been carried out at colliding-beam energies that have previously been accessible only for high-energy physics experiments with collisions of ''elementary'' particles such as protons and electrons. It is at these high energies that the predictions of quantum chromodynamics (QCD), the fundamental theory that describes the role of quarks and gluons in nuclear matter, come into play, and new phenomena are sought that may illuminate our view of the basic structure of matter on the sub-atomic scale, with important implications for the origins of matter on the cosmic scale. The RHIC experiments have recorded data from collisions of gold nuclei at the highest energies ever achieved in man-made particle accelerators. These collisions, of which hundreds of millions have now been examined, result in final states of unprecedented complexity, with thousands of produced particles radiating from the nuclear collision. All four of the RHIC experiments have moved quickly to analyze these data, and have begun to understand the phenomena that unfold from the moment of collision as these particles are produced. In order to provide benchmarks of simpler interactions against which to compare the gold-gold collisions, the experiments have gathered comparable samples of data from collisions of a very light nucleus (deuterium) with gold nuclei, as well as proton-proton collisions, all with identical beam energies and experimental apparatus. The early measurements have revealed compelling evidence for the existence of a new form of nuclear matter at extremely high

  17. Electromagnetic recombination spectra at the quark-hadron phase transition

    NASA Astrophysics Data System (ADS)

    Young, Clint; Pratt, Scott

    2016-10-01

    Because quarks carry electric charge, they can radiate light when they change energy levels, which is exactly what happens when they hadronize. This is true not only in jets but also in heavy-ion collisions, where a thermalized plasma of quarks and gluons cools into a gas of hadrons. First, direct emission of photons from two quarks coalescing from the continuum into pions is calculated using the quark-meson model. The yield of final-state photons to pions is found to be about e2/gπq q 2 , which is on the order of a percent. Second, the yield of photons from the decay of highly excited color singlets, which may exist ephemerally during hadronizaton, is estimated. Because these contributions occur late in the reaction, they should carry significant elliptic flow, which may help explain the large observed flow of direct photons by the PHENIX Collaboration at the BNL Relativistic Heavy Ion Collider. The enhanced emission also helps explain the PHENIX Collaboration's surprisingly large observed γ /π ratio.

  18. Theory of light emission in sonoluminescence as thermal radiation

    SciTech Connect

    Tse, W.-K.; Leung, P. T.

    2006-05-15

    Based on the model proposed by Hilgenfeldt et al. [Nature (London) 398, 401 (1999)], we present here a comprehensive theory of thermal radiation in single-bubble sonoluminescence (SBSL). We first invoke the generalized Kirchhoff's law to obtain the thermal emissivity from the absorption cross section of a multilayered sphere (MLS). A sonoluminescing bubble, whose internal structure is determined from hydrodynamic simulations, is then modeled as a MLS and in turn the thermal radiation is evaluated. Numerical results obtained from simulations for argon bubbles show that our theory successfully captures the major features observed in SBSL experiments.

  19. Theory of light emission in sonoluminescence as thermal radiation

    NASA Astrophysics Data System (ADS)

    Tse, Wang-Kong; Leung, P. T.

    2006-05-01

    Based on the model proposed by Hilgenfeldt [Nature (London) 398, 401 (1999)], we present here a comprehensive theory of thermal radiation in single-bubble sonoluminescence (SBSL). We first invoke the generalized Kirchhoff’s law to obtain the thermal emissivity from the absorption cross section of a multilayered sphere (MLS). A sonoluminescing bubble, whose internal structure is determined from hydrodynamic simulations, is then modeled as a MLS and in turn the thermal radiation is evaluated. Numerical results obtained from simulations for argon bubbles show that our theory successfully captures the major features observed in SBSL experiments.

  20. Theory of light emission in sonoluminescence as thermal radiation.

    PubMed

    Tse, Wang-Kong; Leung, P T

    2006-05-01

    Based on the model proposed by Hilgenfeldt [Nature (London) 398, 401 (1999)], we present here a comprehensive theory of thermal radiation in single-bubble sonoluminescence (SBSL). We first invoke the generalized Kirchhoff's law to obtain the thermal emissivity from the absorption cross section of a multilayered sphere (MLS). A sonoluminescing bubble, whose internal structure is determined from hydrodynamic simulations, is then modeled as a MLS and in turn the thermal radiation is evaluated. Numerical results obtained from simulations for argon bubbles show that our theory successfully captures the major features observed in SBSL experiments.

  1. Spacelike and timelike form factors for the (π0,η ,η')→γ*γ transitions in the light-front quark model

    NASA Astrophysics Data System (ADS)

    Choi, Ho-Meoyng; Ryu, Hui-Young; Ji, Chueng-Ryong

    2017-09-01

    We investigate the (π0,η ,η')→γ*γ transitions both for the spacelike region and the timelike region using the light-front quark model (LFQM). In particular, we present the new direct method to explore the timelike region without resorting to mere analytic continuation from the spacelike region to the timelike region. Our direct calculation in timelike region shows the complete agreement not only with the analytic continuation result from the spacelike region but also with the result from the dispersion relation between the real and imaginary parts of the form factor. For the low energy regime, we compare our LFQM results of the transition form factors (TFFs) for the low timelike momentum transfer region and the slope parameters at q2=0 with the recent experimental data from the Dalitz decays of (π0,η ,η'). For the high energy regime, we incorporate the QCD factorization in our LFQM to examine the asymptotic behavior of TFFs both for the spacelike region and the timelike region. We compare our results with the available experimental data.

  2. SYNCHROTRON RADIATION, FREE ELECTRON LASER, APPLICATION OF NUCLEAR TECHNOLOGY, ETC.: Study on the characteristics of linac based THz light source

    NASA Astrophysics Data System (ADS)

    Zhu, Xiong-Wei; Wang, Shu-Hong; Chen, Sen-Yu

    2009-10-01

    There are many methods based on linac for THz radiation production. As one of the options for the Beijing Advanced Light, an ERL test facility is proposed for THz radiation. In this test facility, there are 4 kinds of methods to produce THz radiation: coherent synchrotron radiation (CSR), synchrotron radiation (SR), low gain FEL oscillator, and high gain SASE FEL. In this paper, we study the characteristics of the 4 kinds of THz light sources.

  3. Radiation monitoring policy at the advanced light source

    SciTech Connect

    Donahue, R.; Heinzelman, K.; Perdue, G.

    1998-02-04

    When the accelerator first began operation it was decided that, until we had the necessary dosimetry data to decide otherwise, we would badge the entire worker and experimental population. Each person was issued a dosimetry badge that contained 4 TLD elements. Badges were processed on a monthly basis. After three years of analyzing a total of 65,000 TLD elements, the decision was made to modify the radiation monitoring policy at the ALS. Only those individuals in the workforce that have any potential for exposure, no matter how small, would be badged. Subsequently, DOE conducted an independent review of the ALS radiation monitoring and dosimetry program. This review concluded that the ALS program, if expanded as proposed, would be adequate under the 10 CFR 835 Rule to establish radiation exposures to an acceptable level of confidence. The review team recommended the ALS provide more comprehensive documentation on the basis for its radiation protection and monitoring program. This document describes the technical justification for that program.

  4. On Einstein, Light Quanta, Radiation, and Relativity in 1905

    ERIC Educational Resources Information Center

    Miller, Arthur I.

    1976-01-01

    Analyzes section 8 of Einstein's relativity paper of 1905, "On the Electrodynamics of Moving Bodies," in its historical context. Relates this section to the rest of the relativity paper, to the genesis of relativity theory, and to contemporaneous work on radiation theory. (Author/MLH)

  5. On Einstein, Light Quanta, Radiation, and Relativity in 1905

    ERIC Educational Resources Information Center

    Miller, Arthur I.

    1976-01-01

    Analyzes section 8 of Einstein's relativity paper of 1905, "On the Electrodynamics of Moving Bodies," in its historical context. Relates this section to the rest of the relativity paper, to the genesis of relativity theory, and to contemporaneous work on radiation theory. (Author/MLH)

  6. Properties of the Top Quark

    SciTech Connect

    Wicke, Daniel; /Wuppertal U., Dept. Math.

    2009-08-01

    The aim of particle physics is the understanding of elementary particles and their interactions. The current theory of elementary particle physics, the Standard Model, contains twelve different types of fermions which (neglecting gravity) interact through the gauge bosons of three forces. In addition a scalar particle, the Higgs boson, is needed for theoretical consistency. These few building blocks explain all experimental results found in the context of particle physics, so far. Nevertheless, it is believed that the Standard Model is only an approximation to a more complete theory. First of all the fourth known force, gravity, has withstood all attempts to be included until now. Furthermore, the Standard Model describes several features of the elementary particles like the existence of three families of fermions or the quantisation of charges, but does not explain these properties from underlying principles. Finally, the lightness of the Higgs boson needed to explain the symmetry breaking is difficult to maintain in the presence of expected corrections from gravity at high scales. This is the so called hierarchy problem. In addition astrophysical results indicate that the universe consists only to a very small fraction of matter described by the Standard Model. Large fractions of dark energy and dark matter are needed to describe the observations. Both do not have any correspondence in the Standard Model. Also the very small asymmetry between matter and anti-matter that results in the observed universe built of matter (and not of anti-matter) cannot be explained until now. It is thus an important task of experimental particle physics to test the predictions of the Standard Model to the best possible accuracy and to search for deviations pointing to necessary extensions or modifications of our current theoretical understanding. The top quark was predicted to exist by the Standard Model as the partner of the bottom quark. It was first observed in 1995 by the

  7. Performance of light sources and radiation sensors under low gravity realized by parabolic airplane flights

    NASA Astrophysics Data System (ADS)

    Hirai, Hiroaki; Kitaya, Yoshiaki; Hirai, Takehiro

    A fundamental study was conducted to establish an experimental system for space farming. Since to ensure optimal light for plant cultivation in space is of grave importance, this study examined the performance of light sources and radiation sensors under microgravity conditions created during the parabolic airplane flight. Three kinds of light sources, a halogen bulb, a fluorescent tube, and blue and red LEDs, and ten models of radiation sensors available in the market were used for the experiment. Surface temperature of the light sources, output signals from the radiation sensors, spectroscopic characteristics were measured at the gravity levels of 0.01, 1.0 and 1.8 G for 20 seconds each during parabolic airplane flights. As a result, the performance of the halogen lamp was affected the most by the gravity level among the three light sources. Under the microgravity conditions which do not raise heat convection, the temperature of the halogen lamp rose and the output of the radiation sensors increased. Spectral distributions of the halogen lamp indicated that peak wavelength appeared the highest at the level of 0.01G, which contributed to the increase in light intensity. In the case of red and blue LEDs, which are promising light sources in space farming, the temperature of both LED chips rose but irradiance from red LED increased and that from blue LED decreased under microgravity conditions due to the different thermal characteristics.

  8. Topology and stability of the Kondo phase in quark matter

    NASA Astrophysics Data System (ADS)

    Yasui, Shigehiro; Suzuki, Kei; Itakura, Kazunori

    2017-07-01

    We investigate properties of the ground state of a light-quark matter with heavy-quark impurities. This system exhibits the "QCD Kondo effect" where the interaction strength between a light quark near the Fermi surface and a heavy quark increases with decreasing energy of the light quark toward the Fermi energy and diverges at some scale near the Fermi energy, called the Kondo scale. Around and below the Kondo scale, we must treat the dynamics nonperturbatively. As a typical nonperturbative method to treat the strong coupling regime, we adopt a mean-field approach where we introduce a condensate, the Kondo condensate, representing a mixing between a light quark and a heavy quark, and determine the ground state in the presence of the Kondo condensate. We show that the ground state is a topologically nontrivial state and the heavy-quark spin forms the hedgehog configuration in the momentum space. We can define the Berry phase for the ground-state wave function in the momentum space, which is associated with a monopole at the position of a heavy quark. We also investigate fluctuations around the mean field in the random-phase approximation and show the existence of (excitonlike) collective excitations made of a hole h of a light quark and a heavy quark Q .

  9. Calcium quarks.

    PubMed

    Niggli, Ernst; Egger, Marcel

    2002-05-01

    Elementary subcellular Ca2+ signals arising from the opening of single ion channels may offer the possibility to examine the stochastic behavior and the microscopic chemical reaction rates of these channel proteins in their natural environment. Such an analysis can yield detailed information about the molecular function that cannot be derived from recordings obtained from an ensemble of channels. In this review, we summarize experimental evidence suggesting that Ca2+ sparks, elementary Ca2+ signaling events of cardiac and skeletal muscle excitation contraction coupling, may be comprised of a number of smaller Ca2+ signaling events, the Ca2+ quarks.

  10. Synchrotron radiation in strongly coupled conformal field theories

    SciTech Connect

    Athanasiou, Christiana; Chesler, Paul M.; Liu, Hong; Rajagopal, Krishna; Nickel, Dominik

    2010-06-15

    Using gauge/gravity duality, we compute the energy density and angular distribution of the power radiated by a quark undergoing circular motion in strongly coupled N=4 supersymmetric Yang-Mills theory. We compare the strong coupling results to those at weak coupling, finding them to be very similar. In both regimes, the angular distribution of the radiated power is in fact similar to that of synchrotron radiation produced by an electron in circular motion in classical electrodynamics: the quark emits radiation in a narrow beam along its velocity vector with a characteristic opening angle {alpha}{approx}1/{gamma}. To an observer far away from the quark, the emitted radiation appears as a short periodic burst, just like the light from a lighthouse does to a ship at sea. Our strong coupling results are valid for any strongly coupled conformal field theory with a dual classical gravity description.

  11. Responses of Crepis japonica induced by supplemental blue light and UV-A radiation.

    PubMed

    Constantino, L F da S; Nascimento, L B Dos S; Casanova, L M; Moreira, N Dos S; Menezes, E A; Esteves, R L; Costa, S S; Tavares, E S

    2017-02-15

    Crepis japonica (L.) D.C. (Asteraceae), a weed with antioxidant, antiallergenic, antiviral and antitumor properties displays both medicinal properties and nutritional value. This study aims to assess the effects of a supplementation of blue light and UV-A radiation on the growth, leaf anatomical structure and phenolic profile of the aerial parts of Crepis japonica. Plants were grown under two light treatments: W (control - white light), W + B (white light supplemented with blue light) and W + UV-A (white light supplemented with UV-A radiation). We recorded the length, width, and weight of fresh and dry leaves, the thickness of the epidermis and mesophyll, and stomata density. The phenolic profiles of the aqueous extracts of the aerial parts were analyzed by HPLC-DAD. There was an increase in the leaf size, stomatal density, and phenolic production, and a thickening of the mesophyll and epidermis. UV-A radiation increased the phenolic production more than blue light. Blue light and UV-A radiation both improved the production of caffeic acid by about 6 and 3 times, respectively, in comparison to control. This compound was first reported as a constituent of the extract from the aerial parts together with caftaric acid. UV-A also promoted the production of chlorogenic acid (about 1.5 times in comparison to the control). We observed that the morphological and chemical parameters of C. japonica are modified in response to blue light and UV-A radiation, which can be used as tools in the cultivation of this species in order to improve its medicinal properties and nutritional value.

  12. Radiative and Excited State Charmonium Physics

    SciTech Connect

    Jozef Dudek

    2007-07-30

    Renewed interest in the spectroscopy of charmonium has arisen from recent unexpected observations at $e^+e^-$ colliders. Here we report on a series of works from the previous two years examining the radiative physics of charmonium states as well as the mass spectrum of states of higher spin and internal excitation. Using new techniques applied to Domain-Wall and Clover quark actions on quenched isotropic and anisotropic lattices, radiative transitions and two-photon decays are considered for the first time. Comparisons are made with experimental results and with model approaches. Forthcoming application to the light-quark sector of relevance to experiments like Jefferson Lab's GlueX is discussed.

  13. Quantitative estimation of UV light dose concomitant to irradiation with ionizing radiation

    NASA Astrophysics Data System (ADS)

    Petin, Vladislav G.; Morozov, Ivan I.; Kim, Jin Kyu; Semkina, Maria A.

    2011-01-01

    A simple mathematical model for biological estimation of UV light dose concomitant to ionizing radiation was suggested. This approach was applied to determine the dependency of equivalent UV light dose accompanied by 100 Gy of ionizing radiation on energy of sparsely ionizing radiation and on volume of the exposed cell suspension. It was revealed that the relative excitation contribution to the total lethal effect and the value of UV dose was greatly increased with an increase in energy of ionizing radiation and volume of irradiated suspensions. It is concluded that these observations are in agreement with the supposition that Čerenkov emission is responsible for the production of UV light damage and the phenomenon of photoreactivation observed after ionizing exposure of bacterial and yeast cells hypersensitive to UV light. A possible synergistic interaction of the damages produced by ionizations and excitations as well as a probable participation of UV component of ionizing radiation in the mechanism of hormesis and adaptive response observed after ionizing radiation exposure is discussed.

  14. SU-E-T-361: Energy Dependent Radiation/light-Field Misalignment On Truebeam Linear Accelerator

    SciTech Connect

    Sperling, N; Tanny, S; Parsai, E

    2015-06-15

    Purpose: Verifying the co-incidence of the radiation and light field is recommended by TG-142 for monthly and annual checks. On a digital accelerator, it is simple to verify that beam steering settings are consistent with accepted and commissioned values. This fact should allow for physicists to verify radiation-light-field co-incidence for a single energy and accept that Result for all energies. We present a case where the radiation isocenter deviated for a single energy without any apparent modification to the beam steering parameters. Methods: The radiation isocenter was determined using multiple Methods: Gafchromic film, a BB test, and radiation profiles measured with a diode. Light-field borders were marked on Gafchromic film and then irradiated for all photon energies. Images of acceptance films were compared with films taken four months later. A phantom with a radio-opaque BB was aligned to isocenter using the light-field and imaged using the EPID for all photon energies. An unshielded diode was aligned using the crosshairs and then beam profiles of multiple field sizes were obtained. Field centers were determined using Omni-Pro v7.4 software, and compared to similar scans taken during commissioning. Beam steering parameter files were checked against backups to determine that the steering parameters were unchanged. Results: There were no differences between the configuration files from acceptance. All three tests demonstrated that a single energy had deviated from accepted values by 0.8 mm in the inline direction. The other two energies remained consistent with previous measurements. The deviated energy was re-steered to be within our clinical tolerance. Conclusions: Our study demonstrates that radiation-light-field coincidence is an energy dependent effect for modern linacs. We recommend that radiation-light-field coincidence be verified for all energies on a monthly basis, particularly for modes used to treat small fields, as these may drift without

  15. Effects of light-emitting diode radiations on human retinal pigment epithelial cells in vitro.

    PubMed

    Chamorro, Eva; Bonnin-Arias, Cristina; Pérez-Carrasco, María Jesús; Muñoz de Luna, Javier; Vázquez, Daniel; Sánchez-Ramos, Celia

    2013-01-01

    Human visual system is exposed to high levels of natural and artificial lights of different spectra and intensities along lifetime. Light-emitting diodes (LEDs) are the basic lighting components in screens of PCs, phones and TV sets; hence it is so important to know the implications of LED radiations on the human visual system. The aim of this study was to investigate the effect of LEDs radiations on human retinal pigment epithelial cells (HRPEpiC). They were exposed to three light-darkness (12 h/12 h) cycles, using blue-468 nm, green-525 nm, red-616 nm and white light. Cellular viability of HRPEpiC was evaluated by labeling all nuclei with DAPI; Production of reactive oxygen species (ROS) was determined by H2DCFDA staining; mitochondrial membrane potential was quantified by TMRM staining; DNA damage was determined by H2AX histone activation, and apoptosis was evaluated by caspases-3,-7 activation. It is shown that LED radiations decrease 75-99% cellular viability, and increase 66-89% cellular apoptosis. They also increase ROS production and DNA damage. Fluorescence intensity of apoptosis was 3.7% in nonirradiated cells and 88.8%, 86.1%, 83.9% and 65.5% in cells exposed to white, blue, green or red light, respectively. This study indicates three light-darkness (12 h/12 h) cycles of exposure to LED lighting affect in vitro HRPEpiC.

  16. Improved light extraction with nano-particles offering directional radiation diagrams

    SciTech Connect

    Jouanin, A.; Hugonin, J. P.; Besbes, M.; Lalanne, P.

    2014-01-13

    We propose a unique approach for light extraction, using engineered nano-particles to efficiently decouple the light guided in transverse-magnetic guided modes into free-space radiation modes that leak out normally to the thin-film stacks. The underlying mechanism takes advantage of a small electric field variation at the nano-particle scale and induces a “polarization conversion,” which renders the induced dipole moment perpendicular to the polarization of the incident light. Our analysis is supported by 2D fully vectorial computational results. Potential applications for light emitting or photovoltaic devices are outlined.

  17. Study of the radiative pion decay

    SciTech Connect

    Chen, Chuan-Hung; Geng, Chao-Qiang; Lih, Chong-Chung

    2011-04-01

    We study the radiative pion decay of {pi}{sup +}{yields}e{sup +}{nu}{sub e}{gamma} in the light-front quark model. We also summarize the result in the chiral perturbation theory. The vector and axial-vector hadronic form factors (F{sub V,A}) for the {pi}{yields}{gamma} transition are evaluated in the whole allowed momentum transfer. In terms of these momentum dependent form factors, we calculate the decay branching ratio and compare our results with the experimental data and other theoretical predictions in the literature. We also constrain the possible size of the tensor interaction in the light-front quark model.

  18. Effect of laser-radiation polarization on the nonlinear scattering of light in nanodiamond suspensions

    NASA Astrophysics Data System (ADS)

    Mikheev, G. M.; Vanyukov, V. V.; Mogileva, T. N.; Puzyr', A. P.; Bondar', V. S.; Svirko, Yu. P.

    2014-07-01

    The effect of laser radiation polarization on the nonlinear scattering of light in aqueous suspensions of detonation nanodiamonds (DNDs) in a regime of optical power limiting (OPL) has been studied. It is established that the nonlinear transmission coefficient of DND suspension in the OPL regime in a field of nanosecond laser pulses with a wavelength of 532 nm is independent of the polarization of incident radiation. The nonlinear scattering of light observed at an angle of 90° in the plane perpendicular to the plane of polarization of the incident radiation depends on the polarization angle in accordance with a trigonometric law. It is shown that the ratio of the signals of scattered radiation for the vertical and horizontal polarizations exhibits nonmonotonic dependence on the laser-beam power density. The results are explained by the Rayleigh-Mie scattering and a change in the size of scattering centers as a result of the effect of a laser upon the DND suspension.

  19. Effect of radiation light characteristics on surface hardness of paint-on resin for shade modification.

    PubMed

    Arikawa, Hiroyuki; Kanie, Takahito; Fujii, Koichi; Ban, Seiji

    2005-12-01

    The purpose of this study was to investigate the effect of radiation light characteristics--of different types of clinical light-curing unit--on polymerization efficiency, as determined by the surface hardness of light-cured paint-on resins. Four shades of paint-on resin for shade modification of restorative resins were used. Materials were cured using one laboratory and three clinical light-curing units with different light sources, namely tungsten-halogen, LED, plasma arc, and xenon flash lamps. Knoop hardness measurements were taken at both the top and bottom surfaces of the specimens to assess the mechanical properties and degree of polymerization. Both LED and plasma arc light units caused significantly poorer surface hardness than the halogen and laboratory xenon lights. In addition, the transparent shade was more sensitive to surface hardness than other chromatic shades. Our results indicated that the polymerization efficiency of paint-on resin was significantly influenced by the radiation light characteristics of clinical light-curing units.

  20. Visible light neutralizes the effect produced by ultraviolet radiation in proteins.

    PubMed

    Espinoza, J Horacio; Mercado-Uribe, Hilda

    2017-02-01

    The damage produced by UV-C radiation (100-280nm) in organisms and cells is a well known fact. The main reactions of proteins to UV-C radiation consist in the alteration of their secondary structures, exposure of hydrophobic residues, unfolding and aggregation. Furthermore, it has been found that electromagnetic radiation of lower energy (visible light, where wavelengths are between 400 and 750nm) also induces different disturbances in biomolecules. For instance, it has been observed that blue visible light from emitting diodes (LEDs) produces severe damage in murine cone photoreceptor-derived cells, and it can be even more harmful for some organisms than UV radiation. Recently, it has been found that the exposure of proteins to green and red light produces conformational changes, considerably increasing their cohesion enthalpies. This is presumably due to the strengthening of the hydrogen bonds and the formation of new ones. Therefore, it seems that visible light acts contrary to what it is observed for UV-C: instead of unfolding the proteins it folds them further, halting the damage produced by UV-C. This can be understood if we consider the modification of the folding energy-landscape; visible light induces the descent of the proteins into deeper states impeding the unfolding produced by UV-C.

  1. Observation of strong radiation pressure forces from squeezed light on a mechanical oscillator

    NASA Astrophysics Data System (ADS)

    Clark, Jeremy B.; Lecocq, Florent; Simmonds, Raymond W.; Aumentado, José; Teufel, John D.

    2016-07-01

    In quantum-enhanced sensing, non-classical states are used to improve the sensitivity of a measurement. Squeezed light, in particular, has proved a useful resource in enhanced mechanical displacement sensing, although the fundamental limit to this enhancement due to the Heisenberg uncertainty principle has not been encountered experimentally. Here we use a microwave cavity optomechanical system to observe the squeezing-dependent radiation pressure noise that necessarily accompanies any quantum enhancement of the measurement precision and ultimately limits the measurement noise performance. By increasing the measurement strength so that radiation pressure forces dominate the thermal motion of the mechanical oscillator, we exploit the optomechanical interaction to implement an efficient quantum nondemolition measurement of the squeezed light. Thus, our results show how the mechanical oscillator improves the measurement of non-classical light, just as non-classical light enhances the measurement of the motion.

  2. Frequency of light-flashes induced by Cerenkov radiation from heavy cosmic-ray nuclei

    NASA Technical Reports Server (NTRS)

    Madey, R.; Mcnulty, P. J.

    1972-01-01

    The expected frequency was calculated for light flashes induced in the dark-adapted eye by Cerenkov radiation from the flux of heavy nuclei that exists in space beyond the geomagnetic field. The expected frequency of light flashes depends on the threshold number of photons that must be absorbed in a rod cluster. The results of the calculation are presented as a curve of the mean frequency of light flashes versus the threshold number of absorbed photons. The results are not sensitive to variations in the path length from 5 to 15 grams per square centimeter of water-equivalent before the nucleus reaches the retina. Calculations were based on the fluxes and energy spectra of galactic cosmic ray nuclei of helium to iron, measured at a time of minimum solar modulation. The expected light flash frequencies induced by Cerenkov radiation are consistent with the frequencies reported by the astronauts on Apollo missions 11 through 14.

  3. Modified blackbody radiation spectrum of a selective emitter with application to incandescent light source design.

    PubMed

    Matsumoto, Takahiro; Tomita, Makoto

    2010-06-21

    Using a selective emitter with high emissivity in the visible wavelength region and low emissivity in the infrared wavelength region, we reduced the infrared contribution to the blackbody radiation spectrum and shifted the peak emission to shorter wavelengths. We made precise measurements of thermal radiation loss. The conversion efficiency from input electric power to visible light radiation was quantitatively evaluated with high accuracy. Using the proposed selective emitter, the conversion efficiencies in excess of 95% could be produced. Our conclusions pave the way for the design of incandescent lamps with luminous efficiencies exceeding 400 lm/W.

  4. On the ideality factor of the radiative recombination current in semiconductor light-emitting diodes

    SciTech Connect

    Lee, Gyeong Won; Shim, Jong-In; Shin, Dong-Soo

    2016-07-18

    While there have been many discussions on the standard Si pn-diodes, little attention has been paid and confusion still arises on the ideality factor of the radiative recombination current in semiconductor light-emitting diodes (LEDs). In this letter, we theoretically demonstrate and experimentally confirm by using blue and infrared semiconductor LEDs that the ideality factor of the radiative recombination current is unity especially for low-current-density ranges. We utilize the data of internal quantum efficiency measured by the temperature-dependent electroluminescence to separate the radiative current component from the total current.

  5. Quark description of hadronic phases

    SciTech Connect

    Schaefer, T.; Wilczek, F.

    1999-10-01

    We extend our proposal that major universality classes of hadronic matter can be understood, and in favorable cases calculated, directly in the microscopic quark variables, to allow for a splitting between strange and light quark masses. A surprisingly simple but apparently viable picture emerges, featuring essentially three phases, distinguished by whether strangeness is conserved (standard nuclear matter), conserved modulo 2 (hypernuclear matter), or locked to color (color flavor locking). These are separated by sharp phase transitions. There is also, potentially, a quark phase matching hadronic {ital K} condensation. The smallness of the secondary gap in two-flavor color superconductivity corresponds to the disparity between the primary dynamical energy scales of QCD and the much smaller energy scales of nuclear physics. {copyright} {ital 1999} {ital The American Physical Society}

  6. Gamma radiation and photospheric white-light flare continuum

    NASA Technical Reports Server (NTRS)

    Hudson, H. S.; Dwivedi, B. N.

    1982-01-01

    It is noted that recent gamma-ray observations of solar flares have provided a better means for estimating the heating of the solar atmosphere by energetic protons. This type of heating has been suggested as the explanation of the continuum emission of the white-light flare. The effects on the photosphere of high-energy particles capable of producing the intense gamma-ray emission observed in the flare of July 11, 1978, are analyzed. A simple energy-balance argument is used, and hydrogen ionization is taken into account. It is found that energy deposition increases with height for the inferred proton spectra and is not strongly dependent upon the assumed angle of incidence. At the top of the photosphere, the computed energy inputs fall in the range 10-100 ergs/cu cm-s.

  7. Inversion of the radiative transfer equation for polarized light

    NASA Astrophysics Data System (ADS)

    del Toro Iniesta, Jose Carlos; Ruiz Cobo, Basilio

    2016-12-01

    Since the early 1970s, inversion techniques have become the most useful tool for inferring the magnetic, dynamic, and thermodynamic properties of the solar atmosphere. Inversions have been proposed in the literature with a sequential increase in model complexity: astrophysical inferences depend not only on measurements but also on the physics assumed to prevail both on the formation of the spectral line Stokes profiles and on their detection with the instrument. Such an intrinsic model dependence makes it necessary to formulate specific means that include the physics in a properly quantitative way. The core of this physics lies in the radiative transfer equation (RTE), where the properties of the atmosphere are assumed to be known while the unknowns are the four Stokes profiles. The solution of the (differential) RTE is known as the direct or forward problem. From an observational point of view, the problem is rather the opposite: the data are made up of the observed Stokes profiles and the unknowns are the solar physical quantities. Inverting the RTE is therefore mandatory. Indeed, the formal solution of this equation can be considered an integral equation. The solution of such an integral equation is called the inverse problem. Inversion techniques are automated codes aimed at solving the inverse problem. The foundations of inversion techniques are critically revisited with an emphasis on making explicit the many assumptions underlying each of them.

  8. The role of coccoliths in protecting Emiliania huxleyi against stressful light and UV radiation

    NASA Astrophysics Data System (ADS)

    Xu, Juntian; Bach, Lennart T.; Schulz, Kai G.; Zhao, Wenyan; Gao, Kunshan; Riebesell, Ulf

    2016-08-01

    Coccolithophores are a group of phytoplankton species which cover themselves with small scales (coccoliths) made of calcium carbonate (CaCO3). The reason why coccolithophores form these calcite platelets has been a matter of debate for decades but has remained elusive so far. One hypothesis is that they play a role in light or UV protection, especially in surface dwelling species like Emiliania huxleyi, which can tolerate exceptionally high levels of solar radiation. In this study, we tested this hypothesis by culturing a calcified and a naked strain under different light conditions with and without UV radiation. The coccoliths of E. huxleyi reduced the transmission of visible radiation (400-700 nm) by 7.5 %, that of UV-A (315-400 nm) by 14.1 % and that of UV-B (280-315 nm) by 18.4 %. Growth rates of the calcified strain (PML B92/11) were about 2 times higher than those of the naked strain (CCMP 2090) under indoor constant light levels in the absence of UV radiation. When exposed to outdoor conditions (fluctuating sunlight with UV radiation), growth rates of calcified cells were almost 3.5 times higher compared to naked cells. Furthermore, the relative electron transport rate was 114 % higher and non-photochemical quenching (NPQ) was 281 % higher in the calcified compared to the naked strain, implying higher energy transfer associated with higher NPQ in the presence of calcification. When exposed to natural solar radiation including UV radiation, the maximal quantum yield of photosystem II was only slightly reduced in the calcified strain but strongly reduced in the naked strain. Our results reveal an important role of coccoliths in mitigating light and UV stress in E. huxleyi.

  9. The impacts of light scattering by clouds on longwave radiative transfer

    NASA Astrophysics Data System (ADS)

    Kuo, C. P.; Yang, P.; Huang, X.; Feldman, D.; Flanner, M.

    2016-12-01

    In the longwave spectrum, clouds modulate energy budgets in the climate system through scattering, absorbing and emitting radiation. On the average, ice clouds tend to warm the climate, while liquid water clouds cool the climate, due to the distinct physical and optical properties of ice and liquid water clouds. General circulation models (GCMs) are the most popular tool to investigate the influences of clouds on climate. However, most GCMs, due to computational complexity, neglect multiple scattering effects in longwave radiative transfer calculations. To evaluate the potential impacts of neglecting longwave multiple scattering, we conduct sensitivity studies, utilizing the ECMWF (European Centre for Medium-Range Weather Forecasts) reanalysis atmospheric profiles, a modified RRTMG_LW (Longwave Rapid Radiative Transfer Model for GCM applications) and the MODIS (Moderate Resolution Imaging Spectroradiometer) collection 6 level 3 cloud retrieval products. The modified RRTMG_LW uses the 16-stream DISORT (Discrete Ordinates Radiative Transfer Program for a Multi-Layered Plane-Parallel Medium) as a robust radiative solver to calculate longwave fluxes. In the study, the bias in longwave flux (simulated without, minus simulated with, light scattering by ice and liquid water clouds) represents the influence of neglecting light scattering. Biases of upward flux at the top of the atmosphere, downward flux at the surface, and net flux into the atmosphere are presented. The preliminary results show that the absence of longwave light scattering could lead to considerable biases in global and regional flux simulations.

  10. Light attraction in endangered procellariiform birds: Reduction by shielding upward radiation

    USGS Publications Warehouse

    Reed, J.R.; Sincock, J.L.; Hailman, J.P.

    1985-01-01

    Autumnal attraction to man-made lighting causes heavy mortality in fledgling Hawaiian seabirds: Newell's shearwater (Puffinus auricularis newelli), dark-rumped petrel (Pterodroma phaeopygia sandwichensis), and band-rumpted storm-petrel (Oceanodroma castro). These threatened, endangered and rare species (respectively) approach and circle lights on their first flight from mountain nesting colonies on the island of Kauai to the sea. Lights of the largest resort were shielded to prevent upward radiation on alternate nights during 2 fledgling seasons. Shielding decreased attraction by nearly 40%. Most attraction occurred 1-4 h after sunset. Full moon dramatically decreased attraction, a phenomenon that has both theoretical and management implications.

  11. Light attraction in endangered procellariiform birds: Reduction by shielding upward radiation

    USGS Publications Warehouse

    Reed, J.R.; Sincock, J.L.; Hailman, J.P.

    1985-01-01

    Autumnal attraction to man-made lighting causes heavy mortality in fledgling Hawaiian seabirds: Newell's Shearwater (Puffinus auricularis newelli), Dark-rumped Petrel (Pterodroma phaeopygia sandwichensis), and Band-rumped Storm-Petrel (Oceanodroma castro). These threatened, endangered, and rare species (respectively) approach and circle lights on their first flight from mountain nesting colonies on the island of Kauai to the sea. We shielded lights of the largest resort to prevent upward radiation on alternate nights during two fledgling seasons. Shielding decreased attraction by nearly 40%. Most attraction occurred 1-4 h after sunset. Full moon dramatically decreased attraction, a phenomenon that has both theoretical and management implications.

  12. Early quark production and approach to chemical equilibrium

    NASA Astrophysics Data System (ADS)

    Gelfand, D.; Hebenstreit, F.; Berges, J.

    2016-04-01

    We perform real-time lattice simulations of out-of-equilibrium quark production in non-Abelian gauge theory in 3 +1 dimensions. Our simulations include the backreaction of quarks onto the dynamical gluon sector, which is particularly relevant for strongly correlated quarks. We observe fast isotropization and universal behavior of quarks and gluons at weak coupling and establish a quantitative connection to previous pure glue results. In order to understand the strongly correlated regime, we perform simulations for a large number of flavors and compare them to those obtained with two light quark flavors. By doing this we are able to provide estimates of the chemical equilibration time.

  13. B -meson decay constants from 2+1 -flavor lattice QCD with domain-wall light quarks and relativistic heavy quarks

    SciTech Connect

    Christ, N. H.; Flynn, J. M.; Izubuchi, T.; Kawanai, T.; Lehner, C.; Soni, A.; Van de Water, R. S.; Witzel, O.

    2015-03-01

    We calculate the B-meson decay constants fB, fBs, and their ratio in unquenched lattice QCD using domain-wall light quarks and relativistic b quarks. We use gauge-field ensembles generated by the RBC and UKQCD collaborations using the domain-wall fermion action and Iwasaki gauge action with three flavors of light dynamical quarks. We analyze data at two lattice spacings of a0.11, 0.086 fm with unitary pion masses as light as Mπ290MeV; this enables us to control the extrapolation to the physical light-quark masses and continuum. For the b quarks we use the anisotropic clover action with the relativistic heavy-quark interpretation, such that discretization errors from the heavy-quark action are of the same size as from the light-quark sector. We renormalize the

  14. Quark confinement in a constituent quark model

    SciTech Connect

    Langfeld, K.; Rho, M.

    1995-07-01

    On the level of an effective quark theory, we define confinement by the absence of quark anti-quark thresholds in correlation function. We then propose a confining Nambu-Jona-Lasinio-type model. The confinement is implemented in analogy to Anderson localization in condensed matter systems. We study the model`s phase structure as well as its behavior under extreme conditions, i.e. high temperature and/or high density.

  15. Measurement of the Radiation Incident on NbFeB Insertion Devices at the Advanced Light Source

    NASA Astrophysics Data System (ADS)

    Krebs, Gary; Holmes, Michael

    1997-05-01

    The Lawrence Berkeley National Laboratories Advanced Light Source is a third generation light source containing NdFeB permanent magnet insertion devices.The lifetime of the permanent magnets in a radiation environment is of paramount importance. Measurements of the radiation incident on the insertion device magnets under various operating conditions are presented.

  16. Radiative forcing by light absorbing impurities in snow from MODIS surface reflectance data

    NASA Astrophysics Data System (ADS)

    Painter, Thomas H.; Bryant, Ann C.; Skiles, S. McKenzie

    2012-09-01

    The episodic deposition of dust and carbonaceous particles to snow decreases snow surface albedo and enhances absorption of solar radiation, leading to accelerated snowmelt, negative glacier mass balance, and the snow-albedo feedback. Until now, no remote sensing retrieval has captured the spatial and temporal variability of this forcing. Here we present the MODIS Dust Radiative Forcing in Snow (MODDRFS) model that retrieves surface radiative forcing by light absorbing impurities in snow cover from Moderate Resolution Imaging Spectroradiometer (MODIS) surface reflectance data. Validation of MODDRFS with a 7-year record of in situ measurements indicates the radiative forcing retrieval has positive bias at lower values and slight negative bias above 200 W m-2, subject to mixed pixel uncertainties. With bias-correction, MODDRFS has a root mean squared error of 32 W m-2 and mean absolute error of 25 W m-2. We demonstrate MODDRFS in the Upper Colorado River Basin and Hindu Kush-Himalaya.

  17. A VMD Based, Nonet and SU(3) Symmetry Broken Model for Radiative Decays of Light Mesons

    SciTech Connect

    Benayoun, M.

    2005-04-06

    We present a VMD based model aiming to describe all radiative decays of light mesons. We show that the SU(3) breaking mechanism proposed by Bando, Kugo and Yamawaki (BKY), supplemented by nonet symmetry breaking in the pseudoscalar sector are sufficient to provide a nice description of all data, except the K*{sup {+-}} radiative width. It is also shown that nonet symmetry breaking has effects which cannot be disentangled from those produced by coupling of glue to the {eta}{prime} meson. Coupling of glue to {eta} is not found to be required by the data. Assuming the K*{sup {+-}} radiative width is indeed at its presently accepted value necessitates to supplement the BKY breaking in a way which finally preserves an equivalence statement between the VMD approach to radiative decays and the Wess-Zumino-Witten Lagrangian.

  18. Point defects controlling non-radiative recombination in GaN blue light emitting diodes: Insights from radiation damage experiments

    NASA Astrophysics Data System (ADS)

    Lee, In-Hwan; Polyakov, A. Y.; Smirnov, N. B.; Shchemerov, I. V.; Lagov, P. B.; Zinov'ev, R. A.; Yakimov, E. B.; Shcherbachev, K. D.; Pearton, S. J.

    2017-09-01

    The role of Shockley-Read-Hall non-radiative recombination centers on electroluminescence (EL) efficiency in blue multi-quantum-well (MQW) 436 nm GaN/InGaN light emitting diodes (LEDs) was examined by controlled introduction of point defects through 6 MeV electron irradiation. The decrease in the EL efficiency in LEDs subjected to irradiation with fluences above 5 × 1015 cm-2 was closely correlated to the increase in concentration of Ec-0.7 eV electron traps in the active MQW region. This increase in trap density was accompanied by an increase in the both diode series resistance and ideality factor (from 1.4 before irradiation to 2.1 after irradiation), as well as the forward leakage current at low forward voltages that compromise the injection efficiency. Hole traps present in the blue LEDs do not have a significant effect on EL changes with radiation because of their low concentration.

  19. Dark Decay of the Top Quark

    SciTech Connect

    Kong, Kyoungchul; Lee, Hye-Sung; Park, Myeonghun

    2014-04-01

    We suggest top quark decays as a venue to search for light dark force carriers. The top quark is the heaviest particle in the standard model whose decays are relatively poorly measured, allowing sufficient room for exotic decay modes from new physics. A very light (GeV scale) dark gauge boson (Z') is a recently highlighted hypothetical particle that can address some astrophysical anomalies as well as the 3.6sigma deviation in the muon g-2 measurement. We present and study a possible scenario that top quark decays as t-->bW+Z's. This is the same as the dominant top quark decay (t-->bW) accompanied by one or multiple dark force carriers. The Z' can be easily boosted, and it can decay into highly collimated leptons (lepton-jet) with large branching ratio. We discuss the implications for the Large Hadron Collider experiments including the analysis based on the lepton-jets.

  20. Dark decay of the top quark

    SciTech Connect

    Kong, Kyoungchul; Lee, Hye -Sung; Park, Myeonghun

    2014-04-01

    We suggest top quark decays as a venue to search for light dark force carriers. Top quark is the heaviest particle in the standard model whose decays are relatively poorly measured, allowing sufficient room for exotic decay modes from new physics. A very light (GeV scale) dark gauge boson (Z') is a recently highlighted hypothetical particle that can address some astrophysical anomalies as well as the 3.6 σ deviation in the muon g-2 measurement. We present and study a possible scenario that top quark decays as t → b W + Z's. This is the same as the dominant top quark decay (t → b W) accompanied by one or multiple dark force carriers. The Z' can be easily boosted, and it can decay into highly collimated leptons (lepton-jet) with large branching ratio. In addition, we discuss the implications for the Large Hadron Collider experiments including the analysis based on the lepton-jets.

  1. Infrared light-emitting diode radiation causes gravitropic and morphological effects in dark-grown oat seedlings

    NASA Technical Reports Server (NTRS)

    Johnson, C. F.; Brown, C. S.; Wheeler, R. M.; Sager, J. C.; Chapman, D. K.; Deitzer, G. F.

    1996-01-01

    Oat (Avena sativa cv Seger) seedlings were irradiated with IR light-emitting diode (LED) radiation passed through a visible-light-blocking filter. Infrared LED irradiated seedlings exhibited differences in growth and gravitropic response when compared to seedlings grown in darkness at the same temperature. Thus, the oat seedlings in this study were able to detect IR LED radiation. These findings call into question the use of IR LED as a safe-light for some photosensitive plant response experiments. These findings also expand the defined range of wavelengths involved in radiation-gravity (light-gravity) interactions to include wavelengths in the IR region of the spectrum.

  2. Infrared light-emitting diode radiation causes gravitropic and morphological effects in dark-grown oat seedlings

    NASA Technical Reports Server (NTRS)

    Johnson, C. F.; Brown, C. S.; Wheeler, R. M.; Sager, J. C.; Chapman, D. K.; Deitzer, G. F.

    1996-01-01

    Oat (Avena sativa cv Seger) seedlings were irradiated with IR light-emitting diode (LED) radiation passed through a visible-light-blocking filter. Infrared LED irradiated seedlings exhibited differences in growth and gravitropic response when compared to seedlings grown in darkness at the same temperature. Thus, the oat seedlings in this study were able to detect IR LED radiation. These findings call into question the use of IR LED as a safe-light for some photosensitive plant response experiments. These findings also expand the defined range of wavelengths involved in radiation-gravity (light-gravity) interactions to include wavelengths in the IR region of the spectrum.

  3. Biological Effects of Sunlight, Ultraviolet Radiation, Visible Light, Infrared Radiation and Vitamin D for Health.

    PubMed

    Holick, Michael F

    2016-03-01

    Humans evolved in sunlight and had depended on sunlight for its life giving properties that was appreciated by our early ancestors. However, for more than 40 years the lay press and various medical and dermatology associations have denounced sun exposure because of its association with increased risk for skin cancer. The goal of this review is to put into perspective the many health benefits that have been associated with exposure to sunlight, ultraviolet A (UVA) ultraviolet B (UVB), visible and infrared radiation. Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  4. Supernova SN2006gy as a first ever Quark Nova?

    NASA Astrophysics Data System (ADS)

    Leahy, Denis; Ouyed, Rachid

    2008-07-01

    The most luminous Supernova SN2006gy (more than 100 times brighter than a typical supernova) has been a challenge to explain by standard models. For example, pair-instability supernovae which are luminous enough seem to have too slow a rise, and core-collapse supernovae do not seem to be luminous enough. We present an alternative scenario involving a Quark Nova (an explosive transition of the newly born neutron star to a quark star) in which a second explosion (delayed) occurs inside the ejecta of a normal supernova. The reheated supernova ejecta can radiate at higher levels for longer periods of time primarily due to reduced adiabatic-expansion losses, unlike the standard supernova case. We find an encouraging match between the resulting light curve and that observed in the case of SN2006gy suggesting that we might have at hand the first ever signature of a Quark Nova. Successful application of our model to SN2005gj and SN2005ap is also presented.

  5. SCATTERING AND REFLECTION OF LASER RADIATION: Multiple dynamic scettering of laser radiation on a light-induced jet of microparticles in suspension

    NASA Astrophysics Data System (ADS)

    Skipetrov, S. E.; Chesnokov, S. S.; Zakharov, S. D.; Kazaryan, M. A.; Korotkov, N. P.; Shcheglov, V. A.

    1998-05-01

    A self-consistent theoretical analysis is made of the multiple scattering of coherent laser radiation in a random medium under conditions of formation of a light-induced jet of scatterers. It is shown, that the laser particle acceleration leads to a qualitative change of the temporal auto-correlation function of scattered light as compared to the case of scattering on chaotically moving Brownian particles. The effect of radiation absorption on the temporal coherence of the multiple-scattered light under conditions of light-induced particle motion in the scattering medium is studied.

  6. A mechanism for the production of light and dark contrasts in radiatively controlled lines.

    NASA Technical Reports Server (NTRS)

    Gebbie, K. B.; Steinitz, R.

    1973-01-01

    It is shown that light and dark contrasts observed in the radiation of strong lines may arise from lateral differences in the local value of the scattering term alone, independently of the local values of temperature and pressure. Mechanisms for the production of such differences are suggested, and regions are pointed out in which they occur as 'features.' From numerical examples presented, it is seen that the effect of such features on the emergent radiation field is determined by their position with respect to the shape of the source function.

  7. Adaptive radiation of photosynthetic physiology in the Hawaiian lobeliads: light regimes, static light responses, and whole-plant compensation points.

    PubMed

    Givnish, Thomas J; Montgomery, Rebecca A; Goldstein, Guillermo

    2004-02-01

    Six endemic genera/sections of lobeliads (Campanulaceae) occupy nearly the full range of light regimes on moist sites in the Hawaiian Islands, from open alpine bogs and seacliffs to densely shaded rainforest interiors. To determine whether this clade has undergone a corresponding adaptive radiation in photosynthetic adaptations, we studied the natural light habitats and physiological characteristics of 11 species representing each sublineage. Across species in the field, average photon flux density (PFD) varies from 2.3 to 30.0 mol · m(-2) · d(-1), and maximum assimilation rate (A(max)) ranges from 0.17 to 0.35 μmol CO(2) · g(-1) · s(-1). Across species, A(max), dark respiration rate (R), Michaelis-Menten constant (k), light compensation point, specific leaf area (SLA), maximum carboxylation rate (V(cmax)), maximum rate of electron transport (J(max)), photosynthesis at saturating CO(2) (A(satCO(2))), and carboxylation efficiency (α) all increase significantly and in tightly coupled fashion with PFD, in accord with classical economic theory. Area-based rates have a higher degree of physiological integration with each other and tighter coupling to PFD than the corresponding mass-based rates, despite the energetic importance of the latter. Area-based rates frequently show adaptive cross-over: high-light species outperform low-light species at high PFD and vice versa at low PFD. A(max)-mass has little relationship to leaf mass per unit area (LMA), leaf N content, or leaf lifespan individually, but a multiple regression explains 96% of the variance in A(max)-mass across species in terms of SLA, leaf N content, and average PFD. Instantaneous leaf compensation points range from 0.1 to 1.2% full sunlight, far lower than the ecological (whole-plant) compensation points (ECPs) of 1.1 to 29.0% sunlight calculated based on photosynthetic parameters, leaf longevity, and allocation to leaf vs. nonleaf tissue. The ECPs are much closer to the lower limits of PFD actually

  8. The Unquenched Quark Model

    SciTech Connect

    Santopinto, E.; Bijker, R.

    2008-10-13

    We present a new generation of unquenched quark models for baryons in which the effects of quark-antiquark pairs are taken into account in an explicit form via a microscopic, QCD-inspired, pair creation mechanism. As an application, we study the effect of quark-antiquark pairs on the spin of the proton.

  9. 37 Years with the light scalar mesons. The learned lessons

    NASA Astrophysics Data System (ADS)

    Achasov, N. N.

    2017-09-01

    Attention is paid to the production mechanisms of light scalars that reveal their nature. We reveal the chiral shielding of the σ(600) meson. We show that the kaon loop mechanism of the ϕ radiative decays, ratified by experiment, is four-quark transition and points to the four-quark nature of light scalars. We show also that the light scalars are produced in the two photon collisions via four-quark transitions in contrast to the classic P wave tensor qq̅ mesons that are produced via two-quark transitions γγ → qq̅. We study the mechanism of production of the light scalar mesons in the D s + → π+π- e +ν decays: D s + → ss̅e +ν → [σ(600) + f 0(980)] e +ν → π+π- e +ν, and compare it with the mechanism of production of the light pseudoscalar mesons in the D s + → (η/η') e +ν decays: D s + → ss̅e +ν → (η/η') e +ν. As a result we find support to four-quark nature of light scalars. In the end, we outline the future research program.

  10. Heavy-quark physics in quantum chromodynamics

    SciTech Connect

    Brodsky, S.J.

    1991-04-01

    Heavy quarks can expose new symmetries and novel phenomena in QCD not apparent in ordinary hadronic systems. In these lectures I discuss the use of effective-Lagrangian and light-cone Fock methods to analyze exclusive heavy hadron decays such as {Upsilon} {yields} p{bar p} and B {yields} {pi}{pi}, and also to derive effective Schroedinger and Dirac equations for heavy quark systems. Two contributions to the heavy quark structure functions of the proton and other light hadrons are identified: an extrinsic'' contribution associated with leading twist QCD evolution of the gluon distribution, and a higher twist intrinsic'' contribution due to the hardness of high-mass fluctuations of multi-gluon correlations in hadronic wavefunctions. A non-perturbative calculation of the heavy quark distribution of a meson in QCD in one space and one time is presented. The intrinsic higher twist contributions to the pion and proton structure functions can dominate the hadronic production of heavy quark systems at large longitudinal momentum fraction x{sub F} and give anomalous contributions to the quark structure functions of ordinary hadrons at large x{sub bj}. I also discuss a number of ways in which heavy quark production in nuclear targets can test fundamental QCD phenomena and provide constraints on hadronic wavefunctions. The topics include color transparency, finite formation time, and predictions for charm production at threshold, including nuclear-bound quarkonium. I also discuss a number of QCD mechanisms for the suppression of J/{psi} and {Upsilon} production in nuclear collisions, including gluon shadowing, the peripheral excitation of intrinsic heavy quark components at large x{sub F}, and the coalescence of heavy quarks with co-moving spectators at low x{sub F}.

  11. Cooking Up Hot Quark Soup

    DOE R&D Accomplishments Database

    Walsh, Karen McNulty

    2011-03-28

    Near-light-speed collisions of gold ions provide a recipe for in-depth explorations of matter and fundamental forces. The Relativistic Heavy Ion Collider (RHIC) has produced the most massive antimatter nucleus ever discovered—and the first containing an anti-strange quark. The presence of strange antimatter makes this antinucleus the first to be entered below the plane of the classic Periodic Table of Elements, marking a new frontier in physics.

  12. Coherent and tunable light radiation from nanoscale surface plasmons array via an exotic Smith-Purcell effect.

    PubMed

    Liu, Weihao

    2015-10-15

    We demonstrate that surface plasmons on a nanoscale metallic array can be transformed into radiation waves via an exotic Smith-Purcell effect. Although the radiation frequency and direction satisfy the Smith-Purcell relation, it is coherent radiation with directions specified, which is essentially different from the ordinary Smith-Purcell radiation. Its radiation spectral density is an order of magnitude higher. By adjusting the material and structure of the array, the radiation frequency can be tuned from an infrared to ultraviolet region. Its remarkable advantages in intensity, coherence, tunability, and miniature size indicate new prospects in developing nanoscale light sources and related techniques.

  13. Image gently, step lightly: increasing radiation dose awareness in pediatric interventions through an international social marketing campaign.

    PubMed

    Sidhu, Manrita K; Goske, Marilyn J; Coley, Brian J; Connolly, Bairbre; Racadio, John; Yoshizumi, Terry T; Utley, Tara; Strauss, Keith J

    2009-09-01

    In the past several decades, advances in imaging and interventional techniques have been accompanied by an increase in medical radiation dose to the public. Radiation exposure is even more important in children, who are more sensitive to radiation and have a longer lifespan during which effects may manifest. To address radiation safety in pediatric computed tomography, in 2008 the Alliance for Radiation Safety in Pediatric Imaging launched an international social marketing campaign entitled Image Gently. This article describes the next phase of the Image Gently campaign, entitled Step Lightly, which focuses on radiation safety in pediatric interventional radiology.

  14. Process for applying light- or radiation-curable resin composition to polyolefin moldings

    SciTech Connect

    Fujii, Y.; Kitadono, K.; Kondo, T.; Shinonaga, H.

    1984-08-28

    A process for applying a light- or radiation-curable resin composition onto a polyolefin molding comprising surface treating a molding of polyolefin composition composed of 99.99 to 0 wt % of a polyolefin and 0.01 to 100 wt % of an olefinic polymeric compound, having polar groups represented by the formula, COOR, -OR-, -COO-CO-, -N(-R)-R', OR -C(-R)<(-O-CH(-R')-) wherein R and R' are each a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, by at least one pretreatment method selected from the group consisting of a treatment with a halogenated hydrocarbon solvent, a low temperature plasma treatment, a corona discharge treatment, a flame treatment and an alkali degreasing treatment, and applying onto the thus treated molding surface a light- or radiation-curable resin composition, is disclosed.

  15. Radiation-damage-induced phasing: a case study using UV irradiation with light-emitting diodes

    PubMed Central

    de Sanctis, Daniele; Zubieta, Chloe; Felisaz, Franck; Caserotto, Hugo; Nanao, Max H.

    2016-01-01

    Exposure to X-rays, high-intensity visible light or ultraviolet radiation results in alterations to protein structure such as the breakage of disulfide bonds, the loss of electron density at electron-rich centres and the movement of side chains. These specific changes can be exploited in order to obtain phase information. Here, a case study using insulin to illustrate each step of the radiation-damage-induced phasing (RIP) method is presented. Unlike a traditional X-ray-induced damage step, specific damage is introduced via ultraviolet light-emitting diodes (UV-LEDs). In contrast to UV lasers, UV-LEDs have the advantages of small size, low cost and relative ease of use. PMID:26960126

  16. Radiation-damage-induced phasing: a case study using UV irradiation with light-emitting diodes.

    PubMed

    de Sanctis, Daniele; Zubieta, Chloe; Felisaz, Franck; Caserotto, Hugo; Nanao, Max H

    2016-03-01

    Exposure to X-rays, high-intensity visible light or ultraviolet radiation results in alterations to protein structure such as the breakage of disulfide bonds, the loss of electron density at electron-rich centres and the movement of side chains. These specific changes can be exploited in order to obtain phase information. Here, a case study using insulin to illustrate each step of the radiation-damage-induced phasing (RIP) method is presented. Unlike a traditional X-ray-induced damage step, specific damage is introduced via ultraviolet light-emitting diodes (UV-LEDs). In contrast to UV lasers, UV-LEDs have the advantages of small size, low cost and relative ease of use.

  17. Computerized microtomography using synchrotron radiation from the NSLS (National Synchrotron Light Source)

    SciTech Connect

    Spanne, P.; Rivers, M.L.

    1986-09-01

    Results of microtomography experiments that employ filtered radiation from the National Synchrotron Light Source X-26 Microprobe beam line are presented. These experiments have yielded images of a freeze-dried caterpillar with a spatial resolution of the order of 30 ..mu..m and show that the limit on the spatial resolution with the present apparatus will be 1 to 10 ..mu..m. Directions for improvement in synchrotron microtomography techniques and some possible applications are discussed. 14 refs., 3 figs.

  18. Radiation Protection Aspects of the Linac Coherent Light Source Front End Enclosure

    SciTech Connect

    Vollaire, J.; Fasso, A.; Liu, J.C.; Mao, X.S.; Prinz, A.; Rokni, S.H.; Leitner, M.Santana; /SLAC

    2010-08-26

    The Front End Enclosure (FEE) of the Linac Coherent Light Source (LCLS) is a shielding housing located between the electron dump area and the first experimental hutch. The upstream part of the FEE hosts the commissioning diagnostics for the FEL beam. In the downstream part of the FEE, two sets of grazing incidence mirror and several collimators are used to direct the beam to one of the experimental stations and reduce the bremsstrahlung background and the hard component of the spontaneous radiation spectrum. This paper addresses the beam loss assumptions and radiation sources entering the FEE used for the design of the FEE shielding using the Monte-Carlo code FLUKA. The beam containment system prevents abnormal levels of radiations inside the FEE and ensures that the beam remains in its intended path is also described.

  19. Quark fragmentation in e/sup +/e/sup -/ collisions

    SciTech Connect

    Oddone, P.

    1984-12-01

    This brief review of new results in quark and gluon fragmentation observed in e/sup +/e/sup -/ collisions concentrates mostly on PEP results and, within PEP, mostly on TPC results. The new PETRA results have been reported at this conference by M. Davier. It is restricted to results on light quark fragmentation since the results on heavy quark fragmentation have been reported by J. Chapman.

  20. Dose-response function for lens forward light scattering after in vivo exposure to ultraviolet radiation.

    PubMed

    Michael, R; Söderberg, P G; Chen, E

    1998-08-01

    It is known that different types of radiation, as well as aging and metabolic disorders, can cause cataract. Several epidemiological investigations show a correlation between cataract development and the dose of ultraviolet radiation (UVR) received. It is well established experimentally that exposure of animal eyes to UVR induces cataract. The purpose of the present study was to determine the dose-response function for UVR-induced opacities in the rat lens after in vivo exposure. Sprague-Dawley rats received 0.1, 0.4, 1.3, 3, 5, 8 or 14 kJ/m2 UVR (lambda MAX = 300 nm, lambda 0.5 = 10 nm) unilaterally for 15 min. At 1 week after exposure both lenses were removed, photographs were taken and the intensity of forward-scattered light was measured. One week after UVR exposure, opacities occurred on the lens surface, as observed with a microscope. With increased UVR dose the opacities became more intense and occurred also in the equatorial area of the lens, but not in the nucleus. The intensity of forward light scattering increased with increased UVR dose between 3 and 14 kJ/m2. No significant change in intensity of forward light scattering was observed for lower UVR doses. The intensity of forward light scattering in the rat lens increase exponentially with increased UVR dose between 0.1 and 14 kJ/m2.

  1. An analysis of Pluto occultation light curves using an atmospheric radiative-conductive model

    NASA Astrophysics Data System (ADS)

    Zalucha, Angela M.; Gulbis, Amanda A. S.; Zhu, Xun; Strobel, Darrell F.; Elliot, J. L.

    2011-01-01

    We use a radiative-conductive model to least-squares fit Pluto stellar occultation light curve data. This model predicts atmospheric temperature based on surface temperature, surface pressure, surface radius, and CH 4 and CO mixing ratios, from which model light curves are to be calculated. The model improves upon previous techniques for deriving Pluto's atmospheric thermal structure from stellar occultation light curves by calculating temperature (as a function of height) caused by heating and cooling by species in Pluto's atmosphere, instead of a general assumption that temperature follows a power law with height or some other idealized function. We are able to fit for model surface radius, surface pressure, and CH 4 mixing ratio with one of the 2006 datasets and for surface pressure and CH 4 mixing ratio for other datasets from the years 1988, 2002, 2006, and 2008. It was not possible to fit for CO mixing ratio and surface temperature because the light curves are not sensitive to these parameters. We determine that the model surface radius, under the assumption of a stratosphere only (i.e. no troposphere) model in radiative-conductive balance, is 1180-10+20km. The CH 4 mixing ratio results are more scattered with time and are in the range of 1.8-9.4 × 10 -3. The surface pressure results show an increasing trend from 1988 to 2002, although it is not as dramatic as the factor of 2 from previous studies.

  2. RADIATIVE HYDRODYNAMIC SIMULATION OF THE CONTINUUM EMISSION IN SOLAR WHITE-LIGHT FLARES

    SciTech Connect

    Cheng, J. X.; Ding, M. D.; Carlsson, Mats

    2010-03-01

    It is believed that solar white-light flares (WLFs) originate in the lower chromosphere and upper photosphere. In particular, some recently observed WLFs show a large continuum enhancement at 1.56 {mu}m where the opacity reaches its minimum. Therefore, it is important to clarify how the energy is transferred to the lower layers responsible for the production of WLFs. Based on radiative hydrodynamic simulations, we study the role of non-thermal electron beams in increasing the continuum emission. We vary the parameters of the electron beam and disk positions and compare the results with observations. The electron beam heated model can explain most of the observational white-light enhancements. For the most energetic WLFs observed so far, however, a very large electron beam flux and a high low-energy cutoff, which are possibly beyond the parameter space in our simulations, are required in order to reproduce the observed white-light emission.

  3. Subcanopy Solar Radiation Model: an irradiation model for predicting light in heavily vegetated landscapes

    NASA Astrophysics Data System (ADS)

    Bode, C. A.; Limm, M. P.; Finlay, J. C.; Power, M.

    2012-12-01

    Solar radiation flux, irradiance, affects many biological (e.g. photosynthesis, germination, metabolism) and hydrological (e.g. snow melt, water cycling) processes. Models of these processes often require data at the watershed scale. GIS based solar models that predict irradiation at the watershed scale take topographic shading into account, but do not account for vegetative shading. Methods that quantify subcanopy irradiation do so only at a single point. Further, calibrating the subcanopy models require significant field effort and knowledge of individual species characteristics (leaf area index, mean leaf angle, clumping factor, etc.). Upscaling from point values to watersheds is a significant source of uncertainty. We propose an approach to modeling irradiation that uses airborne LiDAR to estimate canopy openness as a Light Penetration Index (LPI). We coupled LPI with the GRASS GIS r.sun solar model to produce the Subcanopy Solar Radiation model (SSR). SSR accounts for both topographic shading and vegetative shading at the watershed scale. Output is 52 raster maps (one per week) of 24 hours of irradiation (watt-hours/m2). We calibrated the r.sun model to a weather station at our field site and to field measurements of direct and diffuse solar radiation taken for 24 hours at the weather station site. We validate predictions of the SSR by comparing modeled output to field measurements and to a standard method for point estimation of subcanopy radiation, hemispherical photographs processed with Gap Light Analyzer 2.0 (GLA). Based on ANCOVA analysis, SSR and GLA models exhibit a similar linear relationship with field data, and the models predict similar total solar radiation flux across the range of canopy openness. With similar quality to a standard point method, but with greatly expanded spatial coverage, SSR should become a useful tool in watershed analysis.

  4. Imaging spectroscopy of albedo and radiative forcing by light-absorbing impurities in mountain snow

    NASA Astrophysics Data System (ADS)

    Painter, Thomas H.; Seidel, Felix C.; Bryant, Ann C.; McKenzie Skiles, S.; Rittger, Karl

    2013-09-01

    Recent studies show that deposition of dust and black carbon to snow and ice accelerates snowmelt and perturbs regional climate and hydrologic cycles. Radiative forcing by aerosols is often neglected in climate and hydrological models in part due to scarcity of observations. Here we describe and validate an algorithm suite (Imaging Spectrometer-Snow Albedo and Radiative Forcing (IS-SnARF)) that provides quantitative retrievals of snow grain size, snow albedo, and radiative forcing by light-absorbing impurities in snow and ice (LAISI) from Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data collected on 15 June 2011 in the Senator Beck Basin Study Area (SBBSA), SW Colorado, USA. Radiative forcing by LAISI is retrieved by the integral of the convolution of spectral irradiance with spectral differences between the spectral albedo (scaled from the observed hemispherical-directional reflectance factor (HDRF)) and modeled clean snow spectral albedo. The modeled surface irradiance at time of acquisition at test sites was 1052 W m-2 compared to 1048 W m-2 measured with the field spectroradiometer measurements, a relative difference of 0.4%. HDRF retrievals at snow and bare soil sites had mean errors relative to in situ measurements of -0.4 ± 0.1% reflectance averaged across the spectrum and root-mean-square errors of 1.5 ± 0.1%. Comparisons of snow albedo and radiative forcing retrievals from AVIRIS with in situ measurements in SBBSA showed errors of 0.001-0.004 and 2.1 ± 5.1 W m-2, respectively. A counterintuitive result was that, in the presence of light absorbing impurities, near-surface snow grain size increased with elevation, whereas we generally expect that at lower elevation the grain size would be larger.

  5. Electron, Atomic, and Radiation Kinetics in Plasma Discharge Lighting: Advanced Models and Observations

    NASA Astrophysics Data System (ADS)

    Giuliani, John L.

    2006-10-01

    Non-LTE discharges used in lighting sources provide an excellent testbed for understanding the interplay between plasma, atomic, and radiation physics. Standard models for the Hg fluorescent bulb include non-equilibrium kinetics for the species, but employ both a 0-D Boltzmann equation for the electron distribution function (EDF) and Holstein's probability-of-escape for radiation transport. These assumptions overlook some of the more interesting, and challenging, aspects of plasma lighting. The radial ambipolar potential requires the inclusion of the spatial gradient term in the inhomogeneous electron Boltzmann equation. The resulting EDF is found to depend on both electron energy and radial position [1]. Advanced radiation transport techniques account for non-local photo-pumping, line overlap within the Hg resonance lines, and partial frequency redistribution [2]. The results of our completely coupled model match the observed spatial distribution of Hg excited states and the line-of-sight intensity [3]. Due to environmental initiatives there is also recent interest in non-Hg discharges for high intensity lighting. One example is an RF electrodeless Mo-O-Ar plasma discharge bulb which operates by recycling the emitting Mo with an O catalyst. Based on atomic physics calculations for Mo [4], the kinetic pathways leading to visible emission can be identified [5] and explain the measured lighting efficiency of ˜40 lumens/watt of supplied power.[1] J. Appl. Phys., 94, p.62, 2003. [2] Plasma Sources Sci. Tech., 14, p.236, 2005. [3] J. Phys. D., 38, p.4180, 2005. [4] New J. Physics, 6, p.145, 2004. [5] J. Appl. Phys., 95, p.5284, 2004.

  6. The effect of light radiation and temperature variability on the invasion of marine fouling species

    NASA Astrophysics Data System (ADS)

    Kim, T.; Micheli, F.

    2009-12-01

    Climate change can alter the community structure as species which have adapted to the changed climate can compete better with other species. It can also influence the recruitment and invasion success of marine introduced species. Climate change involves not only global warming but also global dimming. However, it was not tested which of warming or dimming factors more significantly influence the invasion of marine species. To test this, we manipulated both temperature variability and light radiation by deploying different shading devices (black, white, transparent, and no treatment) for recruitment tiles in the warmer region where the species invasion rate is high. We compared the species frequency and coverage between shaded and non-shaded treatments. Interestingly, under opaque white plates where light radiation is lower than under transparent plates but the temperature is higher than under black plates, had the highest frequency and coverage of invasive fouling species. The recruitment tiles under black plates got second higher invasion of exotic species. We also deployed recruitment tiles in 14 different sites to determine if temperature influences the success of invasive species. The coverage of invasive species over native species increased significantly with increasing temperature. The results suggest that both low radiation and higher temperature facilitates the success of species invasion in the intertidal region.

  7. Jitter radiation images, spectra and light curves from a relativistic spherical blastwave

    NASA Astrophysics Data System (ADS)

    Morsony, Brian J.; Workman, Jared C.; Lazzati, Davide; Medvedev, Mikhail V.

    2009-02-01

    We consider radiation emitted by the jitter mechanism in a Blandford-McKee self-similar blastwave. We assume the magnetic field configuration throughout the whole blastwave meets the condition for the emission of jitter radiation and we compute the ensuing images, light curves and spectra. The calculations are performed for both a uniform and a wind environment. We compare our jitter results to synchrotron results. We show that jitter radiation produces slightly different spectra than synchrotron, in particular between the self-absorption and the peak frequency, where the jitter spectrum is flat, while the synchrotron spectrum grows as ν1/3. The spectral difference is reflected in the early decay slope of the light curves. We conclude that jitter and synchrotron afterglows can be distinguished from each other with good quality observations. However, it is unlikely that the difference can explain the peculiar behaviour of several recent observations, such as flat X-ray slopes and uncorrelated optical and X-ray behaviour.

  8. Top quark physics

    SciTech Connect

    Ahmadov, A.; Azuelos, G.; Bauer, U.; Belyaev, A.; Berger, E. L.; Sullivan, Z.; Tait, T. M. P.

    2000-03-24

    The top quark, when it was finally discovered at Fermilab in 1995 completed the three-generation structure of the Standard Model (SM) and opened up the new field of top quark physics. Viewed as just another SM quark, the top quark appears to be a rather uninteresting species. Produced predominantly, in hadron-hadron collisions, through strong interactions, it decays rapidly without forming hadrons, and almost exclusively through the single mode t {r_arrow} Wb. The relevant CKM coupling V{sub tb} is already determined by the (three-generation) unitarity of the CKM matrix. Rare decays and CP violation are unmeasurable small in the SM. Yet the top quark is distinguished by its large mass, about 35 times larger than the mass of the next heavy quark, and intriguingly close to the scale of electroweak (EW) symmetry breaking. This unique property raises a number of interesting questions. Is the top quark mass generated by the Higgs mechanism as the SM predicts and is its mass related to the top-Higgs-Yukawa coupling? Or does it play an even more fundamental role in the EW symmetry breaking mechanism? If there are new particles lighter than the top quark, does the top quark decay into them? Could non-SM physics first manifest itself in non-standard couplings of the top quark which show up as anomalies in top quark production and decays? Top quark physics tries to answer these questions. Several properties of the top quark have already been examined at the Tevatron. These include studies of the kinematical properties of top production, the measurements of the top mass, of the top production cross-section, the reconstruction of t{bar t}pairs in the fully hadronic final states, the study of {tau} decays of the top quark, the reconstruction of hadronic decays of the W boson from top decays, the search for flavor changing neutral current decays, the measurement of the W helicity in top decays, and bounds on t{bar t} spin correlations. Most of these measurements are limited by

  9. Radiative Energy Budgets of Phototrophic Surface-Associated Microbial Communities and their Photosynthetic Efficiency Under Diffuse and Collimated Light

    PubMed Central

    Lichtenberg, Mads; Brodersen, Kasper E.; Kühl, Michael

    2017-01-01

    We investigated the radiative energy budgets of a heterogeneous photosynthetic coral reef sediment and a compact uniform cyanobacterial biofilm on top of coastal sediment. By combining electrochemical, thermocouple and fiber-optic microsensor measurements of O2, temperature and light, we could calculate the proportion of the absorbed light energy that was either dissipated as heat or conserved by photosynthesis. We show, across a range of different incident light regimes, that such radiative energy budgets are highly dominated by heat dissipation constituting up to 99.5% of the absorbed light energy. Highest photosynthetic energy conservation efficiency was found in the coral sediment under low light conditions and amounted to 18.1% of the absorbed light energy. Additionally, the effect of light directionality, i.e., diffuse or collimated light, on energy conversion efficiency was tested on the two surface-associated systems. The effects of light directionality on the radiative energy budgets of these phototrophic communities were not unanimous but, resulted in local spatial differences in heat-transfer, gross photosynthesis, and light distribution. The light acclimation index, Ek, i.e., the irradiance at the onset of saturation of photosynthesis, was >2 times higher in the coral sediment compared to the biofilm and changed the pattern of photosynthetic energy conservation under light-limiting conditions. At moderate to high incident irradiances, the photosynthetic conservation of absorbed energy was highest in collimated light; a tendency that changed in the biofilm under sub-saturating incident irradiances, where higher photosynthetic efficiencies were observed under diffuse light. The aim was to investigate how the physical structure and light propagation affected energy budgets and light utilization efficiencies in loosely organized vs. compact phototrophic sediment under diffuse and collimated light. Our results suggest that the optical properties and the

  10. Radiative Energy Budgets of Phototrophic Surface-Associated Microbial Communities and their Photosynthetic Efficiency Under Diffuse and Collimated Light.

    PubMed

    Lichtenberg, Mads; Brodersen, Kasper E; Kühl, Michael

    2017-01-01

    We investigated the radiative energy budgets of a heterogeneous photosynthetic coral reef sediment and a compact uniform cyanobacterial biofilm on top of coastal sediment. By combining electrochemical, thermocouple and fiber-optic microsensor measurements of O2, temperature and light, we could calculate the proportion of the absorbed light energy that was either dissipated as heat or conserved by photosynthesis. We show, across a range of different incident light regimes, that such radiative energy budgets are highly dominated by heat dissipation constituting up to 99.5% of the absorbed light energy. Highest photosynthetic energy conservation efficiency was found in the coral sediment under low light conditions and amounted to 18.1% of the absorbed light energy. Additionally, the effect of light directionality, i.e., diffuse or collimated light, on energy conversion efficiency was tested on the two surface-associated systems. The effects of light directionality on the radiative energy budgets of these phototrophic communities were not unanimous but, resulted in local spatial differences in heat-transfer, gross photosynthesis, and light distribution. The light acclimation index, Ek, i.e., the irradiance at the onset of saturation of photosynthesis, was >2 times higher in the coral sediment compared to the biofilm and changed the pattern of photosynthetic energy conservation under light-limiting conditions. At moderate to high incident irradiances, the photosynthetic conservation of absorbed energy was highest in collimated light; a tendency that changed in the biofilm under sub-saturating incident irradiances, where higher photosynthetic efficiencies were observed under diffuse light. The aim was to investigate how the physical structure and light propagation affected energy budgets and light utilization efficiencies in loosely organized vs. compact phototrophic sediment under diffuse and collimated light. Our results suggest that the optical properties and the

  11. Dressed Quark Mass Dependence of Pion and Kaon Form Factors

    SciTech Connect

    Ninomiya, Y.; Bentz, W.; Cloet, I. C.

    2015-02-04

    The structure of hadrons is described well by the Nambu-Jona-Lasinio (NJL) model, which is a chiral effective quark theory of QCD. In this work we explore the electromagnetic structure of the pion and kaon using the three-flavor NJL model in the proper-time regularization scheme, including effects of the pion cloud at the quark level. In the calculation there is only one free parameter, which we take as the dressed light quark (u and d) mass. In the regime where the dressed light quark mass is approximately 0.25 GeV we find that the calculated values of the kaon decay constant, current quark masses, and quark condensates are consistent with experiment- and QCD-based analyses. We also investigate the dressed light quark mass dependence of the pion and kaon electromagnetic form factors, where comparison with empirical data and QCD predictions also favors a dressed light quark mass near 0.25 GeV.

  12. Radiation-induced gain degradation in lateral PNP BJTs with lightly and heavily doped emitters

    SciTech Connect

    Wu, A.; Schrimpf, R.D.; Pease, R.L.; Fleetwood, D.M.; Kosier, S.L.

    1997-06-01

    Ionizing radiation may cause failures in ICs due to gain degradation of individual devices. The base current of irradiated bipolar devices increases with total dose, while the collector current remains relatively constant. This results in a decrease in the current gain. Lateral PNP (LPNP) transistors typically exhibit more degradation than vertical PNP devices at the same total dose, and have been blamed as the cause of early IC failures at low dose rates. It is important to understand the differences in total-dose response between devices with heavily- and lightly-doped emitters in order to compare different technologies and evaluate the applicability of proposed low-dose-rate hardness-assurance methods. This paper addresses these differences by comparing two different LPNP devices from the same process: one with a heavily-doped emitter and one with a lightly-doped emitter. Experimental results demonstrate that the lightly-doped devices are more sensitive to ionizing radiation and simulations illustrate that increased recombination on the emitter side of the junction is responsible for the higher sensitivity.

  13. LIGHT MODULATION: Wide-aperture diffraction of unpolarised radiation in a system of two acousto-optic filters

    NASA Astrophysics Data System (ADS)

    Magdich, L. N.; Yushkov, K. B.; Voloshinov, V. B.

    2009-04-01

    Light diffraction is studied in two tandem acousto-optic cells filtering unpolarised radiation with a wide angular spectrum. It is shown that the side lobes of the ultrasonic radiation pattern of a piezoelectric transducer produce side diffraction intensity maxima at the output of the system consisting of two filters. Diffraction in paratellurite filters is studied experimentally at 1.06 μm.

  14. Shining light on skin pigmentation: the darker and the brighter side of effects of UV radiation.

    PubMed

    Maddodi, Nityanand; Jayanthy, Ashika; Setaluri, Vijayasaradhi

    2012-01-01

    The term barrier function as applied to human skin often connotes the physical properties of this organ that provides protection from its surrounding environment. This term does not generally include skin pigmentation. However, skin pigmentation, which is the result of melanin produced in melanocytes residing in the basal layer of the skin and exported to the keratinocytes in the upper layers, serves equally important protective function. Indeed, changes in skin pigmentation are often the most readily recognized indicators of exposure of skin to damaging agents, especially to natural and artificial radiation in the environment. Several recent studies have shed new light on (1) the mechanisms involved in selective effects of subcomponents of UV radiation on human skin pigmentation and (2) the interactive influences between keratinocytes and melanocytes, acting as "epidermal melanin unit," that manifest as changes in skin pigmentation in response to exposure to various forms of radiation. This article provides a concise review of our current understanding of the effects of the nonionizing solar radiation, at cellular and molecular levels, on human skin pigmentation. © 2012 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2012 The American Society of Photobiology.

  15. Radiatively corrected lepton energy distributions in top quark decays t→ bW +→ b( ℓ + ν ℓ ) and t→ bH +→ b( τ + ν τ ) and single-charged prong energy distributions from subsequent τ + decays

    NASA Astrophysics Data System (ADS)

    Ali, Ahmed; Kuraev, Eduard A.; Bystritskiy, Yury M.

    2010-06-01

    We calculate the QED and QCD radiative corrections to the charged lepton energy distributions in the dominant semileptonic decays of the top quark t→ bW +→ b( ℓ + ν ℓ ) ( ℓ= e, μ, τ) in the standard model (SM), and for the decay t→ bH +→ b( τ + ν τ ) in an extension of the SM having a charged Higgs boson H ± with m_{H^{±}}quark decays. As the τ + leptons arising from the decays W +→ τ + ν τ and H +→ τ + ν τ are predominantly left- and right-polarised, respectively, influencing the energy distributions of the decay products in the subsequent decays of the τ +, we work out the effect of the radiative corrections on such distributions in the dominant (one-charged prong) decay channels tau+toπ+bar{ν}_{tau},ρ+bar{ν}_{tau},a1+bar{ν}_{tau} and ell+ν_{ell}bar{ν}_{tau}. The inclusive π + energy spectra in the decay chains tto b(W+,H+)to b(tau+ν_{tau})to b(π+bar{ν}_{tau}ν_{tau}+X) are calculated, which can help in searching for the induced H ± effects at the Tevatron and the LHC.

  16. Radiation emission from ultra-relativistic plasma electrons in short-intense laser light interactions

    NASA Astrophysics Data System (ADS)

    Ondarza-Rovira, R.; Boyd, TJM

    2016-05-01

    Intense femtosecond laser light incident on overcritical density plasmas has shown to emit a prolific number of high-order harmonics of the driver frequency, with spectra characterised by power-law decays. When the laser pulse is p-polarised, plasma effects do modify the harmonic spectrum, weakening the so-called universal decay index p = 8/3 to 5/3. In this work appeal is made to a single particle radiation model in support of the predictions from particle-in-cell (PIC) simulations. Using these, we further show that the emission radiated by electrons -those that are relativistically accelerated inside the plasma, after being expelled into vacuum, the so-called Brunel electrons- is characterised not only by the plasma line but also by ultraviolet harmonic orders characterised by the 5/3 decay index.

  17. Synchrotron radiation shielding design for the Brockhouse sector at the Canadian light source

    NASA Astrophysics Data System (ADS)

    Bassey, Bassey; Moreno, Beatriz; Gomez, Ariel; Ahmed, Asm Sabbir; Ullrich, Doug; Chapman, Dean

    2014-05-01

    At the Canadian Light Source (CLS), the plans for the construction of three beamlines under the Brockhouse Project are underway. The beamlines, to be classified under the CLS Phase III beamlines, will comprise of a wiggler and an undulator, and will be dedicated to x-ray diffraction and scattering experiments. The energy range of these beamlines will be 7-22 keV (low energy wiggler beamline), 20-94 keV (high energy wiggler beamline), and 5-21 keV (undulator beamline). The beamlines will have a total of five hutches. Presented is the shielding design against target scattered white and monochromatic synchrotron radiations for these beamlines. The shielding design is based on: scatter target material-water, dose object-anthropomorphic phantom of the adult human (anteroposterior-AP geometry), and shielding thicknesses of steel and lead that will drop the radiation leakage from the hutches to below 0.5 μSv/h.

  18. Drag of heavy quarks in quark gluon plasma at energies available at the CERN Large Hadron Collider (LHC)

    SciTech Connect

    Das, Santosh K.; Alam, Jan-e; Mohanty, Payal

    2010-07-15

    The drag and diffusion coefficients of charm and bottom quarks propagating through quark gluon plasma (QGP) have been evaluated for conditions relevant to nuclear collisions at the Large Hadron Collider (LHC). The dead cone and Landau-Pomeronchuk-Migdal (LPM) effects on radiative energy loss of heavy quarks have been considered. Both radiative and collisional processes of energy loss are included in the effective drag and diffusion coefficients. With these effective transport coefficients, we solve the Fokker-Plank (FP) equation for the heavy quarks executing Brownian motion in the QGP. The solution of the FP equation has been used to evaluate the nuclear suppression factor, R{sub AA}, for the nonphotonic single-electron spectra resulting from the semileptonic decays of hadrons containing charm and bottom quarks. The effects of mass on R{sub AA} have also been highlighted.

  19. Local changes in arterial oxygen saturation induced by visible and near-infrared light radiation.

    PubMed

    Yesman, S S; Mamilov, S O; Veligotsky, D V; Gisbrecht, A I

    2016-01-01

    In this study, we investigate the efficiency of laser radiation on oxyhemoglobin (HbO2) rate in blood vessels and its wavelength dependence. The results of in vivo experimental measurements of the laser-induced photodissociation of HbO2 in cutaneous blood vessels in the visible and near-infrared (IR) spectral range are presented. Arterial oxygen saturation (SpO2) was measured by a method of fingertip pulse oximetry, which is based on the measurement of the modulated pulse wave of the blood. The light irradiating the finger was provided by corresponding light-emitting diodes (LED) at 15 wavelengths in the 400-940 nm spectrum range. Statistical results with a value of p < 0.05 were viewed as being significant for all volunteers. The results show that there is a decrease in SpO2 in the blood under the influence of the transcutaneous laser irradiation. Three maxima in the spectral range (530, 600, and 850 nm) are revealed, wherein decrease in the relative concentration of SpO2 reaches 5 % ± 0.5 %. Near-IR radiation plays a dominant role in absorption of laser radiation by oxyhemoglobin in deeper layers of tissue blood vessels. The obtained data correlate with the processes of light propagation in biological tissue. The observed reduction in SpO2 indicates the process of photodissociation of HbO2 in vivo and may result in local increase in O2 in the tissue. Such laser-induced enrichment of tissue oxygenation can be used in phototherapy of pathologies, where the elimination of local tissue hypoxia is critical.

  20. Simulations of radiation pressure experiments narrow down the energy and momentum of light in matter.

    PubMed

    Bethune-Waddell, Max; Chau, Kenneth J

    2015-12-01

    Consensus on a single electrodynamic theory has yet to be reached. Discord was seeded over a century ago when Abraham and Minkowski proposed different forms of electromagnetic momentum density and has since expanded in scope with the gradual introduction of other forms of momentum and force densities. Although degenerate sets of electrodynamic postulates can be fashioned to comply with global energy and momentum conservation, hope remains to isolate a single theory based on detailed comparison between force density predictions and radiation pressure experiments. This comparison is two-fold challenging because there are just a handful of quantitative radiation pressure measurements over the past century and the solutions developed from different postulates, which consist of approximate expressions and inferential deductions, are scattered throughout the literature. For these reasons, it is appropriate to conduct a consolidated and comprehensive re-analysis of past experiments under the assumption that the momentum and energy of light in matter are degenerate. We create a combined electrodynamic/fluid dynamic simulation testbed that uses five historically significant sets of electrodynamic postulates, including those by Abraham and Minkowski, to model radiation pressure under diverse configurations with minimal assumptions. This leads to new interpretations of landmark investigations of light momentum, including the Balazs thought experiment, the Jones-Richards and Jones-Leslie measurements of radiation pressure on submerged mirrors, observations of laser-deformed fluid surfaces, and experiments on optical trapping and tractor beaming of dielectric particles. We discuss the merits and demerits of each set of postulates when compared to available experimental evidence and fundamental conservation laws. Of the five sets of postulates, the Abraham and Einstein-Laub postulates provide the greatest consistency with observations and the most physically plausible

  1. Synchrotron Vacuum Ultraviolet Light and Soft X-Ray Radiation Effects on Aluminized Teflon FEP Investigated

    NASA Technical Reports Server (NTRS)

    Dever, Joyce A.; Townsend, Jacqueline A.; Gaier, James R.; Jalics, Alice I.

    1999-01-01

    Since the Hubble Space Telescope (HST) was deployed in low Earth orbit in April 1990, two servicing missions have been conducted to upgrade its scientific capabilities. Minor cracking of second-surface metalized Teflon FEP (DuPont; fluorinated ethylene propylene) surfaces from multilayer insulation (MLI) was first observed upon close examination of samples with high solar exposure retrieved during the first servicing mission, which was conducted 3.6 years after deployment. During the second HST servicing mission, 6.8 years after deployment, astronaut observations and photographic documentation revealed significant cracks in the Teflon FEP layer of the MLI on both the solar- and anti-solar-facing surfaces of the telescope. NASA Goddard Space Flight Center directed the efforts of the Hubble Space Telescope MLI Failure Review Board, whose goals included identifying the low-Earth-orbit environmental constituent(s) responsible for the cracking and embrittling of Teflon FEP which was observed during the second servicing mission. The NASA Lewis Research Center provided significant support to this effort. Because soft x-ray radiation from solar flares had been considered as a possible cause for the degradation of the mechanical properties of Teflon FEP (ref. 1), the effects of soft xray radiation and vacuum ultraviolet light on Teflon FEP were investigated. In this Lewisled effort, samples of Teflon FEP with a 100-nm layer of vapor-deposited aluminum (VDA) on the backside were exposed to synchrotron radiation of various vacuum ultraviolet and soft x-ray wavelengths between 18 nm (69 eV) and 0.65 nm (1900 eV). Synchrotron radiation exposures were conducted using the National Synchrotron Light Source at Brookhaven National Laboratory. Samples of FEP/VDA were exposed with the FEP surface facing the synchrotron beam. Doses and fluences were compared with those estimated for the 20-yr Hubble Space Telescope mission.

  2. Simulations of radiation pressure experiments narrow down the energy and momentum of light in matter

    NASA Astrophysics Data System (ADS)

    Bethune-Waddell, Max; Chau, Kenneth J.

    2015-12-01

    Consensus on a single electrodynamic theory has yet to be reached. Discord was seeded over a century ago when Abraham and Minkowski proposed different forms of electromagnetic momentum density and has since expanded in scope with the gradual introduction of other forms of momentum and force densities. Although degenerate sets of electrodynamic postulates can be fashioned to comply with global energy and momentum conservation, hope remains to isolate a single theory based on detailed comparison between force density predictions and radiation pressure experiments. This comparison is two-fold challenging because there are just a handful of quantitative radiation pressure measurements over the past century and the solutions developed from different postulates, which consist of approximate expressions and inferential deductions, are scattered throughout the literature. For these reasons, it is appropriate to conduct a consolidated and comprehensive re-analysis of past experiments under the assumption that the momentum and energy of light in matter are degenerate. We create a combined electrodynamic/fluid dynamic simulation testbed that uses five historically significant sets of electrodynamic postulates, including those by Abraham and Minkowski, to model radiation pressure under diverse configurations with minimal assumptions. This leads to new interpretations of landmark investigations of light momentum, including the Balazs thought experiment, the Jones-Richards and Jones-Leslie measurements of radiation pressure on submerged mirrors, observations of laser-deformed fluid surfaces, and experiments on optical trapping and tractor beaming of dielectric particles. We discuss the merits and demerits of each set of postulates when compared to available experimental evidence and fundamental conservation laws. Of the five sets of postulates, the Abraham and Einstein-Laub postulates provide the greatest consistency with observations and the most physically plausible

  3. The Quark - A Decade Later

    ERIC Educational Resources Information Center

    Dakin, James T.

    1974-01-01

    Reviews theoretical principles underlying the quark model. Indicates that the agreement with experimental results and the understanding of the quark-quark force are two hurdles for the model to survive in the future. (CC)

  4. The Quark - A Decade Later

    ERIC Educational Resources Information Center

    Dakin, James T.

    1974-01-01

    Reviews theoretical principles underlying the quark model. Indicates that the agreement with experimental results and the understanding of the quark-quark force are two hurdles for the model to survive in the future. (CC)

  5. Track structure based modelling of light ion radiation effects on nuclear and mitochondrial DNA

    NASA Astrophysics Data System (ADS)

    Schmitt, Elke; Ottolenghi, Andrea; Dingfelder, Michael; Friedland, Werner; Kundrat, Pavel; Baiocco, Giorgio

    2016-07-01

    Space radiation risk assessment is of great importance for manned spaceflights in order to estimate risks and to develop counter-measures to reduce them. Biophysical simulations with PARTRAC can help greatly to improve the understanding of initial biological response to ionizing radiation. Results from modelling radiation quality dependent DNA damage and repair mechanisms up to chromosomal aberrations (e.g. dicentrics) can be used to predict radiation effects depending on the kind of mixed radiation field exposure. Especially dicentric yields can serve as a biomarker for an increased risk due to radiation and hence as an indicator for the effectiveness of the used shielding. PARTRAC [1] is a multi-scale biophysical research MC code for track structure based initial DNA damage and damage response modelling. It integrates physics, radiochemistry, detailed nuclear DNA structure and molecular biology of DNA repair by NHEJ-pathway to assess radiation effects on cellular level [2]. Ongoing experiments with quasi-homogeneously distributed compared to sub-micrometre focused bunches of protons, lithium and carbon ions allow a separation of effects due to DNA damage complexity on nanometre scale from damage clustering on (sub-) micrometre scale [3, 4]. These data provide an unprecedented benchmark for the DNA damage response model in PARTRAC and help understand the mechanisms leading to cell killing and chromosomal aberrations (e.g. dicentrics) induction. A large part of space radiation is due to a mixed ion field of high energy protons and few heavier ions that can be only partly absorbed by the shielding. Radiation damage induced by low-energy ions significantly contributes to the high relative biological efficiency (RBE) of ion beams around Bragg peak regions. For slow light ions the physical cross section data basis in PARTRAC has been extended to investigate radiation quality effects in the Bragg peak region [5]. The resulting range and LET values agree with ICRU data

  6. Supernova Shock Breakout Light Curves and Spectra from CASTRO Multigroup Radiation Simulations

    NASA Astrophysics Data System (ADS)

    Lovegrove, Elizabeth; Woosley, S. E.

    2014-01-01

    We present preliminary results from a study of supernova shock breakout with the new multigroup radiation transport version of the CASTRO simulation code. Shock breakout occurs when the outgoing shockwave of a supernova explosion reaches the surface of the progenitor star and produces a bright flash. The breakout flash's spectral temperature, duration, and luminosity carry information about the progenitor star that may otherwise be very difficult to recover. To aid in detection and understanding of this phenomenon, we present integrated light curves and spectra of breakouts from a range of progenitors and explosions, including very low energy supernovae and pair-instability supernovae.

  7. The Advanced Light Source: A third-generation Synchrotron Radiation Source

    SciTech Connect

    Robinson, Arthur L.

    2002-08-14

    The Advanced Light Source (ALS) at the E.O. Lawrence Berkeley National Laboratory (Berkeley Lab) of the University of California is a ''third-generation'' synchrotron radiation source optimized for highest brightness at ultraviolet and soft x-ray photon energies. It also provides world-class performance at hard x-ray photon energies. Berkeley Lab operates the ALS for the United States Department of Energy as a national user facility that is available 24 hours/day around the year for research by scientists from industrial, academic, and government laboratories primarily from the United States but also from abroad.

  8. Search for a Very Light CP-Odd Higgs Boson in Top Quark Decays from pp-bar; Collisions at √s = 1.96 TeV

    DOE PAGES

    Aaltonen, T.

    2011-07-11

    We present the results of a search for a very light CP-odd Higgs boson a10 originating from top quark decays t→H±b → W±(*)a10b, and subsequently decaying into τ+τ-. Using a data sample corresponding to an integrated luminosity of 2.7 fb-1 collected by the CDF II detector in pp-bar collisions at 1.96 TeV, we perform a search for events containing a lepton, three or more jets, and an additional isolated track with transverse momentum in the range 3 to 20 GeV/c. Observed events are consistent with background sources, and 95% C.L. limits are set on the branching ratio of t→H±b formore » various masses of H± and a10.« less

  9. Search for a very light CP-odd Higgs boson in top quark decays from pp collisions at sqrt(s)]=1.96  TeV.

    PubMed

    Aaltonen, T; Álvarez González, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Apresyan, A; Arisawa, T; Artikov, A; Asaadi, J; Ashmanskas, W; Auerbach, B; Aurisano, A; Azfar, F; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Barria, P; Bartos, P; Bauce, M; Bauer, G; Bedeschi, F; Beecher, D; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Bhatti, A; Binkley, M; Bisello, D; Bizjak, I; Bland, K R; Blocker, C; Blumenfeld, B; Bocci, A; Bodek, A; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Brigliadori, L; Brisuda, A; Bromberg, C; Brucken, E; Bucciantonio, M; Budagov, J; Budd, H S; Budd, S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Cabrera, S; Calancha, C; Camarda, S; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carls, B; Carlsmith, D; Carosi, R; Carrillo, S; Carron, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavaliere, V; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, K; Chokheli, D; Chou, J P; Chung, W H; Chung, Y S; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Compostella, G; Convery, M E; Conway, J; Corbo, M; Cordelli, M; Cox, C A; Cox, D J; Crescioli, F; Cuenca Almenar, C; Cuevas, J; Culbertson, R; Dagenhart, D; d'Ascenzo, N; Datta, M; de Barbaro, P; De Cecco, S; De Lorenzo, G; Dell'Orso, M; Deluca, C; Demortier, L; Deng, J; Deninno, M; Devoto, F; d'Errico, M; Di Canto, A; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Donati, S; Dong, P; Dorigo, T; Ebina, K; Elagin, A; Eppig, A; Erbacher, R; Errede, D; Errede, S; Ershaidat, N; Eusebi, R; Fang, H C; Farrington, S; Feindt, M; Fernandez, J P; Ferrazza, C; Field, R; Flanagan, G; Forrest, R; Frank, M J; Franklin, M; Freeman, J C; Furic, I; Gallinaro, M; Galyardt, J; Garcia, J E; Garfinkel, A F; Garosi, P; Gerberich, H; Gerchtein, E; Giagu, S; Giakoumopoulou, V; Giannetti, P; Gibson, K; Ginsburg, C M; Giokaris, N; Giromini, P; Giunta, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldin, D; Goldschmidt, N; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gresele, A; Grinstein, S; Grosso-Pilcher, C; Group, R C; Guimaraes da Costa, J; Gunay-Unalan, Z; Haber, C; Hahn, S R; Halkiadakis, E; Hamaguchi, A; Han, J Y; Happacher, F; Hara, K; Hare, D; Hare, M; Harr, R F; Hatakeyama, K; Hays, C; Heck, M; Heinrich, J; Herndon, M; Hewamanage, S; Hidas, D; Hocker, A; Hopkins, W; Horn, D; Hou, S; Hughes, R E; Hurwitz, M; Husemann, U; Hussain, N; Hussein, M; Huston, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jang, D; Jayatilaka, B; Jeon, E J; Jha, M K; Jindariani, S; Johnson, W; Jones, M; Joo, K K; Jun, S Y; Junk, T R; Kamon, T; Karchin, P E; Kato, Y; Ketchum, W; Keung, J; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, H W; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kimura, N; Klimenko, S; Kondo, K; Kong, D J; Konigsberg, J; Korytov, A; Kotwal, A V; Kreps, M; Kroll, J; Krop, D; Krumnack, N; Kruse, M; Krutelyov, V; Kuhr, T; Kurata, M; Kwang, S; Laasanen, A T; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; LeCompte, T; Lee, E; Lee, H S; Lee, J S; Lee, S W; Leo, S; Leone, S; Lewis, J D; Lin, C-J; Linacre, J; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, C; Liu, Q; Liu, T; Lockwitz, S; Lockyer, N S; Loginov, A; Lucchesi, D; Lueck, J; Lujan, P; Lukens, P; Lungu, G; Lys, J; Lysak, R; Madrak, R; Maeshima, K; Makhoul, K; Maksimovic, P; Malik, S; Manca, G; Manousakis-Katsikakis, A; Margaroli, F; Marino, C; Martínez, M; Martínez-Ballarín, R; Mastrandrea, P; Mathis, M; Mattson, M E; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Menzione, A; Mesropian, C; Miao, T; Mietlicki, D; Mitra, A; Miyake, H; Moed, S; Moggi, N; Mondragon, M N; Moon, C S; Moore, R; Morello, M J; Morlock, J; Movilla Fernandez, P; Mukherjee, A; Muller, Th; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Naganoma, J; Nakano, I; Napier, A; Nett, J; Neu, C; Neubauer, M S; Nielsen, J; Nodulman, L; Norniella, O; Nurse, E; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Ortolan, L; Pagan Griso, S; Pagliarone, C; Palencia, E; Papadimitriou, V; Paramonov, A A; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Pianori, E; Pilot, J; Pitts, K; Plager, C; Pondrom, L; Potamianos, K; Poukhov, O; Prokoshin, F; Pronko, A; Ptohos, F; Pueschel, E; Punzi, G; Pursley, J; Rahaman, A; Ramakrishnan, V; Ranjan, N; Redondo, I; Renton, P; Rescigno, M; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rodriguez, T; Rogers, E; Rolli, S; Roser, R; Rossi, M; Ruffini, F; Ruiz, A; Russ, J; Rusu, V; Safonov, A; Sakumoto, W K; Santi, L; Sartori, L; Sato, K; Saveliev, V; Savoy-Navarro, A; Schlabach, P; Schmidt, A; Schmidt, E E; Schmidt, M P; Schmitt, M; Schwarz, T; Scodellaro, L; Scribano, A; Scuri, F; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Sforza, F; Sfyrla, A; Shalhout, S Z; Shears, T; Shepard, P F; Shimojima, M; Shiraishi, S; Shochet, M; Shreyber, I; Simonenko, A; Sinervo, P; Sissakian, A; Sliwa, K; Smith, J R; Snider, F D; Soha, A; Somalwar, S; Sorin, V; Squillacioti, P; Stanitzki, M; St Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Strycker, G L; Sudo, Y; Sukhanov, A; Suslov, I; Takemasa, K; Takeuchi, Y; Tang, J; Tecchio, M; Teng, P K; Thom, J; Thome, J; Thompson, G A; Thomson, E; Ttito-Guzmán, P; Tkaczyk, S; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Totaro, P; Trovato, M; Tu, Y; Turini, N; Ukegawa, F; Uozumi, S; Varganov, A; Vataga, E; Vázquez, F; Velev, G; Vellidis, C; Vidal, M; Vila, I; Vilar, R; Vogel, M; Volpi, G; Wagner, P; Wagner, R L; Wakisaka, T; Wallny, R; Wang, S M; Warburton, A; Waters, D; Weinberger, M; Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Wilbur, S; Wick, F; Williams, H H; Wilson, J S; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, H; Wright, T; Wu, X; Wu, Z; Yamamoto, K; Yamaoka, J; Yang, T; Yang, U K; Yang, Y C; Yao, W-M; Yeh, G P; Yi, K; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanetti, A; Zeng, Y; Zucchelli, S

    2011-07-15

    We present the results of a search for a very light CP-odd Higgs boson a(1)(0) originating from top quark decays t → H(±)b → W(±(*)) a(1)(0)b, and subsequently decaying into τ+ τ-. Using a data sample corresponding to an integrated luminosity of 2.7  fb(-1) collected by the CDF II detector in pp collisions at 1.96 TeV, we perform a search for events containing a lepton, three or more jets, and an additional isolated track with transverse momentum in the range 3 to 20  GeV/c. Observed events are consistent with background sources, and 95% C.L. limits are set on the branching ratio of t → H(±)b for various masses of H(±) and a(1)(0).

  10. Lighting considerations in controlled environments for nonphotosynthetic plant responses to blue and ultraviolet radiation

    SciTech Connect

    Caldwell, M.M.; Flint, S.D.

    1994-12-31

    This essay will consider both physical and photobiological aspects of controlled environment lighting in the spectral region beginning in the blue and taken to the normal limit of the solar spectrum in the ultraviolet. The primary emphasis is directed to questions of plant response to sunlight. Measurement and computations used in radiation dosimetry in this part of the spectrum are also briefly treated. Because of interest in the ozone depletion problem, there has been some activity in plant UV-B research and there are several recent reviews available. Some aspects of growth chamber lighting as it relates to UV-B research were covered earlier. Apart from work related to the blue/UV-A receptor, less attention has been given to UV-A responses.

  11. Lighting considerations in controlled environments for nonphotosynthetic plant responses to blue and ultraviolet radiation

    NASA Technical Reports Server (NTRS)

    Caldwell, M. M.; Flint, S. D.

    1994-01-01

    This essay will consider both physical and photobiological aspects of controlled environment lighting in the spectral region beginning in the blue and taken to the normal limit of the solar spectrum in the ultraviolet. The primary emphasis is directed to questions of plant response to sunlight. Measurement and computations used in radiation dosimetry in this part of the spectrum are also briefly treated. Because of interest in the ozone depletion problem, there has been some activity in plant UV-B research and there are several recent reviews available. Some aspects of growth chamber lighting as it relates to UV-B research were covered earlier. Apart from work related to the blue/UV-A receptor, less attention has been given to UV-A responses.

  12. Non-Radiative Energy Transfer Mediated by Hybrid Light-Matter States.

    PubMed

    Zhong, Xiaolan; Chervy, Thibault; Wang, Shaojun; George, Jino; Thomas, Anoop; Hutchison, James A; Devaux, Eloise; Genet, Cyriaque; Ebbesen, Thomas W

    2016-05-17

    We present direct evidence of enhanced non-radiative energy transfer between two J-aggregated cyanine dyes strongly coupled to the vacuum field of a cavity. Excitation spectroscopy and femtosecond pump-probe measurements show that the energy transfer is highly efficient when both the donor and acceptor form light-matter hybrid states with the vacuum field. The rate of energy transfer is increased by a factor of seven under those conditions as compared to the normal situation outside the cavity, with a corresponding effect on the energy transfer efficiency. The delocalized hybrid states connect the donor and acceptor molecules and clearly play the role of a bridge to enhance the rate of energy transfer. This finding has fundamental implications for coherent energy transport and light-energy harvesting.

  13. Light dark photon and fermionic dark radiation for the Hubble constant and the structure formation

    NASA Astrophysics Data System (ADS)

    Ko, P.; Tang, Yong

    2016-11-01

    Motivated by the tensions in the Hubble constant H0 and the structure growth σ8 between Planck results and other low redshift measurements, we discuss some cosmological effects of a dark sector model in which dark matter (DM) interacts with fermionic dark radiation (DR) through a light gauge boson (dark photon). Such kind of models are very generic in particle physics with a dark sector with dark gauge symmetries. The effective number of neutrinos is increased by δNeff ∼ 0.5 due to light dark photon and fermionic DR, thereby resolving the conflicts in H0. The elastic scattering between DM and DR induces suppression for DM's density perturbation, but without acoustic oscillations. For weakly-interacting DM around 100 GeV, the new gauge coupling should be ∼10-4 to have sizable effect on matter power spectrum in order to relax the tension in σ8.

  14. Radiation-Pressure Acceleration of Ion Beams from Nanofoil Targets: The Leaky Light-Sail Regime

    SciTech Connect

    Qiao, B.; Zepf, M.; Borghesi, M.; Dromey, B.; Geissler, M.; Karmakar, A.; Gibbon, P.

    2010-10-08

    A new ion radiation-pressure acceleration regime, the 'leaky light sail', is proposed which uses sub-skin-depth nanometer foils irradiated by circularly polarized laser pulses. In the regime, the foil is partially transparent, continuously leaking electrons out along with the transmitted laser field. This feature can be exploited by a multispecies nanofoil configuration to stabilize the acceleration of the light ion component, supplementing the latter with an excess of electrons leaked from those associated with the heavy ions to avoid Coulomb explosion. It is shown by 2D particle-in-cell simulations that a monoenergetic proton beam with energy 18 MeV is produced by circularly polarized lasers at intensities of just 10{sup 19} W/cm{sup 2}. 100 MeV proton beams are obtained by increasing the intensities to 2x10{sup 20} W/cm{sup 2}.

  15. Radiation-pressure acceleration of ion beams from nanofoil targets: the leaky light-sail regime.

    PubMed

    Qiao, B; Zepf, M; Borghesi, M; Dromey, B; Geissler, M; Karmakar, A; Gibbon, P

    2010-10-08

    A new ion radiation-pressure acceleration regime, the "leaky light sail," is proposed which uses sub-skin-depth nanometer foils irradiated by circularly polarized laser pulses. In the regime, the foil is partially transparent, continuously leaking electrons out along with the transmitted laser field. This feature can be exploited by a multispecies nanofoil configuration to stabilize the acceleration of the light ion component, supplementing the latter with an excess of electrons leaked from those associated with the heavy ions to avoid Coulomb explosion. It is shown by 2D particle-in-cell simulations that a monoenergetic proton beam with energy 18 MeV is produced by circularly polarized lasers at intensities of just 10¹⁹  W/cm². 100 MeV proton beams are obtained by increasing the intensities to 2 × 10²⁰  W/cm².

  16. Monitoring temperature and light exposure of biosamples exposed to ultraviolet and low energy radiation.

    PubMed

    Chen, Hsin-Kai; Waite, Gabi Nindl; Miller, Penney L; Hughes, Ellen F; Waite, Lee R

    2007-01-01

    We previously showed that T-lymphocytes produce catalytic amounts of hydrogen peroxide (H2O2) in a membrane-associated process when irradiated with narrowband ultraviolet B (UVB) light. This form of phototherapy is thought to be highly effective for treatment of inflammatory skin diseases such as psoriasis, but also includes the potential for severe burning and development of skin cancer. Consequently, information on the therapeutic mechanism of narrowband UVB phototherapy and its regulation is warranted. Our laboratory is researching the mechanistic involvement of T-cell H2O2 production and its potential regulation by low energy electromagnetic field (EMF) radiation, which has been shown to beneficially influence inflammatory diseases such as psoriasis. To study photochemical H2O2 production in small samples such as suspensions of T-lymphocyte cell extracts, we use a reactor in which 12 microliter-sized samples are exposed to UVB. We simultaneously operate two identical systems, one for experimental, the other for control samples, within a walk-in environmental chamber maintained at 37 degrees C. The current paper addresses the control of UVB light exposure and temperature in our experimental setup. We quantified UVB light b y radiometric sp ot measurements and by chemical potassium ferrioxalate actinometry. We modified the actinometer so that UVB light of 5-hour experiments could be detected. Temperature was controlled by air convection and remained constant within 0.5 degrees C in air and liquid samples. Preliminary data of the effect of low energy EMF radiation on T-cell H2O2 production are presented.

  17. An Analysis of Pluto Occultation Light Curves Using an Atmospheric Radiative-conductive Model

    NASA Astrophysics Data System (ADS)

    Zalucha, Angela M.; Gulbis, A. A. S.; Zhu, X.; Strobel, D. F.; Elliot, J. L.

    2009-09-01

    Using the radiative equilibrium temperature profiles obtained from the radiative-conductive model of Strobel et al. 1996 (Icarus, 120, 266-289), we calculate a set of occultation light curves for Pluto for a range of surface pressures and methane mixing ratios, the latter of which is assumed to be constant with height. We have devised a method to interpolate a grid of model light curves in order to perform least-squares fitting to available Pluto occultation data. Fits without a troposphere and with a surface radius of 1152 km to the 2006 June 12 occultation by Pluto observed at Siding Spring (Elliot et al. 2007, AJ 134, 1-13) return a surface pressure and methane mixing ratio of 18.9 +/- 0.8 microbar and 0.0020 +/- 0.0003, respectively. Best fits to the 2002 August 21 occultation observed using the 2.24m University of Hawaii telescope (Pasachoff et al. 2005, AJ 129, 1718-1723) are 18.5 +/- 0.5 microbar and 0.0020 +/- 0.0001, respectively. For each of these fits, surface temperature and CO mixing ratio (also constant with height) were taken to be 37 K and 0.0005, respectively. The model light curves are not found to be sensitive to either of these parameters; CO mixing ratios as high as 0.02 are found to be consistent with the formal error bars on the fits above. The fitted surface pressure values are higher than those derived from the no troposphere models of Lellouch et al. 2009 (Astron. Astrophys. 495, L17-L21), while the methane mixing ratio values are lower. We will present our methodology of comparing atmospheric models to occultation data, fitting results for other stellar occultation light curves, and implications for Pluto's atmospheric structure. This work was supported in part by NASA grants NNX08AE92G, NNX07AK73G, and NNG05GO91G.

  18. Generation of convergent light beams by using surface plasmon locked Smith-Purcell radiation.

    PubMed

    Lai, Yi-Chieh; Kuang, Tzu Cheng; Cheng, Bo Han; Lan, Yung-Chiang; Tsai, Din Ping

    2017-09-11

    An electron bunch passing through a periodic metal grating can emit Smith-Purcell radiation (SPR). Recently, it has been found that SPR can be locked and enhanced at some emission wavelength and angle by excitation of surface plasmon (SP) on the metal substrate. In this work, the generation of a convergent light beam via using the SP-locked SPR is proposed and investigated by computer simulations. The proposed structure is composed of an insulator-metal-insulator (IMI) substrate with chirped gratings on the substrate. The chirped gratings are designed such that a convergent beam containing a single wavelength is formed directly above the gratings when an electron bunch passes beneath the substrate. The wavelength of the convergent beam changes with the refractive index of dielectric layer of the IMI structure, which is determined by the frequency of SP on the IMI substrate excited by the electron bunch. Moreover, reversing the direction of electron bunch will make the emitted light from the proposed structure to switch from a convergent beam to a divergent beam. Finally, the formation of a convergent beam containing red, green and blue lights just above the chirped gratings is also demonstrated. This work offers potential applications in the fields of optical imaging, optical beam steering, holography, microdisplay, cryptography and light source.

  19. Isolation of uvh1, an Arabidopsis mutant hypersensitive to ultraviolet light and ionizing radiation.

    PubMed Central

    Harlow, G R; Jenkins, M E; Pittalwala, T S; Mount, D W

    1994-01-01

    A genetic screen for mutants of Arabidopsis that are hypersensitive to UV light was developed and used to isolate a new mutant designated uvh1. UV hypersensitivity in uvh1 was due to a single recessive trait that is probably located on chromosome 3. Although isolated as hypersensitive to an acute exposure to UV-C light, uvh1 was also hypersensitive to UV-B wavelengths, which are present in sunlight that reaches the earth's surface. UV-B damage to both wild-type and uvh1 plants could be significantly reduced by subsequent exposure of UV-irradiated plants to photoreactivating light, showing that photoreactivation of UV-B damage is important for plant viability and that uvh1 plants are not defective in photoreactivation. A new assay for DNA damage, the Dral assay, was developed and used to show that exposure of wild-type and uvh1 plants to a given dose of UV light induces the same amount of damage in chloroplast and nuclear DNA. Thus, uvh1 is not defective in a UV protective mechanism. uvh1 plants were also found to be hypersensitive to ionizing radiation. These results suggest that uvh1 is defective in a repair or tolerance mechanism that normally provides plants with resistance to several types of DNA damage. PMID:8148646

  20. Evidence for production of single top quarks

    SciTech Connect

    Abazov, V.M.; Abbott, B.; Abolins, M.; Acharya, B.S.; Adams, M.; Adams, T.; Aguilo, E.; Ahn, S.H.; Ahsan, M.; Alexeev, G.D.; Alkhazov, G.; /St. Petersburg, INP /Michigan U.

    2008-03-01

    We present first evidence for the production of single top quarks in the D0 detector at the Fermilab Tevatron p{bar p} collider. The standard model predicts that the electroweak interaction can produce a top quark together with an antibottom quark or light quark, without the antiparticle top quark partner that is always produced from strong coupling processes. Top quarks were first observed in pair production in 1995, and since then, single top quark production has been searched for in ever larger datasets. In this analysis, we select events from a 0.9 fb{sup -1} dataset that have an electron or muon and missing transverse energy from the decay of a W boson from the top quark decay, and two, three, or four jets, with one or two of the jets identified as originating from a b hadron decay. The selected events are mostly backgrounds such as W+jets and t{bar t} events, which we separate from the expected signals using three multivariate analysis techniques: boosted decision trees, Bayesian neural networks, and matrix element calculations. A binned likelihood fit of the signal cross section plus background to the data from the combination of the results from the three analysis methods gives a cross section for single top quark production of {sigma}(p{bar p} {yields} tb + X, tqb + X) = 4.7 {+-} 1.3 pb. The probability to measure a cross section at this value or higher in the absence of signal is 0.014%, corresponding to a 3.6 standard deviation significance. The measured cross section value is compatible at the 10% level with the standard model prediction for electroweak top quark production. We use the cross section measurement to directly determine the Cabibbo-Kobayashi-Maskawa quark mixing matrix element that describes the Wtb coupling and find |V{sub tb}f{sub 1}{sup L}| = 1.31{sub -0.21}{sup +0.25}, where f{sub 1}{sup L} is a generic vector coupling. This model-independent measurement translates into 0.68 < |V{sub tb}| {le} 1 at the 95% C.L. in the standard model.

  1. The interplay between assumed morphology and the direct radiative effect of light-absorbing organic aerosol

    NASA Astrophysics Data System (ADS)

    Saleh, Rawad; Adams, Peter J.; Donahue, Neil M.; Robinson, Allen L.

    2016-08-01

    Mie theory is widely employed in aerosol top-of-the-atmosphere direct radiative effect (DRE) calculations and to retrieve the absorptivity of light-absorbing organic aerosol (OA) from measurements. However, when OA is internally mixed with black carbon, it may exhibit complex morphologies whose optical behavior is imperfectly predicted by Mie theory, introducing bias in the retrieved absorptivities. We performed numerical experiments and global radiative transfer modeling (RTM) to investigate the effect of this bias on the calculated absorption and thus the DRE. We show that using true OA absorptivity, retrieved with a realistic representation of the complex morphology, leads to significant errors in DRE when the RTM employs the simplified Mie theory. On the other hand, when Mie theory is consistently applied in both OA absorptivity retrieval and the RTM, the errors largely cancel out, yielding accurate DRE. As long as global RTMs use Mie theory, they should implement parametrizations of light-absorbing OA derived from retrievals based on Mie theory.

  2. Plasma Physics and Radiation Hydrodynamics in Development of EUV Light Sources for Lithography

    NASA Astrophysics Data System (ADS)

    Nishihara, Katsunobu

    2007-11-01

    Understanding of radiation generation in laser-produced high-Z plasma (LPP) is important for inertial fusion, astrophysics and x-ray source development. Extreme ultraviolet (EUV) light of 13.5 nm wavelength is strongly desired for manufacture of next-generation microprocessors with node size less than 45 nm. A commercial EUV lithography system would require output EUV power of about 400 W into a solid angle of 2π str within a 2% bandwidth (BW). Laser-produced tin (Sn) plasma at electron temperature of 30-70 eV and ion density of 10^17-20 cm-3 is an attractive light source due to its compactness and high conversion efficiency (CE) from laser to EUV light [1]. The critical issues for practical use are high CE and damage caused by target debris. Many 4d-4f transitions of Sn^8+ to Sn^13+ ions mainly contribute to strong emission around 13.5 nm. We first discuss the importance of satellite lines, opacity and photo excitation in radiation transport, especially in high density plasmas produced by 1 μm laser. Experiment and simulation indicate that the maximum CE of 3% is limited by these effects for 1μm laser. We show that the use of a long wavelength laser, such as CO2 laser, results in higher CE of 3-6%, since the spectral efficiency, the ratio of 13.5 nm emission within 2% BW to total radiation, increases with the reduction of the plasma density. We present theoretical and experimental results of the CE dependence on laser intensity, pulse duration and laser wavelength. Radiation hydrodynamic simulations agree fairly well with EUV spectra observed in the experiments. High energy ions up to 10 keV generated in LPP cause damage to a collecting mirror. We show that the maximum energy is essentially determined from the ratio of plasma radius to Debye length. We also show that the use of the long wavelength laser also reduces the ion energy. We discuss mitigation of high energy ions by a magnetic field and the stability of plasma expansion taking finite ion Larmor radius

  3. Prediction of acoustic radiation from functionally graded shells of revolution in light and heavy fluids

    NASA Astrophysics Data System (ADS)

    Qu, Yegao; Meng, Guang

    2016-08-01

    This paper presents a semi-analytical method for the vibro-acoustic analysis of a functionally graded shell of revolution immersed in an infinite light or heavy fluid. The structural model of the shell is formulated on the basis of a modified variational method combined with a multi-segment technique, whereas a spectral Kirchhoff-Helmholtz integral formulation is employed to model the exterior fluid field. The material properties of the shell are estimated by using the Voigt's rule of mixture and the Mori-Tanaka's homogenization scheme. Displacement and sound pressure variables of each segment are expanded in the form of a mixed series using Fourier series and Chebyshev orthogonal polynomials. A set of collocation nodes distributed over the roots of Chebyshev polynomials are employed to establish the algebraic system of the acoustic integral equations, and the non-uniqueness solution is eliminated using a combined Helmholtz integral equation formulation. Loosely and strongly coupled schemes are implemented for the structure-acoustic interaction problem of a functionally graded shell immersed in a light and heavy fluid, respectively. The present method provides a flexible way to account for the individual contributions of circumferential wave modes to the vibration and acoustic responses of functionally graded shells of revolution in an analytical manner. Numerical tests are presented for sound radiation problems of spherical, cylindrical, conical and coupled shells. The individual contributions of the circumferential modes to the radiated sound pressure and sound power of functionally graded shells are observed. Effects of the material profile on the sound radiation of the shells are also investigated.

  4. A quark cluster approach for pentaquarks

    SciTech Connect

    Jimenez Delgado, P.

    2005-05-06

    A particular triquark-diquark configuration has been pointed out as the most likely for pentaquarks as a consequence of the stability of quark clusters under the color-magnetic interactions. We estimate the masses and the magnetic moments of light pentaquarks in this configuration.

  5. Advances in the determination of quark masses

    SciTech Connect

    Bhattacharya, T.; Gupta, R.

    1998-03-01

    Significant progress has been made in the determination of the light quark masses, using both lattice QCD and sum rule methods, in the last year. The authors discuss the different methods and review the status of current results. Finally, they review the calculation of bottom and charm masses.

  6. Nuclear and quark matter at high temperature

    NASA Astrophysics Data System (ADS)

    Biró, Tamás S.; Jakovác, Antal; Schram, Zsolt

    2017-03-01

    We review important ideas on nuclear and quark matter description on the basis of high-temperature field theory concepts, like resummation, dimensional reduction, interaction scale separation and spectral function modification in media. Statistical and thermodynamical concepts are spotted in the light of these methods concentrating on the -partially still open- problems of the hadronization process.

  7. Comparison of the Light Charged Particles on Scatter Radiation Dose in Thyroid Hadron Therapy

    PubMed Central

    Azizi, M; Mowlavi, AA

    2014-01-01

    Background: Hadron therapy is a novel technique of cancer radiation therapy which employs charged particles beams, 1H and light ions in particular. Due to their physical and radiobiological properties, they allow one to obtain a more conformal treatment, sparing better the healthy tissues located in proximity of the tumor and allowing a higher control of the disease. Objective: As it is well known, these light particles can interact with nuclei in the tissue, and produce the different secondary particles such as neutron and photon. These particles can damage specially the critical organs behind of thyroid gland. Methods: In this research, we simulated neck geometry by MCNPX code and calculated the light particles dose at distance of 2.14 cm in thyroid gland, for different particles beam: 1H, 2H, 3He, and 4He. Thyroid treatment is important because the spine and vertebrae is situated right behind to the thyroid gland on the posterior side. Results: The results show that 2H has the most total flux for photon and neutron, 1.944E-3 and 1.7666E-2, respectively. Whereas 1H and 3He have best conditions, 8.88609E-4 and 1.35431E-3 for photon, 4.90506E-4 and 4.34057E-3 for neutron, respectively. The same calculation has obtained for energy depositions for these particles. Conclusion: In this research, we investigated that which of these light particles can deliver the maximum dose to the normal tissues and the minimum dose to the tumor. By comparing these results for the mentioned light particles, we find out 1H and 3He is the best therapy choices for thyroid glands whereas 2H is the worst. PMID:25505774

  8. Nonperturbative heavy-quark diffusion in the quark-gluon plasma.

    PubMed

    van Hees, H; Mannarelli, M; Greco, V; Rapp, R

    2008-05-16

    We evaluate heavy-quark (HQ) transport properties in a quark-gluon plasma (QGP) within a Brueckner many-body scheme employing interaction potentials extracted from thermal lattice QCD. The in-medium T matrices for elastic charm- and bottom-quark scattering off light quarks in the QGP are dominated by attractive meson and diquark channels which support resonance states up to temperatures of ~1.5T(c). The resulting drag coefficient increases with decreasing temperature, contrary to expectations based on perturbative QCD scattering. Employing relativistic Langevin simulations we compute HQ spectra and elliptic flow in sqrt[s(NN)]=200 GeV Au-Au collisions. A good agreement with electron decay data supports our nonperturbative computation of HQ diffusion, indicative for a strongly coupled QGP.

  9. Regge trajectories of excited baryons, quark-diquark models, and quark-hadron duality

    NASA Astrophysics Data System (ADS)

    Masjuan, Pere; Arriola, Enrique Ruiz

    2017-09-01

    The parton model relations in conjunction with quark-hadron duality in deep inelastic scattering suggests an asymptotic dominance of the quark-diquark type of baryonic excited states with a radial Regge uniformly distributed mass-squared spectrum, Mn2=μ2n +M02. We argue that this points to a linearly quark-diquark confining potential. We analyze the radial (n ) and angular-momentum (J ) Regge trajectories for all light-quark states with baryon number 1 listed in the 2016 edition of the Particle Data Tables. The parameters of the mass-squared trajectories are obtained by linear regression assuming Δ Mn2˜MnΓn weighted with the width Γn of the resonance, and the error analysis is carried out accordingly.

  10. Isospin asymmetry of quark distributions and implications for single top-quark production at the LHC

    NASA Astrophysics Data System (ADS)

    Alekhin, S.; Blümlein, J.; Moch, S.; PlačakytÄ--, R.

    2016-12-01

    We present an improved determination of the up- and down-quark distributions in the proton using recent data on charged lepton asymmetries from W± gauge-boson production at the LHC and Tevatron. The analysis is performed in the framework of a global fit of parton distribution functions. The fit results are consistent with a nonzero isospin asymmetry of the sea, x (d ¯ -u ¯ ) , at small values of Bjorken x ˜10-4 indicating a delayed onset of the Regge asymptotics of a vanishing (d ¯ -u ¯ ) -asymmetry at small x . We compare with up- and down-quark distributions available in the literature and provide accurate predictions for the production of single top-quarks at the LHC, a process which can serve as a standard candle for the light quark flavor content of the proton.

  11. Radiation Safety Aspects of the Linac Coherent Light Source Project At SLAC

    SciTech Connect

    Rokni, S.H.; Fasso, A.; Mao, S.; Vincke, H.; /SLAC /LCLS

    2005-07-06

    The Linac Coherent Light Source (LCLS) is a Self-Amplified Spontaneous Emission based Free Electron Laser (FEL) that is being designed and built at the Stanford Linear Accelerator Center (SLAC) by a multilaboratory collaboration. This facility will provide ultra-short pulses of coherent x-ray radiation with the fundamental harmonic energy tunable over the energy range of 0.82 to 8.2 keV. One-third of the existing SLAC LINAC will compress and accelerate the electron beam to energies ranging from 4.5 GeV to 14.35 GeV. The beam will then be transported through a 130-meter long undulator, emit FEL and spontaneous radiation. After passing through the undulator, the electron beam is bent to the main electron dump. The LCLS will have two experiment halls as well as x-ray optics and infrastructure necessary to make use of the FEL for research and development in a variety of scientific fields. The facility design will incorporate features that would make it possible to expand in future such that up to 6 independent undulators can be used. While some of the radiation protection issues for the LCLS are similar to those encountered at both high-energy electron linacs and synchrotron radiation facilities, LCLS poses new challenges as well. Some of these new issues include: the length of the facility and of the undulator, the experimental floor in line with the electron beam and the occupancy near zero degrees, and the very high instantaneous intensity of the FEL. The shielding design criteria, methodology, and results from Monte Carlo and analytical calculations are presented.

  12. Effect of SiO2 Nanoextractor on Far-Field Radiation Pattern of Vertical Light-Emitting Diodes

    NASA Astrophysics Data System (ADS)

    Son, Hyokun; Key Lee, June; Kim, Sang-Mook

    2013-10-01

    GaN-InGaN vertical-injection light-emitting diodes (VLEDs) having SiO2 nanorod arrays were demonstrated to enhance the light extraction efficiency and light propagation to the side of the LEDs. The full width at half maximum (FWHM) of the radiation patterns of the VLED having a nano-extractor (115-117°) was more extracted than that of conventional VLED (108-110°). Furthermore, the light output power of the VLEDs having nanorods was enhanced by 7.9% compared with that of the conventional VLEDs. Based on the measured far-field radiation patterns, the nanorods suppressed the total internal reflection and extracted the light to the side of the thin-GaN LEDs.

  13. Enhanced tagging of light utilizing acoustic radiation force with speckle pattern analysis.

    PubMed

    Vakili, Ali; Hollmann, Joseph L; Holt, R Glynn; DiMarzio, Charles A

    2017-10-01

    In optical imaging, the depth and resolution are limited due to scattering. Unlike light, scattering of ultrasound (US) waves in tissue is negligible. Hybrid imaging methods such as US-modulated optical tomography (UOT) use the advantages of both modalities. UOT tags light by inducing phase change caused by modulating the local index of refraction of the medium. The challenge in UOT is detecting the small signal. The displacement induced by the acoustic radiation force (ARF) is another US effect that can be utilized to tag the light. It induces greater phase change, resulting in a stronger signal. Moreover, the absorbed acoustic energy generates heat, resulting in change in the index of refraction and a strong phase change. The speckle pattern is governed by the phase of the interfering scattered waves; hence, speckle pattern analysis can obtain information about displacement and temperature changes. We have presented a model to simulate the insonation processes. Simulation results based on fixed-particle Monte Carlo and experimental results show that the signal acquired by utilizing ARF is stronger compared to UOT. The introduced mean irradiance change (MIC) signal reveals both thermal and mechanical effects of the focused US beam in different timescales. Simulation results suggest that variation in the MIC signal can be used to generate a displacement image of the medium. (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

  14. Electron beam diagnostics using synchrotron radiation at the Advanced Light Source

    SciTech Connect

    Keller, R.; Renner, T.; Massoletti, D.J.

    1996-05-01

    Synchrotron light emitted from a bend magnet is being used to diagnose the electron beam stored in the main accelerator of the Advanced Light Source (ALS) at Berkeley Lab. The radiation has maximum intensity in the soft X-ray region and is imaged by a Kirkpatrick-Baez mirror pair from the source point inside the ring onto a Bismuth/Germanium-Oxide (BGO) crystal, converted into visible light and magnified by an attached microscope. The final image is captured by a TV camera-tube and digitized by a frame- grabber device to obtain records of parameters such as beam size, center location and profile. Data obtained from this Diagnostic Beam Line have been very useful in day-to-day operation of the ALS storage ring to assess the quality and repeatability of the stored beam. The line has further been utilized in several dedicated research activities to measure bunch lengths under various conditions and observe transverse beam instabilities. A summary of obtained results is given in this paper , together with a description of the technical features of the Diagnostic Beam Line.

  15. Hybrid optical-thermal devices and materials for light manipulation and radiative cooling

    NASA Astrophysics Data System (ADS)

    Boriskina, Svetlana V.; Tong, Jonathan K.; Hsu, Wei-Chun; Weinstein, Lee; Huang, Xiaopeng; Loomis, James; Xu, Yanfei; Chen, Gang

    2015-09-01

    We report on optical design and applications of hybrid meso-scale devices and materials that combine optical and thermal management functionalities owing to their tailored resonant interaction with light in visible and infrared frequency bands. We outline a general approach to designing such materials, and discuss two specific applications in detail. One example is a hybrid optical-thermal antenna with sub-wavelength light focusing, which simultaneously enables intensity enhancement at the operating wavelength in the visible and reduction of the operating temperature. The enhancement is achieved via light recycling in the form of whispering-gallery modes trapped in an optical microcavity, while cooling functionality is realized via a combination of reduced optical absorption and radiative cooling. The other example is a fabric that is opaque in the visible range yet highly transparent in the infrared, which allows the human body to efficiently shed energy in the form of thermal emission. Such fabrics can find numerous applications for personal thermal management and for buildings energy efficiency improvement.

  16. Chiral extrapolations on the lattice with strange sea quarks

    NASA Astrophysics Data System (ADS)

    Descotes-Genon, Sébastien

    2005-06-01

    The (light but not-so-light) strange quark may play a special role in the low-energy dynamics of QCD. Strange sea-quark pairs may induce significant differences in the pattern of chiral symmetry breaking in the chiral limits of two and three massless flavours, in relation with the violation of the Zweig rule in the scalar sector. This effect could affect chiral extrapolations of unquenched lattice simulations with three dynamical flavours, and it could be detected through the quark-mass dependence of hadron observables [S. Descotes-Genon, hep-ph/0410233].

  17. Effects of morphology on the radiative properties of internally mixed light absorbing carbon aerosols with different aging status.

    PubMed

    Cheng, Tianhai; Wu, Yu; Chen, Hao

    2014-06-30

    Light absorbing carbon aerosols play a substantial role in climate change through radiative forcing, which is the dominant absorber of solar radiation. Radiative properties of light absorbing carbon aerosols are strongly dependent on the morphological factors and the mixing mechanism of black carbon with other aerosol components. This study focuses on the morphological effects on the optical properties of internally mixed light absorbing carbon aerosols using the numerically exact superposition T-matrix method. Three types aerosols with different aging status such as freshly emitted BC particles, thinly coated light absorbing carbon aerosols, heavily coated light absorbing carbon aerosols are studied. Our study showed that morphological factors change with the aging of internally mixed light absorbing carbon aerosols to result in a dramatic change in their optical properties. The absorption properties of light absorbing carbon aerosols can be enhanced approximately a factor of 2 at 0.67 um, and these enhancements depend on the morphological factors. A larger shell/core diameter ratio of volume-equivalent shell-core spheres (S/C), which indicates the degree of coating, leads to stronger absorption. The enhancement of absorption properties accompanies a greater enhancement of scattering properties, which is reflected in an increase in single scattering albedo (SSA). The enhancement of single scattering albedo due to the morphological effects can reach a factor of 3.75 at 0.67 μm. The asymmetry parameter has a similar yet smaller enhancement. Moreover, the corresponding optical properties of shell-and-core model determined by using Lorenz -Mie solutions are presented for comparison. We found that the optical properties of internally mixed light absorbing carbon aerosol can differ fundamentally from those calculated for the Mie theory shell-and-core model, particularly for thinly coated light absorbing carbon aerosols. Our studies indicate that the complex morphology

  18. Effects of electromagnetic radiation (bright light, extremely low-frequency magnetic fields, infrared radiation) on the circadian rhythm of melatonin synthesis, rectal temperature, and heart rate.

    PubMed

    Griefahn, Barbara; Künemund, Christa; Blaszkewicz, Meinolf; Lerchl, Alexander; Degen, Gisela H

    2002-10-01

    Electromagnetic spectra reduce melatonin production and delay the nadirs of rectal temperature and heart rate. Seven healthy men (16-22 yrs) completed 4 permuted sessions. The control session consisted of a 24-hours bedrest at < 30 lux, 18 degrees C, and < 50 dBA. In the experimental sessions, either light (1500 lux), magnetic field (16.7 Hz, 0.2 mT), or infrared radiation (65 degrees C) was applied from 5 pm to 1 am. Salivary melatonin level was determined hourly, rectal temperature and heart rate were continuously recorded. Melatonin synthesis was completely suppressed by light but resumed thereafter. The nadirs of rectal temperature and heart rate were delayed. The magnetic field had no effect. Infrared radiation elevated rectal temperature and heart rate. Only bright light affected the circadian rhythms of melatonin synthesis, rectal temperature, and heart rate, however, differently thus causing a dissociation, which might enhance the adverse effects of shiftwork in the long run.

  19. Measurement of Photon Statistics of Wiggler Radiation from AN Electron Storage Ring at the National Synchrotron Light Source.

    NASA Astrophysics Data System (ADS)

    Tanabe, Toshiya

    1990-01-01

    The photon statistics of wiggler light from the vacuum ultraviolet (VUV) storage ring at the National Synchrotron Light Source (NSLS) in Brookhaven National Laboratory (BNL) have been measured using an analog photon-counting technique. The linear wiggler produces fundamental wavelength light and the third harmonic light at 532 nm for ring energies ~650 MeV and 375 MeV, respectively. The average ring current was ~50 mA for one-electron-bunch operation. The bunch was ~480 psec long and the wiggler light was emitted every 170.2 nsec. The number of photons emitted by an electron bunch was repetitively measured for a given coherence volume. The photon counting distribution, which is the probability of finding n photons versus n, was obtained. The experimental results show that the wiggler radiation is consistent with multi-mode thermal radiation, whereas the bending magnet light gives rise to a distribution consistent with a Neyman Type-A distribution instead of Poisson when the light of large bandwith through a Pyrex window is collected. Near field and electron beam emittance effects have proven to have an important influence on the transverse coherence of the emitted radiation.

  20. Measurements of the top quark mass and decay width with the D0 detector

    SciTech Connect

    Ilchenko, Yuriy

    2011-11-01

    The top quark discovery in 1995 at Fermilab is one of the major proofs of the standard model (SM). Due to its unique place in SM, the top quark is an important particle for testing the theory and probing for new physics. This article presents most recent measurements of top quark properties from the D0 detector. In particular, the measurement of the top quark mass, the top antitop mass difference and the top quark decay width. The discovery of the top quark in 1995 confirmed the existence of a third generation of quarks predicted in the standard model (SM). Being the heaviest elementary particle known, the top quark appears to become an important particle in our understanding of the standard model and physics beyond it. Because of its large mass the top quark has a very short lifetime, much shorter than the hadronization time. The predicted lifetime is only 3.3 {center_dot} 10{sup -25}s. Top quark is the only quark whose properties can be studied in isolation. A Lorentz-invariant local Quantum Field Theory, the standard model is expected to conserve CP. Due to its unique properties, the top quark provides a perfect test of CPT invariance in the standard model. An ability to look at the quark before being hadronized allows to measure directly mass of the top quark and its antiquark. An observation of a mass difference between particle and antiparticle would indicate violation of CPT invariance. Top quark through its radiative loop correction to the W mass constrains the mass of the Higgs boson. A precise measurement of the top quark mass provides useful information to the search of Higgs boson by constraining its region of possible masses. Another interesting aspect is that the top quark's Yukawa coupling to the Higgs boson is very close to unity (0.996 {+-} 0.006). That implies it may play a special role in the electroweak symmetry breaking mechanism.

  1. Radiation-to-light converters for nuclear environments: near-infrared emitters

    SciTech Connect

    Roeske, F.; Rotter, M.D.; Calavan, P.M.; Lutz, S.S.

    1981-05-04

    The use of fiber optics in the diagnosis of hostile nuclear environments has brought about a pressing need for the development of suitable radiation-to-light converters. These converters must meet stringent diagnostic requirements of linearity and time response while having a wavelength of emission that is compatible with transmission over relatively long lengths of optical fibers. Initial investigations of two, near-infrared-emitting semiconducting materials - CdTe and GaAs are described. Data are presented on the wavelength of emission, linearity, time response, and relative efficiency of these semiconductors. Most data were taken at 77 K because of a dramatic increase in efficiency at this temperature. Measurments show that the intensity-vs-dose curves are linear over several decades of useful input levels. Measurements indicate that GaAs has an efficiency and time response that promise to be useful in diagnostic systems.

  2. Molecular mechanisms involved in adaptive responses to radiation, UV light, and heat.

    PubMed

    Takahashi, Akihisa; Ohnishi, Takeo

    2009-09-01

    Viable organisms recognize and respond to environmental changes or stresses. When these environmental changes and their responses by organisms are extreme, they can limit viability. However, organisms can adapt to these different stresses by utilizing different possible responses via signal transduction pathways when the stress is not lethal. In particular, prior mild stresses can provide some aid to prepare organisms for subsequent more severe stresses. These adjustments or adaptations for future stresses have been called adaptive responses. These responses are present in bacteria, plants and animals. The following review covers recent research which can help describe or postulate possible mechanisms which may be active in producing adaptive responses to radiation, ultraviolet light, and heat.

  3. Radiation pressure on submerged mirrors: implications for the momentum of light in dielectric media.

    PubMed

    Mansuripur, Masud

    2007-03-05

    Radiation pressure measurements on mirrors submerged in dielectric liquids have consistently shown an effective Minkowski momentum for the photons within the liquid. Using an exact theoretical calculation based on Maxwell's equations and the Lorentz law of force, we demonstrate that this result is a consequence of the fact that conventional mirrors impart, upon reflection, a 180 degrees phase shift to the incident beam of light. If the mirror is designed to impart a different phase, then the effective momentum will turn out to be anywhere between the two extremes of the Minkowski and Abraham momenta. Since all values in the range between these two extremes are equally likely to be found in experiments, we argue that the photon momentum inside a dielectric host has the arithmetic mean value of the Abraham and Minkowski momenta.

  4. Radiation Pressure on Submerged Mirrors: Implications for the Momentum of Light in Dielectric Media

    NASA Astrophysics Data System (ADS)

    Mansuripur, Masud

    2007-03-01

    Radiation pressure measurements on mirrors submerged in dielectric liquids have consistently shown an effective Minkowski momentum for the photons within the liquid. Using an exact theoretical calculation based on Maxwell’s equations and the Lorentz law of force, we demonstrate that this result is a consequence of the fact that conventional mirrors impart, upon reflection, a 180° phase shift to the incident beam of light. If the mirror is designed to impart a different phase, then the effective momentum will turn out to be anywhere between the two extremes of the Minkowski and Abraham momenta. Since all values in the range between these two extremes are equally likely to be found in experiments, we argue that the photon momentum inside a dielectric host has the arithmetic mean value of the Abraham and Minkowski momenta.

  5. Applications of Light Amplification by Stimulated Emission of Radiation (Lasers) for Restorative Dentistry.

    PubMed

    Najeeb, Shariq; Khurshid, Zohaib; Zafar, Muhammad Sohail; Ajlal, Syed

    2016-01-01

    Light amplification by stimulated emission of radiation (laser) has been used widely in a range of biomedical and dental applications in recent years. In the field of restorative dentistry, various kinds of lasers have been developed for diagnostic (e.g. caries detection) and operative applications (e.g. tooth ablation, cavity preparation, restorations, bleaching). The main benefits for laser applications are patient comfort, pain relief and better results for specific applications. Major concerns for using dental lasers frequently are high cost, need for specialized training and sensitivity of the technique, thereby compromising its usefulness particularly in developing countries. The main aim of this paper is to evaluate and summarize the applications of lasers in restorative dentistry, including a comparison of the applications of lasers for major restorative dental procedures and conventional clinical approaches. A remarkable increase in the use of lasers for dental application is expected in the near future. © 2015 S. Karger AG, Basel.

  6. Effects of Diffuse Light on Radiation Use Efficiency of Two Anthurium Cultivars Depend on the Response of Stomatal Conductance to Dynamic Light Intensity

    PubMed Central

    Li, Tao; Kromdijk, Johannes; Heuvelink, Ep; van Noort, F. R.; Kaiser, Elias; Marcelis, Leo F. M.

    2016-01-01

    The stimulating effect of diffuse light on radiation use efficiency (RUE) of crops is often explained by the more homogeneous spatial light distribution, while rarely considering differences in temporal light distribution at leaf level. This study investigated whether diffuse light effects on crop RUE can be explained by dynamic responses of leaf photosynthesis to temporal changes of photosynthetic photon flux density (PPFD). Two Anthurium andreanum cultivars (‘Pink Champion’ and ‘Royal Champion’) were grown in two glasshouses covered by clear (control) and diffuse glass, with similar light transmission. On clear days, diffusing the light resulted in less temporal fluctuations of PPFD. Stomatal conductance (gs) varied strongly in response to transient PPFD in ‘Royal Champion,’ whereas it remained relatively constant in ‘Pink Champion.’ Instantaneous net leaf photosynthesis (Pn) in both cultivars approached steady state Pn in diffuse light treatment. In control treatment this only occurred in ‘Pink Champion.’ These cultivar differences were reflected by a higher RUE (8%) in ‘Royal Champion’ in diffuse light treatment compared with control, whereas no effect on RUE was observed in ‘Pink Champion.’ We conclude that the stimulating effect of diffuse light on RUE depends on the stomatal response to temporal PPFD fluctuations, which response is cultivar dependent. PMID:26870071

  7. The generation of short-wave UV light in cells under the action of ultrashort pulses of intense visible radiation

    NASA Astrophysics Data System (ADS)

    Kovarsky, V. A.; Philipp, B. S.; Kovarsky, E. V.

    1997-02-01

    The action of intense laser pulses ( λ = 0.53 μm) on E.coli cells is considered (the cells are transparent in this range). The transformation of laser radiation into UV light due to the high-harmonics generation on the protein molecules (the dipole moment is 100-1000 D) leads to the appearance of thymine dimers in bacterial DNA and results in a lethal effect for strains of E.coli which are highly sensitive to UV radiation.

  8. Radiative decays of negative parity heavy baryons in the framework of the light cone QCD sum rules

    NASA Astrophysics Data System (ADS)

    Agamaliev, A. K.; Aliev, T. M.; Savcı, M.

    2017-02-01

    The transition form factors responsible for the radiative ΣQ →ΛQ γ and ΞQ‧ →ΞQ γ decays of the negative parity baryons are examined within light cone QCD sum rules. The decay widths of the radiative transitions are calculated using the obtained results of the form factors. A comparison of our predictions on decay widths with the corresponding widths of positive parity baryons is given.

  9. A tumbling top-quark condensate model

    SciTech Connect

    Martin, S.P.

    1992-07-01

    We propose a renormalizable model with no fundamental scalars which breaks itself in the manner of a ``tumbling`` gauge theory down to the standard model with a top-quark condensate. Because of anomaly cancellation requirements, this model contains two color sextet fermions (quixes), which are vector-like with respect to the standard model gauge group. The model also has a large number of pseudo-Nambu-Goldstone bosons, some of which can be light. The top-quark condensate is responsible for breaking the electroweak gauge symmetry and gives the top quark a large mass. We discuss the qualitative features and instructive shortcomings of the model in its present form. We also show that this model can be naturally embedded into an aesthetically pleasing model in which the standard model fermion appear symmetrically.

  10. The effects of gamma radiation, UV and visible light on ATP levels in yeast cells depend on cellular melanization.

    PubMed

    Bryan, Ruth; Jiang, Zewei; Friedman, Matthew; Dadachova, Ekaterina

    2011-10-01

    Previously we have shown that growth of melanized fungi is stimulated by low levels of gamma radiation. The goal of this study was to examine the effects of visible light, UV light, and gamma radiation on the energy level (ATP concentration) in melanized Cryptococcus neoformans cells. Melanized C. neoformans cells as well as non-melanized controls were subjected to visible, UV or gamma radiation, and ATP was quantified by measuring the amount of light emitted by the ATP-dependent reaction of luciferase with luciferin. We found that all three forms of radiation led to a reduction in the ATP levels in melanized C. neoformans cells. This points to a universal melanin-related mechanism underlying observation of ATP decrease in irradiated melanized cells. In contrast, in non-melanized cells visible light led to increase in ATP levels; gamma radiation did not cause any changes while UV exposure resulted in some ATP decrease, however, much less pronounced than in melanized cells. Copyright © 2011 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  11. Hausdorff dimension of quark trajectories from SCSB and confinement

    SciTech Connect

    Antonov, D.; Ribeiro, J. E. F. T.

    2011-05-23

    The quark condensate is calculated using the effective-action formalism, by imposing an ansatz for the Wilson loop, which interpolates between the area-law for large loops and the area-squared law for small loops. For 3 colors and 2 light flavors, a lower bound of 460 MeV for the constituent quark mass is found to be accessible, provided an effective scale-dependent string tension of a light quark falls off linearly with the Schwinger proper time. This behavior of the effective string tension yields the Hausdorff dimension of a light-quark trajectory equal to 4, which shows that these trajectories are similar to branched polymers. A gluonic chain based on such trajectories provides an example of a model describing weak first-order deconfinement phase transition, which takes place in SU(3) Yang-Mills theory.

  12. Light absorption properties and radiative effects of primary organic aerosol emissions

    DOE PAGES

    Lu, Zifeng; Streets, David G.; Winijkul, Ekbordin; ...

    2015-03-26

    Organic aerosols (OAs) in the atmosphere affect Earth’s energy budget by not only scattering but also absorbing solar radiation due to the presence of the so-called “brown carbon” (BrC) component. However, the absorptivities of OAs are not represented or are poorly represented in current climate and chemical transport models. In this study, we provide a method to constrain the BrC absorptivity at the emission inventory level using recent laboratory and field observations. We review available measurements of the light-absorbing primary OA (POA), and quantify the wavelength-dependent imaginary refractive indices (kOA, the fundamental optical parameter determining the particle’s absorptivity) and theirmore » uncertainties for the bulk POA emitted from biomass/biofuel, lignite, propane, and oil combustion sources. In particular, we parametrize the kOA of biomass/biofuel combustion sources as a function of the black carbon (BC)-to-OA ratio, indicating that the absorptive properties of POA depend strongly on burning conditions. The derived fuel-type-based kOA profiles are incorporated into a global carbonaceous aerosol emission inventory, and the integrated kOA values of sectoral and total POA emissions are presented. The results of a simple radiative transfer model show that the POA absorptivity warms the atmosphere significantly and leads to ~27% reduction in the amount of the net global average POA cooling compared to results from the nonabsorbing assumption.« less

  13. Exoplanet Atmospheres: From Light-Curve Analyses to Radiative-Transfer Modeling

    NASA Astrophysics Data System (ADS)

    Cubillos, Patricio; Harrington, Joseph; Blecic, Jasmina; Rojo, Patricio; Stemm, Madison; Lust, Nathaniel B.; Foster, Andrew S.; Loredo, Thomas J.

    2015-01-01

    Multi-wavelength transit and secondary-eclipse light-curve observations are some of the most powerful techniques to probe the thermo-chemical properties of exoplanets. Although the small planet-to-star constrast ratios demand a meticulous data analysis, and the limited available spectral bands can further restrain constraints, a Bayesian approach can robustly reveal what constraints can we set, given the data.We review the main aspects considered during the analysis of Spitzer time-series data by our group with an aplication to WASP-8b and TrES-1. We discuss the applicability and limitations of the most commonly used correlated-noise estimators. We describe our open-source Bayesian Atmospheric Radiative Transfer (BART) code. BART calculates the planetary emission or transmission spectrum by solving a 1D line-by-line radiative-transfer equation. The generated spectra are integrated over determined bandpasses for comparison to the data. Coupled to our Multi-core Markov-chain Monte Carlo (MC3) statistical package, BART constrains the temperature profile and chemical abundances in the planet's atmosphere. We apply the BART retrieval code to the HD 209458b data set to estimate the planet's temperature profile and molecular abundances.This work was supported by NASA Planetary Atmospheres grant NNX12AI69G and NASA Astrophysics Data Analysis Program grant NNX13AF38G. JB holds a NASA Earth and Space Science Fellowship.

  14. Light absorption properties and radiative effects of primary organic aerosol emissions.

    PubMed

    Lu, Zifeng; Streets, David G; Winijkul, Ekbordin; Yan, Fang; Chen, Yanju; Bond, Tami C; Feng, Yan; Dubey, Manvendra K; Liu, Shang; Pinto, Joseph P; Carmichael, Gregory R

    2015-04-21

    Organic aerosols (OAs) in the atmosphere affect Earth's energy budget by not only scattering but also absorbing solar radiation due to the presence of the so-called "brown carbon" (BrC) component. However, the absorptivities of OAs are not represented or are poorly represented in current climate and chemical transport models. In this study, we provide a method to constrain the BrC absorptivity at the emission inventory level using recent laboratory and field observations. We review available measurements of the light-absorbing primary OA (POA), and quantify the wavelength-dependent imaginary refractive indices (kOA, the fundamental optical parameter determining the particle's absorptivity) and their uncertainties for the bulk POA emitted from biomass/biofuel, lignite, propane, and oil combustion sources. In particular, we parametrize the kOA of biomass/biofuel combustion sources as a function of the black carbon (BC)-to-OA ratio, indicating that the absorptive properties of POA depend strongly on burning conditions. The derived fuel-type-based kOA profiles are incorporated into a global carbonaceous aerosol emission inventory, and the integrated kOA values of sectoral and total POA emissions are presented. Results of a simple radiative transfer model show that the POA absorptivity warms the atmosphere significantly and leads to ∼27% reduction in the amount of the net global average POA cooling compared to results from the nonabsorbing assumption.

  15. Radiative forcing impacts of boreal forest biofuels: a scenario study for Norway in light of albedo.

    PubMed

    Bright, Ryan M; Strømman, Anders Hammer; Peters, Glen P

    2011-09-01

    Radiative forcing impacts due to increased harvesting of boreal forests for use as transportation biofuel in Norway are quantified using simple climate models together with life cycle emission data, MODIS surface albedo data, and a dynamic land use model tracking carbon flux and clear-cut area changes within productive forests over a 100-year management period. We approximate the magnitude of radiative forcing due to albedo changes and compare it to the forcing due to changes in the carbon cycle for purposes of attributing the net result, along with changes in fossil fuel emissions, to the combined anthropogenic land use plus transport fuel system. Depending on albedo uncertainty and uncertainty about the geographic distribution of future logging activity, we report a range of results, thus only general conclusions about the magnitude of the carbon offset potential due to changes in surface albedo can be drawn. Nevertheless, our results have important implications for how forests might be managed for mitigating climate change in light of this additional biophysical criterion, and in particular, on future biofuel policies throughout the region. Future research efforts should be directed at understanding the relationships between the physical properties of managed forests and albedo, and how albedo changes in time as a result of specific management interventions.

  16. Shielding NSLS-II light source: Importance of geometry for calculating radiation levels from beam losses

    NASA Astrophysics Data System (ADS)

    Kramer, S. L.; Ghosh, V. J.; Breitfeller, M.; Wahl, W.

    2016-11-01

    Third generation high brightness light sources are designed to have low emittance and high current beams, which contribute to higher beam loss rates that will be compensated by Top-Off injection. Shielding for these higher loss rates will be critical to protect the projected higher occupancy factors for the users. Top-Off injection requires a full energy injector, which will demand greater consideration of the potential abnormal beam miss-steering and localized losses that could occur. The high energy electron injection beam produces significantly higher neutron component dose to the experimental floor than a lower energy beam injection and ramped operations. Minimizing this dose will require adequate knowledge of where the miss-steered beam can occur and sufficient EM shielding close to the loss point, in order to attenuate the energy of the particles in the EM shower below the neutron production threshold (<10 MeV), which will spread the incident energy on the bulk shield walls and thereby the dose penetrating the shield walls. Designing supplemental shielding near the loss point using the analytic shielding model is shown to be inadequate because of its lack of geometry specification for the EM shower process. To predict the dose rates outside the tunnel requires detailed description of the geometry and materials that the beam losses will encounter inside the tunnel. Modern radiation shielding Monte-Carlo codes, like FLUKA, can handle this geometric description of the radiation transport process in sufficient detail, allowing accurate predictions of the dose rates expected and the ability to show weaknesses in the design before a high radiation incident occurs. The effort required to adequately define the accelerator geometry for these codes has been greatly reduced with the implementation of the graphical interface of FLAIR to FLUKA. This made the effective shielding process for NSLS-II quite accurate and reliable. The principles used to provide supplemental

  17. Kondo cloud of single heavy quark in cold and dense matter

    NASA Astrophysics Data System (ADS)

    Yasui, Shigehiro

    2017-10-01

    The Kondo effect is a universal phenomena observed in a variety of fermion systems containing a heavy impurity particle whose interaction is governed by the non-Abelian interaction. At extremely high density, I study the Kondo effect by color exchange in quark matter containing a single heavy (charm or bottom) quark as an impurity particle. To obtain the ground state with the Kondo effect, I introduce the condensate mixing the light quark and the heavy quark (Kondo cloud) in the mean-field approximation. I estimate the energy gain by formation of the Kondo cloud, and present that the Kondo cloud exhibits the resonant structure. I also evaluate the scattering cross section for the light quark and the heavy quark, and discuss its effect to the finite size quark matter.

  18. Ultraviolet radiation-induced damage to human Langerhans cells in vivo is not reversed by ultraviolet A or visible light.

    PubMed

    Alcalay, J; Goldberg, L H; Wolf, J E; Kripke, M L

    1990-08-01

    Exposure of human skin in vivo to UVB radiation induces pyrimidine dimers in DNA and alters the morphology and function of epidermal Langerhans cells. Cells in human skin have been reported to contain a photoreactivation repair mechanism that, following exposure to UVA or visible light, repairs UVB-induced pyrimidine dimers. The purpose of this study was to determine whether exposure to photoreactivating light would also reverse the UVB-induced morphologic alterations in human Langerhans cells. The skin of eight healthy volunteers was exposed to a low dose of UVB radiation (between 0.75 and 1.5 times the minimal erythema dose), and immediately thereafter exposed to photoreactivating light from either BLB fluorescent lamps (UVA radiation) or incandescent bulbs (visible light). After exposure to UVB radiation, the number of ATPase+ epidermal Langerhans cells was reduced in all subjects to between 21% and 65% of that in unirradiated skin, and the majority of the remaining cells exhibited morphologic alterations. Exposure of the UVB-irradiated skin to photoreactivating light did not reverse or reduce these effects. We conclude that UVB-induced morphologic alterations of human Langerhans cells are not subject to photoreactivation. These results imply either that pyrimidine dimers are not involved in these effects of UVB irradiation, or that photoreactivation does not occur in human Langerhans cells in situ.

  19. Top quark and neutrino composite Higgs bosons

    NASA Astrophysics Data System (ADS)

    Smetana, Adam

    2013-08-01

    In the context of top-quark condensation models, the top quark alone is too light to saturate the correct value of the electroweak scale by its condensate. Within the seesaw scenario the neutrinos can have their Dirac masses large enough so that their condensates can provide a significant contribution to the value of the electroweak scale. We address the question of a phenomenological feasibility of the top-quark and neutrino condensation conspiracy against the electroweak symmetry. It is mandatory to reproduce the masses of electroweak gauge bosons, the top-quark mass and the recently observed scalar mass of 125 GeV and to satisfy the upper limits on absolute value of active neutrino masses. To accomplish that we design a reasonably simplified effective model with two composite Higgs doublets. Additionally, we work with a general number N of right-handed neutrino flavor triplets participating on the seesaw mechanism. There are no experimental constraints limiting this number. The upper limit is set by the model itself. Provided that the condensation scale is of order 1017-18 GeV and the number of right-handed neutrinos is , the model predicts masses of additional Higgs bosons below 250 GeV and a suppression of the top-quark Yukawa coupling to the 125 GeV particle at the ˜60 % level of the Standard model value.

  20. Top quark mass measurements

    SciTech Connect

    Hill, Christopher S.; /UC, Santa Barbara

    2004-12-01

    The top quark, with its extraordinarily large mass (nearly that of a gold atom), plays a significant role in the phenomenology of EWSB in the Standard Model. In particular, the top quark mass when combined with the W mass constrains the mass of the as yet unobserved Higgs boson. Thus, a precise determination of the mass of the top quark is a principal goal of the CDF and D0 experiments. With the data collected thus far in Runs 1 and 2 of the Tevatron, CDF and D0 have measured the top quark mass in both the lepton+jets and dilepton decay channels using a variety of complementary experimental techniques. The author presents an overview of the most recent of the measurements.

  1. Effects of radiation upon the light-sensing elements of the retina as characterized by scanning electron microscopy

    NASA Technical Reports Server (NTRS)

    Malachowski, M. J.; Tobias, C. A.; Leith, J. T.

    1977-01-01

    A model system using Necturus maculosus, the common mudpuppy, was established for evaluating effects of radiation upon the light-sensing elements of the retina. Accelerated heavy ions of helium and neon from the Berkeley Bevalac were used. A number of criteria were chosen to characterize radiation damage by observing morphological changes with the scanning electron microscope. The studies indicated retina sensitivity to high-LET (neon) particles at radiation levels below 10 rads (7 particles per visual element) whereas no significant effects were seen from fast helium ions below 50 rads.

  2. Effects of radiation upon the light-sensing elements of the retina as characterized by scanning electron microscopy

    NASA Technical Reports Server (NTRS)

    Malachowski, M. J.; Tobias, C. A.; Leith, J. T.

    1977-01-01

    A model system using Necturus maculosus, the common mudpuppy, was established for evaluating effects of radiation upon the light-sensing elements of the retina. Accelerated heavy ions of helium and neon from the Berkeley Bevalac were used. A number of criteria were chosen to characterize radiation damage by observing morphological changes with the scanning electron microscope. The studies indicated retina sensitivity to high-LET (neon) particles at radiation levels below 10 rads (7 particles per visual element) whereas no significant effects were seen from fast helium ions below 50 rads.

  3. Top quark properties

    SciTech Connect

    Hong, Ziqing

    2014-10-31

    The top quark physics has entered the precision era. The CDF and D0 collaborations are finalizing their legacy results of the properties of the top quark after the shutdown of the Fermilab Tevatron three years ago. The ATLAS and CMS collaborations have been publishing results from the LHC Run I with 7 TeV and 8 TeV proton-proton collisions, with many more forthcoming. We present a selection of recent results produced by the Tevatron and LHC experiments.

  4. Control of electric field in CdZnTe radiation detectors by above-bandgap light

    SciTech Connect

    Franc, J.; Dědič, V.; Rejhon, M.; Zázvorka, J.; Praus, P.; Touš, J.; Sellin, P. J.

    2015-04-28

    We have studied the possibility of above bandgap light induced depolarization of CdZnTe planar radiation detector operating under high flux of X-rays by Pockels effect measurements. In this contribution, we show a similar influence of X-rays at 80 kVp and LED with a wavelength of 910 nm irradiating the cathode on polarization of the detector due to an accumulation of a positive space charge of trapped photo-generated holes. We have observed the depolarization of the detector under simultaneous cathode-site illumination with excitation LED at 910 nm and depolarization above bandgap LED at 640 nm caused by trapping of drifting photo-generated electrons. Although the detector current is quite high during this depolarization, we have observed that it decreases relatively fast to its initial value after switching off the depolarizing light. In order to get detailed information about physical processes present during polarization and depolarization and, moreover, about associated deep levels, we have performed the Pockels effect infrared spectral scanning measurements of the detector without illumination and under illumination in polarized and optically depolarized states.

  5. Analysis of light scattering by two-dimensional inhomogeneities in paper using general radiative transfer theory

    SciTech Connect

    Nukala, Madhuri; Mendrok, Jana

    2014-12-10

    Lateral light scattering simulations of printed dots are analyzed using general radiative transfer theory. We investigated the appearance of a printed paper in relation to the medium parameters like thickness of the paper sample, its optical properties, and the asymmetry factor. It was found that the appearance of a print greatly depends on these factors making it either brighter or darker. A thicker substrate with higher single scattering albedo backed with an absorbing surface makes the dots brighter due to increased number of scattering events. Additionally, it is shown that the optical effects of print also depend on illuminating and viewing angles along with the depth of ink penetration. A larger single scattering angle implies less intensity and the dots appear much blurred due to the shadowing effect prominent when viewed from sides. A fully penetrated dot of the same extinction coefficient as a partial penetrated one is darker due to increased absorption. These results can be used in applications dealing with lateral light scattering.

  6. The physics of heavy quark distributions in hadrons: Collider tests

    DOE PAGES

    Brodsky, S. J.; Bednyakov, V. A.; Lykasov, G. I.; ...

    2016-12-18

    Here, we present a review of the current understanding of the heavy quark distributions in the nucleon and their impact on collider physics. The origin of strange, charm and bottom quark pairs at high light-front (LF) momentum fractions in hadron wavefunction—the “intrinsic” quarks, is reviewed. The determination of heavy-quark parton distribution functions (PDFs) is particularly significant for the analysis of hard processes at LHC energies. We show that a careful study of the inclusive production of open charm and the production of γ/Z/W particles, accompanied by the heavy jets at large transverse momenta can give essential information on the intrinsicmore » heavy quark (IQ) distributions. We also focus on the theoretical predictions concerning other observables which are very sensitive to the intrinsic charm contribution to PDFs including Higgs production at high xF and novel fixed target measurements which can be tested at the LHC.« less

  7. The physics of heavy quark distributions in hadrons: Collider tests

    NASA Astrophysics Data System (ADS)

    Brodsky, S. J.; Bednyakov, V. A.; Lykasov, G. I.; Smiesko, J.; Tokar, S.

    2017-03-01

    We present a review of the current understanding of the heavy quark distributions in the nucleon and their impact on collider physics. The origin of strange, charm and bottom quark pairs at high light-front (LF) momentum fractions in hadron wavefunction-the "intrinsic" quarks, is reviewed. The determination of heavy-quark parton distribution functions (PDFs) is particularly significant for the analysis of hard processes at LHC energies. We show that a careful study of the inclusive production of open charm and the production of γ / Z / W particles, accompanied by the heavy jets at large transverse momenta can give essential information on the intrinsic heavy quark (IQ) distributions. We also focus on the theoretical predictions concerning other observables which are very sensitive to the intrinsic charm contribution to PDFs including Higgs production at high xF and novel fixed target measurements which can be tested at the LHC.

  8. The physics of heavy quark distributions in hadrons: Collider tests

    SciTech Connect

    Brodsky, S. J.; Bednyakov, V. A.; Lykasov, G. I.; Smiesko, J.; Tokar, S.

    2016-12-18

    Here, we present a review of the current understanding of the heavy quark distributions in the nucleon and their impact on collider physics. The origin of strange, charm and bottom quark pairs at high light-front (LF) momentum fractions in hadron wavefunction—the “intrinsic” quarks, is reviewed. The determination of heavy-quark parton distribution functions (PDFs) is particularly significant for the analysis of hard processes at LHC energies. We show that a careful study of the inclusive production of open charm and the production of γ/Z/W particles, accompanied by the heavy jets at large transverse momenta can give essential information on the intrinsic heavy quark (IQ) distributions. We also focus on the theoretical predictions concerning other observables which are very sensitive to the intrinsic charm contribution to PDFs including Higgs production at high xF and novel fixed target measurements which can be tested at the LHC.

  9. Radiative transfer within seagrass canopies: impact on carbon budgets and light requirements

    NASA Astrophysics Data System (ADS)

    Zimmerman, Richard C.; Mobley, Curtis D.

    1997-02-01

    Seagrasses are ecologically important but extremely vulnerable to anthropogenic modifications of the coastal zone that affect light availability within these unique ecosystems. Strongly pigmented seagrass leaves can extend for more than 1 m above the substrate and biomass is distributed unevenly throughout the canopy. in this study, light attenuation in a 7 m water column that contained a seagrass canopy extending 1.5 m above the bottom was calculated by the radiative transfer model Hydrolight using the spectral absorbance of eelgrass leaves and a non-uniform vertical distribution of biomass. Runs were performed in clear and turbid water columns, over san d and mud substrates, and with shoot densities ranging from 25 to 200 m-2 using solar angles for both winter and summer solstices. The flux of photosynthetically active irradiance (EPAR) reaching the top of the seagrass canopy was twice as high in summer compared to winter, and in clear water compared to turbid water. Sediment type had a measurable effect on EPAR only within the bottom third of the canopy. Light penetration within the canopy was inversely proportional to shoot density. Introduction of daylength and a sinusoidal distribution of EPAR throughout the day greatly increased the importance of solar elevation on daily integrated production relative to water column turbidity and sediment type. Shoot-specific productivity decreased and the position of maximum shoot productivity within the canopy shallowed as shoot density increased. Positive net photosynthesis for entire shoots was possible only when plant density was lower than 100 shoots m-2 in winter; values consistent with field observations. Although very simplistic with regard to inherent optical properties of real seagrass leaves, this model was able to generate estimates of maximum sustainable shoot density that were fully testable by, and wholly consistent with, field observations.

  10. Effects of low-intensity polarized visible laser radiation on skin burns: a light microscopy study.

    PubMed

    Ribeiro, Martha Simões; Da Silva, Daniela De Fátima Teixeira; De Araújo, Carlos Eugênio Nabuco; De Oliveira, Sérgio Ferreira; Pelegrini, Cleusa Maria Raspantini; Zorn, Telma Maria Tenório; Zezell, Denise Maria

    2004-02-01

    This study was carried out to investigate the influence of low-intensity polarized visible laser radiation on the acceleration of skin wound healing. Low-level laser therapy (LLLT) at adequate wavelength, intensity, and dose can accelerate tissue repair. However, there is still unclear information about light characteristics, such as coherence and polarization. Some studies indicate that linearly polarized light can survive through long propagation distance in biological tissue. Three burns about 6 mm in diameter were created on the back of rats with liquid N(2). Lesion "L(//)" was irradiated by He-Ne laser (lambda = 632.8 nm), D= 1.0 J/cm(2), with linear polarization parallel to the spinal column of the rat. Lesion "L(inverted v)" was irradiated using the same laser and dose, but the light polarization was aligned perpendicularly to the relative orientation. Lesion "C" was not irradiated in order to be considered as control. The animals were sacrificed at day 3-17 after lesion creation. Samples were collected and prepared for histological analysis. Histological analysis showed that the healing of irradiated wounds was faster than that of non-irradiated wounds. Moreover, it was observed that skin wound repair is dependent on polarization orientation with respect to a referential axis as the animal's spinal column. Consequently, "L(//)" was completely healed after 17 days, whereas "L (perpendicular) " showed a moderate degree of healing after the same period. These results indicate that the relative direction of the laser polarization plays an important role in the wound healing process when highly coherent He-Ne laser is used.

  11. Effects of ultraviolet radiation produced from artificial lights on serum 25-hydroxyvitamin D concentration in captive domestic rabbits (Oryctolagus cuniculi).

    PubMed

    Emerson, Jessica A; Whittington, Julia K; Allender, Matthew C; Mitchell, Mark A

    2014-04-01

    To determine the effects of UVB radiation produced by artificial lights on serum 25-hydroxyvitamin D concentrations in domestic rabbits (Oryctolagus cuniculi). 9 juvenile domestic rabbits. After an acclimation period, rabbits were anesthetized with isoflurane, and an initial blood sample was collected for determination of serum 25-hydroxyvitamin D concentration. Rabbits were randomly assigned to receive 12-hour exposure to UVB radiation produced by 2 compact fluorescent lights daily (n = 5) or no UVB supplementation (4) commencing on day 1. The UVB radiation emitted into the cage was measured at 9 points approximately 34 cm from the surface of the UVB light sources (representing the position of the rabbits in the cage) after 10 hours of exposure on days 1, 8, and 14. On day 14, another blood sample was collected from anesthetized rabbits for determination of serum 25-hydroxyvitamin D concentration. The UVB radiation level was 8.3 to 58.1 μW/cm² for the exposed rabbits and consistently < 0.001 μW/cm² for the control rabbits. Mean ± SD serum 25-hydroxyvitamin D concentrations in the rabbits that were or were not provided supplemental UVB radiation for 14 days differed significantly (66.4 ± 14.3 nmol/L and 31.7 ± 9.9 nmol/L, respectively). Exposure to UVB radiation produced by artificial light significantly increased serum 25-hydroxyvitamin D concentration in juvenile rabbits. Because vitamin D is an essential hormone in vertebrates, these findings suggested that the provision of supplemental UVB radiation to captive rabbits may be important.

  12. Search for Invisible Decays of a Light Scalar in Radiative Transitions Y(3S)->gamma A0

    SciTech Connect

    Aubert, B

    2008-11-05

    We search for a light scalar particle produced in single-photon decays of the {Upsilon}(3S) resonance through the process {Upsilon}(3S) {yields} {gamma} + A{sup 0}, A{sup 0} {yields} invisible. Such an object appears in Next-to-Minimal Supersymmetric extensions of the Standard Model, where a light CP-odd Higgs boson naturally couples strongly to b-quarks. If, in addition, there exists a light, stable neutralino, decays of A{sup 0} could be preferentially to an invisible final state. We search for events with a single high-energy photon and a large missing mass, consistent with a 2-body decay of {Upsilon}(3S). We find no evidence for such processes in a sample of 122 x 10{sup 6} {Upsilon}(3S) decays collected by the BABAR collaboration at the PEP-II B-factory, and set 90% C.L. upper limits on the branching fraction {Beta}({Upsilon}(3S) {yields} {gamma}A{sup 0}) x {Beta}(A{sup 0} {yields} invisible) at (0.7-31) x 10{sup -6} in the mass range m{sub A{sup 0}} {le} 7.8 GeV. The results are preliminary.

  13. Lighting.

    SciTech Connect

    United States. Bonneville Power Administration.

    1992-09-01

    Since lighting accounts for about one-third of the energy used in commercial buildings, there is opportunity to conserve. There are two ways to reduce lighting energy use: modify lighting systems so that they used less electricity and/or reduce the number of hours the lights are used. This booklet presents a number of ways to do both. Topics covered include: reassessing lighting levels, reducing lighting levels, increasing bulb & fixture efficiency, using controls to regulate lighting, and taking advantage of daylight.

  14. Detection of Higgs bosons decaying to bottom quarks

    SciTech Connect

    Gilman, F.J.; Price, L.E.

    1986-11-01

    Several developments affecting the possibility of Higgs detection are discussed. These include the level of certainty about the t quark mass, Monte Carlo programs to generate both signal and background events, and separation and/or enhancement of heavy quark jets from jets due to light quarks or gluons, and the possibility that the neutral Higgs decay into bottom quarks might be the decay mode of choice for detecting the intermediate mass Higgs. Possible means of detection of an intermediate mass Higgs at the SSC, particularly if a prominent decay mode is to bottom quarks, are examined, using the PYTHIA Monte Carlo program to generate both signal and background events. For the signal, events were generated in which Higgs bosons are created in proton-proton collisions, with the Higgs decaying into bottom quarks. The presence of W or Z bosons, created in the same proton-proton collision, is used to enhance the likelihood of Higgs production and to reduce the potentially enormous background. It is found that the Higgs decay to bottom quarks, if important, would be more favorable for detection of the Higgs than decay to top quarks was found to be because of the smaller background. 3 refs., 4 figs. (LEW)

  15. Dark decay of the top quark

    DOE PAGES

    Kong, Kyoungchul; Lee, Hye -Sung; Park, Myeonghun

    2014-04-01

    We suggest top quark decays as a venue to search for light dark force carriers. Top quark is the heaviest particle in the standard model whose decays are relatively poorly measured, allowing sufficient room for exotic decay modes from new physics. A very light (GeV scale) dark gauge boson (Z') is a recently highlighted hypothetical particle that can address some astrophysical anomalies as well as the 3.6 σ deviation in the muon g-2 measurement. We present and study a possible scenario that top quark decays as t → b W + Z's. This is the same as the dominant topmore » quark decay (t → b W) accompanied by one or multiple dark force carriers. The Z' can be easily boosted, and it can decay into highly collimated leptons (lepton-jet) with large branching ratio. In addition, we discuss the implications for the Large Hadron Collider experiments including the analysis based on the lepton-jets.« less

  16. Inactivation of Staphylococcus saprophyticus in chicken meat and exudate using high pressure processing, gamma radiation, and ultraviolet light

    USDA-ARS?s Scientific Manuscript database

    Stapylococcus saprophyticus is a common contaminant in foods and causes urinary tract infections in humans. Three nonthermal food safety intervention technologies used to improve the safety foods include high pressure processing (HPP), ionizing (gamma) radiation (GR), and ultraviolet light (UV-C). A...

  17. Interactions of monochromatic visible light and near-IR radiation with cells: currently discussed mechanisms

    NASA Astrophysics Data System (ADS)

    Karu, Tiina I.

    1995-05-01

    Biological responses of cells to visible and near IR (laser) radiation occur due to physical and/or chemical changes in photoacceptor molecules, components of respiratory chains (cyt a/a3 in mitochondria, and cyt d in E. coli). As a result of the photoexcitation of electronic states, the following physical and/or chemical changes can occur: alteration of redox properties and acceleration of electron transfer, changes in biochemical activity due to local transient heating of chromophores, one-electron auto-oxidation and O2- production, and photodynamic action and 1O2 production. Different reaction channels can be activated to achieve the photobiological macroeffect. The primary physical and/or chemical changes induced by light in photoacceptor molecules are followed by a cascade of biochemical reactions in the cell that do not need further light activation and occur in the dark (photosignal transduction and amplification chains). These reactions are connected with changes in cellular homeostasis parameters. The crucial step here is thought to be an alteration of the cellular redox state: a shift towards oxidation is associated with stimulation of cellular vitality, and a shift towards reduction is linked to inhibition. Cells with a lower than normal pH, where the redox state is shifted in the reduced direction, are considered to be more sensitive to the stimulative action of light than those with the respective parameters being optimal or near optimal. This circumstance explains the possible variations in observed magnitudes of low-power laser effects. Light action on the redox state of a cell via the respiratory chain also explains the diversity of low-power laser effects. Beside explaining many controversies in the field of low-power laser effects (i.e., the diversity of effects, the variable magnitude or absence of effects in certain studies), the proposed redox-regulation mechanism may be a fundamental explanation of some clinical effects of irradiation, for

  18. Performance of Different Light Sources for the Absolute Calibration of Radiation Thermometers

    NASA Astrophysics Data System (ADS)

    Martín, M. J.; Mantilla, J. M.; del Campo, D.; Hernanz, M. L.; Pons, A.; Campos, J.

    2017-09-01

    The evolving mise en pratique for the definition of the kelvin (MeP-K) [1, 2] will, in its forthcoming edition, encourage the realization and dissemination of the thermodynamic temperature either directly (primary thermometry) or indirectly (relative primary thermometry) via fixed points with assigned reference thermodynamic temperatures. In the last years, the Centro Español de Metrología (CEM), in collaboration with the Instituto de Óptica of Consejo Superior de Investigaciones Científicas (IO-CSIC), has developed several setups for absolute calibration of standard radiation thermometers using the radiance method to allow CEM the direct dissemination of the thermodynamic temperature and the assignment of the thermodynamic temperatures to several fixed points. Different calibration facilities based on a monochromator and/or a laser and an integrating sphere have been developed to calibrate CEM's standard radiation thermometers (KE-LP2 and KE-LP4) and filter radiometer (FIRA2). This system is based on the one described in [3] placed in IO-CSIC. Different light sources have been tried and tested for measuring absolute spectral radiance responsivity: a Xe-Hg 500 W lamp, a supercontinuum laser NKT SuperK-EXR20 and a diode laser emitting at 6473 nm with a typical maximum power of 120 mW. Their advantages and disadvantages have been studied such as sensitivity to interferences generated by the laser inside the filter, flux stability generated by the radiant sources and so forth. This paper describes the setups used, the uncertainty budgets and the results obtained for the absolute temperatures of Cu, Co-C, Pt-C and Re-C fixed points, measured with the three thermometers with central wavelengths around 650 nm.

  19. Basic features of the pion valence-quark distribution function

    DOE PAGES

    Chang, Lei; Mezrag, Cédric; Moutarde, Hervé; ...

    2014-10-07

    The impulse-approximation expression used hitherto to define the pion's valence-quark distribution function is flawed because it omits contributions from the gluons which bind quarks into the pion. A corrected leading-order expression produces the model-independent result that quarks dressed via the rainbow–ladder truncation, or any practical analogue, carry all the pion's light-front momentum at a characteristic hadronic scale. Corrections to the leading contribution may be divided into two classes, responsible for shifting dressed-quark momentum into glue and sea-quarks. Working with available empirical information, we use an algebraic model to express the principal impact of both classes of corrections. This enables amore » realistic comparison with experiment that allows us to highlight the basic features of the pion's measurable valence-quark distribution, qπ(x); namely, at a characteristic hadronic scale, qπ(x)~(1-x)2 for x≳0.85; and the valence-quarks carry approximately two-thirds of the pion's light-front momentum.« less

  20. Enhancement of new physics signal sensitivity with mistagged charm quarks

    NASA Astrophysics Data System (ADS)

    Kim, Doojin; Park, Myeonghun

    2016-07-01

    We investigate the potential for enhancing search sensitivity for signals having charm quarks in the final state, using the sizable bottom-mistagging rate for charm quarks at the LHC. Provided that the relevant background processes contain light quarks instead of charm quarks, the application of b-tagging on charm quark-initiated jets enables us to reject more background events than signal ones due to the relatively small mistagging rate for light quarks. The basic idea is tested with two rare top decay processes: i) t → ch → cb b bar and ii) t → bH+ → b b bar c where h and H+ denote the Standard Model-like higgs boson and a charged higgs boson, respectively. The major background source is a hadronic top quark decay such as t → bW+ → b s bar c. We test our method with Monte Carlo simulation at the LHC 14 TeV, and find that the signal-over-background ratio can be increased by a factor of O (6- 7) with a suitably designed (heavy) flavor tagging algorithm and scheme.

  1. Quark-mass dependence of two-nucleon observables

    NASA Astrophysics Data System (ADS)

    Chen, Jiunn-Wei; Lee, Tze-Kei; Liu, C.-P.; Liu, Yu-Sheng

    2012-11-01

    We study the potential implications of lattice QCD determinations of the S-wave nucleon-nucleon scattering lengths with unphysical light quark masses. If the light quark masses are small enough such that nuclear effective field theory (NEFT) can be used to perform quark-mass extrapolations, then the leading quark-mass dependence of not only the effective range and the two-body current, but also all the low-energy deuteron matrix elements up to next-to-leading-order in NEFT can be obtained. As a proof of principle, we compute the quark-mass dependence of the deuteron charge radius, magnetic moment, polarizability, and the deuteron photodisintegration cross section using the lattice calculation of the scattering lengths at 354 MeV pion mass by the ``Nuclear Physics with Lattice QCD'' (NPLQCD) collaboration and the NEFT power counting scheme of Beane, Kaplan, and Vuorinen (BKV), even though it is not yet established that the 354 MeV pion mass is within the radius of convergence of the BKV scheme. Once the lattice result with quark mass within the NEFT radius of convergence is obtained, our observation can be used to constrain the time variation of isoscalar combination of u and d quark mass mq, to help the anthropic principle study to find the mq range that allows the existence of life, and to provide a weak test of the multiverse conjecture.

  2. Search for a Very Light CP-Odd Higgs Boson in Top Quark Decays from pp-bar; Collisions at √s = 1.96 TeV

    SciTech Connect

    Aaltonen, T.

    2011-07-11

    We present the results of a search for a very light CP-odd Higgs boson a10 originating from top quark decays t→H±b → W±(*)a10b, and subsequently decaying into τ+τ-. Using a data sample corresponding to an integrated luminosity of 2.7 fb-1 collected by the CDF II detector in pp-bar collisions at 1.96 TeV, we perform a search for events containing a lepton, three or more jets, and an additional isolated track with transverse momentum in the range 3 to 20 GeV/c. Observed events are consistent with background sources, and 95% C.L. limits are set on the branching ratio of t→H±b for various masses of H± and a10.

  3. Light extraction enhancement with radiation pattern shaping of LEDs by waveguiding nanorods with impedance-matching tips.

    PubMed

    Hsiao, Yu-Hsuan; Chen, Cheng-Ying; Huang, Li-Chuan; Lin, Guan-Jhong; Lien, Der-Hsien; Huang, Jian-Jang; He, Jr-Hau

    2014-03-07

    Syringe-like ZnO nanorods (NRs) were fabricated on InGaN/GaN light emitting diodes (LEDs) by a hydrothermal method. Without sacrificing the electrical performances of LEDs, syringe-like NRs can enhance light extraction capability by 10.5% at 20 mA and shape the radiation profile with a view angle collimated from 136° to 121°. By performing optical experiments and simulation, it is found that the superior light extraction efficiency with a more collimated radiation pattern is attributed to the waveguiding effect of NRs and the mitigation of abrupt index change by the tapered ends of syringe-like ZnO NRs. This work demonstrates the importance of the nanostructure morphology in LED performances and provides the architecture design guidelines of nanostructures to a variety of optical devices.

  4. Shielding NSLS-II light source: Importance of geometry for calculating radiation levels from beam losses

    SciTech Connect

    Kramer, S. L.; Ghosh, V. J.; Breitfeller, M.; Wahl, W.

    2016-08-10

    We present that third generation high brightness light sources are designed to have low emittance and high current beams, which contribute to higher beam loss rates that will be compensated by Top-Off injection. Shielding for these higher loss rates will be critical to protect the projected higher occupancy factors for the users. Top-Off injection requires a full energy injector, which will demand greater consideration of the potential abnormal beam miss-steering and localized losses that could occur. The high energy electron injection beam produces significantly higher neutron component dose to the experimental floor than a lower energy beam injection and ramped operations. Minimizing this dose will require adequate knowledge of where the miss-steered beam can occur and sufficient EM shielding close to the loss point, in order to attenuate the energy of the particles in the EM shower below the neutron production threshold (<10 MeV), which will spread the incident energy on the bulk shield walls and thereby the dose penetrating the shield walls. Designing supplemental shielding near the loss point using the analytic shielding model is shown to be inadequate because of its lack of geometry specification for the EM shower process. To predict the dose rates outside the tunnel requires detailed description of the geometry and materials that the beam losses will encounter inside the tunnel. Modern radiation shielding Monte-Carlo codes, like FLUKA, can handle this geometric description of the radiation transport process in sufficient detail, allowing accurate predictions of the dose rates expected and the ability to show weaknesses in the design before a high radiation incident occurs. The effort required to adequately define the accelerator geometry for these codes has been greatly reduced with the implementation of the graphical interface of FLAIR to FLUKA. In conclusion, this made the effective shielding process for NSLS-II quite accurate and reliable. The principles

  5. Shielding NSLS-II light source: Importance of geometry for calculating radiation levels from beam losses

    DOE PAGES

    Kramer, S. L.; Ghosh, V. J.; Breitfeller, M.; ...

    2016-08-10

    We present that third generation high brightness light sources are designed to have low emittance and high current beams, which contribute to higher beam loss rates that will be compensated by Top-Off injection. Shielding for these higher loss rates will be critical to protect the projected higher occupancy factors for the users. Top-Off injection requires a full energy injector, which will demand greater consideration of the potential abnormal beam miss-steering and localized losses that could occur. The high energy electron injection beam produces significantly higher neutron component dose to the experimental floor than a lower energy beam injection and rampedmore » operations. Minimizing this dose will require adequate knowledge of where the miss-steered beam can occur and sufficient EM shielding close to the loss point, in order to attenuate the energy of the particles in the EM shower below the neutron production threshold (<10 MeV), which will spread the incident energy on the bulk shield walls and thereby the dose penetrating the shield walls. Designing supplemental shielding near the loss point using the analytic shielding model is shown to be inadequate because of its lack of geometry specification for the EM shower process. To predict the dose rates outside the tunnel requires detailed description of the geometry and materials that the beam losses will encounter inside the tunnel. Modern radiation shielding Monte-Carlo codes, like FLUKA, can handle this geometric description of the radiation transport process in sufficient detail, allowing accurate predictions of the dose rates expected and the ability to show weaknesses in the design before a high radiation incident occurs. The effort required to adequately define the accelerator geometry for these codes has been greatly reduced with the implementation of the graphical interface of FLAIR to FLUKA. In conclusion, this made the effective shielding process for NSLS-II quite accurate and reliable. The

  6. The discovery of quarks

    NASA Astrophysics Data System (ADS)

    Friedman, J. I.

    2001-01-01

    In the period following World War II, there was a rapid development of particle physics. With the construction of synchrotrons and the development of detector technology, many new particles were discovered and the systematics of their interactions investigated. The invention of the bubble chamber played an especially important role in uncovering the rich array of hadrons that were discovered in this period.In 1961 Murray Gell-Mann [1] and Yuval Ne'eman [2] independently introduced a classification scheme, based on SU(3) symmetry, which placed hadrons into families on the basis of spin and parity. Like the periodic table for the elements, this scheme was predictive as well as descriptive, and various hadrons, such as the - , were predicted within this framework and were later discovered.In 1964 Gell-Mann [3] and George Zweig [4] independently proposed quarks as the building blocks of hadrons as a way of generating the SU(3) classification scheme. When the quark model was first proposed, it postulated three types of quarks: up (u), down (d), and strange (s), with charges 2/3, - 1/3, and - 1/3 respectively. Each of these was hypothesized to be a spin1/2 particle. In this model the nucleon (and all other baryons) is made up of three quarks, and each meson consists of a quark and an antiquark. For example, as the proton and neutron both have ero strangeness, they are (u,u,d) and (d,d,u) systems respectively.

  7. Bremsstrahlung emission from quark stars

    SciTech Connect

    Caron, Jean-Francois; Zhitnitsky, Ariel R.

    2009-12-15

    We calculate numerically the emissivity and surface flux of electron-electron bremsstrahlung radiation from the surface of a bare quark star. The restricted electronic phase space due to the presence of an effective photon mass results in a strong suppression. The emissivity and surface flux are found to be substantially smaller than those found in previous work, to the point where electron-positron pair production would remain the dominant mechanism at all temperatures in the relativistic regime. As a consequence, e{sup +}e{sup -} pair production remains a dominant process even at low surface temperatures T{approx}10{sup 9} K as originally suggested by Usov [V. V. Usov, Phys. Rev. Lett. 80, 230 (1998).].

  8. Light extraction enhancement with radiation pattern shaping of LEDs by waveguiding nanorods with impedance-matching tips

    NASA Astrophysics Data System (ADS)

    Hsiao, Yu-Hsuan; Chen, Cheng-Ying; Huang, Li-Chuan; Lin, Guan-Jhong; Lien, Der-Hsien; Huang, Jian-Jang; He-Hau, Jr.

    2014-02-01

    Syringe-like ZnO nanorods (NRs) were fabricated on InGaN/GaN light emitting diodes (LEDs) by a hydrothermal method. Without sacrificing the electrical performances of LEDs, syringe-like NRs can enhance light extraction capability by 10.5% at 20 mA and shape the radiation profile with a view angle collimated from 136° to 121°. By performing optical experiments and simulation, it is found that the superior light extraction efficiency with a more collimated radiation pattern is attributed to the waveguiding effect of NRs and the mitigation of abrupt index change by the tapered ends of syringe-like ZnO NRs. This work demonstrates the importance of the nanostructure morphology in LED performances and provides the architecture design guidelines of nanostructures to a variety of optical devices.Syringe-like ZnO nanorods (NRs) were fabricated on InGaN/GaN light emitting diodes (LEDs) by a hydrothermal method. Without sacrificing the electrical performances of LEDs, syringe-like NRs can enhance light extraction capability by 10.5% at 20 mA and shape the radiation profile with a view angle collimated from 136° to 121°. By performing optical experiments and simulation, it is found that the superior light extraction efficiency with a more collimated radiation pattern is attributed to the waveguiding effect of NRs and the mitigation of abrupt index change by the tapered ends of syringe-like ZnO NRs. This work demonstrates the importance of the nanostructure morphology in LED performances and provides the architecture design guidelines of nanostructures to a variety of optical devices. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr05226e

  9. [Effects of Light Near-Infrared Radiation on Rats Assessed by Succinate Dehydrogenase Activity in Lymphocytes on Blood Smears].

    PubMed

    Khunderyakova, N V; Zakharchenko, A V; Zakharchenko, M V; Muller, H; Fedotcheva, I; Kondrashova, M N

    2015-01-01

    Biological effects of light near infrared radiation (850 nm), with modulation acoustic frequency of 101 Hz, was studied. The study was conducted on rats, the effect was recorded by succinate dehydrogenase activity in lymphocytes on the blood smear after administration of the activating dose of adrenaline, which simulates the state of the organism in the early stages of the pathogenic effects (stress). A pronounced regulating effect of infrared radiation on the activity of succinate dehydrogenase in animals activated by adrenaline was shown. Infrared radiation has a normalizing effect reducing the degree of inhibition or activation of the enzyme induced by adrenaline and had no effect on the control animals. Thus, by modulating the activity of succinate dehydrogenase infrared radiation regulates energy production in the mitochondria supported by the most powerful oxidation substrate--succinic acid, which is especially pronounced under stress.

  10. Radiation heat transfer calculations for the uranium fuel-containment region of the nuclear light bulb engine.

    NASA Technical Reports Server (NTRS)

    Rodgers, R. J.; Latham, T. S.; Krascella, N. L.

    1971-01-01

    Calculation results are reviewed of the radiant heat transfer characteristics in the fuel and buffer gas regions of a nuclear light bulb engine based on the transfer of energy by thermal radiation from gaseous uranium fuel in a neon vortex, through an internally cooled transparent wall, to seeded hydrogen propellant. The results indicate that the fraction of UV energy incident on the transparent walls increases with increasing power level. For the reference engine power level of 4600 megw, it is necessary to employ space radiators to reject the UV radiated energy absorbed by the transparent walls. This UV energy can be blocked by employing nitric oxide and oxygen seed gases in the fuel and buffer gas regions. However, this results in increased UV absorption in the buffer gas which also requires space radiators to reject the heat load.

  11. Radiation heat transfer calculations for the uranium fuel-containment region of the nuclear light bulb engine.

    NASA Technical Reports Server (NTRS)

    Rodgers, R. J.; Latham, T. S.; Krascella, N. L.

    1971-01-01

    Calculation results are reviewed of the radiant heat transfer characteristics in the fuel and buffer gas regions of a nuclear light bulb engine based on the transfer of energy by thermal radiation from gaseous uranium fuel in a neon vortex, through an internally cooled transparent wall, to seeded hydrogen propellant. The results indicate that the fraction of UV energy incident on the transparent walls increases with increasing power level. For the reference engine power level of 4600 megw, it is necessary to employ space radiators to reject the UV radiated energy absorbed by the transparent walls. This UV energy can be blocked by employing nitric oxide and oxygen seed gases in the fuel and buffer gas regions. However, this results in increased UV absorption in the buffer gas which also requires space radiators to reject the heat load.

  12. Fermion masses and neutrino mixing in an U(1){sub H} flavor symmetry model with hierarchical radiative generation for light charged fermion masses

    SciTech Connect

    Hernandez-Galeana, Albino

    2007-11-01

    I report the analysis performed on fermion masses and mixing, including neutrino mixing, within the context of a model with hierarchical radiative mass generation mechanism for light charged fermions, mediated by exotic scalar particles at one and two loops, respectively, meanwhile the neutrinos get Majorana mass terms at tree level through the Yukawa couplings with two SU(2){sub L} Higgs triplets. All the resulting mass matrices in the model, for the u, d, and e fermion charged sectors, the neutrinos and the exotic scalar particles, are diagonalized in exact analytical form. Quantitative analysis shows that this model is successful to accommodate the hierarchical spectrum of masses and mixing in the quark sector as well as the charged lepton masses. The lepton mixing matrix, V{sub PMNS}, is written completely in terms of the neutrino masses m{sub 1}, m{sub 2}, and m{sub 3}. Large lepton mixing for {theta}{sub 12} and {theta}{sub 23} is predicted in the range of values 0.7 < or approx. sin{sup 2}2{theta}{sub 12} < or approx. 0.7772 and 0.87 < or approx. sin{sup 2}2{theta}{sub 23} < or approx. 0.9023 by using 0.033 < or approx. s{sub 13}{sup 2} < or approx. 0.04. These values for lepton mixing are consistent with 3{sigma} allowed ranges provided by recent global analysis of neutrino data oscillation. From {delta}m{sub sol}{sup 2} bounds, neutrino masses are predicted in the range of values m{sub 1}{approx_equal}(1.706-2.494)x10{sup -3} eV, m{sub 2}{approx_equal}(6.675-12.56)x10{sup -3} eV, and m{sub 3}{approx_equal}(1.215-2.188)x10{sup -2} eV, respectively. The above allowed lepton mixing leads to the quark-lepton complementary relations {theta}{sub 12}{sup CKM}+{theta}{sub 12}{sup PMNS}{approx_equal}41.543 deg. -44.066 deg. and {theta}{sub 23}{sup CKM}+{theta}{sub 23}{sup PMNS}{approx_equal}36.835 deg. -38.295 deg. The new exotic scalar particles induce flavor changing neutral currents and contribute to lepton flavor violating processes such as E{yields}e{sub 1}e

  13. The artefacts of radiochromic film dosimetry with flatbed scanners and their causation by light scattering from radiation-induced polymers.

    PubMed

    Schoenfeld, Andreas A; Poppinga, Daniela; Harder, Dietrich; Doerner, Karl-Joachim; Poppe, Bjoern

    2014-07-07

    Optical experiments and theoretical considerations have been undertaken in order to understand the causes of the 'orientation effect' and the 'parabola effect', the artefacts impairing the desired light absorption measurement on radiochromic EBT3 films with flatbed scanners. EBT3 films exposed to doses up to 20.9 Gy were scanned with an Epson Expression 10000XL flatbed scanner in landscape and portrait orientation. The horizontally and vertically polarized light components of the scanner were determined, and another Epson Expression 10000XL flatbed scanner was disassembled to examine its optical components. The optical properties of exposed and unexposed EBT3 films were studied with incident polarized and unpolarized white light, and the transmitted red light was investigated for its polarization and scattering properties including the distribution of the scattering angles. Neutral density filters were studied for comparison. Guidance was sought from the theory of light scattering from rod-like macromolecular structures. The drastic dose-dependent variation of the transmitted total light current as function of the orientation of front and rear polarizers, interpreted by light scattering theory, shows that the radiation-induced polymerization of the monomers of EBT3 films produces light scattering oscillators preferably polarized at right angles with the coating direction of the film. The directional distribution of the scattered light is partly anisotropic, with a preferred scattering plane at right angles with the coating direction, indicating light scattering from stacks of coherently vibrating oscillators piled up along the monomer crystals. The polyester carrier film also participates in these effects. The 'orientation' and 'parabola' artefacts due to flatbed scanning of radiochromic films can be explained by the interaction of the polarization-dependent and anisotropic light scattering from exposed and unexposed EBT3 films with the quantitative difference

  14. The Quark's Model and Confinement

    ERIC Educational Resources Information Center

    Novozhilov, Yuri V.

    1977-01-01

    Quarks are elementary particles considered to be components of the proton, the neutron, and others. This article presents the quark model as a mathematical concept. Also discussed are gluons and bag models. A bibliography is included. (MA)

  15. Quark search at the CBA

    SciTech Connect

    Larsen, R.C.; Leipuner, L.B.; Morse, W.M.; Adair, R.K.; Kasha, H.; Schmidt, M.P.

    1983-03-13

    An experiment to search for quarks at the CBA is described. The cross sections for the production of massive quark-antiquark pairs in nucleon-nucleon interactions is estimated, and the experimental design and procedures are described. (WHK)

  16. Quark structure of chiral solitons

    SciTech Connect

    Dmitri Diakonov

    2004-05-01

    There is a prejudice that the chiral soliton model of baryons is something orthogonal to the good old constituent quark models. In fact, it is the opposite: the spontaneous chiral symmetry breaking in strong interactions explains the appearance of massive constituent quarks of small size thus justifying the constituent quark models, in the first place. Chiral symmetry ensures that constituent quarks interact very strongly with the pseudoscalar fields. The ''chiral soliton'' is another word for the chiral field binding constituent quarks. We show how the old SU(6) quark wave functions follow from the ''soliton'', however, with computable relativistic corrections and additional quark-antiquark pairs. We also find the 5-quark wave function of the exotic baryon Theta+.

  17. The Quark's Model and Confinement

    ERIC Educational Resources Information Center

    Novozhilov, Yuri V.

    1977-01-01

    Quarks are elementary particles considered to be components of the proton, the neutron, and others. This article presents the quark model as a mathematical concept. Also discussed are gluons and bag models. A bibliography is included. (MA)

  18. Heavy quarks and lattice QCD

    SciTech Connect

    Andreas S. Kronfeld

    2003-11-05

    This paper is a review of heavy quarks in lattice gauge theory, focusing on methodology. It includes a status report on some of the calculations that are relevant to heavy-quark spectroscopy and to flavor physics.

  19. Heavy-quark and lepton-pair production on nuclei

    SciTech Connect

    Boreskov, K.; Capella, A.; Kaidalov, A.; Tran Thanh Van, J. )

    1993-02-01

    We present a description of the [ital A] dependence of heavy-quark and Drell-Yan pair production in hadron-nucleus collisions, based on the Reggeon approach to strong interactions at high energies and the parton model. The same method has been successfully applied to the production of light-quark states. The existence of a new energy scale, which depends on the mass and [ital x][sub [ital F

  20. Precambrian palaeontology in the light of molecular phylogeny - an example: the radiation of the green algae

    NASA Astrophysics Data System (ADS)

    Teyssèdre, B.

    2007-09-01

    The problem of the antiquity of the radiation of the green algae (phylum Viridiplantae) has been hotly debated and is still controversial today. A method combining Precambrian paleontology and molecular phylogeny is applied to shed light on this topic. As a critical method, molecular phylogeny is essential for avoiding taxonomic mistakes. As a heuristic method, it helps us to discern to what extent the presence of such and such clade is likely at such and such time, and it may even suggest the attribution of some fossil to a clade whose taxonomic position will be distinctly defined even though it has no previously known representative. Some well characterized Precambrian fossils of green algae are Palaeastrum and Proterocladus at Svanbergfjellet (ca. 750 Ma), Tasmanites and Pterospermella at Thule (ca. 1200 Ma), Spiromorpha at Ruyang (ca. 1200 Ma) and Leiosphaeridia crassa at Roper (ca. 1450 Ma). The position of these fossils in the taxonomy and the phylogeny of the Viriplantae is discussed. The conclusions are that the Chlorophyceae and the Ulvophyceae were separated long before 750 Ma, that the Chlorophyta and the Streptophyta were separated long before 1200 Ma and that the last common ancestor of the Viridiplantae and the Rhodophyta was possibly two billion years old.

  1. Search for Hadronic Decays of a Light Higgs Boson in the Radiative Decay

    SciTech Connect

    Lees, J.P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Milanes, D.A.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Brown, D.N.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; Koch, H.; Schroeder, T.; Asgeirsson, D.J.; Hearty, C.; Mattison, T.S.; McKenna, J.A.

    2012-02-16

    The authors search for hadronic decays of a light Higgs boson (A{sup 0}) produced in radiative decays of an {Upsilon}(2S) or {Upsilon}(3S) meson, {Upsilon} {yields} {gamma}A{sup 0}. The data have been recorded by the BABAR experiment at the {Upsilon}(3S) and {Upsilon}(2S) center of mass energies, and include (121.3 {+-} 1.2) x 10{sup 6} {Upsilon}(3S) and (98.3 {+-} 0.9) x 10{sup 6} {Upsilon}(2S) mesons. No significant signal is observed. We set 90% confidence level upper limits on the product branching fractions {beta}({Upsilon}(nS) {yields} {gamma}A{sup 0}) {center_dot} {beta}(A{sup 0} {yields} hadrons) (n = 2 or 3) that range from 1 x 10{sup -6} for an A{sup 0} mass of 0.3 GeV/c{sup 2} to 8 x 10{sup -5} at 7 GeV/c{sup 2}.

  2. Melatonin in Glycyrrhiza uralensis: response of plant roots to spectral quality of light and UV-B radiation.

    PubMed

    Afreen, F; Zobayed, S M A; Kozai, T

    2006-09-01

    Melatonin (N-acetyl-5-methoxytryptamine) is known to be synthesized and secreted by the pineal gland in vertebrates. Evidence for the occurrence of melatonin in the roots of Glycyrrhiza uralensis plants and the response of this plant to the spectral quality of light including red, blue and white light (control) and UV-B radiation (280-315 nm) for the synthesis of melatonin were investigated. Melatonin was extracted and quantified in seed, root, leaf and stem tissues and results revealed that the root tissues contained the highest concentration of melatonin; melatonin concentrations also increased with plant development. After 3 months of growth under red, blue and white fluorescent lamps, the melatonin concentrations were highest in red light exposed plants and varied depending on the wavelength of light spectrum in the following order red > blue > or = white light. Interestingly, in a more mature plant (6 months) melatonin concentration was increased considerably; the increments in concentration were X4, X5 and X3 in 6-month-old red, blue and white light exposed (control) plants, respectively. The difference in melatonin concentrations between blue and white light exposed (control) plants was not significant. The concentration of melatonin quantified in the root tissues was highest in the plants exposed to high intensity UV-B radiation for 3 days followed by low intensity UV-B radiation for 15 days. The reduction of melatonin under longer periods of UV-B exposure indicates that melatonin synthesis may be related to the integrated (intensity and duration) value of UV-B irradiation. Melatonin in G. uralensis plant is presumably for protection against oxidative damage caused as a response to UV irradiation.

  3. Bound States of (Anti-)Scalar-Quarks in SU(3)c Lattice QCD

    SciTech Connect

    Iida, H.; Takahashi, T. T.; Suganuma, H.

    2007-06-13

    Light scalar-quarks {phi} (colored scalar particles or idealized diquarks) and their color-singlet hadronic states are studied with quenched SU(3)c lattice QCD in terms of mass generation. We investigate 'scalar-quark mesons' {phi}{dagger}{phi} and 'scalar-quark baryons' {phi}{phi}{phi} as the bound states of scalar-quarks {phi}. We also investigate the bound states of scalar-quarks {phi} and quarks {psi}, i.e., {phi}{dagger}{psi}, {psi}{psi}{phi} and {phi}{phi}{psi}, which we name 'chimera hadrons'. All the new-type hadrons including {phi} are found to have a large mass due to large quantum corrections by gluons, even for zero bare scalar-quark mass m{phi} = 0 at a-1 {approx} 1GeV. We conjecture that all colored particles generally acquire a large effective mass due to dressed gluon effects.

  4. Quark confinement dynamics

    SciTech Connect

    Allen, T.J.; Olsson, M.G.; Veseli, S.; Williams, K. |

    1997-05-01

    Starting from Buchm{umlt u}ller{close_quote}s observation that a chromoelectric flux tube meson will exhibit only the Thomas-type spin-orbit interaction, we show that a model built upon the related assumption that a quark feels only a constant radial chromoelectric field in its rest frame implies a complete relativistic effective Hamiltonian that can be written explicitly in terms of quark canonical variables. The model yields linear Regge trajectories and exhibits some similarities to scalar confinement, but with the advantage of being more closely linked to QCD. {copyright} {ital 1997} {ital The American Physical Society}

  5. Top quark physics: Future measurements

    SciTech Connect

    Frey, R.; Vejcik, S.; Berger, E.L.

    1997-04-04

    The authors discuss the study of the top quark at future experiments and machines. Top`s large mass makes it a unique probe of physics at the natural electroweak scale. They emphasize measurements of the top quark`s mass, width, and couplings, as well as searches for rare or nonstandard decays, and discuss the complementary roles played by hadron and lepton colliders.

  6. Attenuation and Scattering of Light in Optical Fibers-Effects of Nuclear Radiation (Modulation and Display of Laser Radiation)

    DTIC Science & Technology

    1981-12-01

    8217··· .• 7_’- <’" ..n ...,6..J / /j/; i,· ,. , ·’ · /.’• ... , /\\ !-·"’~:; ..... ·<’- ,.J --F/ F.r · / ’ I ’ • _’’ ’ ’ ,’ / . ,; • ir ...decrease in transmitted power was monitored as a function of wavelength and radiation dose. The wave- lengths examined were in the Visible and near IR ...radiation dose. The wavelengths examined were in the visible and near IR regions that are of specific interest for optical fiber communications. The

  7. Radiation Force Caused by Scattering, Absorption, and Emission of Light by Nonspherical Particles

    NASA Technical Reports Server (NTRS)

    Mishchenko, Michael I.; Hansen, James E. (Technical Monitor)

    2001-01-01

    General formulas for computing the radiation force exerted on arbitrarily oriented and arbitrarily shaped nonspherical particles due to scattering, absorption, and emission of electromagnetic radiation are derived. For randomly oriented particles with a plane of symmetry, the formula for the average radiation force caused by the particle response to external illumination reduces to the standard Debye formula derived from the Lorenz-Mie theory, whereas the average radiation force caused by emission vanishes.

  8. Dressed-quarks and the Roper resonance

    NASA Astrophysics Data System (ADS)

    Roberts, C. D.; Cloët, I. C.; Chang, L.; Roberts, H. L. L.

    2012-04-01

    A Dyson-Schwinger equation calculation of the light hadron spectrum, which correlates the masses of meson and baryon ground- and excited-states within a single framework, produces a description of the Roper resonance that corresponds closely with conclusions drawn recently by EBAC. Namely, the Roper is a particular type of radial excitation of the nucleon's dressed-quark core augmented by a material meson cloud component. There are, in addition, some surprises.

  9. SU-E-T-24: Development and Implementation of an Automated Algorithm to Determine Radiation Isocenter, Radiation vs. Light Field Coincidence, and Analyze Strip Tests.

    PubMed

    Hyer, D; Mart, C

    2012-06-01

    The aim of this study was to develop a phantom and analysis software that could be used to quickly and accurately determine the location of radiation isocenter using the Electronic Portal Imaging Device (EPID). The phantom could then be used as a static reference point for performing other tests including: radiation vs. light field coincidence, MLC and Jaw strip tests, and Varian Optical Guidance Platform (OGP) calibration. The solution proposed uses a collimator setting of 10×10 cm to acquire EPID images of the new phantom constructed from LEGO® blocks. Images from a number of gantry and collimator angles are analyzed by the software to determine the position of the jaws and center of the phantom in each image. The distance between a chosen jaw and the phantom center is then compared to the same distance measured after a 180 degree collimator rotation to determine if the phantom is centered in the dimension being investigated. The accuracy of the algorithm's measurements were verified by independent measurement to be approximately equal to the detector's pitch. Light versus radiation field as well as MLC and Jaw strip tests are performed using measurements based on the phantom center once located at the radiation isocenter. Reproducibility tests show that the algorithm's results were objectively repeatable. Additionally, the phantom and software are completely independent of linac vendor and this study presents results from two major linac manufacturers. An OGP calibration array was also integrated into the phantom to allow calibration of the OGP while the phantom is positioned at radiation isocenter to reduce setup uncertainty contained in the calibration. This solution offers a quick, objective method to perform isocenter localization as well as laser alignment, OGP calibration, and other tests on a monthly basis. © 2012 American Association of Physicists in Medicine.

  10. A simple quality assurance test tool for the visual verification of light and radiation field congruent using electronic portal images device and computed radiography

    PubMed Central

    2012-01-01

    Background The radiation field on most megavoltage radiation therapy units are shown by a light field projected through the collimator by a light source mounted inside the collimator. The light field is traditionally used for patient alignment. Hence it is imperative that the light field is congruent with the radiation field. Method A simple quality assurance tool has been designed for rapid and simple test of the light field and radiation field using electronic portal images device (EPID) or computed radiography (CR). We tested this QA tool using Varian PortalVision and Elekta iViewGT EPID systems and Kodak CR system. Results Both the single and double exposure techniques were evaluated, with double exposure technique providing a better visualization of the light-radiation field markers. The light and radiation congruency could be detected within 1 mm. This will satisfy the American Association of Physicists in Medicine task group report number 142 recommendation of 2 mm tolerance. Conclusion The QA tool can be used with either an EPID or CR to provide a simple and rapid method to verify light and radiation field congruence. PMID:22452821

  11. An enhancing effect of visible light and UV radiation on phenolic compounds and various antioxidants in broad bean seedlings.

    PubMed

    Younis, Mahmoud El-Baz; Hasaneen, Mohammed Naguib Abdel-Ghany; Abdel-Aziz, Heba Mahmoud Mohammed

    2010-10-01

    Exposure of dark- or ambient visible light-grown broad bean seedlings to low (LL) and high (HL) visible light intensities, UV-A or UV-C, either alone or in combination, induced significant increases in total phenolic compounds as well as in anthocyanins content, throughout the germination period, as compared with the respective levels in control seedlings. In general, as compared with control levels, exposure of both dark- or light-grown broad bean seedlings to LL, HL, UV-A or UV-C, induced significant increases in the contents of non-enzymatic antioxidants (total ascorbate; ASA-DASA and total glutathione; GSSG-GSH) and enzymatic antioxidant activities (superoxide dismutase; SOD, catalase; CAT, ascorbate peroxidase; APO and glutathione reductase; GR). The obtained results are discussed in relation to induced mechanisms of protection and repair from the inevitable exposure to damaging visible light and UV-radiation. © 2010 Landes Bioscience

  12. An enhancing effect of visible light and UV radiation on phenolic compounds and various antioxidants in broad bean seedlings

    PubMed Central

    Hasaneen, Mohammed Naguib Abdel-Ghany; Abdel-Aziz, Heba Mahmoud Mohammed

    2010-01-01

    Exposure of dark- or ambient visible light-grown broad bean seedlings to low (LL) and high (HL) visible light intensities, UV-A or UV-C, either alone or in combination, induced significant increases in total phenolic compounds as well as in anthocyanins content, throughout the germination period, as compared with the respective levels in control seedlings. In general, as compared with control levels, exposure of both dark- or light-grown broad bean seedlings to LL, HL, UV-A or UV-C, induced significant increases in the contents of non-enzymatic antioxidants (total ascorbate; ASA-DASA and total glutathione; GSSG-GSH) and enzymatic antioxidant activities (superoxide dismutase; SOD, catalase; CAT, ascorbate peroxidase; APO and glutathione reductase; GR). The obtained results are discussed in relation to induced mechanisms of protection and repair from the inevitable exposure to damaging visible light and UV radiation. PMID:20505357

  13. Time-resolved synchrotron radiation excited optical luminescence: light-emission properties of silicon-based nanostructures.

    PubMed

    Sham, Tsun-Kong; Rosenberg, Richard A

    2007-12-21

    The recent advances in the study of light emission from matter induced by synchrotron radiation: X-ray excited optical luminescence (XEOL) in the energy domain and time-resolved X-ray excited optical luminescence (TRXEOL) are described. The development of these element (absorption edge) selective, synchrotron X-ray photons in, optical photons out techniques with time gating coincide with advances in third-generation, insertion device based, synchrotron light sources. Electron bunches circulating in a storage ring emit very bright, widely energy tunable, short light pulses (<100 ps), which are used as the excitation source for investigation of light-emitting materials. Luminescence from silicon nanostructures (porous silicon, silicon nanowires, and Si-CdSe heterostructures) is used to illustrate the applicability of these techniques and their great potential in future applications.

  14. Hybrid model of light propagation in random media based on the time-dependent radiative transfer and diffusion equations

    NASA Astrophysics Data System (ADS)

    Fujii, Hiroyuki; Okawa, Shinpei; Yamada, Yukio; Hoshi, Yoko

    2014-11-01

    Numerical modeling of light propagation in random media has been an important issue for biomedical imaging, including diffuse optical tomography (DOT). For high resolution DOT, accurate and fast computation of light propagation in biological tissue is desirable. This paper proposes a space-time hybrid model for numerical modeling based on the radiative transfer and diffusion equations (RTE and DE, respectively) in random media under refractive-index mismatching. In the proposed model, the RTE and DE regions are separated into space and time by using a crossover length and the time from the ballistic regime to the diffusive regime, ρDA 10 / μt‧ and tDA 20 / v μt‧ where μt‧ and v represent a reduced transport coefficient and light velocity, respectively. The present model succeeds in describing light propagation accurately and reduces computational load by a quarter compared with full computation of the RTE.

  15. Flavor asymmetry of the nucleon sea and the five-quark components of the nucleons.

    PubMed

    Chang, Wen-Chen; Peng, Jen-Chieh

    2011-06-24

    The existence of the five-quark Fock states for the intrinsic charm quark in the nucleons was suggested some time ago, but conclusive evidence is still lacking. We generalize the previous theoretical approach to the light-quark sector and study possible experimental signatures for such five-quark states. In particular, we compare the d-ū and ū + d-s-s data with the calculations based on the five-quark Fock states. The qualitative agreement between the data and the calculations is interpreted as evidence for the existence of the intrinsic light-quark sea in the nucleons. The probabilities for the |uuduū and |uuddd Fock states are also extracted.

  16. Top quark physics at CDF

    SciTech Connect

    Nielsen, Jason

    2004-04-30

    The existence of the top quark, discovered by CDF and D0 in 1995, has been re-established in the burgeoning dataset being collected in Run 2 of the Tevatron at Fermilab. Results from CDF on the top quark production cross section and top quark mass are consistent with the Standard Model expectations. The well-characterized top data samples will make it possible in the future to probe further for new physics in the top quark sector. This report summarizes recent CDF top quark physics results.

  17. Top quark mass measurement

    SciTech Connect

    Maki, Tuula

    2008-03-18

    The top quark is the heaviest elementary particle. Its mass is one of the fundamental parameters of the standard model of particle physics, and an important input to precision electroweak tests. This thesis describes three measurements of the top-quark mass in the dilepton decay channel. The dilepton events have two neutrinos in the final state; neutrinos are weakly interacting particles that cannot be detected with a multipurpose experiment. Therefore, the signal of dilepton events consists of a large amount of missing energy and momentum carried off by the neutrinos. The top-quark mass is reconstructed for each event by assuming an additional constraint from a top mass independent distribution. Template distributions are constructed from simulated samples of signal and background events, and parametrized to form continuous probability density functions. The final top-quark mass is derived using a likelihood fit to compare the reconstructed top mass distribution from data to the parametrized templates. One of the analyses uses a novel technique to add top mass information from the observed number of events by including a cross-section-constraint in the likelihood function. All measurements use data samples collected by the CDF II detector.

  18. Planck’s radiation law, the light quantum, and the prehistory of indistinguishability in the teaching of quantum mechanics

    NASA Astrophysics Data System (ADS)

    Passon, Oliver; Grebe-Ellis, Johannes

    2017-05-01

    Planck’s law for black-body radiation marks the origin of quantum theory and is discussed in all introductory (or advanced) courses on this subject. However, the question whether Planck really implied quantisation is debated among historians of physics. We present a simplified account of this debate which also sheds light on the issue of indistinguishability and Einstein’s light quantum hypothesis. We suggest that the teaching of quantum mechanics could benefit from including this material beyond the question of historical accuracy.

  19. [Study on the stability variation mechanism of humic acid water solution after radiated by the UV light].

    PubMed

    Wang, Wen-Dong; Zhou, Li-chuan; Ding, Zhen-Zhen; Wang, Hong-Ping; Sun, Xue-Jun

    2013-10-01

    Humic acid widely presents in various surface waters. Molecular structure has significant impacts on its physical and chemical properties. To explore the stability variation of humic acid before and after the UV light radiation, spectroscopic and electrochemical analysis were applied in this paper. Structural parameters selected in the experiments include reactive sites, such as phenolic hydroxyl and carboxyl contents, Zeta potential, and colloidal size. It was found that there was little humic acid being removed in the solution without UV radiation pretreatment; while its remove ratio increased notably with radiation time. After 3 h pretreatment, humic acid removal ratio was above 80% in coagulation. Spectroscopy analysis results showed that partial of the groups with fluorescent effects might be shed or rearranged after the radiation; while its aromatic structure was not destroyed. Both the Zeta potential and average colloidal size decreased with the radiation time, which was not conducive to the aggregation of humic acid. However, -OH content decreased slightly after the UV radiation, and new carboxyl and carbonyl groups formed simultaneously. The increasing of the reactive sites and the improvement of the reaction effectiveness were the major reasons leading to humic acid stability decrease in PAC! coagulation.

  20. The effect of UV light on the thermooxidative stability of linear low density polyethylene films crosslinked by ionizing radiation

    NASA Astrophysics Data System (ADS)

    Sen, M.; Basfar, A. A.

    1998-06-01

    The effect of ultraviolet (UV) light on the thermooxidative stability of Linear Low Density Polyethylene(LLDPE) films was studied. LLDPE was stabilized with phenolic type antioxidant known as Irganox 1010, hindered amine light stabilizer known as Chimmasorb 944 and phenolic type gamma stabilizer. The influence of these additives on the thermooxidative stability of gamma and UV irradiated LLDPE were investigated by isothermal Differential Scanning Calorimeter (DSC). The oxidation induction time (OIT) experiments indicate that antirad free LLDPE films which contains antioxidant and UV stabilizer are more sensitive to gamma and UV radiation. On the other hand, films which contain antirad and irradiated to different doses of γ-radiation demonstrated improved thermooxidative stability.

  1. Implications of using transmitted vs. reflected light for determining cloud properties, cloud radiative effects and aerosol-cloud-interactions

    NASA Astrophysics Data System (ADS)

    LeBlanc, S. E.; Redemann, J.; Segal-Rosenhaimer, M.; Kacenelenbogen, M. S.; Shinozuka, Y.; Flynn, C. J.; Schmidt, S.; Pilewskie, P.; Song, S.; Woods, S.; Lawson, P.; Nenes, A.; Lin, J. J.; Ziemba, L. D.

    2015-12-01

    Light transmitted through clouds is sensitive to a different cloud volume than reflected light at cloud top. This difference in sampling volumes has implications when calculating the radiative effects of clouds (CRE) and aerosol-cloud-interactions (ACI). We present a comparison of retrieved cloud properties and the corresponding CRE and ACI based on transmitted and reflected light for a cloud sampled during the Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS, 2013) field campaign. Measurements of zenith radiances were obtained from the NASA DC-8 aircraft using the Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) instrument. 4STAR was deployed on an airborne platform during SEAC4RS alongside the Solar Spectral Flux Radiometer (SSFR). To retrieve cloud properties from transmitted shortwave radiation, we use a retrieval utilizing spectrally resolved measurements. Spectral features in shortwave radiation transmitted through clouds are sensitive to changes in cloud optical thickness, effective radius, and thermodynamic phase. The spectral features due to absorption and scattering processes by liquid water and ice cloud particles include shifts in spectral slopes, curvatures, maxima, and minima of cloud-transmitted radiance. These spectral features have been quantified by 15 parameters used to retrieve cloud properties from the 4STAR zenith radiances. Retrieved cloud optical thicknesses and effective radii based on transmitted shortwave radiation are compared to their counterparts obtained from reflected shortwave radiation measured above cloud with MODIS and with the enhanced MODIS Airborne Simulator (eMAS), the Research Scanning Polarimeter (RSP), and SSFR operating aboard the NASA ER-2 aircraft. Remotely sensed cloud particle effective radius are combined with in situ measurements of cloud and aerosol particles from the NASA Langley Aerosol Research Group Experiment (LARGE) CCN Counter

  2. Properties of relativistically rotating quark stars

    NASA Astrophysics Data System (ADS)

    Zhou, Enping

    2017-06-01

    In this work, quasi-equilibrium models of rapidly rotating triaxially deformed quark stars are computed in general relativistic gravity, assuming a conformally flat spatial geometry (Isenberg-Wilson-Mathews formulation) and a polynomial equation of state. Especially, since we are using a full 3-D numerical relativity initial data code, we are able to consider the triaxially deformed rotating quark stars at very high spins. Such triaxially deformed stars are possible gravitational radiation sources detectable by ground based gravitational wave observatories. Additionally, the bifurcation from axisymmetric rotating sequence to triaxially rotating sequence hints a more realistic spin up limit for rotating compact stars compared with the mass-shedding limit. With future observations such as sub-millisecond pulsars, we could possibly distinguish between equation of states of compact stars, thus better understanding strong interaction in the low energy regime.

  3. Strange quark matter and quark stars with the Dyson-Schwinger quark model

    NASA Astrophysics Data System (ADS)

    Chen, H.; Wei, J.-B.; Schulze, H.-J.

    2016-09-01

    We calculate the equation of state of strange quark matter and the interior structure of strange quark stars in a Dyson-Schwinger quark model within rainbow or Ball-Chiu vertex approximation. We emphasize constraints on the parameter space of the model due to stability conditions of ordinary nuclear matter. Respecting these constraints, we find that the maximum mass of strange quark stars is about 1.9 solar masses, and typical radii are 9-11km. We obtain an energy release as large as 3.6 × 10^{53} erg from conversion of neutron stars into strange quark stars.

  4. A Calculation and Measurement of Radiative Moller Scattering at 100 MeV with DarkLight

    NASA Astrophysics Data System (ADS)

    Epstein, Charles; DarkLight Collaboration

    2017-01-01

    A number of current experiments rely on precise knowledge of electron-electron (Moller) and positron-electron (Bhabha) scattering. Many of these experiments, which have lepton beams on atomic targets, use these QED processes as normalization. In other cases, such as DarkLight (at the Jefferson Lab ERL), with electron beams at relatively low energy (100 MeV) and very high power (1 Megawatt), Moller scattering and radiative Moller scattering have such enormous cross-sections that they produce extensive amounts of noise that must be understood. In this low-energy regime, the electron mass can also not be neglected. As a result, we have developed a new Monte Carlo event generator for the radiative Moller and Bhabha processes, extending existing soft-photon radiative corrections with new, exact single-photon bremsstrahlung calculations, and including the electron mass:. DarkLight provides us a unique opportunity to study this process experimentally and compare it with our work. As a result, we are preparing a dedicated apparatus consisting of two magnetic spectrometers as part of the first phase of DarkLight in order to directly measure this process. An overview of the calculation and the status of the experiment's construction will be presented.

  5. Radiation burden from secondary doses to patients undergoing radiation therapy with photons and light ions and radiation doses from imaging modalities.

    PubMed

    Gudowska, I; Ardenfors, O; Toma-Dasu, I; Dasu, A

    2014-10-01

    Ionising radiation is increasingly used for the treatment of cancer, being the source of a considerable fraction of the medical irradiation to patients. With the increasing success rate of cancer treatments and longer life expectancy of the treated patients, the issue of secondary cancer incidence is of growing concern, especially for paediatric patients who may live long after the treatment and be more susceptible to carcinogenesis. Also, additional imaging procedures like computed tomography, kilovoltage and megavoltage imaging and positron emission tomography, alone or in conjunction with radiation therapy, may add to the radiation burden associated with the risk of occurrence of secondary cancers. This work has been based on literature studies and is focussed on the assessment of secondary doses to healthy tissues that are delivered by the use of modern radiation therapy and diagnostic imaging modalities in the clinical environment.

  6. Effect of 16 and 24 hours daily radiation (light) on lettuce growth

    NASA Technical Reports Server (NTRS)

    Koontz, H. V.; Prince, R. P.; Knott, W. M. (Principal Investigator)

    1986-01-01

    A 50% increase in total radiation by extending the photoperiod from 16 to 24 hr doubled the weight of all cultivars of loose-leaf lettuce (Lactuca sativa L.) 'Grand Rapids Forcing', 'Waldmanns Green', 'Salad Bowl', and 'RubyConn', but not a Butterhead cultivar, 'Salina'. When total daily radiation (moles of photons) was the same, plants under continuous radiation weighed 30% to 50% more than plants under a 16 hr photoperiod. By using continuous radiation on loose-leaf lettuce, fewer lamp fixtures were required and yield was increased.

  7. Effect of 16 and 24 hours daily radiation (light) on lettuce growth

    NASA Technical Reports Server (NTRS)

    Koontz, H. V.; Prince, R. P.; Knott, W. M. (Principal Investigator)

    1986-01-01

    A 50% increase in total radiation by extending the photoperiod from 16 to 24 hr doubled the weight of all cultivars of loose-leaf lettuce (Lactuca sativa L.) 'Grand Rapids Forcing', 'Waldmanns Green', 'Salad Bowl', and 'RubyConn', but not a Butterhead cultivar, 'Salina'. When total daily radiation (moles of photons) was the same, plants under continuous radiation weighed 30% to 50% more than plants under a 16 hr photoperiod. By using continuous radiation on loose-leaf lettuce, fewer lamp fixtures were required and yield was increased.

  8. Effect of 16 and 24 hours daily radiation (light) on lettuce growth.

    PubMed

    Koontz, H V; Prince, R P

    1986-02-01

    A 50% increase in total radiation by extending the photoperiod from 16 to 24 hr doubled the weight of all cultivars of loose-leaf lettuce (Lactuca sativa L.) 'Grand Rapids Forcing', 'Waldmanns Green', 'Salad Bowl', and 'RubyConn', but not a Butterhead cultivar, 'Salina'. When total daily radiation (moles of photons) was the same, plants under continuous radiation weighed 30% to 50% more than plants under a 16 hr photoperiod. By using continuous radiation on loose-leaf lettuce, fewer lamp fixtures were required and yield was increased.

  9. Effects of heavy sea quarks at low energies.

    PubMed

    Bruno, Mattia; Finkenrath, Jacob; Knechtli, Francesco; Leder, Björn; Sommer, Rainer

    2015-03-13

    We present a factorization formula for the dependence of light hadron masses and low energy hadronic scales on the mass M of a heavy quark: apart from an overall mass-independent factor Q, ratios such as r_{0}(M)/r_{0}(0) are computable in perturbation theory at large M. The perturbation theory part is stable concerning different loop orders. Our nonperturbative Monte Carlo results obtained in a model calculation, where a doublet of heavy quarks is decoupled, match quantitatively to the perturbative prediction. Upon taking ratios of different hadronic scales at the same mass, the perturbative function drops out and the ratios are given by the decoupled theory up to M^{-2} corrections. We verify-in the continuum limit-that the sea quark effects of quarks with masses around the charm mass are very small in such ratios.

  10. Quark mass variation constraints from Big Bang nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Bedaque, Paulo F.; Luu, Thomas; Platter, Lucas

    2011-04-01

    We study the impact on the primordial abundances of light elements created by a variation of the quark masses at the time of Big Bang nucleosynthesis (BBN). In order to navigate through the particle and nuclear physics required to connect quark masses to binding energies and reaction rates in a model-independent way, we use lattice QCD data and a hierarchy of effective field theories. We find that the measured He4 abundances put a bound of -1%≲δmq/mq≲0.7% on a possible variation of quark masses. The effect of quark mass variations on the deuterium abundances can be largely compensated by changes of the baryon-to-photon ratio η. Including bounds on the variation of η coming from WMAP results and adding some additional assumptions further narrows the range of allowed values of δmq/mq.

  11. Effects of UV-B radiation on tetraspores of Chondrus ocellatus Holm (Rhodophyta), and effects of red and blue light on repair of UV-B-induced damage

    NASA Astrophysics Data System (ADS)

    Ju, Qing; Xiao, Hui; Wang, You; Tang, Xuexi

    2015-05-01

    We evaluated the effects of red and blue light on the repair of UV-B radiation-induced damage in tetraspores of Chondrus ocellatus Holm. Tetraspores of C. ocellatus were treated with different UV-B radiation levels (0, 36, 72, 108, 144 and 180 J/m2), and thereafter subjected to PAR, darkness, or red or blue light during a 2-h repair stage, each day for 48 days. The diameters and cellular contents of cyclobutane pyrimidine dimmers (CPDs), chlorophyll a (Chl a), phycoerythrin, and UV-B-absorbing mycosporinelike amino acids (MAAs) contents of the tetraspores were determined. Our results show that low doses of UV-B radiation (36 and 72 J/m2) promoted the growth of C. ocellatus; however, increased UV-B radiation gradually reduced the C. ocellatus growth (greater than 72 J/m2). The MAAs (palythine and asterina-330) in C. ocellatus were detected and analyzed by LC/MS. Our results suggest that moderate red light could induce the growth of this alga in aquaculture. In addition, photorepair was inhibited by red light, so there may be some other DNA repair mechanism activated by red light. Blue light promoted the activity of DNA photolyase, greatly improving remediation efficiency. Red and blue lights were found to reduce the capacity of C. ocellatus to form MAAs. Therefore, PAR, red light, and blue light play different roles during the repair processes for damage induced by UV-B radiation.

  12. Valence-quark distribution functions in the kaon and pion

    SciTech Connect

    Chen, Chen; Chang, Lei; Roberts, Craig D.; Wan, Shaolong; Zong, Hong-Shi

    2016-04-18

    We describe expressions for pion and kaon dressed-quark distribution functions that incorporate contributions from gluons which bind quarks into these mesons and hence overcome a flaw of the commonly used handbag approximation. The distributions therewith obtained are purely valence in character, ensuring that dressed quarks carry all the meson’s momentum at a characteristic hadronic scale and vanish as ( 1 - x ) 2 when Bjorken- x → 1 . Comparing such distributions within the pion and kaon, it is apparent that the size of S U ( 3 ) -flavor symmetry breaking in meson parton distribution functions is modulated by the flavor dependence of dynamical chiral symmetry breaking. Corrections to these leading-order formulas may be divided into two classes, responsible for shifting dressed-quark momentum into glue and sea quarks. Working with available empirical information, we build an algebraic framework that is capable of expressing the principal impact of both classes of corrections. This enables a realistic comparison with experiment which allows us to identify and highlight basic features of measurable pion and kaon valence-quark distributions. We find that whereas roughly two thirds of the pion’s light-front momentum is carried by valence dressed quarks at a characteristic hadronic scale; this fraction rises to 95% in the kaon; evolving distributions with these features to a scale typical of available Drell-Yan data produces a kaon-to-pion ratio of u -quark distributions that is in agreement with the single existing data set, and predicts a u -quark distribution within the pion that agrees with a modern reappraisal of π N Drell-Yan data. Precise new data are essential in order to validate this reappraisal and because a single modest-quality measurement of the kaon-to-pion ratio cannot be considered definitive.

  13. Blue light hazard optimization for white light-emitting diode sources with high luminous efficacy of radiation and high color rendering index

    NASA Astrophysics Data System (ADS)

    Zhang, Jingjing; Guo, Weihong; Xie, Bin; Yu, Xingjian; Luo, Xiaobing; Zhang, Tao; Yu, Zhihua; Wang, Hong; Jin, Xing

    2017-09-01

    Blue light hazard of white light-emitting diodes (LED) is a hidden risk for human's photobiological safety. Recent spectral optimization methods focus on maximizing luminous efficacy and improving color performances of LEDs, but few of them take blue hazard into account. Therefore, for healthy lighting, it's urgent to propose a spectral optimization method for white LED source to exhibit low blue light hazard, high luminous efficacy of radiation (LER) and high color performances. In this study, a genetic algorithm with penalty functions was proposed for realizing white spectra with low blue hazard, maximal LER and high color rendering index (CRI) values. By simulations, white spectra from LEDs with low blue hazard, high LER (≥297 lm/W) and high CRI (≥90) were achieved at different correlated color temperatures (CCTs) from 2013 K to 7845 K. Thus, the spectral optimization method can be used for guiding the fabrication of LED sources in line with photobiological safety. It is also found that the maximum permissible exposure duration of the optimized spectra increases by 14.9% than that of bichromatic phosphor-converted LEDs with equal CCT.

  14. Measurement of jet shapes in top-quark pair events at [Formula: see text] using the ATLAS detector.

    PubMed

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Schram, M; Schroeder, C; Schroer, N; Schultens, M J; Schultz-Coulon, H-C; Schulz, H; Schumacher, M; Schumm, B A; Schune, Ph; Schwartzman, A; Schwegler, Ph; Schwemling, Ph; Schwienhorst, R; Schwindling, J; Schwindt, T; Schwoerer, M; Sciacca, F G; Scifo, E; Sciolla, G; Scott, W G; Scutti, F; Searcy, J; Sedov, G; Sedykh, E; Seidel, S C; Seiden, A; Seifert, F; Seixas, J M; Sekhniaidze, G; Sekula, S J; Selbach, K E; Seliverstov, D M; Sellers, G; Seman, M; Semprini-Cesari, N; Serfon, C; Serin, L; Serkin, L; Serre, T; Seuster, R; Severini, H; Sfyrla, A; Shabalina, E; Shamim, M; Shan, L Y; Shank, J T; Shao, Q T; Shapiro, M; Shatalov, P B; Shaw, K; Sherwood, P; Shimizu, S; Shimojima, M; Shin, T; Shiyakova, M; Shmeleva, A; Shochet, M J; Short, D; Shrestha, S; Shulga, E; Shupe, M A; Sicho, P; Sidoti, A; Siegert, F; Sijacki, Dj; Silbert, O; Silva, J; Silver, Y; Silverstein, D; Silverstein, S B; Simak, V; Simard, O; Simic, Lj; Simion, S; Simioni, E; Simmons, B; Simoniello, R; Simonyan, M; Sinervo, P; Sinev, N B; Sipica, V; Siragusa, G; Sircar, A; Sisakyan, A N; Sivoklokov, S Yu; Sjölin, J; Sjursen, T B; Skinnari, L A; Skottowe, H P; Skovpen, K Yu; Skubic, P; Slater, M; Slavicek, T; Sliwa, K; Smakhtin, V; Smart, B H; Smestad, L; Smirnov, S Yu; Smirnov, Y; Smirnova, L N; Smirnova, O; Smith, K M; Smizanska, M; Smolek, K; Snesarev, A A; Snidero, G; Snow, J; Snyder, S; Sobie, R; Sodomka, J; Soffer, A; Soh, D A; Solans, C A; Solar, M; Solc, J; Soldatov, E Yu; Soldevila, U; Solfaroli Camillocci, E; Solodkov, A A; Solovyanov, O V; Solovyev, V; Soni, N; Sood, A; Sopko, V; Sopko, B; Sosebee, M; Soualah, R; Soueid, P; Soukharev, A M; South, D; Spagnolo, S; Spanò, F; Spighi, R; Spigo, G; Spiwoks, R; Spousta, M; Spreitzer, T; Spurlock, B; St Denis, R D; Stahlman, J; Stamen, R; Stanecka, E; Stanek, R W; Stanescu, C; Stanescu-Bellu, M; Stanitzki, M M; Stapnes, S; Starchenko, E A; Stark, J; Staroba, P; Starovoitov, P; Staszewski, R; Staude, A; Stavina, P; Steele, G; Steinbach, P; Steinberg, P; Stekl, I; Stelzer, B; Stelzer, H J; Stelzer-Chilton, O; Stenzel, H; Stern, S; Stewart, G A; Stillings, J A; Stockton, M C; Stoebe, M; Stoerig, K; Stoicea, G; Stonjek, S; Stradling, A R; Straessner, A; Strandberg, J; Strandberg, S; Strandlie, A; Strang, M; Strauss, E; Strauss, M; Strizenec, P; Ströhmer, R; Strom, D M; Strong, J A; Stroynowski, R; Stugu, B; Stumer, I; Stupak, J; Sturm, P; Styles, N A; Su, D; Subramania, Hs; Subramaniam, R; Succurro, A; Sugaya, Y; Suhr, C; Suk, M; Sulin, V V; Sultansoy, S; Sumida, T; Sun, X; Sundermann, J E; Suruliz, K; Susinno, G; Sutton, M R; Suzuki, Y; Suzuki, Y; Svatos, M; Swedish, S; Swiatlowski, M; Sykora, I; Sykora, T; Ta, D; Tackmann, K; Taffard, A; Tafirout, R; Taiblum, N; Takahashi, Y; Takai, H; Takashima, R; Takeda, H; Takeshita, T; Takubo, Y; Talby, M; Talyshev, A A; Tam, J Y C; Tamsett, M C; Tan, K G; Tanaka, J; Tanaka, R; Tanaka, S; Tanaka, S; Tanasijczuk, A J; Tani, K; Tannoury, N; Tapprogge, S; Tarem, S; Tarrade, F; Tartarelli, G F; Tas, P; Tasevsky, M; Tashiro, T; Tassi, E; Tayalati, Y; Taylor, C; Taylor, F E; Taylor, G N; Taylor, W; Teinturier, M; Teischinger, F A; Teixeira Dias Castanheira, M; Teixeira-Dias, P; Temming, K K; Ten Kate, H; Teng, P K; Terada, S; Terashi, K; Terron, J; Testa, M; Teuscher, R J; Therhaag, J; Theveneaux-Pelzer, T; Thoma, S; Thomas, J P; Thompson, E N; Thompson, P D; Thompson, P D; Thompson, A S; Thomsen, L A; Thomson, E; Thomson, M; Thong, W M; Thun, R P; Tian, F; Tibbetts, M J; Tic, T; Tikhomirov, V O; Tikhonov, Yu A; Timoshenko, S; Tiouchichine, E; Tipton, P; Tisserant, S; Todorov, T; Todorova-Nova, S; Toggerson, B; Tojo, J; Tokár, S; Tokushuku, K; Tollefson, K; Tomlinson, L; Tomoto, M; Tompkins, L; Toms, K; Tonoyan, A; Topfel, C; Topilin, N D; Torrence, E; Torres, H; Torró Pastor, E; Toth, J; Touchard, F; Tovey, D R; Tran, H L; Trefzger, T; Tremblet, L; Tricoli, A; Trigger, I M; Trincaz-Duvoid, S; Tripiana, M F; Triplett, N; Trischuk, W; Trocmé, B; Troncon, C; Trottier-McDonald, M; Trovatelli, M; True, P; Trzebinski, M; Trzupek, A; Tsarouchas, C; Tseng, J C-L; Tsiakiris, M; Tsiareshka, P V; Tsionou, D; Tsipolitis, G; Tsiskaridze, S; Tsiskaridze, V; Tskhadadze, E G; Tsukerman, I I; Tsulaia, V; Tsung, J-W; Tsuno, S; Tsybychev, D; Tua, A; Tudorache, A; Tudorache, V; Tuggle, J M; Tuna, A N; Turala, M; Turecek, D; Turk Cakir, I; Turra, R; Tuts, P M; Tykhonov, A; Tylmad, M; Tyndel, M; Uchida, K; Ueda, I; Ueno, R; Ughetto, M; Ugland, M; Uhlenbrock, M; Ukegawa, F; Unal, G; Undrus, A; Unel, G; Ungaro, F C; Unno, Y; Urbaniec, D; Urquijo, P; Usai, G; Vacavant, L; Vacek, V; Vachon, B; Vahsen, S; Valencic, N; Valentinetti, S; Valero, A; Valery, L; Valkar, S; Valladolid Gallego, E; Vallecorsa, S; Valls Ferrer, J A; Van Berg, R; Van Der Deijl, P C; van der Geer, R; van der Graaf, H; Van Der Leeuw, R; van der Ster, D; van Eldik, N; van Gemmeren, P; Van Nieuwkoop, J; van Vulpen, I; Vanadia, M; Vandelli, W; Vaniachine, A; Vankov, P; Vannucci, F; Vari, R; Varnes, E W; Varol, T; Varouchas, D; Vartapetian, A; Varvell, K E; Vassilakopoulos, V I; Vazeille, F; Vazquez Schroeder, T; Veloso, F; Veneziano, S; Ventura, A; Ventura, D; Venturi, M; Venturi, N; Vercesi, V; Verducci, M; Verkerke, W; Vermeulen, J C; Vest, A; Vetterli, M C; Vichou, I; Vickey, T; Vickey Boeriu, O E; Viehhauser, G H A; Viel, S; Villa, M; Villaplana Perez, M; Vilucchi, E; Vincter, M G; Vinogradov, V B; Virzi, J; Vitells, O; Viti, M; Vivarelli, I; Vives Vaque, F; Vlachos, S; Vladoiu, D; Vlasak, M; Vogel, A; Vokac, P; Volpi, G; Volpi, M; Volpini, G; von der Schmitt, H; von Radziewski, H; von Toerne, E; Vorobel, V; Vos, M; Voss, R; Vossebeld, J H; Vranjes, N; Vranjes Milosavljevic, M; Vrba, V; Vreeswijk, M; Vu Anh, T; Vuillermet, R; Vukotic, I; Vykydal, Z; Wagner, W; Wagner, P; Wahrmund, S; Wakabayashi, J; Walch, S; Walder, J; Walker, R; Walkowiak, W; Wall, R; Waller, P; Walsh, B; Wang, C; Wang, H; Wang, H; Wang, J; Wang, J; Wang, K; Wang, R; Wang, S M; Wang, T; Wang, X; Warburton, A; Ward, C P; Wardrope, D R; Warsinsky, M; Washbrook, A; Wasicki, C; Watanabe, I; Watkins, P M; Watson, A T; Watson, I J; Watson, M F; Watts, G; Watts, S; Waugh, A T; Waugh, B M; Weber, M S; Webster, J S; Weidberg, A R; Weigell, P; Weingarten, J; Weiser, C; Wells, P S; Wenaus, T; Wendland, D; Weng, Z; Wengler, T; Wenig, S; Wermes, N; Werner, M; Werner, P; Werth, M; Wessels, M; Wetter, J; Whalen, K; White, A; White, M J; White, R; White, S; Whitehead, S R; Whiteson, D; Whittington, D; Wicke, D; Wickens, F J; Wiedenmann, W; Wielers, M; Wienemann, P; Wiglesworth, C; Wiik-Fuchs, L A M; Wijeratne, P A; Wildauer, A; Wildt, M A; Wilhelm, I; Wilkens, H G; Will, J Z; Williams, E; Williams, H H; Williams, S; Willis, W; Willocq, S; Wilson, J A; Wilson, A; Wingerter-Seez, I; Winkelmann, S; Winklmeier, F; Wittgen, M; Wittig, T; Wittkowski, J; Wollstadt, S J; Wolter, M W; Wolters, H; Wong, W C; Wooden, G; Wosiek, B K; Wotschack, J; Woudstra, M J; Wozniak, K W; Wraight, K; Wright, M; Wrona, B; Wu, S L; Wu, X; Wu, Y; Wulf, E; Wynne, B M; Xella, S; Xiao, M; Xie, S; Xu, C; Xu, D; Xu, L; Yabsley, B; Yacoob, S; Yamada, M; Yamaguchi, H; Yamaguchi, Y; Yamamoto, A; Yamamoto, K; Yamamoto, S; Yamamura, T; Yamanaka, T; Yamauchi, K; Yamazaki, T; Yamazaki, Y; Yan, Z; Yang, H; Yang, H; Yang, U K; Yang, Y; Yang, Z; Yanush, S; Yao, L; Yasu, Y; Yatsenko, E; Yau Wong, K H; Ye, J; Ye, S; Yen, A L; Yildirim, E; Yilmaz, M; Yoosoofmiya, R; Yorita, K; Yoshida, R; Yoshihara, K; Young, C; Young, C J S; Youssef, S; Yu, D; Yu, D R; Yu, J; Yu, J; Yuan, L; Yurkewicz, A; Zabinski, B; Zaidan, R; Zaitsev, A M; Zambito, S; Zanello, L; Zanzi, D; Zaytsev, A; Zeitnitz, C; Zeman, M; Zemla, A; Zenin, O; Ženiš, T; Zerwas, D; Zevi Della Porta, G; Zhang, D; Zhang, H; Zhang, J; Zhang, L; Zhang, X; Zhang, Z; Zhao, Z; Zhemchugov, A; Zhong, J; Zhou, B; Zhou, N; Zhou, Y; Zhu, C G; Zhu, H; Zhu, J; Zhu, Y; Zhuang, X; Zibell, A; Zieminska, D; Zimin, N I; Zimmermann, C; Zimmermann, R; Zimmermann, S; Zimmermann, S; Zinonos, Z; Ziolkowski, M; Zitoun, R; Živković, L; Zmouchko, V V; Zobernig, G; Zoccoli, A; Zur Nedden, M; Zutshi, V; Zwalinski, L

    A measurement of jet shapes in top-quark pair events using 1.8 fb(-1) of [Formula: see text]pp collision data recorded by the ATLAS detector at the LHC is presented. Samples of top-quark pair events are selected in both the single-lepton and dilepton final states. The differential and integrated shapes of the jets initiated by bottom-quarks from the top-quark decays are compared with those of the jets originated by light-quarks from the hadronic W-boson decays [Formula: see text] in the single-lepton channel. The light-quark jets are found to have a narrower distribution of the momentum flow inside the jet area than b-quark jets.

  15. Influence on photosynthesis of starlight, moonlight, planetlight, and light pollution (reflections on photosynthetically active radiation in the universe).

    PubMed

    Raven, J A; Cockell, C S

    2006-08-01

    Photosynthesis on Earth can occur in a diversity of organisms in the photosynthetically active radiation (PAR) range of 10 nmol of photons m(-2) s(-1) to 8 mmol of photons m(-2) s(-1). Similar considerations would probably apply to photosynthetic organisms on Earth-like planets (ELPs) in the continuously habitable zone of other stars. On Earth, starlight PAR is inadequate for photosynthetically supported growth. An increase in starlight even to reach the minimum theoretical levels to allow for photosynthesis would require a universe that was approximately ten million times older, or with a ten million times greater density of stars, than is the case for the present universe. Photosynthesis on an ELP using PAR reflected from a natural satellite with the same size as our Moon, but at the Roche limit, could support a low rate of photosynthesis at full Moon. Photosynthesis on an ELP-like satellite of a Jupiter-sized planet using light reflected from the planet could be almost 1% of the rate in full sunlight on Earth when the planet was full. These potential contributions to photosynthesis require that the contribution is compared with the rate of photosynthesis driven by direct radiation from the star. Light pollution on Earth only energizes photosynthesis by organisms that are very close to the light source. However, effects of light pollution on photosynthesis can be more widespread if the photosynthetic canopy is retained for more of the year, caused by effects on photoperiodism, with implications for the influence of civilizations on photosynthesis.

  16. Characterization of Damage of Al2O3/Ge Gate Stack Structure Induced with Light Radiation during Plasma Nitridation

    NASA Astrophysics Data System (ADS)

    Kusumandari; Takeuchi, Wakana; Kato, Kimihiko; Shibayama, Shigehisa; Sakashita, Mitsuo; Nakatsuka, Osamu; Zaima, Shigeaki

    2012-01-01

    We have investigated the effects of light radiation during plasma nitridation on the electrical properties of an Al2O3/Ge gate stack structure using the pallet for plasma evaluation (PAPE) technique. From the capacitance-voltage characteristics, the flatband voltage shift due to fixed oxide charges significantly increases after light exposure with an energy higher than 7.5 eV. In addition, the density of trapped charges near the interface and the interface state density (Dit) also significantly increase after light exposure with an energy over 11.3 eV. The net density of positive fixed oxide charges, the density of trapped charges near the interface, and Dit can be reduced by post-metallization annealing (PMA) in N2 ambient at 300 °C.

  17. Light Absorbing Impurities in Snow in the Western US: Partitioning Radiative Impacts from Mineral Dust and Black Carbon

    NASA Astrophysics Data System (ADS)

    Skiles, M.; Painter, T. H.

    2013-12-01

    Melt of annual mountain snow cover dominates water resources in the western United States. Recent studies in the Upper Colorado River Basin have shown that radiative forcing by light absorbing impurities (LAIs) in mountain snow cover has accelerated snowmelt, impacted runoff timing and magnitude, and reduced annual flow. However, these studies have assumed that LAIs are primarily mineral dust, and have not quantified the radiative contribution by carbonaceous particles from bio and fossil fuel (industrial and urban) sources. Here we quantify both dust and black carbon (BC) content and assess the unique BC radiative forcing contribution in this dust dominated impurity regime using a suite of advanced field, lab, and modeling techniques. Daily measurements of surface spectral albedo and optical grain radius were collected with a field spectrometer over the 2013 spring melt season in Senator Beck Basin Study Area in the San Juan Mountains, CO, Southwestern US. Coincident snow samples were collected daily and processed for; (1) dust and BC content (2) impurity particle size, and (3) impurity optical properties. Measured snow and impurity properties were then used to drive the Snow, Ice, and Aerosol Radiation (SNICAR) model. Partitioning the unique radiative contribution from each constituents is achieved through unique model runs for clean snow, dust only, and BC only.

  18. Towards high efficiency thin-film crystalline silicon solar cells: The roles of light trapping and non-radiative recombinations

    SciTech Connect

    Bozzola, A. Kowalczewski, P.; Andreani, L. C.

    2014-03-07

    Thin-film solar cells based on silicon have emerged as an alternative to standard thick wafers technology, but they are less efficient, because of incomplete absorption of sunlight, and non-radiative recombinations. In this paper, we focus on the case of crystalline silicon (c-Si) devices, and we present a full analytic electro-optical model for p-n junction solar cells with Lambertian light trapping. This model is validated against numerical solutions of the drift-diffusion equations. We use this model to investigate the interplay between light trapping, and bulk and surface recombination. Special attention is paid to surface recombination processes, which become more important in thinner devices. These effects are further amplified due to the textures required for light trapping, which lead to increased surface area. We show that c-Si solar cells with thickness of a few microns can overcome 20% efficiency and outperform bulk ones when light trapping is implemented. The optimal device thickness in presence of light trapping, bulk and surface recombination, is quantified to be in the range of 10–80 μm, depending on the bulk quality. These results hold, provided the effective surface recombination is kept below a critical level of the order of 100 cm/s. We discuss the possibility of meeting this requirement, in the context of state-of-the-art techniques for light trapping and surface passivation. We show that our predictions are within the capability of present day silicon technologies.

  19. Domain wall QCD with physical quark masses

    NASA Astrophysics Data System (ADS)

    Blum, T.; Boyle, P. A.; Christ, N. H.; Frison, J.; Garron, N.; Hudspith, R. J.; Izubuchi, T.; Janowski, T.; Jung, C.; Jüttner, A.; Kelly, C.; Kenway, R. D.; Lehner, C.; Marinkovic, M.; Mawhinney, R. D.; McGlynn, G.; Murphy, D. J.; Ohta, S.; Portelli, A.; Sachrajda, C. T.; Soni, A.; Rbc; Ukqcd Collaborations

    2016-04-01

    We present results for several light hadronic quantities (fπ , fK, BK, mu d, ms, t01 /2, w0) obtained from simulations of 2 +1 flavor domain wall lattice QCD with large physical volumes and nearly physical pion masses at two lattice spacings. We perform a short, O (3 )%, extrapolation in pion mass to the physical values by combining our new data in a simultaneous chiral/continuum "global fit" with a number of other ensembles with heavier pion masses. We use the physical values of mπ, mK and mΩ to determine the two quark masses and the scale—all other quantities are outputs from our simulations. We obtain results with subpercent statistical errors and negligible chiral and finite-volume systematics for these light hadronic quantities, including fπ=130.2 (9 ) MeV ; fK=155.5 (8 ) MeV ; the average up/down quark mass and strange quark mass in the MS ¯ scheme at 3 GeV, 2.997(49) and 81.64(1.17) MeV respectively; and the neutral kaon mixing parameter, BK, in the renormalization group invariant scheme, 0.750(15) and the MS ¯ scheme at 3 GeV, 0.530(11).

  20. Development of Radiation-Resistant In-Water Wireless Transmission System Using Light Emitting Diodes and Photo Diodes

    NASA Astrophysics Data System (ADS)

    Takeuchi, T.; Shibata, H.; Otsuka, N.; Uehara, T.; Tsuchiya, K.; Shibagaki, T.; Komanome, H.

    2016-10-01

    Several kinds of commercially available light emitting diodes (LED) and photo diodes (PD) were irradiated with 60Co gamma ray up to 1 MGy for development of a radiation-resistant in-water wireless transmission system using visible light. The lens parts of the LEDs turned brown by the irradiation and their colors became dark with the absorbed dose. The total luminous fluxes decreased with the absorbed dose and the LED with shorter emission wavelength had the higher decrease rate. Meanwhile, the current-voltage characteristics hardly changed. These results indicate that the decreases of the total luminous flux of the LEDs were mainly caused not by the degradation of the semiconductor parts but by the coloring of the lens parts by the irradiation. On the other hand, the light sensitivities of the PDs decreased with the absorbed dose. The PDs with the window part which turned a darker color had the higher decrease rate. These results indicate that the decreases of light sensitivities of the PDs were also mainly caused by the coloring of the resin parts by the irradiation. If the wireless transmission is performed using the candidate LED and PD between 5 meters in water, using a few LEDs and PDs, the PD's output current generated by the emission light of the LED is estimated to be detectable even considering the effects of the absorption of the light in water and the increased dark current by the irradiation. Therefore, a radiation resistant in-water transmission system can be constructed using commercially available LEDs and PDs in principle.

  1. Light

    NASA Astrophysics Data System (ADS)

    Vernon, C. G.

    2016-09-01

    Preface; 1. Historical; 2. Waves and wave-motion; 3. The behaviour of ripples; 4. The behaviour of light; 5. Refraction through glass blocks and prisms; 6. The imprinting of curvatures; 7. Simple mathematical treatment; 8. More advanced mathematical treatment; 9. The velocity of light; 10. The spectrum and colour; 11. Geometrical optics; 12. The eye and optical instruments; 13. Sources of light; 14. Interference, diffraction and polarisation; 15. Suggestions for class experiments; Index.

  2. Using the human eye to image space radiation or the history and status of the light flash phenomena

    NASA Astrophysics Data System (ADS)

    Fuglesang, C.

    2007-10-01

    About 80% of people who travel in space experience sudden phosphenes, commonly called light flashes (LF). Although the detailed physiological process is still not known, the LFs are caused by particles in the cosmic radiation field. Indeed, by counting LFs one can even make a crude image of the radiation environment around the Earth. Studies on the space station Mir with the SilEye experiment correlated LFs with charged particles traversing the eye. It was found that a nucleus in the radiation environment has roughly a 1% probability of causing a light flash, whereas the proton's probability is almost three orders of magnitude less. As a function of linear energy transfer (LET), the probability increased with ionization above 10 keV/μm, reaching about 5% at 50 keV/μm. The investigations are continuing on the International Space Station (ISS) with the Alteino/SileEye-3 detector, which is also a precursor to the large Anomalous Long Term Effects on Astronauts (ALTEA) facility. These detectors are also measuring—imaging—the radiation environment inside the ISS, which will be compared to Geant4 simulations from the DESIRE project. To further the understanding of the LF phenomena, a survey among current NASA and ESA astronauts was recently conducted. The LFs are predominantly noticed before sleep and some respondents even thought it disturbed their sleep. The LFs appear white, have elongated shapes, and most interestingly, often come with a sense of motion. Comparing the shapes quoted from space observations with ground experiments done by researchers in the 1970s, it seems likely that some 5-10% of the LFs in space are due to Cherenkov light in the eye. However, the majority is most likely caused by some direct interaction in the retina.

  3. What is a quark?

    NASA Astrophysics Data System (ADS)

    Kane, Gordon L.; Perry, Malcolm J.

    2015-01-01

    We are used to thinking of quarks as fundamental particles in the same way we think of the electron, or gauge bosons, neutrinos, leptons. In strong theory, these objects are unified with gravitation and the physics of spacetime into what is hoped to be an ultimate theory, string/M theory. The string/M theory paradigm completely changes the way we think of the so-called elementary particles in quantum field theory.

  4. What is a Quark?

    NASA Astrophysics Data System (ADS)

    Kane, Gordon L.; Perry, Malcolm J.

    2015-03-01

    We are used to thinking of quarks as fundamental particles in the same way we think of the electron, or gauge bosons, neutrinos, leptons. In strong theory, these objects are unified with gravitation and the physics of spacetime into what is hoped to be an ultimate theory, string/M theory. The string/M theory paradigm completely changes the way we think of the socalled elementary particles in quantum field theory.

  5. Variations of nuclear binding with quark masses

    NASA Astrophysics Data System (ADS)

    Carrillo-Serrano, M. E.; Cloët, I. C.; Tsushima, K.; Thomas, A. W.; Afnan, I. R.

    2013-01-01

    We investigate the variation with light quark mass of the mass of the nucleon as well as the masses of the mesons commonly used in a one-boson-exchange model of the nucleon-nucleon force. Care is taken to evaluate the meson mass shifts at the kinematic point relevant to that problem. Using these results, we evaluate the corresponding changes in the energy of the 1S0 antibound state and the binding energies of the deuteron, triton, and selected finite nuclei by using a one-boson exchange model. The results are discussed in the context of possible corrections to the standard scenario for Big Bang nucleosynthesis in the case where, as suggested by recent observations of quasar absorption spectra, the quark masses may have changed over the age of the Universe.

  6. Top quark pair production and top quark properties at CDF

    SciTech Connect

    Moon, Chang-Seong

    2016-06-02

    We present the most recent measurements of top quark pairs production and top quark properties in proton-antiproton collisions with center-of-mass energy of 1.96 TeV using CDF II detector at the Tevatron. The combination of top pair production cross section measurements and the direct measurement of top quark width are reported. The test of Standard Model predictions for top quark decaying into $b$-quarks, performed by measuring the ratio $R$ between the top quark branching fraction to $b$-quark and the branching fraction to any type of down quark is shown. The extraction of the CKM matrix element $|V_{tb}|$ from the ratio $R$ is discussed. We also present the latest measurements on the forward-backward asymmetry ($A_{FB}$) in top anti-top quark production. With the full CDF Run II data set, the measurements are performed in top anti-top decaying to final states that contain one or two charged leptons (electrons or muons). In addition, we combine the results of the leptonic forward-backward asymmetry in $t\\bar t$ system between the two final states. All the results show deviations from the next-to-leading order (NLO) standard model (SM) calculation.

  7. Heavy Quark Fluorescence

    SciTech Connect

    Torres-Rincon, Juan M.; Llanes-Estrada, Felipe J.

    2010-07-09

    Heavy hadrons containing heavy quarks (for example, {Upsilon} mesons) feature a scale separation between the heavy-quark mass and the QCD scale that controls the effective masses of lighter constituents. As in ordinary molecules, the deexcitation of the lighter, faster degrees of freedom leaves the velocity distribution of the heavy quarks unchanged, populating the available decay channels in qualitatively predictable ways. Automatically an application of the Franck-Condon principle of molecular physics explains several puzzling results of {Upsilon}(5S) decays as measured by the Belle Collaboration, such as the high rate of B{sub s}*B{sub s}* versus B{sub s}*B{sub s} production, the strength of three-body B{sup *}B{pi} decays, or the dip in B momentum shown in these decays. We argue that the data show the first Sturm-Liouville zero of the {Upsilon}(5S) quantum-mechanical squared wave function and provide evidence for a largely bb composition of this meson.

  8. Properties of charmonium in lattice QCD with 2+1 flavors of improved staggered sea quarks

    SciTech Connect

    Massimo Di Pierro et al.

    2004-03-16

    We use the dynamical gluon configurations provided by the MILC collaboration in a study of the charmonium spectrum and {psi} leptonic width. We examine sea quark effects on mass splitting and on the leptonic decay matrix element for light masses as low as m{sub s}/5, while keeping the strange quark mass fixed and the lattice spacing nearly constant.

  9. Quark description of nuclear matter

    SciTech Connect

    Berges, Jurgen

    2001-07-01

    We discuss the role of an adjoint chiral condensate for color superconducting quark matter. Its presence leads to color-flavor locking in two-flavor quark matter. Color is broken completely as well as chiral symmetry in the two-flavor theory with coexisting adjoint quark-antiquark and antitriplet quark-quark condensates. The qualitative properties of this phase match the properties of ordinary nuclear matter without strange baryons. This complements earlier proposals by Schaefer and Wilczek for a quark description of hadronic phases. We show for a class of models with effective four-fermion interactions that adjoint chiral and diquark condensates do not compete, in the sense that simultaneous condensation occurs for sufficiently strong interactions in the adjoint chiral channel.

  10. Quark Contributions to Nucleon Momentum and Spin from Domain Wall fermion calculations

    SciTech Connect

    S. N. Syritsyn, J. R. Green, J. W. Negele, A. V. Pochinsky, M. Engelhardt, Ph. Hagler, B. Musch, W. Schroers

    2011-12-01

    We report contributions to the nucleon spin and momentum from light quarks calculated using dynamical domain wall fermions with pion masses down to 300 MeV and fine lattice spacing a=0.084 fm. Albeit without disconnected diagrams, we observe that spin and orbital angular momenta of both u and d quarks are opposite, almost canceling in the case of the d quark, which agrees with previous calculations using a mixed quark action. We also present the full momentum dependence of n=2 generalized form factors showing little variation with the pion mass.

  11. Phenomenology of heavy quark systems

    SciTech Connect

    Gilman, F.J.

    1987-03-01

    The spectroscopy of heavy quark systems is examined with regards to spin independent and spin dependent potentials. It is shown that a qualitative picture exists of the spin-independent forces, and that a semi-quantitative understanding exists for the spin-dependent effects. A brief review is then given of the subject of the decays of hadrons containing heavy quarks, including weak decays at the quark level, and describing corrections to the spectator model. (LEW)

  12. Exotic Signals of Vectorlike Quarks

    SciTech Connect

    Dobrescu, Bogdan A.; Yu, Felix

    2016-12-06

    Vectorlike fermions are an important target for hadron collider searches. We show that the vectorlike quarks may predominantly decay via higher-dimensional operators into a quark plus a couple of other Standard Model fermions. Pair production of vectorlike quarks of charge 2/3 at the LHC would then lead to a variety of possible final states, including $t\\bar t + 4\\tau$, $t\\bar b\

  13. Quark matter or new particles?

    NASA Technical Reports Server (NTRS)

    Michel, F. Curtis

    1988-01-01

    It has been argued that compression of nuclear matter to somewhat higher densities may lead to the formation of stable quark matter. A plausible alternative, which leads to radically new astrophysical scenarios, is that the stability of quark matter simply represents the stability of new particles compounded of quarks. A specific example is the SU(3)-symmetric version of the alpha particle, composed of spin-zero pairs of each of the baryon octet (an 'octet' particle).

  14. CO{sub 2}-utilization under the influence of ionizing radiation and UV-light: A short review

    SciTech Connect

    Getoff, N.

    1996-12-31

    As a sequence of worldwide industrial development and the combustion of fossil fuels, a rapid increase in CO{sub 2} concentrations in the atmosphere is observed. A good deal of it is dissolved in oceans, seas and rivers. As a result CO{sub 2} is blamed for the significant change in climate. It has been previously demonstrated that aqueous CO{sub 2} can be converted into simple organic substances under the influence of ionizing radiation and of UV-light. It has also been proven that aqueous CO{sub 2} can be incorporated into various organic substances as carboxylic group. In this review data are reported concerning the following: Radiation- and UV-light induced conversion of aqueous CO{sub 2} into simple organic substances; incorporation of CO{sub 2} in organic compounds under the influence of radiation; and possible reaction mechanisms involved in the above mentioned processes. Finally, some aspects for possible CO{sub 2} utilization in the future will be discussed.

  15. Radiative hc /b decays to η or η '

    NASA Astrophysics Data System (ADS)

    Zhu, Ruilin; Dai, Jian-Ping

    2016-11-01

    Motivated by recent measurements of the radiative decay rates of the P -wave spin singlet charmonium hc to the light meson η or η' by the BESIII Collaboration, we investigate the decay rates of these channels at order α αs4. The photon is radiated mainly from charm quark pairs in the lowest-order Feynman diagrams, because the diagrams where a photon radiated from light quarks are suppressed by αs or the relative charm quark velocity v , due to charge-parity conservation. The form factors of two gluons to η or η', which are the major mechanism for η and η' production, are employed. η (η') is treated as a light-cone object when we consider that the parent charmonium mass is much heavier than that of the final light meson. We obtain the branching ratio B (hc→γ η')=(1.9 4-0.51+0.70)×10-3 in the nonrelativistic QCD approach, which is in agreement with the BESIII measurement. The prediction of the branching ratio of hc→γ η is also within the range of experimental error after including the larger uncertainty of the total decay width Γh c. The applications of these formulas to the radiative decays to η (η') of the P -wave spin singlet bottomonium hb(n P ) are presented. These studies will shed some light on the η -η' mixing effects, the flavor SU(3) symmetry breaking, and the nonperturbative dynamics of charmonium and bottomonium.

  16. Gas sensing based on detection of light radiation from a region of modified cladding (nanocrystalline ZnO) of an optical fiber

    NASA Astrophysics Data System (ADS)

    Devendiran, S.; Sastikumar, D.

    2017-03-01

    A new type of fiber optic gas sensor is proposed by detecting a light radiated from a region of cladding modified with metal oxide (nanocrystalline ZnO). The intensity of radiated light is found to vary with different gasses and concentrations. Sensing characteristics are studied for ammonia, methanol, ethanol and acetone gasses. Gas sensitivity of the proposed sensor is compared with clad-modified fiber optic gas sensor. The new sensor exhibits enhanced sensitivity. Time response characteristics of the sensor are reported.

  17. PREFACE: Hot Quarks 2004

    NASA Astrophysics Data System (ADS)

    Antinori, Federico; Bass, Steffen A.; Bellwied, Rene; Ullrich, Thomas; Velkovska, Julia; Wiedemann, Urs

    2005-04-01

    Why another conference devoted to ultra-relativistic heavy-ion physics? As we looked around the landscape of the existing international conferences and workshops, we realized that there was not a single one tailored to the people who are most directly involved with the actual research work: students, post-docs, and junior faculty/research scientists. Of course there are schools, but that was not what we had in mind. We wanted a meeting where young researchers could come together to discuss in depth the physics that they are working on without any hindrance. The major conferences have very limited time for discussions which is often shared amongst the most established. This leaves little room for young people to ask their questions and to get the detailed feedback which they deserve and which satisfies their curiosity. A discussion-driven workshop, centering on those without whom there will be no future—that seemed like what was needed. And thus the Hot Quarks workshop was born. The aim of Hot Quarks was to enhance the direct exchange of scientific information among the younger members of the community, from both experiment and theory. Participation was by invitation only in order to emphasize the contributions from junior researchers. This approach makes the workshop unique among the many forums in the field. For young scientists it represented an opportunity for exposure that they would not have had in one of the major conferences. The hope is that this meeting has helped to stimulate the next generation of scientists in our field and, at the same time, strengthened their sense of community. It all came together from 18 24 July 2004, when the 77 participants met at The Inn at Snakedance in the Taos Ski Valley, New Mexico, USA, for the first Hot Quarks workshop. Photograph Participants gather in the sunshine at the foot of the Taos Ski Valley chairlift. By all accounts, Hot Quarks 2004 was a great success. Every participant had the opportunity to present her or

  18. Quark forces from hadronic spectroscopy.

    PubMed

    Pirjol, Dan; Schat, Carlos

    2009-04-17

    We consider the implications of the most general two-body quark-quark interaction Hamiltonian for the spin-flavor structure of the negative parity L = 1 excited baryons. Assuming the most general two-body quark interaction Hamiltonian, we derive two correlations among the masses and mixing angles of these states, which constrain the mixing angles, and can be used to test for the presence of three-body quark interactions. We find that the pure gluon-exchange model is disfavored by data, independently of any assumptions about hadronic wave functions.

  19. Valence quark spin distribution functions

    SciTech Connect

    Nathan Isgur

    1998-09-01

    The hyperfine interactions of the constituent quark model provide a natural explanation for many nucleon properties, including the {Delta} - N splitting, the charge radius of the neutron, and the observation that the proton's quark distribution function ratio d(x)/u(x) {r_arrow} 0 as x {r_arrow} 1. The hyperfine-perturbed quark model also makes predictions for the nucleon spin-dependent distribution functions. Precision measurements of the resulting asymmetries A{sub 1}{sup p}(x) and A{sub 1}{sup n}(x) in the valence region can test this model and thereby the hypothesis that the valence quark spin distributions are ''normal''.

  20. Top quark physics at CDF

    SciTech Connect

    Potamianos, Karolos

    2011-12-01

    We present the recent results of top-quark physics using up to 6 fb{sup -1} of p{bar p} collisions analyzed by the CDF collaboration. The large number of top quark events analyzed, of the order of several thousands, allows stringent checks of the standard model predictions. Also, the top quark is widely believed to be a window to new physics. We present the latest measurements of top quark intrinsic properties as well as direct searches for new physics in the top sector.

  1. High Conductivity Carbon-Carbon Heat Pipes for Light Weight Space Power System Radiators

    NASA Technical Reports Server (NTRS)

    Juhasz, Albert J.

    2008-01-01

    Based on prior successful fabrication and demonstration testing of a carbon-carbon heat pipe radiator element with integral fins this paper examines the hypothetical extension of the technology via substitution of high thermal conductivity composites which would permit increasing fin length while still maintaining high fin effectiveness. As a result the specific radiator mass could approach an ultimate asymptotic minimum value near 1.0 kg/m2, which is less than one fourth the value of present day satellite radiators. The implied mass savings would be even greater for high capacity space and planetary surface power systems, which may require radiator areas ranging from hundreds to thousands of square meters, depending on system power level.

  2. Radiative Transfer Modeling to Estimate the Impact of CDOM on Light Absorption within Changing Arctic Sea Ice

    NASA Astrophysics Data System (ADS)

    Carns, R.; Light, B.; Frey, K. E.

    2016-12-01

    First-year sea ice differs from multi-year sea ice in several ways that can influence its optical properties. It is thinner than multi-year ice, which tends to increase light transmission. Also, first-year ice retains higher brine volumes in comparison to more heavily drained multi-year ice, in isolated pockets and channels. During melt season, patterns of pond formation on first-year sea ice differ from those on multi-year ice. As first-year sea ice comprises an increasingly large fraction of Arctic sea ice, it becomes more important to understand how much sunlight reaches the ecosystems within the ice, and how those changing ecosystems can feed back into the transmission of light. Colored dissolved organic matter (CDOM) and chlorophyll within the ice can absorb light, heating the ice and reducing transmission to the ocean below. Light also encourages algal growth within the ice while degrading CDOM, creating complex feedbacks. We use radiative transfer models to determine the overall effect of colored dissolved organic matter on the light regime within sea ice, both on the overall amount of energy transmitted and on the spectral distribution of energy. Using models allows us to estimate the impact of varying CDOM levels on a wide range of sea ice types, improving our ability to respond to conditions in a rapidly changing Arctic and predict important phenomena such as algal blooms.

  3. Searches for new physics in the top quark samples at the CDF experiment

    SciTech Connect

    Scodellaro, Luca; /Cantabria Inst. of Phys.

    2007-10-01

    Twelve years after the discovery of the top quark at Fermilab's Tevatron, they are now finally beginning to shed light on this peculiarily massive quark. With 1-1.7 fb{sup -1} of integrated luminosity collected by the CDF detector, they are able to probe the knowledge of the top quark physics, and to search for signals of physics beyond the Standard Model. In this paper, they present results of measurements of top quark properties, as well as tests for the production mechanism of the top quark. They also describe CDF latest searches for beyond Standard Model couplings of the top quark. Finally, they present the most recent searches for direct production of new particles in the collected data samples.

  4. Changes in sensory and pain perception thresholds after linear polarized near-infrared light radiation in the trigeminal region.

    PubMed

    Kashima, Koji; Watanabe, Naoshi; Higashinaka, Shuichi; Maeda, Sho; Shiba, Ryosuke

    2005-07-01

    Linearly polarized light in the near-infrared portion of the spectrum has recently been associated with a variety of musculoskeletal disorders including temporomandibular disorders. The purpose of this study was to determine whether short-term linearly polarized near-infrared light radiation in the trigeminal region affects sensory and pain perception thresholds in the trigeminally mediated region and in the cervically mediated region of normal subjects. Thirty-five normal female volunteers participated in this study. Each subject received an 8-minute course of irradiation in the right cheek, and sensory/nociceptive perception thresholds were compared before and immediately after the irradiation in the right cheek and the right forearm. As a result, this study demonstrated a significant elevation of the heat-induced pain threshold in both regions and a tendency for the warm sensation threshold to elevate in the cervical region. In addition, a significant increase in vibratory sensitivity was observed in the trigeminal region. In conclusion, our results provided additional evidence that the warming sensation has a negative feedback influence on heat pain intensity in humans, and provides a theoretical basis for the application of linear polarized near-infrared light radiation to the trigeminal region.

  5. Last orbits of binary strange quark stars

    SciTech Connect

    Limousin, Francois; Gourgoulhon, Eric; Gondek-Rosinska, Dorota

    2005-03-15

    We present the first relativistic calculations of the final phase of inspiral of a binary system consisting of two stars built predominantly of strange quark matter (strange quark stars). We study the precoalescing stage within the Isenberg-Wilson-Mathews approximation of general relativity using a multidomain spectral method. A hydrodynamical treatment is performed under the assumption that the flow is either rigidly rotating or irrotational, taking into account the finite density at the stellar surface--a distinctive feature with respect to the neutron star case. The gravitational-radiation driven evolution of the binary system is approximated by a sequence of quasiequilibrium configurations at fixed baryon number and decreasing separation. We find that the innermost stable circular orbit (ISCO) is given by an orbital instability both for synchronized and irrotational systems. This contrasts with neutron stars for which the ISCO is given by the mass-shedding limit in the irrotational case. The gravitational wave frequency at the ISCO, which marks the end of the inspiral phase, is found to be {approx}1400 Hz for two irrotational 1.35 M{sub {center_dot}} strange stars and for the MIT bag model of strange matter with massless quarks and a bag constant B=60 MeV fm{sup -3}. Detailed comparisons with binary neutrons star models, as well as with third order post-Newtonian point-mass binaries are given.

  6. Numerical investigation of the propagation of light-induced detonation waves during the absorption of high-power laser radiation in air at elevated density

    NASA Astrophysics Data System (ADS)

    Pirogov, S. Yu.; Belyanin, D. G.; Yur'ev, A. S.; Tipaev, V. V.; Filatov, A. V.

    2010-12-01

    Spatiotemporal gasdynamic plasma structures formed in quiescent air of elevated density by high-power unfocused laser radiation absorbed in the light-induced detonation (LID) wave regime have been numerically studied using a model of inviscid, equilibrium emitting air. Laser radiation intensity and air density serve as parameters of the model. Dependences of the velocity of LID wave on the laser radiation intensity at elevated air densities are presented.

  7. SHEDDING LIGHT ON CORALS HEALTH: INTERACTIONS OF CLIMATE CHANGE AND SOLAR RADIATION WITH BLEACHING

    EPA Science Inventory

    Coral bleaching and declines in coral reef health in recent years have been attributed in part to processes driven by UV and/or visible light. For coral assemblages, exposure to UV light is often an unavoidable consequence of having access to visible (photosynthetically active) ...

  8. SHEDDING LIGHT ON CORALS HEALTH: INTERACTIONS OF CLIMATE CHANGE AND SOLAR RADIATION WITH BLEACHING

    EPA Science Inventory

    Coral bleaching and declines in coral reef health in recent years have been attributed in part to processes driven by UV and/or visible light. For coral assemblages, exposure to UV light is often an unavoidable consequence of having access to visible (photosynthetically active) ...

  9. Impacts of Diffuse Radiation on Light Use Efficiency across Terrestrial Ecosystems Based on Eddy Covariance Observation in China

    PubMed Central

    Huang, Kun; Wang, Shaoqiang; Zhou, Lei; Wang, Huimin; Zhang, Junhui; Yan, Junhua; Zhao, Liang; Wang, Yanfen; Shi, Peili

    2014-01-01

    Ecosystem light use efficiency (LUE) is a key factor of production models for gross primary production (GPP) predictions. Previous studies revealed that ecosystem LUE could be significantly enhanced by an increase on diffuse radiation. Under large spatial heterogeneity and increasing annual diffuse radiation in China, eddy covariance flux data at 6 sites across different ecosystems from 2003 to 2007 were used to investigate the impacts of diffuse radiation indicated by the cloudiness index (CI) on ecosystem LUE in grassland and forest ecosystems. Our results showed that the ecosystem LUE at the six sites was significantly correlated with the cloudiness variation (0.24≤R2≤0.85), especially at the Changbaishan temperate forest ecosystem (R2 = 0.85). Meanwhile, the CI values appeared more frequently between 0.8 and 1.0 in two subtropical forest ecosystems (Qianyanzhou and Dinghushan) and were much larger than those in temperate ecosystems. Besides, cloudiness thresholds which were favorable for enhancing ecosystem carbon sequestration existed at the three forest sites, respectively. Our research confirmed that the ecosystem LUE at the six sites in China was positively responsive to the diffuse radiation, and the cloudiness index could be used as an environmental regulator for LUE modeling in regional GPP prediction. PMID:25393629

  10. Impacts of diffuse radiation on light use efficiency across terrestrial ecosystems based on Eddy covariance observation in China.

    PubMed

    Huang, Kun; Wang, Shaoqiang; Zhou, Lei; Wang, Huimin; Zhang, Junhui; Yan, Junhua; Zhao, Liang; Wang, Yanfen; Shi, Peili

    2014-01-01

    Ecosystem light use efficiency (LUE) is a key factor of production models for gross primary production (GPP) predictions. Previous studies revealed that ecosystem LUE could be significantly enhanced by an increase on diffuse radiation. Under large spatial heterogeneity and increasing annual diffuse radiation in China, eddy covariance flux data at 6 sites across different ecosystems from 2003 to 2007 were used to investigate the impacts of diffuse radiation indicated by the cloudiness index (CI) on ecosystem LUE in grassland and forest ecosystems. Our results showed that the ecosystem LUE at the six sites was significantly correlated with the cloudiness variation (0.24 ≤ R(2) ≤ 0.85), especially at the Changbaishan temperate forest ecosystem (R(2) = 0.85). Meanwhile, the CI values appeared more frequently between 0.8 and 1.0 in two subtropical forest ecosystems (Qianyanzhou and Dinghushan) and were much larger than those in temperate ecosystems. Besides, cloudiness thresholds which were favorable for enhancing ecosystem carbon sequestration existed at the three forest sites, respectively. Our research confirmed that the ecosystem LUE at the six sites in China was positively responsive to the diffuse radiation, and the cloudiness index could be used as an environmental regulator for LUE modeling in regional GPP prediction.

  11. Light histories influence the impacts of solar ultraviolet radiation on photosynthesis and growth in a marine diatom, Skeletonema costatum.

    PubMed

    Guan, Wanchun; Gao, Kunshan

    2008-05-29

    Phytoplanktonic species acclimated to high light are known to show less photoinhibition. However, little has been documented on how cells grown under indoor conditions for decades without exposure to UV radiation (UVR, 280-400 nm) would respond differently to solar UVR compared to those in situ grown under natural solar radiation. Here, we have shown the comparative photosynthetic and growth responses to solar UVR in an indoor- (IS) and a naturally grown (WS) Skeletonema costatum type. In short-term experiment (<1 day), Phi(PSII) and photosynthetic carbon fixation rate were more inhibited by UVR in the IS than in the WS cells. The rate of UVR-induced damages of PSII was faster and their repair was significantly slower in IS than in WS. Even under changing solar radiation simulated for vertical mixing, solar UVR-induced higher inhibition of photosynthetic rate in IS than in WS cells. During long-term (10 days) exposures to solar radiation, the specific growth rate was much lower in IS than WS at the beginning, then increased 3 days later to reach an equivalent level as that of WS. UVR-induced inhibition of photosynthetic carbon fixation in the IS was identical with that of WS at the end of the long-term exposure. The photosynthetic acclimation was not accompanied with increased contents of UV-absorbing compounds, indicating that repair processes for UVR-induced damages must have been accelerated or upgraded.

  12. Visible supercontinuum radiation of light bullets in the femtosecond filamentation of IR pulses in fused silica

    SciTech Connect

    Chekalin, S V; Kompanets, V O; Dokukina, A E; Dormidonov, A E; Smetanina, E O; Kandidov, V P

    2015-05-31

    We report experimental and theoretical investigations of visible supercontinuum generation in the formation of light bullets in a filament produced by IR pulses. In the filamentation of a 1700 – 2200 nm pulse in fused silica, bright tracks are recorded resulting from the recombination glow of carriers in the laser plasma produced by a sequence of light bullets and from the scattering in silica of the visible supercontinuum generated by the light bullets. It is found that the formation of a light bullet is attended with an outburst of a certain portion of supercontinuum energy in the visible range. The energy outburst is the same for all bullets in the sequence and becomes smaller with increasing pulse wavelength. (extreme light fields and their applications)

  13. The Discovery of the Top Quark

    DOE R&D Accomplishments Database

    Sinervo, P.K.

    1995-12-01

    The top quark and the Higgs boson are the heaviest elementary particles predicted by the standard model. The four lightest quark flavours, the up, down, strange and charm quarks, were well-established by the mid-1970's. The discovery in 1977 of the {Tau} resonances, a new family of massive hadrons, required the introduction of the fifth quark flavour. Experimental and theoretical studies have indicated that this quark also has a heavier partner, the top quark.

  14. Dominant Mutations (lex) in Escherichia coli K-12 Which Affect Radiation Sensitivity and Frequency of Ultraviolet Light-Induced Mutations

    PubMed Central

    Mount, David W.; Low, K. Brooks; Edmiston, Susan J.

    1972-01-01

    Three mutations, denoted lex-1, -2 and -3, which increase the sensitivity of Escherichia coli K-12 to ultraviolet light (UV) and ionizing radiation, have been found by three-factor transduction crosses to be closely linked to uvrA on the E. coli K-12 linkage map. Strains bearing these mutations do not appear to be defective in genetic recombination although in some conjugational crosses they may fail to produce a normal yield of genetic recombinants depending upon the time of mating and the marker selected. The mutagenic activity of UV is decreased in the mutant strains. After irradiation with UV, cultures of the strains degrade their deoxyribonucleic acid at a high rate, similar to recA− mutant strains. Stable lex+/lec− heterozygotes are found to have the mutant radiation-sensitive phenotype of haploid lex− strains. PMID:4343824

  15. Quark and Gluon Relaxation in Quark-Gluon Plasmas

    NASA Technical Reports Server (NTRS)

    Heiselberg, H.; Pethick, C. J.

    1993-01-01

    The quasiparticle decay rates for quarks and gluons in quark-gluon plasmas are calculated by solving the kinetic equation. Introducing an infrared cutoff to allow for nonperturbative effects, we evaluate the quasiparticle lifetime at momenta greater than the inverse Debye screening length to leading order in the coupling constant.

  16. Mass generation in QCD — Oscillating quarks and gluons

    NASA Astrophysics Data System (ADS)

    Minkowski, Peter

    2014-08-01

    The present lecture is devoted to embedding the approximate genuine harmonic oscillator structure of valence q\\bar {q} mesons and in more detail the qqq configurations for u, d, s flavored baryons in QCD for three light flavors of quark. It includes notes, preparing the counting of "oscillatory modes of Nfl = 3 light quarks, u, d, s in baryons," using the SU(2N fl = 6) × SO3(\\vec{L}) broken symmetry classification, extended to the harmonic oscillator symmetry of 3 paired oscillator modes. \\vec{L} = ∑ {n = 1}{N fl}\\vec{L}n stands for the space rotation group generated by the sum of the 3 individual angular momenta of quarks in their c.m. system. The oscillator extension to valence gauge boson states is not yet developed to a comparable level.

  17. Radiation

    NASA Image and Video Library

    Outside the protective cocoon of Earth's atmosphere, the universe is full of harmful radiation. Astronauts who live and work in space are exposed not only to ultraviolet rays but also to space radi...

  18. Effects of Kaolin Application on Light Absorption and Distribution, Radiation Use Efficiency and Photosynthesis of Almond and Walnut Canopies

    PubMed Central

    Rosati, Adolfo; Metcalf, Samuel G.; Buchner, Richard P.; Fulton, Allan E.; Lampinen, Bruce D.

    2007-01-01

    Background and Aims Kaolin applied as a suspension to plant canopies forms a film on leaves that increases reflection and reduces absorption of light. Photosynthesis of individual leaves is decreased while the photosynthesis of the whole canopy remains unaffected or even increases. This may result from a better distribution of light within the canopy following kaolin application, but this explanation has not been tested. The objective of this work was to study the effects of kaolin application on light distribution and absorption within tree canopies and, ultimately, on canopy photosynthesis and radiation use efficiency. Methods Photosynthetically active radiation (PAR) incident on individual leaves within the canopy of almond (Prunus dulcis) and walnut (Juglans regia) trees was measured before and after kaolin application in order to study PAR distribution within the canopy. The PAR incident on, and reflected and transmitted by, the canopy was measured on the same day for kaolin-sprayed and control trees in order to calculate canopy PAR absorption. These data were then used to model canopy photosynthesis and radiation use efficiency by a simple method proposed in previous work, based on the photosynthetic response to incident PAR of a top-canopy leaf. Key Results Kaolin increased incident PAR on surfaces of inner-canopy leaves, although there was an estimated 20 % loss in PAR reaching the photosynthetic apparatus, due to increased reflection. Assuming a 20 % loss of PAR, modelled photosynthesis and photosynthetic radiation use efficiency (PRUE) of kaolin-coated leaves decreased by only 6·3 %. This was due to (1) more beneficial PAR distribution within the kaolin-sprayed canopy, and (2) with decreasing PAR, leaf photosynthesis decreases less than proportionally, due to the curvature of the photosynthesis response-curve to PAR. The relatively small loss in canopy PRUE (per unit of incident PAR), coupled with the increased incident PAR on the leaf surface on

  19. Effects of kaolin application on light absorption and distribution, radiation use efficiency and photosynthesis of almond and walnut canopies.

    PubMed

    Rosati, Adolfo; Metcalf, Samuel G; Buchner, Richard P; Fulton, Allan E; Lampinen, Bruce D

    2007-02-01

    Kaolin applied as a suspension to plant canopies forms a film on leaves that increases reflection and reduces absorption of light. Photosynthesis of individual leaves is decreased while the photosynthesis of the whole canopy remains unaffected or even increases. This may result from a better distribution of light within the canopy following kaolin application, but this explanation has not been tested. The objective of this work was to study the effects of kaolin application on light distribution and absorption within tree canopies and, ultimately, on canopy photosynthesis and radiation use efficiency. Photosynthetically active radiation (PAR) incident on individual leaves within the canopy of almond (Prunus dulcis) and walnut (Juglans regia) trees was measured before and after kaolin application in order to study PAR distribution within the canopy. The PAR incident on, and reflected and transmitted by, the canopy was measured on the same day for kaolin-sprayed and control trees in order to calculate canopy PAR absorption. These data were then used to model canopy photosynthesis and radiation use efficiency by a simple method proposed in previous work, based on the photosynthetic response to incident PAR of a top-canopy leaf. Kaolin increased incident PAR on surfaces of inner-canopy leaves, although there was an estimated 20 % loss in PAR reaching the photosynthetic apparatus, due to increased reflection. Assuming a 20 % loss of PAR, modelled photosynthesis and photosynthetic radiation use efficiency (PRUE) of kaolin-coated leaves decreased by only 6.3 %. This was due to (1) more beneficial PAR distribution within the kaolin-sprayed canopy, and (2) with decreasing PAR, leaf photosynthesis decreases less than proportionally, due to the curvature of the photosynthesis response-curve to PAR. The relatively small loss in canopy PRUE (per unit of incident PAR), coupled with the increased incident PAR on the leaf surface on inner-canopy leaves, resulted in an estimated

  20. Light, literacy and the absence of ultraviolet radiation in the development of myopia.

    PubMed

    Prepas, Stephen B

    2008-01-01

    As the prevalence of myopia steadily increases, reaching as high as 90% in some populations, investigators continue to look for causative factors other than family history. Most current research suggests an association of axial myopia with reading or either the presence or absence of light. Even though these studies are frequently inconsistent, non-reproducible or contradictory, many clinicians utilize them in recommending treatments for children, such as bifocals or atropine. By reviewing the biologic effects of non-ionizing electromagnetic fields, we may gain insight into these discrepancies as well as unify the combined role of literacy and light in the pathogenesis of myopia. These biologic effects are wavelength specific. The wavelength of artificial (either incandescent or fluorescent) light is primarily 700-400 nm, while the wavelength of natural light is 700-200 nm, inclusive of the ultraviolet spectrum. So the opposite findings of myopia resulting from either accommodation under continuous light or under darkness (form deprivation) can be reconciled by restating it: Close focusing in the absence of UV light may provoke axial myopia. Experimental evidence exhibiting both scleral remodeling under accommodation as well as the inhibition of scleral remodeling by the hardening of collagen under ultraviolet exposure may support this concept. Perhaps new research can look into the role of the presence or absence of UV light in animal models of myopia.

  1. Gene expression under laser and light-emitting diodes radiation for modulation of cell adhesion: Possible applications for biotechnology.

    PubMed

    Karu, Tiina; Pyatibrat, Ludmila

    2011-09-01

    Experimental data about the modulation of adhesion and proliferation of anchorage-dependent HeLa cells with monochromatic or quasimonochromatic radiation in red to near-infrared region are presented. Cell adhesion and proliferation can be increased by irradiation with light of certain wavelengths (maxima in action spectrum are 619, 675, 740, 760, and 820 nm) or decreased when the activity of photoacceptor (cytochrome c oxidase in mitochondrial respiratory chain) is inhibited by chemicals before the irradiation. This modality allows controlling the number of attached and/or proliferating cells. Possible biotechnology applications of this method are outlined. Copyright © 2011 International Union of Biochemistry and Molecular Biology, Inc.

  2. Determination of the radiative efficiency of GaN-based light-emitting diodes via bias dependent resonant photoluminescence

    NASA Astrophysics Data System (ADS)

    Mounir, Christian; Schwarz, Ulrich T.

    2017-01-01

    We report a method to determine the radiative efficiency (ηrad) of GaN-based light-emitting diodes using excitation density and bias dependent room temperature photoluminescence (PL) measurements selectively exciting the active region. Considering carrier escape by tunnelling out of the active region, we extrapolate the generation rate of charge carriers from photocurrent measurements under reverse bias. A model describing the recombination of carriers including phase-space filling is then fitted to excitation density dependent PL data obtained under forward bias to extract ηrad. Results show that ηrad vs. carrier density is asymmetric around its maximum due to phase-space filling.

  3. Mechanical effects of light on material media: radiation pressure and the linear and angular momenta of photons

    NASA Astrophysics Data System (ADS)

    Mansuripur, Masud

    2014-09-01

    Electromagnetic waves carry energy as well as linear and angular momenta. Interactions between light and material media typically involve the exchange of all three entities. In all such interactions energy and momentum (both linear and angular) are conserved. Johannes Kepler seems to have been the first person to notice that the pressure of sunlight is responsible for the tails of the comets pointing away from the Sun. Modern applications of radiation pressure and photon momentum include solar sails, optical tweezers for optical trapping and micro-manipulation, and optically-driven micro-motors and actuators. This paper briefly describes certain fundamental aspects underlying the mechanical properties of light, and examines several interesting phenomena involving the linear and angular momenta of photons.

  4. Photon Activation Analysis Of Light Elements Using 'Non-Gamma' Radiation Spectroscopy - The Instrumental Determination Of Phosphorus

    SciTech Connect

    Segebade, Christian; Goerner, Wolf

    2011-06-01

    Unlike metal determinations the analysis of light elements (e.g., carbon, oxygen, phosphorus) is frequently problematic, in particular if analysed instrumentally. In photon activation analysis (PAA) the respective activation products do not emit gamma radiation in the most cases. Usually, annihilation quanta counting and subsequent decay curve analysis have been used for determinations of C, N, O, and F. However, radiochemical separation of the respective radioisotopes mostly is indispensable. For several reasons, some of the light elements cannot be analysed following this procedure, e.g. phosphorus. In this contribution the instrumental PAA of phosphorus in organic matrix by activation with bremsstrahlung of an electron linear accelerator and subsequent beta spectroscopy is described. The accuracy of the results was excellent as obtained by analysis of a BCR Reference Material.

  5. Sneaky light stop

    DOE PAGES

    Eifert, Till; Nachman, Benjamin

    2015-02-20

    A light supersymmetric top quark partner (stop) with a mass nearly degenerate with that of the standard model (SM) top quark can evade direct searches. The precise measurement of SM top properties such as the cross-section has been suggested to give a handle for this ‘stealth stop’ scenario. We present an estimate of the potential impact a light stop may have on top quark mass measurements. The results indicate that certain light stop models may induce a bias of up to a few GeV, and that this effect can hide the shift in, and hence sensitivity from, cross-section measurements. Duemore » to the different initial states, the size of the bias is slightly different between the LHC and the Tevatron. The studies make some simplifying assumptions for the top quark measurement technique, and are based on truth-level samples.« less

  6. Sneaky light stop

    SciTech Connect

    Eifert, Till; Nachman, Benjamin

    2015-04-01

    A light supersymmetric top quark partner (stop) with a mass nearly degenerate with that of the standard model (SM) top quark can evade direct searches. The precise measurement of SM top properties such as the cross-section has been suggested to give a handle for this ‘stealth stop’ scenario. We present an estimate of the potential impact a light stop may have on top quark mass measurements. The results indicate that certain light stop models may induce a bias of up to a few GeV, and that this effect can hide the shift in, and hence sensitivity from, cross-section measurements. Due to the different initial states, the size of the bias is slightly different between the LHC and the Tevatron. The studies make some simplifying assumptions for the top quark measurement technique, and are based on truth-level samples.

  7. Sneaky light stop

    SciTech Connect

    Eifert, Till; Nachman, Benjamin

    2015-02-20

    A light supersymmetric top quark partner (stop) with a mass nearly degenerate with that of the standard model (SM) top quark can evade direct searches. The precise measurement of SM top properties such as the cross-section has been suggested to give a handle for this ‘stealth stop’ scenario. We present an estimate of the potential impact a light stop may have on top quark mass measurements. The results indicate that certain light stop models may induce a bias of up to a few GeV, and that this effect can hide the shift in, and hence sensitivity from, cross-section measurements. Due to the different initial states, the size of the bias is slightly different between the LHC and the Tevatron. The studies make some simplifying assumptions for the top quark measurement technique, and are based on truth-level samples.

  8. Astronaut Exposures to Ionizing Radiation in a Lightly-Shielded Spacesuit

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.; Simonsen, L. C.; Shinn, J. L.; Kim, M.-H. Y.; Cucinotta, F. A.; Badavi, F. F.; Atwell, W.

    1999-01-01

    The normal working and living areas of the astronauts are designed to provide an acceptable level of protection against the hazards of ionizing radiation of the space environment. Still there are occasions when they must don a spacesuit designed mainly for environmental control and mobility and leave the confines of their better-protected domain. This is especially true for deep space exploration. The impact of spacesuit construction on the exposure of critical astronaut organs will be examined in the ionizing radiation environments of free space, the lunar surface and the Martian surface. The computerized anatomical male model is used to evaluate astronaut self-shielding factors and to determine space radiation exposures to critical radiosensitive human organs.

  9. Productivity, absorbed photosynthetically active radiation, and light use efficiency in crops: implications for remote sensing of crop primary production.

    PubMed

    Gitelson, Anatoly A; Peng, Yi; Arkebauer, Timothy J; Suyker, Andrew E

    2015-04-01

    Vegetation productivity metrics such as gross primary production (GPP) at the canopy scale are greatly affected by the efficiency of using absorbed radiation for photosynthesis, or light use efficiency (LUE). Thus, close investigation of the relationships between canopy GPP and photosynthetically active radiation absorbed by vegetation is the basis for quantification of LUE. We used multiyear observations over irrigated and rainfed contrasting C3 (soybean) and C4 (maize) crops having different physiology, leaf structure, and canopy architecture to establish the relationships between canopy GPP and radiation absorbed by vegetation and quantify LUE. Although multiple LUE definitions are reported in the literature, we used a definition of efficiency of light use by photosynthetically active "green" vegetation (LUE(green)) based on radiation absorbed by "green" photosynthetically active vegetation on a daily basis. We quantified, irreversible slowly changing seasonal (constitutive) and rapidly day-to-day changing (facultative) LUE(green), as well as sensitivity of LUE(green) to the magnitude of incident radiation and drought events. Large (2-3-fold) variation of daily LUE(green) over the course of a growing season that is governed by crop physiological and phenological status was observed. The day-to-day variations of LUE(green) oscillated with magnitude 10-15% around the seasonal LUE(green) trend and appeared to be closely related to day-to-day variations of magnitude and composition of incident radiation. Our results show the high variability of LUE(green) between C3 and C4 crop species (1.43 g C/MJ vs. 2.24 g C/MJ, respectively), as well as within single crop species (i.e., maize or soybean). This implies that assuming LUE(green) as a constant value in GPP models is not warranted for the crops studied, and brings unpredictable uncertainties of remote GPP estimation, which should be accounted for in LUE models. The uncertainty of GPP estimation due to facultative and

  10. Quark Gluon Plasma

    ScienceCinema

    Lincoln, Don

    2016-07-12

    Matter is malleable and can change its properties with temperature. This is most familiar when comparing ice, liquid water and steam, which are all different forms of the same thing. However beyond the usual states of matter, physicists can explore other states, both much colder and hotter. In this video, Fermilab’s Dr. Don Lincoln explains the hottest known state of matter – a state that is so hot that protons and neutrons from the center of atoms can literally melt. This form of matter is called a quark gluon plasma and it is an important research topic being pursued at the LHC.

  11. Quark Gluon Plasma

    SciTech Connect

    Lincoln, Don

    2015-05-07

    Matter is malleable and can change its properties with temperature. This is most familiar when comparing ice, liquid water and steam, which are all different forms of the same thing. However beyond the usual states of matter, physicists can explore other states, both much colder and hotter. In this video, Fermilab’s Dr. Don Lincoln explains the hottest known state of matter – a state that is so hot that protons and neutrons from the center of atoms can literally melt. This form of matter is called a quark gluon plasma and it is an important research topic being pursued at the LHC.

  12. Cool Quark Matter.

    PubMed

    Kurkela, Aleksi; Vuorinen, Aleksi

    2016-07-22

    We generalize the state-of-the-art perturbative equation of state of cold quark matter to nonzero temperatures, needed in the description of neutron star mergers and core collapse processes. The new result is accurate to O(g^{5}) in the gauge coupling, and is based on a novel framework for dealing with the infrared sensitive soft field modes of the theory. The zero Matsubara mode sector is treated via a dimensionally reduced effective theory, while the soft nonzero modes are resummed using the hard thermal loop approximation. This combination of known effective descriptions offers unprecedented access to small but nonzero temperatures, both in and out of beta equilibrium.

  13. Quark nova model for fast radio bursts

    NASA Astrophysics Data System (ADS)

    Shand, Zachary; Ouyed, Amir; Koning, Nico; Ouyed, Rachid

    2016-05-01

    Fast radio bursts (FRBs) are puzzling, millisecond, energetic radio transients with no discernible source; observations show no counterparts in other frequency bands. The birth of a quark star from a parent neutron star experiencing a quark nova - previously thought undetectable when born in isolation - provides a natural explanation for the emission characteristics of FRBs. The generation of unstable r-process elements in the quark nova ejecta provides millisecond exponential injection of electrons into the surrounding strong magnetic field at the parent neutron star's light cylinder via β-decay. This radio synchrotron emission has a total duration of hundreds of milliseconds and matches the observed spectrum while reducing the inferred dispersion measure by approximately 200 cm-3 pc. The model allows indirect measurement of neutron star magnetic fields and periods in addition to providing astronomical measurements of β-decay chains of unstable neutron rich nuclei. Using this model, we can calculate expected FRB average energies (˜ 1041 erg) and spectral shapes, and provide a theoretical framework for determining distances.

  14. Exposure of Metarhizium acridum mycelium to light induces tolerance to UV-B radiation.

    PubMed

    Brancini, Guilherme T P; Rangel, Drauzio E N; Braga, Gilberto Ú L

    2016-03-01

    Metarhizium acridum is an entomopathogenic fungus commonly used as a bioinsecticide. The conidium is the fungal stage normally employed as field inoculum in biological control programs and must survive under field conditions such as high ultraviolet-B (UV-B) exposure. Light, which is an important stimulus for many fungi, has been shown to induce the production of M. robertsii conidia with increased stress tolerance. Here we show that a two-hour exposure to white or blue/UV-A light of fast-growing mycelium induces tolerance to subsequent UV-B irradiation. Red light, however, does not have the same effect. In addition, we established that this induction can take place with as little as 1 min of white-light exposure. This brief illumination scheme could be relevant in future studies of M. acridum photobiology and for the production of UV-B resistant mycelium used in mycelium-based formulations for biological control.

  15. Top quark physics: Future Measurements

    SciTech Connect

    Frey, Raymond; Gerdes, David; Jaros, John; Vejcik, Steve; Berger, Edmond L.; Chivukula, R. Sekhar; Cuypers, Frank; Drell, Persis S.; Fero, Michael; Hadley, Nicholas; Han, Tao; Heinson, Ann P.; Knuteson, Bruce; Larios, Francisco; Miettinen, Hannu; Orr, Lynne H.; Peskin, Michael E.; Rizzo, Thomas; Sarid, Uri; Schmidt, Carl; Stelzer, Tim; Sullivan, Zack

    1996-12-31

    We discuss the study of the top quark at future experiments and machines. Top's large mass makes it a unique probe of physics at the natural electroweak scale. We emphasize measurements of the top quark's mass, width, and couplings, as well as searches for rare or nonstandard decays, and discuss the complementary roles played by hadron and lepton colliders.

  16. Properties of the Top Quark

    SciTech Connect

    Déliot, Frédéric; Hadley, Nicholas; Parke, Stephen; Schwarz, Tom

    2014-10-01

    The top quark is the heaviest known elementary particle, and it is often seen as a window to search for new physics processes in particle physics. A large program to study the top-quark properties has been performed both at the Tevatron and LHC colliders by the D0, CDF, ATLAS and CMS experiments. The most recent results are discussed in this article.

  17. Taste changing in staggered quarks

    SciTech Connect

    Quentin Mason et al.

    2004-01-05

    The authors present results from a systematic perturbative investigation of taste-changing in improved staggered quarks. They show one-loop taste-changing interactions can be removed perturbatively by an effective four-quark term and calculate the necessary coefficients.

  18. The radiation hardness and temperature stability of Planar Light-wave Circuit splitters for the High Luminosity LHC

    NASA Astrophysics Data System (ADS)

    Ryder, N. C.; Hamilton, P.; Huffman, B. T.; Teng, P. K.; Weidberg, A. R.; Issever, C.

    2011-10-01

    High Luminosity LHC (HL-LHC) Inner Tracker designs may include the sharing of Timing, Trigger and Control (TTC) signals between several tracker modules. This is possible because the highest frequency signals are common to all modules. Such designs are an attractive option because they reduce the number of optical links required and hence the cost. These designs will require optical signal splitters that are radiation hard up to high doses and capable of operating in cold temperatures. Optical splitters are available as either fused-fibre splitters or Planar Light-wave Circuit (PLC) splitters. PLC splitters are preferable because they are smaller than fused-fibre splitters. A selection of PLC splitters from different manufacturers and of two different technologies (silica and glass based) have been tested for radiation hardness up to a dose of 500 kGy(Si) and for temperature stability. All the tested splitters displayed small increases in insertion losses ( < 0.1 dB) in reducing the operating temperature from 25°C to -25°C. The silica based splitters from all manufacturers did not exhibit significant radiation induced insertion losses, despite the high dose they were exposed to. The glass based sample, however, had a per channel radiation induced insertion loss of up to 1.16 dB. Whilst the silica based splitters can be considered as qualified for HL-LHC use with regards to radiation hardness, the glass technology would require further testing at a lower, more realistic, dose to also be considered as a potential component for HL-LHC upgrade designs.

  19. Preliminary evidence on photoreactivation of Frankia spores with visible light after exposure to UV-C radiation.

    PubMed

    Sayed, W F

    2011-06-01

    Spores of four Frankia strains, the nitrogen-fixing actinomycete, were exposed to short wavelength UV-C radiation of 254 nm at 1 lux cm(2) (0.24 mw cm2 of energy) for 10 min. The used strains were HFP020203, UGL020604, UGL020602q and ORS021001. Exposure to UV was followed by reactivation with visible white light at 327.4 lux cm(2) for the same period of time. Spore germination percentage, spore protein content, and cell growth were damaged by this treatment. The lower and higher percentages of reduction in spore germination were 32 and 63% and, for the same strains, the recovery by white light was 7.2 and 37%. The lower percentages of UV damage and subsequent low recovery were recorded for strain ORS021001 that is considered more resistant to UV than the other strains. The higher percentages were recorded for strain HFP020203 that is more sensitive to UV but having more efficient repairing mechanisms. All the tested strains showed repairing activity induced by white light as indicated from the increase in their spore germination, protein content and almost restoring the normal shape of Frankia hyphae, after being damaged, as revealed by scanning electron microscope. This is the first evidence that photo-repairing systems are present in Frankia strains although there are variations in their response to both UV-C and photoreactivation by white light.

  20. Development and applications of radiative transfer models for unpolarized and polarized light

    NASA Astrophysics Data System (ADS)

    Lin, Zhenyi

    Radiative transfer models play an important role in satellite remote sensing of the atmosphere and the underlying surface including the ocean as well as for studying the energy budget of the Earth. Proper analysis of radiance and polarized radiation measurements rely on accurate and reliable radiative transfer models. Among the various numerical approaches developed to solve the radiative transfer equation, the ones based on the discrete-ordinate method, DISORT, as well as its polarized (vector) version VDISORT, have led to quite successful radiative transfer models that have been widely applied as forward models for the simulation of radiative transfer in coupled atmosphere-ocean media. In this dissertation, we first discuss new developments of DISORT and VDISORT, and review the relevant radiative transfer theory behind the upgraded algorithms. We then proceed to discuss applications of radiative transfer simulations that make use of each model. The upgrade of DISORT discussed in this thesis includes in the following improvements: (1) enhanced computational efficiency, accuracy and stability; (2) implementation new lower boundary conditions to simulate reflection from realistic (rough) land and ocean surfaces; (3) a revised treatment of the single-scattering correction. Numerical results are provided to demonstrate and quantify the improvements in accuracy and efficiency by comparing previous and upgraded versions of the numerical codes. One challenging problem in remote sensing applications is the simulation of ocean glint reflectance, which is reflected solar radiation from a wind-roughened ocean surface. For geometries close to specular reflection the glint signal is sufficiently strong that it may saturate the sensor, and even when saturation does not occur correct simulation of this signal is a difficult problem. In an exciting new application, we show for the first time that glint radiances in the near infrared spectral range simulated with the upgraded

  1. Distribution of radiation from organic light-emitting diode structures with wavelength-scale gratings as a function of azimuth and polar angles.

    PubMed

    Tutt, Lee; Revelli, Joseph F

    2008-03-01

    The angular distribution of radiation emitted from organic electroluminescent diodes fabricated on substrates with wavelength-scale gratings was measured using an optical Fourier transform instrument. A simple geometrical model is derived that specifies the polar angle of the exiting photon as a function of the azimuth angle, the grating pitch, the wavelength of light, and the effective index of the refraction of the light emitted by the fluorescing excitons. The radiation pattern of the extracted light is shown to fit that predicted by the model if one assumes that it comes from surface plasmon polaritons and bound TE waveguide modes.

  2. STRANGE GOINGS ON IN QUARK MATTER.

    SciTech Connect

    SCHAFER,T.

    2001-06-05

    We review recent work on how the superfluid state of three flavor quark matter is affected by non-zero quark masses and chemical potentials. The study of hadronic matter at high baryon density has recently attracted a lot of interest. At zero baryon density chiral symmetry is broken by a quark-anti-quark condensate. At high density condensation in the quark-anti-quark channel is suppressed. Instead, attractive interactions in the color anti-symmetric quark-quark channel favor the formation of diquark condensates. As a consequence, cold dense quark matter is expected to be a color superconductor. The symmetry breaking pattern depends on the density, the number of quark flavors, and their masses. A particularly symmetric phase is the color-flavor-locked (CFL) phase of three flavor quark matter. This phase is believed to be the true ground state of ordinary matter at very large density.

  3. Quantum Collapse in Quark Stars?

    SciTech Connect

    Perez Martinez, A.; Perez Rojas, H.; Mosquera Cuesta, H. J.

    2006-06-19

    Quark matter is expected to exist in the interior of compact stellar objects as neutron stars or even the more exotic strange stars. Bare strange quark stars and (normal) strange quark-matter stars, those possessing a baryon (electron-supported) crust, are hypothesized as good candidates to explain the properties of a set of peculiar stellar sources. In this presentation, we modify the MIT Bag Model by including the electromagnetic interaction. We also show that this version of the MIT model implies the anisotropy of the Bag pressure due to the presence of the magnetic field. The equations of state of degenerate quarks gases are studied in the presence of ultra strong magnetic fields. The behavior of a system made-up of quarks having (or not) anomalous magnetic moment is reviewed. A structural instability is found, which is related to the anisotropic nature of the pressures in this highly magnetized matter.

  4. Interactions of Changing Solar Ultraviolet Radiation and Climate with Light Induced Chemical Reactions in Aquatic Environments

    EPA Science Inventory

    Changes in the ozone layer over the past two decades have resulted in increases in solar ultraviolet radiation that reach the surface of North American aquatic environments. Concurrent changes in atmospheric CO2 are resulting in changes in stratification and precipitation that ar...

  5. Asymmetric lateral coherence of betatron radiation emitted in laser-driven light sources

    NASA Astrophysics Data System (ADS)

    Paroli, B.; Chiadroni, E.; Ferrario, M.; Petrillo, V.; Potenza, M. A. C.; Rossi, A. R.; Serafini, L.; Shpakov, V.

    2015-08-01

    We show that the radiation emitted by betatron oscillations of a high-energy electron beam undergoing wake-field acceleration is endowed with peculiar coherence properties which deliver quantitative information about the electron trajectories. Such results are achieved by means of accurate numerical simulations and a simple geometrical model gives a clear physical interpretation.