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Sample records for hard exclusive electroproduction

  1. Tests of quantum chromodynamics in exclusive and inclusive electroproduction

    SciTech Connect

    Brodsky, S.J.

    1989-06-01

    This paper discusses the following topics: overview of electroproduction phenomenology; hadronization of the quark and spectator systems; hadronization in nuclei; shadowing and anti- shadowing; color transparency; exclusive channels in electroproduction; hadronic wavefunction phenomenology; diffractive electroproduction; exclusive nuclear processes in QCD; and relation of electroproduction to QCD wavefunctions. 58 refs., 22 figs. (LSP)

  2. Exclusive Pion Electroproduction Results from Jefferson Lab

    NASA Astrophysics Data System (ADS)

    Huber, Garth

    2013-04-01

    Forward exclusive meson production is a particularly useful tool in the study of hadronic structure. Measurements at different squared four-momenta of the exchanged virtual photon, Q^2, and at different four-momentum transfer, t, allow one to probe QCD's transition from meson-nucleon degrees of freedom at long distances to quark-gluon degrees of freedom at short scales. Furthermore, by forming ratios of separated response functions in ^ and ^ electroproduction, there may be a partial cancellation of nonperturbative QCD contributions, allowing this transition to be more readily apparent. These strong theoretical motivations make worthwhile the significant experimental challenges needed to accurately separate the four response functions in forward, exclusive -/+ electroproduction off deuterium. We report the results of our study from Jefferson Lab Hall C, where for the first time ratios of separated response functions were extracted at several kinematic settings: Q^2 = 0.6, 1.0, 1.6 GeV^2 with W=1.95 GeV, and Q^2=2.45 GeV^2 with W=2.22 GeV, respectively.

  3. QED Radiative Corrections in Processes of Exclusive Pion Electroproduction

    SciTech Connect

    Andrei Afanasev; I. Akushevich; Volker Burkert; K. Joo

    2002-03-01

    Formalism for radiative correction (RC) calculation in exclusive pion electroproduction on the proton is presented. A FORTRAN code EXCLURAD is developed for the RC procedure. The numerical analysis is done in the kinematics of current Jefferson Lab experiments.

  4. QCD description of backward vector meson hard electroproduction

    NASA Astrophysics Data System (ADS)

    Pire, B.; Semenov-Tian-Shansky, K.; Szymanowski, L.

    2015-05-01

    We consider backward vector meson exclusive electroproduction off nucleons in the framework of collinear QCD factorization. Nucleon to vector meson transition distribution amplitudes (TDAs) arise as building blocks for the corresponding factorized amplitudes. In the near-backward kinematics, the suggested factorization mechanism results in the dominance of the transverse cross section of vector meson production (σT≫σL ) and in the characteristic 1 /Q8-scaling behavior of the cross section. We evaluate nucleon to vector meson TDAs in the cross-channel nucleon exchange model and present estimates of the differential cross section for backward ρ0, ω and ϕ meson production off protons. The resulting cross sections are shown to be measurable in the forthcoming JLab@12 GeV experiments.

  5. Exclusive J/Psi electroproduction in a dual model

    SciTech Connect

    R. Fiore, L.L. Jenkovszky, V.K. Magas, S. Melis, A. Prokudin

    2009-12-01

    Exclusive J/Psi electroproduction is studied in the framework of the analytic S-matrix theory. The differential and integrated elastic cross sections are calculated using the Modified Dual Amplitude with Mandelstam Analyticity (M-DAMA) model. The model is applied to the description of the available experimantal data and proves to be valid in a wide region of the kinematical variables s, t and Q^2. Our amplitude can be used also as a universal background parametrization for the extraction of tiny resonance signals.

  6. Nucleon Resonance Structure Studies via Exclusive KY Electroproduction

    NASA Astrophysics Data System (ADS)

    Carman, Daniel S.

    2016-10-01

    Studying the structure of excited nucleon states employing the electroproduction of exclusive reactions is an important avenue for exploring the nature of the non-perturbative strong interaction. The electrocouplings of N^* states in the mass range below 1.8 GeV have been determined from analyses of CLAS π N, η N, and π π N data. This work has made it clear that consistent results from independent analyses of several exclusive channels with different couplings and non-resonant backgrounds but the same N^* electro-excitation amplitudes, is essential to have confidence in the extracted results. In terms of hadronic coupling, many high-lying N^* states preferentially decay through the π π N channel instead of π N. Data from the KY channels will therefore be critical to provide an independent analysis to compare the extracted electrocouplings for the high-lying N^* states against those determined from the π N and π π {N} channels. A program to study excited N^* state structure in both non-strange and strange exclusive electroproduction channels using CLAS12 will measure differential cross sections and polarization observables to be used as input to extract the γ _v{it{NN}}^* electrocoupling amplitudes for the most prominent N^* states in the range of invariant energy W up 3 GeV in the virtually unexplored domain of momentum transfers Q^2 up to 12 GeV^2.

  7. Nucleon resonance structure studies via exclusive KY electroproduction

    DOE PAGESBeta

    Carman, Daniel S.

    2016-06-16

    Studying the structure of excited nucleon states employing the electroproduction of exclusive reactions is an important avenue for exploring the nature of the non-perturbative strong interaction. The electrocouplings ofmore » $N^*$ states in the mass range below 1.8~GeV have been determined from analyses of CLAS $$\\pi N$$, $$\\eta N$$, and $$\\pi \\pi N$$ data. This work has made it clear that consistent results from independent analyses of several exclusive channels with different couplings and non-resonant backgrounds but the same $N^*$ electro excitation amplitudes, is essential to have confidence in the extracted results. In terms of hadronic coupling, many high-lying $N^*$ states preferentially decay through the $$\\pi \\pi N$$ channel instead of $$\\pi N$$. Data from the $KY$ channels will therefore be critical to provide an independent analysis to compare the extracted electrocouplings for the high-lying $N^*$ states against those determined from the $$\\pi N$$ and $$\\pi \\pi N$$ channels. Lastly, a program to study excited $N^*$ state structure in both non-strange and strange exclusive electroproduction channels using CLAS12 will measure differential cross sections and polarization observables to be used as input to extract the $$\\gamma_vNN^*$$ electrocoupling amplitudes for the most prominent $N^*$ states in the range of invariant energy $W$ up 3~GeV in the virtually unexplored domain of momentum transfers $Q^2$ up to 12~GeV$^2$.« less

  8. Nucleon Resonance Structure Studies via Exclusive KY Electroproduction

    NASA Astrophysics Data System (ADS)

    Carman, Daniel S.

    2016-06-01

    Studying the structure of excited nucleon states employing the electroproduction of exclusive reactions is an important avenue for exploring the nature of the non-perturbative strong interaction. The electrocouplings of N^* states in the mass range below 1.8 GeV have been determined from analyses of CLAS π N , η N , and π π N data. This work has made it clear that consistent results from independent analyses of several exclusive channels with different couplings and non-resonant backgrounds but the same N^* electro-excitation amplitudes, is essential to have confidence in the extracted results. In terms of hadronic coupling, many high-lying N^* states preferentially decay through the π π N channel instead of π N . Data from the KY channels will therefore be critical to provide an independent analysis to compare the extracted electrocouplings for the high-lying N^* states against those determined from the π N and π π {N} channels. A program to study excited N^* state structure in both non-strange and strange exclusive electroproduction channels using CLAS12 will measure differential cross sections and polarization observables to be used as input to extract the γ _v{{NN}}^* electrocoupling amplitudes for the most prominent N^* states in the range of invariant energy W up 3 GeV in the virtually unexplored domain of momentum transfers Q^2 up to 12 GeV^2.

  9. Exclusive Single Pion Electroproduction off the Proton: Results from CLAS

    NASA Astrophysics Data System (ADS)

    Park, Kijun

    2016-08-01

    Exclusive meson electroproduction off protons is a powerful tool to probe the effective degrees of freedom in excited nucleon states at the varying distance scale where the transition from the contributions of both quark core and meson-baryon cloud to the quark core dominance. During the past decade, the CLAS collaboration has executed a broad experimental program to study the excited states of the proton using polarized electron beam and both polarized and unpolarized proton targets. The measurements covered a broad kinematic range in the invariant mass W and photon virtuality Q^2 with nearly full coverage in polar and azimuthal angles in the hadronic CM system. As results, several low-lying nucleon resonance states in particular from pion threshold to W < 1.6 GeV have been explored. These include Δ (1232)3/2^+ , N(1440)1/2^+ , N(1520)3/2^- , and N(1535)1/2^- states. In addition, we recently published the differential cross sections and helicity amplitudes of the reaction γ ^*p→ nπ ^+ at higher W (1.6-2.0 GeV) which are the N(1675)5/2^- , N(1680)5/2^+ , and N(1710)1/2^+ states. These excited states with isospin 1/2 and with masses near 1.7 GeV can be accessed in single nπ ^+ production as there are no isospin 3/2 states present in this mass range with the same spin-parity assignments. I will briefly discuss these states from CLAS results of the single charged pion electroproduction data.

  10. Exclusive single pion electroproduction off the proton: Results from CLAS

    DOE PAGESBeta

    Park, Kijun

    2016-08-13

    Exclusive meson electroproduction off protons is a powerful tool to probe the effective degrees of freedom in excited nucleon states at the varying distance scale where the transition from the contributions of both quark core and meson-baryon cloud to the quark core dominance. During the past decade, the CLAS collaboration has executed a broad experimental program to study the excited states of the proton using polarized electron beam and both polarized and unpolarized proton targets. The measurements covered a broad kinematic range in the invariant massmore » $W$ and photon virtuality $Q^2$ with nearly full coverage in polar and azimuthal angles in the hadronic CM system. As results, several low-lying nucleon resonance states in particular from pion threshold to $W < 1.6$ GeV have been explored. These include $$\\Delta$$(1232)$$\\frac{3}{2}^+$$, $$N(1440)\\frac{1}{2}^+$$, $$N(1520)\\frac{3}{2}^-$$, and $$N(1535)\\frac{1}{2}^-$$ states. In addition, we recently published the differential cross sections and helicity amplitudes of the reaction $$\\gamma^*p\\to n\\pi^+$$ at higher $W$ (1.6 to 2.0 GeV) which are the $$N(1675)\\frac{5}{2}^-$$, $$N(1680)\\frac{5}{2}^+$$, and $$N(1710)\\frac{1}{2}^+$$ states. These excited states with isospin $1/2$ and with masses near 1.7 GeV can be accessed in single $$n\\pi^+$$ production as there are no isospin $3/2$ states present in this mass range with the same spin-parity assignments. As a result, I will briefly discuss these states from CLAS results of the single charged pion electroproduction data.« less

  11. Transverse-Target-Spin Asymmetry in Exclusive {omega}-Meson Electroproduction

    SciTech Connect

    Airapetian, A.; Akopov, N.; Akopov, Z.; Aschenauer, E. C.; Augustyniak, W.; Avetissian, A.; Belostotski, S.; Blok, H. P.; Borissov, A.; Bryzgalov, V.; Jackson, H. E.; Reimer, P. E.

    2015-12-17

    Hard exclusive electroproduction of omega mesons is studied with the HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off a transversely polarized hydrogen target. The amplitudes of five azimuthal modulations of the single-spin asymmetry of the cross section with respect to the transverse proton polarization are measured. They are determined in the entire kinematic region as well as for two bins in photon virtuality and momentum transfer to the nucleon. Also, a separation of asymmetry amplitudes into longitudinal and transverse components is done. These results are compared to a phenomenological model that includes the pion pole contribution. Within this model, the data favor a positive pi omega transition form factor.

  12. Transverse-target-spin asymmetry in exclusive ω -meson electroproduction. The HERMES Collaboration

    NASA Astrophysics Data System (ADS)

    Airapetian, A.; Akopov, N.; Akopov, Z.; Aschenauer, E. C.; Augustyniak, W.; Avetissian, A.; Belostotski, S.; Blok, H. P.; Borissov, A.; Bryzgalov, V.; Capitani, G. P.; Ciullo, G.; Contalbrigo, M.; Dalpiaz, P. F.; Deconinck, W.; De Leo, R.; De Sanctis, E.; Diefenthaler, M.; Di Nezza, P.; Düren, M.; Elbakian, G.; Ellinghaus, F.; Felawka, L.; Frullani, S.; Gabbert, D.; Gapienko, G.; Gapienko, V.; Gharibyan, V.; Giordano, F.; Gliske, S.; Hasch, D.; Hoek, M.; Holler, Y.; Ivanilov, A.; Jackson, H. E.; Joosten, S.; Kaiser, R.; Karyan, G.; Keri, T.; Kinney, E.; Kisselev, A.; Korotkov, V.; Kozlov, V.; Krivokhijine, V. G.; Lagamba, L.; Lapikás, L.; Lehmann, I.; Lenisa, P.; Lorenzon, W.; Ma, B.-Q.; Manaenkov, S. I.; Mao, Y.; Marianski, B.; Marukyan, H.; Miyachi, Y.; Movsisyan, A.; Muccifora, V.; Naryshkin, Y.; Nass, A.; Negodaev, M.; Nowak, W.-D.; Pappalardo, L. L.; Perez-Benito, R.; Petrosyan, A.; Reimer, P. E.; Reolon, A. R.; Riedl, C.; Rith, K.; Rosner, G.; Rostomyan, A.; Rubin, J.; Ryckbosch, D.; Salomatin, Y.; Schnell, G.; Seitz, B.; Shibata, T.-A.; Statera, M.; Steffens, E.; Steijger, J. J. M.; Stinzing, F.; Taroian, S.; Terkulov, A.; Truty, R.; Trzcinski, A.; Tytgat, M.; Van Haarlem, Y.; Van Hulse, C.; Vikhrov, V.; Vilardi, I.; Vogel, C.; Wang, S.; Yaschenko, S.; Yen, S.; Zihlmann, B.; Zupranski, P.

    2015-12-01

    Hard exclusive electroproduction of ω mesons is studied with the HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off a transversely polarized hydrogen target. The amplitudes of five azimuthal modulations of the single-spin asymmetry of the cross section with respect to the transverse proton polarization are measured. They are determined in the entire kinematic region as well as for two bins in photon virtuality and momentum transfer to the nucleon. Also, a separation of asymmetry amplitudes into longitudinal and transverse components is done. These results are compared to a phenomenological model that includes the pion pole contribution. Within this model, the data favor a positive π ω transition form factor.

  13. Deeply virtual and exclusive electroproduction of omega mesons

    SciTech Connect

    Morand, L; Et. Al.

    2005-04-01

    The exclusive omega electroproduction off the proton was studied in a large kinematical domain above the nucleon resonance region and for the highest possible photon virtuality (Q{sup 2}) with the 5.75 GeV beam at CEBAF and the CLAS spectrometer. Cross sections were measured up to large values of the four-momentum transfer (-t < 2.7 GeV{sup 2}) to the proton. The contributions of the interference terms sigma{sub TT} and sigma{sub TL} to the cross sections, as well as an analysis of the omega spin density matrix, indicate that helicity is not conserved in this process. The t-channel pi{sup 0} exchange, or more generally the exchange of the associated Regge trajectory, seems to dominate the reaction {gamma}* p {yields} omega p, even for Q{sup 2} as large as 5 GeV{sub 2}. Contributions of handbag diagrams, related to Generalized Parton Distributions in the nucleon, are therefore difficult to extract for this process. Remarkably, the high-t behavior of the cross sections is nearly Q{sup 2}-independent, which may be interpreted as a coupling of the photon to a point-like object in this kinematical limit.

  14. Hard Exclusive Pion Leptoproduction

    NASA Astrophysics Data System (ADS)

    Kroll, Peter

    2016-08-01

    In this talk it is reported on an analysis of hard exclusive leptoproduction of pions within the handbag approach. It is argued that recent measurements of this process performed by HERMES and CLAS clearly indicate the occurrence of strong contributions from transversely polarized photons. Within the handbag approach such γ ^{ *}_T→ π transitions are described by the transversity GPDs accompanied by twist-3 pion wave functions. It is shown that the handbag approach leads to results on cross sections and single-spin asymmetries in fair agreement with experiment. Predictions for other pseudoscalar meson channels are also briefly discussed.

  15. Nucleon resonances in exclusive reactions of photo- and electroproduction of mesons

    SciTech Connect

    Skorodumina, Iu. A.; Burkert, V. D.; Golovach, E. N.; Gothe, R. W.; Isupov, E. L.; Ishkhanov, B. S.; Mokeev, V. I.; Fedotov, G. V.

    2015-11-01

    Methods for extracting nucleon resonance parameters from experimental data are reviewed. The formalism for the description of exclusive reactions of meson photo- and electroproduction off nucleons is discussed. Recent experimental data on exclusive meson production in the scattering of electrons and photons off protons are analyzed.

  16. Exclusive measurements of omega electroproduction off the proton in the resonance region

    SciTech Connect

    Phelps, Evan

    2014-01-01

    A complete theory of strong interactions must describe the excited baryon spectrum as well as the structure of prominent states, which reflects the dynamics of nonperturbative QCD. Beyond the discriminating power of exclusive single- and double-pion electroproduction, the omega channel provides an additional probe of high-mass excited states. The current analysis provides preliminary differential and integrated cross sections of omega electroproduction off the proton from W = 1.7 to 3.2 GeV and Q{sup 2} = 1.5 to 5.5 GeV{sup 2}. The data was collected by JLab's CLAS detector during two run periods and comprises the largest sample of exclusive resonance-region omega electroproduction ever analyzed. Preliminary Legendre decomposition of the cross sections supports previous indications of s-channel contributions to cross sections in the resonance region.

  17. Hard Exclusive Reactions at Jlab

    SciTech Connect

    Kubarovsky, Valery P.

    2011-09-20

    Dedicated experiments to study Deeply Virtual Compton Scattering (DVCS) and Deeply Virtual Meson Production (DVMP) have been carried out at Jefferson Lab. DVCS helicity--dependent and helicity--independent cross sections and beam spin asymmetries have been measured, as well as cross sections and asymmetries for the $\\pi^0$, $\\eta$, $\\rho^0$, $\\rho^+$, $\\omega$ and $\\phi$ for exclusive electroproduction. The data were taken in a wide kinematic range in $Q^2$=1--4.5 GeV$^2$, $x_B$=0.1--0.5, and $|t|$ up to 2 GeV$^2$. The presented results offer a unique opportunity to study the structure of the nucleon at the parton level as one has access to Bjorken $x_B$ and momentum transfer to the nucleon $t$ at the same time.

  18. Hard Exclusive Meson Production at COMPASS

    NASA Astrophysics Data System (ADS)

    Ter Wolbeek, Johannes

    2016-02-01

    The concept of Generalized Parton Distributions (GPDs) combines two-dimensional spatial information given by form factors, with longitudinal momentum information from Parton Distribution Functions. GPDs provide comprehensive description of the nucleon structure involving a wealth of new information. For instance, according to Ji’s sum rule, the GPDs H and E enable access to the total angular momenta of quarks, antiquarks and gluons. While H can be approached using measurements of electroproduction cross sections, asymmetry measurements in hard exclusive meson production off transversely polarized targets can help to constrain the GPD E and chiral-odd GPDs. In 2007 and 2010 the COMPASS experiment at CERN collected data by scattering a 160GeV/c muon beam off a transversely polarized NH3 target. Exclusive vector-meson production μ + p → μ‧ + p + V with a ρ0 or ω meson in the final state is studied and five single-spin and three double-spin azimuthal asymmetries are measured.

  19. Exclusive Electroproduction of meson rho on the nucleon Virtualite Intermediate With the CLAS Detector at Jlab; Electroproduction Exclusive de meson rho sur le nucleon Virtualite Intermediaire Avec le Detecteur CLAS at Jlab

    SciTech Connect

    Cynthia Hadjidakis

    2002-12-01

    This report presents the exclusive rho0 meson electroproduction on the nucleon at intermediate square momentum transfers Q{sup 2} (1.5 < Q{sup 2} < 3 GeV{sup 2}) and above the resonance region. The experiment has been taken place at the Jefferson laboratory with the CLAS detector, with a 4.2 GeV beam energy on a hydrogen target in the February-March 1999 period. They present the results and in particular the L/T separated cross sections. This experimentally unexplored domain experimentally is at the intersection between traditional ''soft'' hadronic physics models (VDM and Regge inspired models) and ''hard'' pQCD inspired approaches (recently introduced Generalized Parton Distribution). They discuss both approaches and their domain of validity.

  20. Separated Response Functions in Exclusive, Forward π+/- Electroproduction on 2H

    NASA Astrophysics Data System (ADS)

    Huber, Garth; Pion Form Factor Collaboration

    2013-10-01

    The study of exclusive π+/- electroproduction on the nucleon, including separation of the various structure functions, is of interest for a number of reasons. The ratio RL =σLπ- /σLπ+ is sensitive to isoscalar contamination to the dominant isovector pion exchange amplitude, which is the basis for the determination of the charged pion form factor, Fπ (Q2) , from electroproduction data. Furthermore, RL is an experimentally accessible ratio of longitudinal photon observables, and its value may have implications for constraining polarized GPDs. A change in RT =σTπ- /σTπ+ from unity at small - t , to 1/4 at large - t , would suggest a transition from coupling to a (virtual) pion to coupling to individual quarks. If there is a partial cancellation of nonperturbative QCD contributions, the ratio may show an earlier approach to pQCD than the individual cross sections. We report the results of our study from Jefferson Lab Hall C, where the first complete separation of the four unpolarized electromagnetic structure functions were obtained in forward, exclusive π+/- electroproduction at central qsq values of 0.6, 1.0, 1.6 gevsq at W=1.95 GeV, and Q2 = 2 . 45 gevsq at W = 2.22 GeV. Supported by the Natural Sciences and Engineering Research Council of Canada.

  1. Nucleon Resonance Structure from Exclusive Meson Electroproduction with CLAS and CLAS12

    SciTech Connect

    Philip L. Cole, Volker D. Burkert, Ralf W. Gothe, Victor I. Mokeev

    2012-12-01

    The CLAS detector at Jefferson Lab is a unique instrument, which has provided the lion's share of the world's data on meson photo- and electroproduction in the resonance excitation region. The electroexcitation amplitudes for the low-lying resonances P{sub 33} (1232), P{sub 11} (1440), D{sub 13} (1520), and S {sub 11} (1535) were determined over a wide range of Q{sub 2} < 5.0 GeV{sub 2} in a comprehensive analysis of exclusive single-meson ( {pi}{sup +} n, {pi}{sup 0} p) reactions in the electroproduction off protons. Further, we were able to precisely measure {pi}{sup +}{pi}{sup -}p electroproduction differential cross sections provided by the nearly full kinematic coverage of the CLAS detector. And, for the first time, the electrocouplings of the P{sub 11} (1440), D{sub 13} (1520) excited states are determined from the exclusive-{pi}{sup +}{pi}{sup -}p reaction. Consistent results on the electrocouplings from two-independent analyses (single- and double-pion electroproduction) have provided compelling evidence for the reliable extraction of the N* electrocouplings. And preliminary results on the electrocouplings of the S{sub 31} (1620), S{sub 11} (1650), D{sub 33} (1700), and P{sub 13} (1720) states, which decay preferentially to the N{pi} {pi} final states, have recently become available. Theoretical analyses of these results have revealed that there are two major contributions to the resonance structure: a) an internal quark core and b) an external meson-baryon cloud. These CLAS results have had considerable impact on QCD-based studies on N* structure and in the search for manifestations of the dynamical masses of the dressed quarks. Future CLAS12 N* structure studies at high photon virtualities will considerably extend our capabilities in exploring the nature of confinement in baryons.

  2. Testing quantum chromodynamics in electroproduction

    SciTech Connect

    Brodsky, S.J.

    1987-05-01

    The exclusive channels in electroproduction are discussed. The study of color transparency, the formation zone, and other novel aspects of QCD by measuring exclusive reactions inside nuclear targets is covered. Diffractive electroproduction channels are discussed, and exclusive nuclear processes in QCD are examined. Non-additivity of nuclear structure functions (EMC effect) is also discussed, as well as jet coalescence in electroproduction. (LEW)

  3. Measurement of Exclusive $π^0$ Electroproduction Structure Functions and their Relationship to Transverse Generalized Parton Distributions

    SciTech Connect

    Bedlinskiy, Ivan; Niccolai, Silvia; Stoler, Paul; Adhikari, Krishna; Aghasyan, Mher; Amaryan, Moskov; Anghinolfi, Marco; Avagyan, Harutyun; Baghdasaryan, Hovhannes; Ball, Jacques; Baltzell, Nathan; Battaglieri, Marco; Bennett, Robert; Biselli, Angela; Bookwalter, Craig; Boyarinov, Sergey; Briscoe, William; Brooks, Williams; Burkert, Volker; Carman, Daniel; Celentano, Andrea; Chandavar, Shloka; Charles, Gabriel; Contalbrigo, Marco; Crede, Volker; D'Angelo, Annalisa; Daniel, Aji; Dashyan, Natalya; De Vita, Raffaella; De Sanctis, Enzo; Deur, Alexandre; Djalali, Chaden; Doughty, David; Dupre, Raphael; Egiyan, Hovanes; El Alaoui, Ahmed; Elfassi, Lamiaa; Elouadrhiri, Latifa; Eugenio, Paul; Fedotov, Gleb; Fegan, Stuart; Fleming, Jamie; Forest, Tony; Garcon, Michel; Gevorgyan, Nerses; Giovanetti, Kevin; Girod, Francoi-Xavier; Gohn, Wesley; Gothe, Ralf; Graham, Lewis; Griffioen, Keith; Guegan, Baptiste; Guidal, Michel; Guo, Lei; Hafidi, Kawtar; Hakobyan, Hayk; Hanretty, Charles; Heddle, David; Hicks, Kenneth; Holtrop, Maurik; Ilieva, Yordanka; Ireland, David; Ishkhanov, Boris; Isupov, Evgeny; Jo, Hyon-Suk; Joo, Kyungseon; Keller, Dustin; Khanddaker, Mahbubul; Khertarpal, Puneet; Kim, Andrey; Kim, Wooyoung; Klein, Franz; Koirala, Suman; Kubarovsky, A; Kuhn, Sebastian; Kuleshov, Sergey; Kvaltine, Nicholas; Livingston, Kenneth; Lu, Haiyun; MacGregor, Ian; Mao, Yuqing; Markov, Nikolai; Martinez, D; Mayer, Michael; McKinnon, Bryan; Meyer, Curtis; Mineeva, Taisiya; Mirazita, Marco; Mokeev, Viktor; Moutarde, Herve; Munevar Espitia, Edwin; Munoz Camacho, Carlos; Nadel-Turonski, Pawel; Niculescu, Gabriel; Niculescu, Maria-Ioana; Osipenko, Mikhail; Ostrovidov, Alexander; Pappalardo, Luciano; Permuzyan, Rafayel; Park, Kijun; Park, Sungkyun; Pasyuk, Eugene; Pereira, Sergio; Phelps, Evan; Pisano, Silvia; Pogorelko, Oleg; Pozdnyakov, Sergey; Price, John; Procureur, Sebastien; Prok, Yelena; Protopopescu, Dan; Puckett, Andrew; Raue, Brian; Ricco, Giovanni; Rimal, Dipak; Ripani, Marco; Rosner, Guenther; Rossi, Patrizia; Sabatie, Franck; Saini, Mukesh; Salgado, Carlos; Saylor, Nicholas; Schott, Diane; Schumacher, Reinhard; Seder, Erin; Seraydaryan, Heghine; Sharabian, Youri; Smith, Gregory; Sober, Daniel; Sokhan, Daria; Stepanyan, Samuel; Strauch, Steffen; Taiuti, Mauro; Tang, Wei; Taylor, Charles; Tian, Ye; Tkachenko, Svyatoslav; Ungaro, Maurizio; Vineyard, Michael; Vlasov, Alexander; Voskanyan, Hakob; Voutier, Eric; Walford, Natalie; Watts, Daniel; Weinstein, Lawrence; Weygan, Dennis; Wood, Michael; Zachariou, Nicholas; Zhang, Jixie; Zhao, Zhiwen; Zonta, Irene

    2012-09-01

    Exclusive $\\pi^0$ electroproduction at a beam energy of 5.75 GeV has been measured with the Jefferson Lab CLAS spectrometer. Differential cross sections were measured at more than 1800 kinematic values in $Q^2$, $x_B$, $t$, and $\\phi_\\pi$, in the $Q^2$ range from 1.0 to 4.6 GeV$^2$,\\ $-t$ up to 2 GeV$^2$, and $x_B$ from 0.1 to 0.58. Structure functions $\\sigma_T +\\epsilon \\sigma_L, \\sigma_{TT}$ and $\\sigma_{LT}$ were extracted as functions of $t$ for each of 17 combinations of $Q^2$ and $x_B$. The data were compared directly with two handbag-based calculations including both longitudinal and transversity GPDs. Inclusion of only longitudinal GPDs very strongly underestimates $\\sigma_T +\\epsilon \\sigma_L$ and fails to account for $\\sigma_{TT}$ and $\\sigma_{LT}$, while inclusion of transversity GPDs brings the calculations into substantially better agreement with the data. There is very strong sensitivity to the relative contributions of nucleon helicity flip and helicity non-flip processes. The results confirm that exclusive $\\pi^0$ electroproduction offers direct experimental access to the transversity GPDs.

  4. Beam spin asymmetry in deep and exclusive pi0 electroproduction

    SciTech Connect

    R. De Masi

    2007-12-07

    The beam spin asymmetry (BSA) in the exclusive reaction ep->ep pi0 was measured with the CEBAF 5.77 GeV polarized electron beam and Large Acceptance Spectrometer(CLAS). The xB, Q2, t and phi dependences of the pi0 BSA are presented in the deep inelastic regime. The asymmetries are fitted with a sin(phi) function and their amplitudes are extracted. Overall, they are of the order of 0.04 - 0.11 and roughly independent of t. This is the signature of a non-zero longitudinal-transverse interference. The implications concerning the applicability of a formalism based on generalized parton distributions, as well as the extension of a Regge formalism at high photon virtualities, are discussed.

  5. Exclusive rho^0 electroproduction on the proton at CLAS

    SciTech Connect

    Morrow, Steven; Guidal, Michel; Garcon, Michel; Laget, Jean; Smith, Elton; Adams, Gary; Adhikari, Krishna; Aghasyan, Mher; Amaryan, Moscov; Amaryan, Moskov; Anghinolfi, Marco; Asryan, G.; Audit, Gerard; Avagyan, Harutyun; Bagdasaryan, H.; Baillie, Nathan; Ball, J.P.; Ball, Jacques; Baltzell, Nathan; Barrow, Steve; Battaglieri, Marco; Bedlinskiy, Ivan; Bektasoglu, Mehmet; Bellis, Matthew; Benmouna, Nawal; Berman, Barry; Biselli, Angela; Blaszczyk, Lukasz; Bonner, Billy; Bookwalter, Craig; Bouchigny, Sylvain; Boyarinov, Sergey; Bradford, Robert; Branford, Derek; Briscoe, William; Brooks, William; Bultmann, S.; Bueltmann, Stephen; Burkert, Volker; Butuceanu, Cornel; Calarco, John; Careccia, Sharon; Carman, Daniel; Carnahan, Bryan; Casey, Liam; Cazes, Antoine; Chen, Shifeng; Cheng, Lu; Cole, Philip; Collins, Patrick; Coltharp, Philip; Cords, Dieter; Corvisiero, Pietro; Crabb, Donald; Crannell, Hall; Crede, Volker; Cummings, John; Dale, Daniel; Dashyan, Natalya; De Masi, Rita; De Vita, Raffaella; De Sanctis, Enzo; Degtiarenko, Pavel; Denizli, Haluk; Dennis, Lawrence; Deur, Alexandre; Dhamija, Seema; Dharmawardane, Kahanawita; Dhuga, Kalvir; Dickson, Richard; Didelez, Jean-Pierre; Djalali, Chaden; Dodge, Gail; Doughty, David; Dugger, Michael; Dytman, Steven; Dzyubak, Oleksandr; Egiyan, Hovanes; Egiyan, Kim; Elfassi, Lamiaa; Elouadrhiri, Latifa; Eugenio, Paul; Fatemi, Renee; Fedotov, Gleb; Fersch, Robert; Feuerbach, Robert; Forest, Tony; Fradi, Ahmed; Gavalian, Gagik; Gevorgyan, Nerses; Gilfoyle, Gerard; Giovanetti, Kevin; Girod, Francois-Xavier; Goetz, John; Gohn, Wesley; Gordon, Christopher; Gothe, Ralf; Graham, Lewis; Griffioen, Keith; Guillo, Matthieu; Guler, Nevzat; Guo, Lei; Gyurjyan, Vardan; Hadjidakis, Cynthia; Hafidi, Kawtar; Hakobyan, Hayk; Hanretty, Charles; Hardie, John; Hassall, Neil; Heddle, David; Hersman, F.; Hicks, Kenneth; Hleiqawi, Ishaq; Holtrop, Maurik; Hourany, E.; Hyde, Charles; Ilieva, Yordanka; Ireland, David; Ishkhanov, Boris; Isupov, Evgeny; Ito, Mark; Jenkins, David; Jo, Hyon-Suk; Johnstone, John; Joo, Kyungseon; Juengst, Henry; Kalantarians, Narbe; Keller, Dustin; Kellie, James; Khandaker, Mahbubul; Khetarpal, Puneet; Kim, Wooyoung; Klein, Andreas; Klein, Franz; Klimenko, Alexei; Kossov, Mikhail; Kramer, Laird; Kubarovsky, Valery; Kuhn, Joachim; Kuhn, Sebastian; Kuleshov, Sergey; Kuznetsov, Viacheslav; Lachniet, Jeff; Langheinrich, Jorn; Lawrence, Dave; Li, Ji; Livingston, Kenneth; Lu, Haiyun; MacCormick, Marion; Marchand, Claude; Markov, Nikolai; Mattione, Paul; McAleer, Simeon; McCracken, Michael; McKinnon, Bryan; McNabb, John; Mecking, Bernhard; Mehrabyan, Surik; Melone, Joseph; Mestayer, Mac; Meyer, Curtis; Mibe, Tsutomu; Mikhaylov, Konstantin; Minehart, Ralph; Mirazita, Marco; Miskimen, Rory; Mokeev, Viktor; Morand, Ludyvine; Moreno, Brahim; Moriya, Kei; Moteabbed, Maryam; Mueller, James; Munevar Espitia, Edwin; Mutchler, Gordon; Nadel-Turonski, Pawel; Nasseripour, Rakhsha; Niccolai, Silvia; Niculescu, Gabriel; Niculescu, Maria-Ioana; Niczyporuk, Bogdan; Niroula, Megh; Niyazov, Rustam; Nozar, Mina; O'Rielly, Grant; Osipenko, Mikhail; Ostrovidov, Alexander; Park, Kijun; Park, Sungkyun; Pasyuk, Evgueni; Paterson, Craig; Pereira, S.Anefalos; Philips, Sasha; Pierce, Joshua; Pivnyuk, Nikolay; Pocanic, Dinko; Pogorelko, Oleg; Polli, Ermanno; Popa, Iulian; Pozdnyakov, Sergey; Preedom, Barry; Price, John; Procureur, Sebastien; Prok, Yelena; Protopopescu, Dan; Qin, Liming; Raue, Brian; Riccardi, Gregory; Ricco, Giovanni; Ripani, Marco; Ritchie, Barry; Rosner, Guenther; Rossi, Patrizia; Rubin, Philip; Sabatie, Franck; Saini, Mukesh; Salamanca, Julian; Salgado, Carlos; Santoro, Joseph; Sapunenko, Vladimir; Schott, Diane; Schumacher, Reinhard; Serov, Vladimir; Sharabian, Youri; Sharov, Dmitri; Shvedunov, Nikolay; Skabelin, Alexander; Smith, Lee; Sober, Daniel; Sokhan, Daria; Stavinskiy, Aleksey; Stepanyan, Samuel; Stepanyan, Stepan; Stokes, Burnham; Stoler, Paul; Strakovski, Igor; Strauch, Steffen; Taiuti, Mauro

    2009-01-01

    The $e p\\to e^\\prime p \\rho^0$ reaction has been measured, using the 5.754 GeV electron beam of Jefferson Lab and the CLAS detector. This represents the largest ever set of data for this reaction in the valence region. Integrated and differential cross sections are presented. The $W$, $Q^2$ and $t$ dependences of the cross section are compared to theoretical calculations based on $t$-channel meson-exchange Regge theory on the one hand and on quark handbag diagrams related to Generalized Parton Distributions (GPDs) on the other hand. The Regge approach can describe at the $\\approx$ 30% level most of the features of the present data while the two GPD calculations that are presented in this article which succesfully reproduce the high energy data strongly underestimate the present data. The question is then raised whether this discrepancy originates from an incomplete or inexact way of modelling the GPDs or the associated hard scattering amplitude or whether the GPD formalism is simply in

  6. Exclusive electroproduction of strange mesons with JLab 12 GeV

    SciTech Connect

    Strikman, Mark; Weiss, Christian

    2009-01-01

    We summarize the physics topics which can be addressed by measurements of high-Q^2 exclusive electroproduction of strange mesons, gamma* N -> phi N, K* Lambda, K Lambda, K Sigma, at Jefferson Lab with 11 GeV beam energy. The proposed investigations are aimed both at exploring the reaction mechanism (dominance of point-like configurations) and extracting information about baryon structure from the data (generalized parton distributions, or GPDs). They include (a) probing the t-dependence of the nucleon's gluon GPD (transverse spatial distribution of gluons) in phi meson production; (b) separating the nucleon helicity-flip and nonflip quark GPDs in K* Lambda production with measurement of the Lambda recoil polarization; (c) probing strangeness polarization in the nucleon in K Lambda and K Sigma production. These studies rely only on the analysis of cross section ratios, which are less affected by the theoretical uncertainties of present GPD-based calculations than absolute cross sect

  7. Single and double polarization asymmetries from deeply virtual exclusive pi^0 electroproduction

    SciTech Connect

    Kim, Andrey; Avakian, Harut A.; Burkert, Volker D.

    2014-10-01

    The target and double spin asymmetry measurements of exclusive p0 electroproduction were performed for the first time in DIS region at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS) and longitudinally polarized proton target. The wide kinematic coverage and good resolution of CLAS allowed measurements in full azimuthal range providing an opportunity to extract single and double spin asymmetries proportional to polarized structure functions. Their angular dependencies in hadronic center-of-mass system were analyzed, and extracted moments are compared to recent theoretical handbag-based calculations based on chiral-even and chiral-odd GPDs contributions. The interpretation of present results within the framework of the modified perturbative approach and their use as a constraint for models of the t behavior will be discussed.

  8. Exclusive pi^0 electroproduction at W > 2 GeV with CLAS

    SciTech Connect

    Bedlinskiy, I; Kubarovsky, V; Niccolai, S; Stoler, P; Adhikari, K P; Anderson, M D; Pereira, S Anefalos; Avakian, H; Ball, J; Baltzell, N A; Battaglieri, M; Batourine, V; Biselli, A S; Boiarinov, S; Bono, J; Briscoe, W J; Brooks, W K; Burkert, V D; Carman, D S; Celentano, A; Chandavar, S; Colaneri, L; Cole, P L; Contalbrigo, M; Cortes, O; Crede, V; D'Angelo, A; Dashyan, N; De Vita, R; De Sanctis, E; Deur, A; Djalali, C; Doughty, D; Dupre, R; Egiyan, H; El Alaoui, A; El Fassi, L; Elouadrhiri, L; Eugenio, P; Fedotov, G; Fegan, S; Fleming, J A; Forest, T A; Garillon, B; Garcon, M; Gavalian, G; Gevorgyan, N; Ghandilyan, Y; Gilfoyle, G P; Giovanetti, K L; Girod, F X; Golovatch, E; Gothe, R W; Griffioen, K A; Guegan, B; Guo, L; Hafidi, K; Hakobyan, H; Harrison, N; Hattawy, M; Hicks, K; Holtrop, M; Ireland, D G; Ishkhanov, B S; Isupov, E L; Jenkins, D; Jo, H S; Joo, K; Keller, D; Khandaker, M; Kim, A; Kim, W; Klein, A; Klein, F J; Koirala, S; Kuhn, S E; Kuleshov, S V; Lenisa, P; Levine, W I; Livingston, K; Lu, H Y; MacGregor, I J.D.; Markov, N; Mayer, M; McKinnon, B; Mirazita, M; Mokeev, V; Montgomery, R A; Moody, C I; Moutarde, H; Movsisyan, A; Munoz Camacho, C; Nadel-Turonski, P; Niculescu, I; Osipenko, M; Ostrovidov, A I; Pappalardo, L L; Park, K; Park, S; Pasyuk, E; Phelps, E; Phelps, W; Phillips, J J; Pisano, S; Pogorelko, O; Price, J W; Prok, Y; Protopopescu, D; Procureur, S; Puckett, A J.R.; Raue, B A; Ripani, M; Ritchie, B G; Rizzo, A; Rossi, P; Roy, P; Sabatié, F; Salgado, C; Schott, D; Schumacher, R A; Seder, E; Senderovich, I; Sharabian, Y G; Simonyan, A; Smith, G D; Sober, D I; Sokhan, D; Stepanyan, S S; Strauch, S; Sytnik, V; Tang, W; Tian, Ye; Ungaro, M; Vlassov, A V; Voskanyan, H; Voutier, E; Walford, N K; Watts, D; Wei, X; Weinstein, L B; Yurov, M; Zachariou, N; Zana, L; Zhang, J; Zhao, Z W; Zonta, I

    2014-08-01

    Exclusive neutral-pion electroproduction (ep-->e'p'pi0) was measured at Jefferson Lab with a 5.75-GeV electron beam and the CLAS detector. Differential cross sections d4sigma/dtdQ2dxBdphipi and structure functions sigmaT+epsilonsigmaL,sigmaTT and σLT as functions of t were obtained over a wide range of Q2 and xB. The data are compared with Regge and handbag theoretical calculations. Analyses in both frameworks find that a large dominance of transverse processes is necessary to explain the experimental results. For the Regge analysis it is found that the inclusion of vector meson rescattering processes is necessary to bring the magnitude of the calculated and measured structure functions into rough agreement. In the handbag framework, there are two independent calculations, both of which appear to roughly explain the magnitude of the structure functions in terms of transversity generalized parton distributions.

  9. Exclusive, Hard Diffraction in QCD

    NASA Astrophysics Data System (ADS)

    Freund, Andreas

    1999-03-01

    In the first chapter we give an introduction to hard diffractive scattering in QCD to introduce basic concepts and terminology. In the second chapter we make predictions for the evolution of skewed parton distributions in a proton in the LLA. We calculate the DGLAP-type evolution kernels in the LLA and solve the skewed GLAP evolution equations with a modified version of the CTEQ-package. In the third chapter, we discuss the algorithms used in the LO evolution program for skewed parton distributions in the DGLAP region, discuss the stability of the code and reproduce the LO diagonal evolution within less than 0.5% of the original CTEQ-code. In chapter 4, we show that factorization holds for the deeply virtual Compton scattering amplitude in QCD, up to power suppressed terms, to all orders in perturbation theory. In chapter 5, we demonstrate that perturbative QCD allows one to calculate the absolute cross section of diffractive, exclusive production of photons (DVCS) at large Q^2 at HERA, while the aligned jet model allows one to estimate the cross section for intermediate Q^2 ˜ 2 GeV^2. We find a significant DVCS counting rate for the current generation of experiments at HERA and a large azimuthal angle asymmetry for HERA kinematics. In the last chapter, we propose a new methodology of gaining shape fits to skewed parton distributions and, for the first time, to determine the ratio of the real to imaginary part of the DIS amplitude. We do this by using several recent fits to F_2(x,Q^2) to compute the asymmetry A for the combined DVCS and Bethe-Heitler cross section. In the appendix, we give an application of distributional methods as discussed abstractly in chapter 4.

  10. Separated response functions in exclusive, forward π± electroproduction on deuterium

    NASA Astrophysics Data System (ADS)

    Huber, G. M.; Blok, H. P.; Butuceanu, C.; Gaskell, D.; Horn, T.; Mack, D. J.; Abbott, D.; Aniol, K.; Anklin, H.; Armstrong, C.; Arrington, J.; Assamagan, K.; Avery, S.; Baker, O. K.; Barrett, B.; Beise, E. J.; Bochna, C.; Boeglin, W.; Brash, E. J.; Breuer, H.; Chang, C. C.; Chant, N.; Christy, M. E.; Dunne, J.; Eden, T.; Ent, R.; Fenker, H.; Gibson, E. F.; Gilman, R.; Gustafsson, K.; Hinton, W.; Holt, R. J.; Jackson, H.; Jin, S.; Jones, M. K.; Keppel, C. E.; Kim, P. H.; Kim, W.; King, P. M.; Klein, A.; Koltenuk, D.; Kovaltchouk, V.; Liang, M.; Liu, J.; Lolos, G. J.; Lung, A.; Margaziotis, D. J.; Markowitz, P.; Matsumura, A.; McKee, D.; Meekins, D.; Mitchell, J.; Miyoshi, T.; Mkrtchyan, H.; Mueller, B.; Niculescu, G.; Niculescu, I.; Okayasu, Y.; Pentchev, L.; Perdrisat, C.; Pitz, D.; Potterveld, D.; Punjabi, V.; Qin, L. M.; Reimer, P. E.; Reinhold, J.; Roche, J.; Roos, P. G.; Sarty, A.; Shin, I. K.; Smith, G. R.; Stepanyan, S.; Tang, L. G.; Tadevosyan, V.; Tvaskis, V.; van der Meer, R. L. J.; Vansyoc, K.; Van Westrum, D.; Vidakovic, S.; Volmer, J.; Vulcan, W.; Warren, G.; Wood, S. A.; Xu, C.; Yan, C.; Zhao, W.-X.; Zheng, X.; Zihlmann, B.; Jefferson Lab Fπ Collaboration

    2015-01-01

    Background: Measurements of forward exclusive meson production at different squared four-momenta of the exchanged virtual photon, Q2, and at different four-momentum transfer, t , can be used to probe QCD's transition from meson-nucleon degrees of freedom at long distances to quark-gluon degrees of freedom at short scales. Ratios of separated response functions in π- and π+ electroproduction are particularly informative. The ratio for transverse photons may allow this transition to be more easily observed, while the ratio for longitudinal photons provides a crucial verification of the assumed pole dominance, needed for reliable extraction of the pion form factor from electroproduction data. Purpose: We perform the first complete separation of the four unpolarized electromagnetic structure functions L /T /L T /T T in forward, exclusive π± electroproduction on deuterium above the dominant resonances. Method: Data were acquired with 2.6-5.2-GeV electron beams and the HMS +SOS spectrometers in Jefferson Lab Hall C at central Q2 values of 0.6, 1.0, and 1.6 GeV2 at W =1.95 GeV, and Q2=2.45 GeV2 at W =2.22 GeV. There was significant coverage in ϕ and ɛ , which allowed separation of σL ,T ,L T ,T T. Results: σL shows a clear signature of the pion pole, with a sharp rise at small -t . In contrast, σT is much flatter versus t . The longitudinal/transverse ratios evolve with Q2 and t and at the highest Q2=2.45 GeV2 show a slight enhancement for π- production compared to π+. The π-/π+ ratio for transverse photons exhibits only a small Q2 dependence, following a nearly universal curve with t , with a steep transition to a value of about 0.25, consistent with s -channel quark knockout. The σT T/σT ratio also drops rapidly with Q2, qualitatively consistent with s -channel helicity conservation. The π-/π+ ratio for longitudinal photons indicates a small isoscalar contamination at W =1.95 GeV, consistent with what was observed in our earlier determination of the

  11. Exclusive, hard diffraction in QCD

    NASA Astrophysics Data System (ADS)

    Freund, Andreas

    In the first chapter we give an introduction to hard diffractive scattering in QCD to introduce basic concepts and terminology, thus setting the stage for the following chapters. In the second chapter we make predictions for nondiagonal parton distributions in a proton in the LLA. We calculate the DGLAP-type evolution kernels in the LLA, solve the nondiagonal GLAP evolution equations with a modified version of the CTEQ-package and comment on the range of applicability of the LLA in the asymmetric regime. We show that the nondiagonal gluon distribution g(x1,x2,t,μ2) can be well approximated at small x by the conventional gluon density xG(x,μ2). In the third chapter, we discuss the algorithms used in the LO evolution program for nondiagonal parton distributions in the DGLAP region and discuss the stability of the code. Furthermore, we demonstrate that we can reproduce the case of the LO diagonal evolution within less than 0.5% of the original code as developed by the CTEQ-collaboration. In chapter 4, we show that factorization holds for the deeply virtual Compton scattering amplitude in QCD, up to power suppressed terms, to all orders in perturbation theory. Furthermore, we show that the virtuality of the produced photon does not influence the general theorem. In chapter 5, we demonstrate that perturbative QCD allows one to calculate the absolute cross section of diffractive exclusive production of photons at large Q2 at HERA, while the aligned jet model allows one to estimate the cross section for intermediate Q2~2GeV2. Furthermore, we find that the imaginary part of the amplitude for the production of real photons is larger than the imaginary part of the corresponding DIS amplitude, leading to predictions of a significant counting rate for the current generation of experiments at HERA. We also find a large azimuthal angle asymmetry in ep scattering for HERA kinematics which allows one to directly measure the real part of the DVCS amplitude and hence the

  12. Exclusive pπ+π- electroproduction in the resonance region at high Q2

    NASA Astrophysics Data System (ADS)

    Isupov, Evgeny; Burkert, Volker; Mokeev, Victor

    2013-10-01

    We report on the analysis of charged 2-pion electroproduction in the kinematical region of nucleon resonances. The data were taken with a 5 . 75 GeV continuous electron beam at Jefferson Lab impinging on a liquid hydrogen target to measure the process ep --> epπ+π- . Scattered electrons and at least two of the final state hadrons were detected in the CEBAF Large Acceptance Spectrometer (CLAS), and the fully exclusive process was determined using kinematical constraints from the over-determined reaction. The data were used to measure nine differential cross sections and the fully integrated cross section in the invariant mass range of the hadronic final state from 1 . 4 to 2 . 0 and at photon virtualities 2 . 0

  13. Deep exclusive {pi}{sup +} electroproduction off the proton at CLAS

    SciTech Connect

    Park, Kijun; Gothe, Ralf; Guidal, Michel; Laget, Jean; Adhikari, K P; Bennet, R P; Biselli, A S; Chandavar, S; MacGregor, I. J. D; Munoz Camacho, C; Anefalos-Pereira, S; Rimal, D; Tang, W

    2013-01-01

    The exclusive electroproduction of {pi}{sup +} above the resonance region was studied using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Laboratory by scattering a 6 GeV continuous electron beam off a hydrogen target. The large acceptance and good resolution of CLAS, together with the high luminosity, allowed us to measure the cross section for the {gamma}* p {yields} n {pi}{sup +} process in 140 (Q{sup 2}, x{sub B}, t) bins: 0.16

  14. Observation of a Coherence Length Effect in Exclusive {rho}{sup 0} Electroproduction

    SciTech Connect

    Galumian, P.; Green, P.W.; Greeniaus, L.G.; Kitching, P.; Martens, F.K.; Miller, C.A.; Gao, H.; Hansen, J.; Jackson, H.E.; Jones, C.; Makins, N.C.; ONeill, T.G.; Potterveld, D.H.; Bray, B.; Carter, P.; Dvoredsky, A.; Filippone, B.W.; Korsch, W.; Lung, A.; McIlhany, K.; McKeown, R.D.; Pitt, M.; Belz, J.E.; Brack, J.; Ely, J.; Fox, B.; Kinney, E.; Mercer, D.; Rakness, G.; Ristinen, R.; Ackerstaff, K.; Funk, M.; Holler, Y.; Ihssen, H.; Meyners, N.; Roeper, G.; Schueler, K.P.; Sinram, K.; Spengos, M.; Woller, K.; Zapfe-Dueren, K.; Akushevich, I.; Aschenauer, E.C.; Boettcher, H.; Borissov, A.; Brons, S.; Gaerber, Y.; Hasch, D.; Korotkov, V.; Krause, B.; Meissner, F.; Nowak, W.; Roloff, H.; Schwind, A.; Stoesslein, U.; Fechtchenko, A.; Gagunashvili, N.D.; Krivokhijine, V.G.; Mitsyn, V.; Nagaitsev, A.; Savin, I.; Shutov, V.; Benisch, T.; Bernreuther, S.; Braun, B.; Dueren, M.; Ferstl, M.; Fiedler, K.; Grosshauser, C.; Gute, A.; Henoch, M.; Kirsch, M.; Lachnit, W.; Neunreither, F.; Rith, K.; Schmidt, F.; Steffens, E.; Stenger, J.; Stock, F.; Wander, W.; Woelfel, T.; Dalpiaz, P.F.; Frabetti, S.; Masoli, F.; Reali, A.; Simani, C.; Slavich, P.; Avakian, H.; Bianchi, N.; Capitani, G.P.; De Sanctis, E.; Di Nezza, P.; Fantoni, A.; Giordjian, V.; Gyurjyan, V.; and others

    1999-04-01

    Exclusive incoherent electroproduction of the {rho}{sup 0}{number_sign}770 meson from {sup 1}H , {number_sign}{sup 2}H , {number_sign}{sup 3}He , and {number_sign}{sup 14}N targets has been studied by the HERMES experiment at squared four-momentum transfer Q{sup 2}{gt}0.4 GeV{sup 2} and positron energy loss {nu} from 9 to 20 GeV. The ratio of the {number_sign}{sup 14}N to {number_sign}{sup 1}H cross sections per nucleon, known as the nuclear transparency, was found to decrease with increasing coherence length of quark-antiquark fluctuations of the virtual photon. The data provide clear evidence of the interaction of the quark-antiquark fluctuations with the nuclear medium. {copyright} {ital 1999} {ital The American Physical Society}

  15. Nucleon Resonance Electrocouplings from the CLAS Data on Exclusive Meson Electroproduction off Protons

    SciTech Connect

    Victor I. Mokeev, Inna G. Aznauryan, Volker D. Burkert

    2011-12-01

    {gamma}{sub v}NN* transition helicity amplitudes (electrocouplings) of several prominent excited proton states are determined for the first time in independent analyses of {pi}{sup +}n, {pi}{sup 0}p, and {pi}{sup +}{pi}{sup -}p electroproduction off protons. Consistent results on resonance electrocouplings obtained from major meson electroproduction channels offer an evidence for reliable extraction of these fundamental quantities. Analysis of {pi}{sup +}{pi}{sup -}p electroproduction has extended considerably information on electrocouplings of high lying N* states, which decay preferentially to the N{pi}{pi} final states.

  16. Separated response functions in exclusive, forward π± electroproduction on deuterium

    DOE PAGESBeta

    Huber, G. M.; Blok, H. P.; Butuceanu, C.; Gaskell, D.; Horn, T.; Mack, D. J.; Abbott, D.; Aniol, K.; Anklin, H.; Armstrong, C.; et al

    2015-01-07

    Background: Measurements of forward exclusive meson production at different squared four-momenta of the exchanged virtual photon, Q2, and at different four-momentum transfer, t, can be used to probe QCD's transition from meson-nucleon degrees of freedom at long distances to quark-gluon degrees of freedom at short scales. Ratios of separated response functions in π⁻ and π⁺ electroproduction are particularly informative. Ratio for transverse photons may allow this transition to be more easily observed, while the ratio for longitudinal photons provides a crucial verification of the assumed pole dominance, needed for reliable extraction of the pion form factor from electroproduction data. Method:more » Data were acquired with 2.6-5.2 GeV electron beams and the HMS+SOS spectrometers in Jefferson Lab Hall C, at central Q2 values of 0.6, 1.0, 1.6 GeV2 at W=1.95 GeV, and Q2=2.45 GeV2 at W=2.22 GeV. There was significant coverage in Φ And ϵ, which allowed separation of σL,T,LT,TT. Results: σL shows a clear signature of the pion pole, with a sharp rise at small -t. In contrast, σT is much flatter versus t. The longitudinal/transverse ratios evolve with Q2 and t, and at the highest Q2=2.45 GeV2 show a slight enhancement for π⁻ Production compared to π⁺. The π⁻/π⁺+ ratio for transverse photons exhibits only a small Q2-dependence, following a nearly universal curve with t, with a steep transition to a value of about 0.25, consistent with s-channel quark knockout. The σTT/σT ratio also drops rapidly with Q2, qualitatively consistent with s-channel helicity conservation. The π⁻/π⁺ ratio for longitudinal photons indicates a small isoscalar contamination at W=1.95 GeV, consistent with what was observed in our earlier determination of the pion form factor at these kinematics.« less

  17. Separated Structure Functions for the Exclusive Electroproduction of K+Lambda and K+Sigma0 Final States

    SciTech Connect

    Pawel Ambrozewicz; Daniel Carman; Rob Feuerbach; Mac Mestayer; Brian Raue; Reinhard Schumacher; Avtandil Tkabladze

    2006-11-19

    We report measurements of the exclusive electroproduction of K{sup +}{Lambda} and K{sup +}{Sigma}{sup 0} final states from a proton target using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The separated structure functions {sigma}{sub T}, {sigma}{sub L},{sigma}{sub TT}, and {sigma}{sub LT} were extracted from the {Phi}- and {epsilon}-dependent differential cross sections taken with electron beam energies of 2.567, 4.056, and 4.247 GeV. This analysis represents the first {sigma}{sub L}/{sigma}{sub T} separation with the CLAS detector, and the first measurement of the kaon electroproduction structure functions away from parallel kinematics. The data span a broad range of momentum transfers from 0.5 {le} Q{sup 2} {le} 2.8 GeV{sup 2} and invariant energy from 1.6 {le} W {le} 2.4 GeV, while spanning nearly the full center-of-mass angular range of the kaon. The separated structure functions reveal clear differences between the production dynamics for the {Lambda} and {Sigma}{sup 0} hyperons. These results provide an unprecedented data sample with which to constrain current and future models for the associated production of strangeness, which will allow for a better understanding of the underlying resonant and non-resonant contributions to hyperon production.

  18. Separated Response Function Ratios in Exclusive, Forward π± Electroproduction

    SciTech Connect

    Huber, G. M.; Blok, H. P.; Butuceanu, C.; Gaskell, D.; Horn, T.; Mack, D. J.; Abbott, D.; Aniol, K.; Anklin, H.; Armstrong, C.; Arrington, J.; Assamagan, K.; Avery, S.; Baker, O. K.; Barrett, B.; Beise, E. J.; Bochna, C.; Boeglin, W.; Brash, E. J.; Breuer, H.; Chang, C. C.; Chant, N.; Christy, M. E.; Dunne, J.; Eden, T.; Ent, R.; Fenker, H.; Gibson, E. F.; Gilman, R.; Gustafsson, K.; Hinton, W.; Holt, R. J.; Jackson, H.; Jin, S.; Jones, M. K.; Keppel, C. E.; Kim, P. H.; Kim, W.; King, P. M.; Klein, A.; Koltenuk, D.; Kovaltchouk, V.; Liang, M.; Liu, J.; Lolos, G. J.; Lung, A.; Margaziotis, D. J.; Markowitz, P.; Matsumura, A.; McKee, D.; Meekins, D.; Mitchell, J.; Miyoshi, T.; Mkrtchyan, H.; Mueller, B.; Niculescu, G.; Niculescu, I.; Okayasu, Y.; Pentchev, L.; Perdrisat, C.; Pitz, D.; Potterveld, D.; Punjabi, V.; Qin, L. M.; Reimer, P. E.; Reinhold, J.; Roche, J.; Roos, P. G.; Sarty, A.; Shin, I. K.; Smith, G. R.; Stepanyan, S.; Tang, L. G.; Tadevosyan, V.; Tvaskis, V.; van der Meer, R. L. J.; Vansyoc, K.; Van Westrum, D.; Vidakovic, S.; Volmer, J.; Vulcan, W.; Warren, G.; Wood, S. A.; Xu, C.; Yan, C.; Zhao, W. -X.; Zheng, X.; Zihlmann, B.

    2014-05-01

    The study of exclusive π{sup ±} electroproduction on the nucleon, including separation of the various structure functions, is of interest for a number of reasons. The ratio R{sub L}=σ{sup π{sup -}}{sub L}/σ{sup π{sup +}}{sub L} is sensitive to isoscalar contamination to the dominant isovector pion exchange amplitude, which is the basis for the determination of the charged pion form factor from electroproduction data. A change in the value of R{sub T}=σ{sup π{sup -}}{sub T}/σ{sup π{sup +}}{sub T} from unity at small -t, to 1/4 at large -t, would suggest a transition from coupling to a (virtual) pion to coupling to individual quarks. Furthermore, the mentioned ratios may show an earlier approach to pQCD than the individual cross sections. We have performed the first complete separation of the four unpolarized electromagnetic structure functions above the dominant resonances in forward, exclusive π± electroproduction on the deuteron at central Q{sup 2} values of 0.6, 1.0, 1.6 GeV{sup 2} at W=1.95 GeV, and Q{sup 2}=2.45 GeV{sup 2} at W=2.22 GeV. Here, we present the L and T cross sections, with emphasis on R{sub L} and R{sub T}, and compare them with theoretical calculations. Results for the separated ratio RL indicate dominance of the pion-pole diagram at low -t, while results for R{sub T} are consistent with a transition between pion knockout and quark knockout mechanisms.

  19. Exclusive single pion electroproduction off the proton in the high-lying resonances at Q2 < 5 GeV2 from CLAS

    SciTech Connect

    Park, Kijun

    2014-09-01

    The differential cross sections and structure functions for the exclusive electroproduction process ep --> e'n pi+ were measured in the range of the invariantmass for the np+ system 1.6 GeV lte W lte 2.0 GeV, and the photon virtuality 1.8 GeV2 lte Q2 lte 4.0 GeV2 using CLAS at Jefferson Lab. For the first time, these kinematics are probed in the exclusive p+ production from the protons with nearly full coverage in the azimuthal and polar angles of the np+ center-of-mass system. In this analysis, approximately 39,000 differential cross-section data points in terms of W, Q2, cosq theta* _ pi, and phi*_p-, were obtained. The preliminary differential cross section and structure function analyses are carried out, which allow us to extract the helicity amplitudes in high-lying resonances.

  20. Some news about GPDs and hard exclusive processes

    NASA Astrophysics Data System (ADS)

    Kumerički, K.; Mueller, D.

    2015-04-01

    We report on some new theoretical results for the representation of generalized parton distributions (GPDs), the understanding of next-to-leading order corrections to hard exclusive processes, the calculation of higher twist corrections to deeply virtual Compton scattering, and the progress in describing experimental measurements in terms of GPD models.

  1. QED radiative effects in the processes of exclusive photon electroproduction from polarized protons with the next-to-leading accuracy

    SciTech Connect

    Akushevich, Igor V.; Ilyichev, Alexander; Shumeiko, Nikolai M

    2014-08-01

    Radiative effects in the electroproduction of photons in polarized ep-scattering are calculated with the next-to-leading (NLO) accuracy. The contributions of loops and two photon emission were presented in analytical form. The covariant approach of Bardin and Shumeiko was used to extract the infrared divergence. All contributions to the radiative correction were presented in the form of the correction to the leptonic tensor thus allowing for further applications in other experiments, e.g., deep inelastic scattering. The radiative corrections (RC) to the cross sections and polarization asymmetries were analyzed numerically for kinematical conditions of the current measurement at Jefferson Lab. Specific attention was paid on analyzing kinematical conditions for the process with large radiative effect when momenta of two photons in the final state are collinear to momenta of initial and final electrons, respectively.

  2. Target and beam-target spin asymmetries in exclusive π+ and π– electroproduction with 1.6- to 5.7-GeV electrons

    DOE PAGESBeta

    Bosted, P. E.; Biselli, A. S.; Careccia, S.; Dodge, G.; Fersch, R.; Guler, N.; Kuhn, S. E.; Pierce, J.; Prok, Y.; Zheng, X.; et al

    2016-11-01

    Here, beam-target double-spin asymmetries and target single-spin asymmetries in exclusive π+ and quasiexclusive π– electroproduction were obtained from scattering of 1.6- to 5.7-GeV longitudinally polarized electrons from longitudinally polarized protons (for π+) and deuterons (for π–) using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The kinematic range covered is 1.1 < W < 2.6 GeV and 0.05 < Q2 < 5GeV2, with good angular coverage in the forward hemisphere. The asymmetry results were divided into approximately 40 000 kinematic bins for π+ from free protons and 15 000 bins for π– production from bound nucleons in the deuteron.more » The present results are found to be in reasonable agreement with fits to previous world data for W < 1.7 GeV and Q2 < 0.5GeV2, with discrepancies increasing at higher values of Q2, especially for W > 1.5 GeV. Very large target-spin asymmetries are observed for W > 1.6 GeV. When combined with cross-section measurements, the present results can provide powerful constraints on nucleon resonance amplitudes at moderate and large values of Q2, for resonances with masses as high as 2.3 GeV.« less

  3. Kaon electroproduction

    SciTech Connect

    Markowitz, P.

    1994-04-01

    The talk will focus on the physics which can be addressed by looking at semi-inclusive and exclusive channels in the DIS region. In particular, the author examines how this physics is reflected in the separated response functions.

  4. Investigating of the exclusive reaction of π⁺π⁻ pair electroproduction on a proton bound in a deuteron

    SciTech Connect

    Skorodumina, Yu. A.; Golovach, Evgeny N.; Gothe, Ralf W.; Ishkhanov, Boris S.; Isupov, Evgeny L.; Mokeev, Viktor I.; Fedotov, Gleb V.

    2015-04-01

    Preliminary results from analyzing π⁺π⁻ pair electroproduction on a proton bound in a deuteron are presented. Procedures for considering the Fermi motion of the initial proton in the deuteron and assessing the effects of interaction in the final states are developed. The yield of the reaction ep(n) → e'p'(n')π⁺π⁻ is obtained for the first time.

  5. Interplay of Hard and Soft Processes at JLAB Energies

    SciTech Connect

    Andrei Afanasev; Carl E. Carlson

    2002-07-01

    Even at moderate energy machines, there is a regime where hard pion electroproduction proceeds by a perturbatively calculable process. The process, we claim, is not the leading twist fragmentation one but a rather higher twist process that produces kinematically isolated pions. Semiexclusive data may teach us more about parton distribution functions of the target and the pion distribution amplitude. In addition, there is a connection to generalized parton distribution calculations of exclusive processes in that the perturbative kernel is the same.

  6. Hard Pomeron in Exclusive Meson Production at ILC

    NASA Astrophysics Data System (ADS)

    Enberg, R.; Pire, B.; Szymanowski, L.; Wallon, S.

    2006-03-01

    We calculate the exclusive process gamma *L (Q12)gamma *L(Q22) to rho 0L rho 0L, at high energy. The Born level estimate and the leading (LLA) and next to leading order (NLLA) BFKL resummation effects show the feasibility of experimental detection in a quite large range of Q2 values at future high energy e+e- linear colliders ILC.

  7. Imaging the proton via hard exclusive production in diffractive pp scattering

    SciTech Connect

    Charles Hyde; Leonid Frankfurt; Mark Strikman; Christian Weiss

    2007-05-21

    We discuss the prospects for probing Generalized Parton Distributions (GPDs) via exclusive production of a high-mass system (H = heavy quarkonium, di-photon, di-jet, Higgs boson) in diffractive pp scattering, pp -> p + H + p. In such processes the interplay of hard and soft interactions gives rise to a diffraction pattern in the final-state proton transverse momenta, which is sensitive to the transverse spatial distribution of partons in the colliding protons. We comment on the plans for diffractive pp measurements at RHIC and LHC. Such studies could complement future measurements of GPDs in hard exclusive ep scattering (JLab, COMPASS, EIC).

  8. Measurement of the N --> Delta^+ (1232) Transition at High-Momentum Transfer by pi^0 Electroproduction

    SciTech Connect

    M. Ungaro; P. Stoler; I. Aznauryan; V. D. Burkert; K. Joo; L. C. Smith; G. Adams; M. Amarian; P. Ambrozewicz; M. Anghinolfi; G. Asryan; G. Audit; H. Avakian; H. Bagdasaryan; J. P. Ball; N. A. Baltzell; S. Barrow; V. Batourine; M. Battaglieri; I. Bedliski; M. Bektasoglu; M. Bellis; N. Benmouna; B. L. Berman; A. S. Biselli; B. E. Bonner; S. Bouchigny; S. Boiarinov; R. Bradford; D. Branford; W. J. Briscoe; W. K. Brooks; S. Bültmann; C. Butuceanu; J. R. Calarco; S. L. Careccia; D. S. Carman; A. Cazes; S. Chen; P. L. Cole; P. Coltharp; D. Cords; P. Corvisiero; D. Crabb; J. P. Cummings; E. De Sanctis; R. DeVita; P. V. Degtyarenko; H. Denizli; L. Dennis; A. Deur; K. V. Dharmawardane; C. Djalali; G. E. Dodge; J. Donnelly; D. Doughty; M. Dugger; S. Dytman; O. P. Dzyubak; H. Egiyan; K. S. Egiyan; L. Elouadrhiri; P. Eugenio; R. Fatemi; G. Fedotov; G. Feldman; R. J. Feuerbach; H. Funsten; M. Garçon; G. Gavalian; G. P. Gilfoyle; K. L. Giovanetti; F. X. Girod; J. Goetz; C. I. O. Gordon; R. W. Gothe; K. A. Griffioen; M. Guidal; M. Guillo; N. Guler; L. Guo; V. Gyurjyan; C. Hadjidakis; R. S. Hakobyan; J. Hardie; D. Heddle; F. W. Hersman; I. Hleiqawi; M. Holtrop; K. Hicks; C. E. Hyde-Wright; Y. Ilieva; D. G. Ireland; B. S. Ishkhanov; M. M. Ito; D. Jenkins; H. S. Jo; H. G. Juengst; J. D. Kellie; M. Khandaker; W. Kim; A. Klein; F. J. Klein; A. V. Klimenko; M. Kossov; L. H. Kramer; V. Kubarovsky; J. Kuhn; S. E. Kuhn; J. Lachniet; J. M. Laget; J. Langheinrich; D. Lawrence; T. Lee; Ji Li; K. Livingston; C. Marchand; N. Markov; S. McAleer; B. McKinnon; J. W. C. McNabb; B. A. Mecking; S. Mehrabyan; J. J. Melone; M. D. Mestayer; C. A. Meyer; K. Mikhailov; R. Minehart; M. Mirazita; R. Miskimen; V. Mokeev; L. Morand; S. A. Morrow; J. Mueller; G. S. Mutchler; J. Napolitano; R. Nasseripour; S. Niccolai; G. Niculescu; I. Niculescu; B. B. Niczyporuk; M. Niroula; R. A. Niyazov; M. Nozar; G. V. O'Rielly; M. Osipenko; A. I. Ostrovidov; K. Park; E. Pasyuk; S. A. Philips; N. Pivnyuk; D. Pocanic; O. Pogorelko; E. Polli; S. Pozdniakov; B. M. Preedom; J. W. Price; Y. Prok; D. Protopopescu; L. M. Qin; B. A. Raue; G. Riccardi; G. Ricco; M. Ripani; B. G. Ritchie; F. Ronchetti; G. Rosner; P. Rossi; P. D. Rubin; F. Sabatié; C. Salgado; J. P. Santoro; V. Sapunenko; R. A. Schumacher; V. S. Serov; Y. G. Sharabian; A. V. Skabelin; E. S. Smith; D. I. Sober; A. Stavinsky; S. S. Stepanyan; S. Stepanyan; B. E. Stokes; I. I. Strakovsky; S. Strauch; M. Taiuti; D. J. Tedeschi; U. Thoma; A. Tkabladze; L. Todor; S. Tkachenko; C. Tur; M. F. Vineyard; A. V. Vlassov; L. B. Weinstein; D. P. Weygand; M. Williams; E. Wolin; M. H. Wood; A. Yegneswaran; L. Zana; B. Zhang; J. Zhang; and B. Zhao

    2006-09-01

    We report a new measurement of the exclusive electroproduction reaction gamma*_p --> pi0_p to explore the evolution from soft nonperturbative physics to hard processes via the Q2 dependence of the magnetic (M1+), electric (E1+), and scalar (S1+) multipoles in the N --> Delta transition. 9000 differential cross section data points cover W from threshold to 1.4 GeV/c2, 4pi center-of-mass solid angle, and Q2 from 3 to 6 GeV2/c2, the highest yet achieved. It is found that the magnetic form factor G^*M decreases with Q2 more steeply than the proton magnetic form factor, the ratio E1+/M1+ is small and negative, indicating strong helicity nonconservation, and the ratio S1+/M1+ is negative, while its magnitude increases with Q2.

  9. Electroproduction of Strange Nuclei

    SciTech Connect

    E.V. Hungerford

    2002-06-01

    The advent of high-energy, CW-beams of electrons now allows electro-production and precision studies of nuclei containing hyperons. Previously, the injection of strangeness into a nucleus was accomplished using secondary beams of mesons, where beam quality and target thickness limited the missing mass resolution. We review here the theoretical description of the (e, e'K+) reaction mechanism, and discuss the first experiment demonstrating that this reaction can be used to precisely study the spectra of light hypernuclei. Future experiments based on similar techniques, are expected to attain even better resolutions and rates.

  10. New results from the studies of the Ν (1440) 1/2+, Ν (1520) 3/2–, and Δ (1620) 1/2– resonances in exclusive ep → e'p'π+π– electroproduction with the CLAS detector

    DOE PAGESBeta

    Mokeev, Viktor I.; Burkert, Volker D.; Carman, Daniel S.; Elouadrhiri, Latifa; Fedotov, Gleb V.; Golovatch, Evgeny N.; Gothe, Ralf W.; Hicks, Ken; Ishkhanov, Boris S.; Isupov, Evgeny L.; et al

    2016-02-25

    In this study, the transition helicity amplitudes from the proton ground state to the N(1440)1/2+, N(1520)3/2–, and Δ(1620)1/2– resonances (γvpN* electrocouplings) were determined from the analysis of nine independent onefold differential π+π–p electroproduction cross sections off a proton target, taken with CLAS at photon virtualities 0.5GeV2 < Q2 < 1.5 GeV2. The phenomenological reaction model employed for separation of the resonant and nonresonant contributions to this exclusive channel was further developed.

  11. Studies of semi-inclusive and hard exclusive processes at Jlab

    SciTech Connect

    Harutyun Avagyan

    2008-06-19

    The main goal of experiments proposed for the {\\tt CLAS12} detector in conjunction with the 12-GeV CEBAF accelerator is the study of the nucleon through hard exclusive, semi-inclusive, and inclusive processes. This will provide new insights into nucleon dynamics at the elementary quark and gluon level. In this contribution we provide an overview of ongoing studies of the structure of nucleon in terms of quark and gluon degrees of freedom and future physics program planned with CLAS and {\\tt CLAS12}.

  12. Deeply Pseudoscalar Meson Electroproduction with CLAS and Generalized Parton Distributions

    SciTech Connect

    Guidal, Michel; Kubarovsky, Valery P.

    2015-06-01

    We discuss the recent data of exclusive $\\pi^0$ (and $\\pi^+$) electroproduction on the proton obtained by the CLAS collaboration at Jefferson Lab. It is observed that the cross sections, which have been decomposed in $\\sigma_T+\\epsilon\\sigma_L$, $\\sigma_{TT}$ and $\\sigma_{LT}$ structure functions, are dominated by transverse amplitude contributions. The data can be interpreted in the Generalized Parton Distribution formalism provided that one includes helicity-flip transversity GPDs.

  13. Electroproduction of $Λ$(1405)

    SciTech Connect

    Haiyun Lu, Reinhard Schumacher, Brian Raue, Marianna Gabrielyan

    2012-04-01

    The electroproduction of K{sup +} {Lambda}(1405) was studied by analyzing the E1F data set collected in Hall B at Jefferson Lab. The analysis utilized the decay channel {Sigma}{sup +} {pi}{sup -} of the {Lambda}(1405) and p{pi}{sup 0} of the {Sigma}{sup +}. Simulations of background, {Lambda}(1405) and {Lambda}(1520) production according to PDG values were performed by using standard CLAS analysis tools adapted for the E1F run. Fits of the acceptance-corrected simulations were made to the acceptance-corrected data to determine contributions from signal and background processes. The line shape of {Lambda}(1405) varies with the four momentum transfer, Q{sup 2}, and does not match the line shape based on PDG resonance parameters. It corresponds approximately to predictions of a recent two-pole meson-baryon picture of this state.

  14. Azimuthal Asymmetries in Meson Electroproduction at HERMES

    NASA Astrophysics Data System (ADS)

    Hasch, Delia

    2003-07-01

    The measurement of single-spin azimuthal asymmetries for pseudoscalar meson production in semi-inclusive deep-inelastic scattering of 27.6 GeV electrons off a longitudinally polarised hydrogen and deuterium target is reported by the HERMES experiment. A significant target-spin asymmetry amplitude in the azimuthal distribution of charged and neutral pions and positively charged kaons relative to the lepton scattering plane has been observed. The dependence on the relevant kinematic variables which are the Bjorken variable x, the meson fractional energy z and the meson transverse momentum P⊥ has been investigated as well. The results are compared to predictions of model calculations which are base on a fragmentation function that varies with the transverse polarisation of the struck quark. In addition, data from the measurement of a single beam-spin azimuthal asymmetry in the electroproduction of positive pions in semi-inclusive and semi-exclusive deep-inelastic scattering will be presented.

  15. Exclusive channels in semi-inclusive production of pions and kaons

    SciTech Connect

    Markus Diehl; Wolfgang Kugler; Andreas Schaefer; Christian Weiss

    2005-06-01

    We investigate the role of exclusive channels in semi-inclusive electroproduction of pions and kaons. Using the QCD factorization theorem for hard exclusive processes we evaluate the cross sections for exclusive pseudoscalar and vector meson production in terms of generalized parton distributions and meson distribution amplitudes. We investigate the uncertainties arising from the modeling of the nonperturbative input quantities. Combining these results with available experimental data, we compare the cross sections for exclusive channels to that obtained from quark fragmentation in semi-inclusive deep inelastic scattering. We find that rho0 production is the only exclusive channel with significant contributions to semi-inclusive pion production at large z and moderate Q2. The corresponding contribution to kaon production from the decay of exclusively produced phi and Kstar is rather small.

  16. Studies of N* Structure from the CLAS Meson Electroproduction Data

    SciTech Connect

    Mokeev, Viktor I.; Aznauryan, Inna G.

    2014-01-01

    The transition {gamma}{sub v}pN amplitudes (electrocouplings) for prominent excited nucleon states obtained in a wide area of photon virtualities offer valuable information for the exploration of the N structure at different distances and allow us to access the complex dynamics of non-perturbative strong interaction. The current status in the studies of {gamma}{sub v}pN electrocouplings from the data on exclusive meson electroproduction off protons measured with the CLAS detector at Jefferson Lab is presented. The impact of these results on exploration of the N structure is discussed.

  17. Electroproduction of baryon-meson states and strangeness suppression

    NASA Astrophysics Data System (ADS)

    Santopinto, E.; García-Tecocoatzi, H.; Bijker, R.

    2016-08-01

    We describe the electroproduction ratios of baryon-meson states from nucleon, inferring from the sea quarks in the nucleon using an extension of the quark model that takes into account the sea. As a result we provide, with no adjustable parameters, the predictions of ratios of exclusive meson-baryon final states: ΛK+, Σ* K, ΣK, pπ0, and nπ+. These predictions are in agreement with the new JLab experimental data showing that sea quarks play an important role in the electroproduction. We also predicted further ratios of exclusive reactions that can be measured and tested in future experiments. In particular, we suggested new experiments on deuterium and tritium. Such measurements can provide crucial tests of different predictions concerning the structure of nucleon and its sea quarks helping to solve an outstanding problem. Finally, we compute the so called strangeness suppression factor, λs, that is the suppression of strange quark-antiquark pairs compared to nonstrange pairs, and we found that our finding with this simple extension of the quark model is in good agreement with the results of JLab and CERN experiments.

  18. Neutral Pion Electroproduction in the Δ Resonance Region

    SciTech Connect

    Villano, Anthony

    2007-11-01

    The electroproduction of baryon resonances at high Q2 is examined. Analysis focuses on the Δ(1232) resonance via exclusive pseudoscalar meson production of π0 particles. Differential cross sections are extracted for exclusive π0 electroproduction. In the central invariant mass (W) region the cross sections are used to extract resonant multipole amplitudes. In particular, the ratio of the electric quadrupole to magnetic dipole amplitudes (E2/M1) will be discussed for the Δ(1232) resonance. The transition to pQCD is discussed in terms of E2/M1 and other multipoles. The helicity amplitude A3/2 can be used as a baryon helicity conservation meter in this context and will be discussed. The fast shrinking of the resonant contribution in the Δ region is observed at this high momentum transfer. Apart from the observables related to pQCD scaling, the transition form factor G$*\\atop{M}$ is extracted along with the scalar to magnetic dipole ratio C2/M1.

  19. Measurement of the N ---> Delta+(1232) transition at high momentum transfer by pi0 electroproduction

    SciTech Connect

    M. Ungaro; K. Joo; P. Stoler

    2006-06-01

    The measurement of the differential cross section of the exclusive electroproduction reaction gamma*p --> pi^0p in W region of the Delta^+(1232) resonance is reported. The magnetic form factor (G*_M) and ratios of electric to magnetic and scaler to magnetic multipole amplitudes R_EM = E_1+/M_1+ and R_SM = S_1+/M_1+ for the gamma*p --> Delta+(1232) transition are extracted in the framework of a unitary isobar model.

  20. Electroproduction of pseudoscalar mesons above the resonance region

    SciTech Connect

    Niczyporuk, B.B.

    1994-04-01

    In this paper, the author has revisited twenty year old data considering the progress achieved in related fields. To make further progress in our understanding of strong interactions, one needs much better quality of exclusive electroproduction data. A measurement of the differential cross section {sigma}(t, W, Q{sup 2}) for the reactions e{sup {minus}} + p {r_arrow} e{sup {minus}} + {pi}{sup +}(K{sup +}) + n({Lambda}{degrees}) at a beam energy of {ge} 4 GeV is proposed. Data will be collected simultaneously for both reactions using the CLAS detector at CEBAF in the following kinematical region: Q{sup 2} > 1 GeV{sup 2} and W > 2 GeV. One of the most interesting aspects of electroproduction is that it can be used to measure photoproduction amplitudes as functions of the photon mass squared Q{sup 2} and momentum transfer t. Emphasis is given to measuring the differential cross sections for t {approximately} m{sup 2}{sub {pi},{kappa}}. Above the resonance region (W > 2 GeV), the cross section is dominated by the amplitudes for scalar photons. Measured angular distributions of produced mesons will be used to estimate the contribution of various amplitudes to the cross sections. High statistics and good quality data collected simultaneously using a large acceptance detector will improve our understanding of nucleon structure as well as the hadronic properties of the photon.

  1. Nucleon Resonance Electrocouplings from the CLAS Meson Electroproduction Data.

    SciTech Connect

    Inna Aznauryan, Volker Burkert, Viktor Mokeev

    2012-04-01

    Transition helicity amplitudes {gamma}{sub {nu}}NN* (electrocouplings) were determined for prominent excited proton states with masses less than 1.8 GeV in independent analyses of major meson electroproduction channels: {pi}{sup +}n, {pi}{sup 0}p and {pi}{sup +}{pi}{sup -}p. Consistent results on resonance electrocouplings obtained from analyses of these exclusive reactions with very different non-resonant contributions demonstrated reliable extraction of these fundamental quantities for states that have significant decays for either N{pi} or N{pi}{pi} channels. Preliminary results on electrocouplings of N* states with masses above 1.6 GeV have become available from the CLAS data on {pi}{sup +}{pi}{sup -}p electroproduction off protons for the first time. Comparison with quark models and coupled channel approaches strongly suggest that N* structure is determined by contributions from an internal core of three constituent quarks and an external meson-baryon cloud at the distance scales covered in measurements with the CLAS detector.

  2. Spin Observables in Kaon Electroproduction

    SciTech Connect

    O.K. Baker

    1998-06-01

    The CEBAF accelerator at Jefferson Lab has proven to be a powerful tool for use in studying the electromagnetic production of hadronic systems containing a strange constituent quark. The electromagnetic probe only marginally disturbs the system being investigated, and is well understood. Its use as a means to probe the internal structure of hadronic systems has been well documented. Among the most studied of these hadronic systems, currently, is the nucleon. The unique opportunities afforded by the use of polarized, high-current, high-duty-factor electron beams provides an even more powerful probe of the electromagnetic structure of hadronic systems; the study of the spin dependence of the electromagnetic production and weak decay of the hyperon, specifically the {Lambda}-hyperon, becomes feasible. An experiment to study the electroproduction of the {Lambda} as a function of virtual photon momentum transfer, angle, and energy, using spin polarization observables in order to extract insights into its production and weak decay dynamics has already been approved at Jefferson Lab (E98-101; Spin Polarization in Kaon Electroproduction). The experiment aims to study the mechanism of polarization transfer in the reaction e + p {yields} e' + K + {Lambda}. The experiment requires only moderate momentum resolution and no specialized equipment other than that associated with the polarized beam. The data quality is expected to improve with higher electron beam energies, for higher Q{sup 2} measurements. Additionally, at higher energies the increased virtual photon flux allows the 4experiment to be run at lower currents (and therefore high beam polarization). A polarized electron beam and an unpolarized cryogenic hydrogen target are required. The study uses the electron arm spectrometer and the hadron arm spectrometer to detect the scattered electron and the electroproduced kaon before it decays in flight, respectively. Additionally, the hadron arm will be used to detect the

  3. ^amp;+^amp;-p Electroproduction Cross Sections off Protons in the Second Resonance Region

    NASA Astrophysics Data System (ADS)

    Fedotov, Gleb; Gothe, Ralf; Mokeev, Victor

    2013-04-01

    In this talk we present preliminary ^amp;+^amp;-p electroproduction cross sections off protons in the kinematical area of W from 1.4 to 1.8 GeV and Q^2 from 0.4 to 1.1 GeV^2. Our kinematical coverage in part overlap with previous CLAS measurements, but offers more than a factor six finer binning in Q^2. The physics analysis of these data within the framework of the JM model will allow us to determine the electrocouplings and the partial πδ, ρp decay widths of several high lying nucleon resonances S31(1620), S11(1650), F15(1685), D33(1700), P13(1720) and to further explore the evidence for the 3/2^+(1720) candidate-state. Analysis of the single pion electroproduction data measured with CLAS in the aforementioned kinematic region is in progress. Single and charged double pion exclusive channels are major contributors to the meson electroproduction in the N* excitation region with different non-resonant mechanisms. A successful description of all observables in these exclusive channels with consistent N* electrocouplings will offer evidence for the reliable evaluation of these fundamental quantities.

  4. Exclusive Reactions at High Momentum Transfer

    NASA Astrophysics Data System (ADS)

    Radyushkin, Anatoly; Stoler, Paul

    2008-03-01

    Hard exclusive scattering at JLab / P. Kroll -- AdS/CFT and exclusive processes in QCD / S. J. Brodsky and G. F. de Téramond -- Hadron structure matters in collisions at high energy and momentum / A. W. Thomas -- Inclusive perspectives / P. Hoyer -- Fitting DVCS at NLO and beyond / K. Kumericki, D. Müller and K. Passek-Kumericki -- Spin-orbit correlations and single-spin asymmetries / M. Burkardt -- Electroproduction of soft pions at large momentum transfers / V. M. Braun, D. Yu. Ivanov and A. Peters -- Color transparency: 33 years and still running / M. Strikman -- Meson clouds and nucleon electromagnetic form factors / G. A. Miller -- Covariance, dynamics and symmetries, and hadron form factors / M. S. Bhagwat, I. C. Cloët and C. D. Roberts -- N to [symbol] electromagnetic and axial form factors in full QCD / C. Alexandrou -- Real and virtual compton scattering in perturbative QCD / C.-R. Ji and R. Thomson -- Deeply virtual compton scattering at Jefferson Lab / F. Sabatie -- DVCS at HERMES: recent results / F. Ellinghaus -- Deeply virtual compton scattering with CLAS / F. X. Girod -- Deeply virtual compton scattering off the neutron at JLab Hall A / M. Mazouz -- The future DVCS experiments in Hall A at JLab / J. Roche -- Deeply virtual compton scattering with CLAS12 / L. Elouadrhiri -- Quark helicity flip and the transverse spin dependence of inclusive DIS / A. Afanasev, M. Strikman and C. Weiss -- Deeply virtual pseudoscalar meson production / V. Kubarovsky and P. Stoler -- Exclusive p[symbol] electroproduction on the proton: GPDs or not GPDs? / M. Guidal and S. Morrow -- p[symbol] transverse target spin asymmetry at HERMES / A. Airapetian -- Electroproduction of ø(1020) mesons / J. P. Santoro and E. S. Smith -- Generalized parton distributions from hadronic observables / S. Ahmad ... [et al.] -- Imaging the proton via hard exclusive production in diffractive pp scattering / G. E. Hyde ... [et al.] -- Regge contributions to exclusive electro-production / A

  5. Exclusive Reactions at High Momentum Transfer

    NASA Astrophysics Data System (ADS)

    Radyushkin, Anatoly; Stoler, Paul

    2008-03-01

    Hard exclusive scattering at JLab / P. Kroll -- AdS/CFT and exclusive processes in QCD / S. J. Brodsky and G. F. de Téramond -- Hadron structure matters in collisions at high energy and momentum / A. W. Thomas -- Inclusive perspectives / P. Hoyer -- Fitting DVCS at NLO and beyond / K. Kumericki, D. Müller and K. Passek-Kumericki -- Spin-orbit correlations and single-spin asymmetries / M. Burkardt -- Electroproduction of soft pions at large momentum transfers / V. M. Braun, D. Yu. Ivanov and A. Peters -- Color transparency: 33 years and still running / M. Strikman -- Meson clouds and nucleon electromagnetic form factors / G. A. Miller -- Covariance, dynamics and symmetries, and hadron form factors / M. S. Bhagwat, I. C. Cloët and C. D. Roberts -- N to [symbol] electromagnetic and axial form factors in full QCD / C. Alexandrou -- Real and virtual compton scattering in perturbative QCD / C.-R. Ji and R. Thomson -- Deeply virtual compton scattering at Jefferson Lab / F. Sabatie -- DVCS at HERMES: recent results / F. Ellinghaus -- Deeply virtual compton scattering with CLAS / F. X. Girod -- Deeply virtual compton scattering off the neutron at JLab Hall A / M. Mazouz -- The future DVCS experiments in Hall A at JLab / J. Roche -- Deeply virtual compton scattering with CLAS12 / L. Elouadrhiri -- Quark helicity flip and the transverse spin dependence of inclusive DIS / A. Afanasev, M. Strikman and C. Weiss -- Deeply virtual pseudoscalar meson production / V. Kubarovsky and P. Stoler -- Exclusive p[symbol] electroproduction on the proton: GPDs or not GPDs? / M. Guidal and S. Morrow -- p[symbol] transverse target spin asymmetry at HERMES / A. Airapetian -- Electroproduction of ø(1020) mesons / J. P. Santoro and E. S. Smith -- Generalized parton distributions from hadronic observables / S. Ahmad ... [et al.] -- Imaging the proton via hard exclusive production in diffractive pp scattering / G. E. Hyde ... [et al.] -- Regge contributions to exclusive electro-production / A

  6. Duality in Semi-Inclusive Pion Electroproduction

    SciTech Connect

    F E Close, W Melnitchouk

    2009-05-01

    We explore quark-hadron duality in semi-inclusive pion electroproduction on proton and neutron targets. Using the spin-flavor symmetric quark model, we compute ratios of $\\pi^+$ and $\\pi^-$ cross sections for both unpolarized and polarized scattering, and discuss realizations of duality in several symmetry breaking scenarios. The model calculations allow one to understand some of the key features of recent data on semi-inclusive pion production at low energies.

  7. Delta Electroproduction in 12-C

    SciTech Connect

    Steven McLauchlan

    2003-01-31

    The Delta-nucleus potential is a crucial element in the understanding of the nuclear system. Previous electroexcitation measurements in the delta region reported a Q2 dependence of the delta mass indicating that this potential is dependent on the momentum of the delta. Such a dependence is not observed for protons and neutrons in the nuclear medium. This thesis presents the experimental study of the electroexcitation of the delta resonance in 12C, performed using the high energy electron beam at the Thomas Jefferson National Accelerator Facility, and the near 4(pie) acceptance detector CLAS that enables the detection of the full reaction final state. Inclusive, semi inclusive, and exclusive cross sections were measured with an incident electron beam energy of 1.162GeV over the Q2 range 0.175-0.475 (GeV/c)2. A Q2 dependence of the delta mass was only observed in the exclusive measurements indicating that the delta-nucleus potential is affected by the momentum of the delta.

  8. Electroproduction of tensor mesons in QCD

    NASA Astrophysics Data System (ADS)

    Braun, V. M.; Kivel, N.; Strohmaier, M.; Vladimirov, A. A.

    2016-06-01

    Due to multiple possible polarizations hard exclusive production of tensor mesons by virtual photons or in heavy meson decays offers interesting possibilities to study the helicity structure of the underlying short-distance process. Motivated by the first measurement of the transition form factor γ∗γ → f 2(1270) at large momentum transfers by the BELLE collaboration we present an improved QCD analysis of this reaction in the framework of collinear factorization including contributions of twist-three quark-antiquark-gluon operators and an estimate of soft end-point corrections using light-cone sum rules. The results appear to be in good agreement with the data, in particular the predicted scaling behavior is reproduced in all cases.

  9. Phenomenological studies of CLAS data on double charge pion electroproduction

    NASA Astrophysics Data System (ADS)

    Mokeev, Victor; Burkert, Volker

    2007-10-01

    Comprehensive studies of unpolarized &-circ;&+circ;p electroproduction cross-sections, for the first time available from CLAS [1,2], were carried out within the framework of phenomenological approach [3]. Analysis of these data allowed us to establish all important mechanisms, contributing to this exclusive channel in N^* excitation region at photon virtualities from 0.2 to 1.5 GeV^2. Electrocouplings for P11(1440), D13(1520) states at Q^2 < 0.6GeV^2 were obtained from the analysis of CLAS data [1]. The contributions from various mechanisms in terms of both amplitudes and single differential cross-sections were determined from the data fit. This information is of particular interest for N^* studies in coupled channel approaches under development at EBAC [4]. [1] G.V.Fedotov, et. al., Bull. of Russian Academy of Science,71,328 (2007). [2] M.Ripani, et. al., Phys. Rev.,91,0222002 (2003). [3] V.I.Mokeev, et. al., Int. Workshop on the Physics of Excited Baryons (NSTAR05) Tallahassee, Florida, 10-15 Oct 2005, ed by V.Crede, P.Eugenio and S.Capstick, p.47. [4] A.Matsuyama, et.al., Phys.Rep.,439,193 (2007); B.Julia-Diaz, et.al., arXiv:0704.1615.

  10. Unitary constraints on neutral pion electroproduction

    SciTech Connect

    Laget, J. -M.

    2010-11-10

    At large virtuality $Q^2$, the coupling to the vector meson production channels provides us with a natural explanation of the surprisingly large cross section of the neutral pion electroproduction recently measured at Jefferson Laboratory, without destroying the good agreement between the Regge pole model and the data at the real photon point. Lastly, elastic rescattering of the $\\pi^0$ provides us with a way to explain why the node, that appears at $t\\sim -0.5$~GeV$^2$ at the real photon point, disappears as soon as $Q^2$ differs from zero.

  11. Unitary constraints on neutral pion electroproduction

    DOE PAGESBeta

    Laget, J. -M.

    2010-11-10

    At large virtualitymore » $Q^2$, the coupling to the vector meson production channels provides us with a natural explanation of the surprisingly large cross section of the neutral pion electroproduction recently measured at Jefferson Laboratory, without destroying the good agreement between the Regge pole model and the data at the real photon point. Lastly, elastic rescattering of the $$\\pi^0$$ provides us with a way to explain why the node, that appears at $$t\\sim -0.5$$~GeV$^2$ at the real photon point, disappears as soon as $Q^2$ differs from zero.« less

  12. A dynamical model for pion electroproduction on the nucleon

    SciTech Connect

    George L. Caia; Louis E. Wright; Vladimir Pascalutsa

    2005-06-01

    We develop a Lorenz- and gauge-invariant dynamical model for pion electroproduction in the resonance region. The model is based on solving of the Salpeter (instantaneous) equation for the pion-nucleon interaction with a hadron-exchange potential. We find that the one-particle-exchange kernel of the Salpeter equation for pion electroproduction develops an unphysical singularity for a finite value of Q{sup 2}. We analyze two methods of dealing with this problem. Results of our model are compared with recent single-polarization data for pion electroproduction.

  13. Electroproduction of the Λ(1520) hyperon

    NASA Astrophysics Data System (ADS)

    Barrow, S. P.; Dennis, L.; McAleer, S. B.; Adams, G.; Amaryan, M. J.; Anciant, E.; Anghinolfi, M.; Asavapibhop, B.; Asryan, G.; Audit, G.; Auger, T.; Avakian, H.; Ball, J. P.; Battaglieri, M.; Beard, K.; Bektasoglu, M.; Bianchi, N.; Biselli, A. S.; Boiarinov, S.; Bonner, B. E.; Bouchigny, S.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Calarco, J. R.; Capitani, G. P.; Carman, D. S.; Carnahan, B.; Ciciani, L.; Clark, R.; Cole, P. L.; Coleman, A.; Connelly, J.; Cords, D.; Corvisiero, P.; Crabb, D.; Crannell, H.; Cummings, J. P.; Desanctis, E.; Devita, R.; Degtyarenko, P. V.; Demirchyan, R.; Deppman, A.; Dhuga, K. S.; Djalali, C.; Dodge, G. E.; Domingo, J.; Doughty, D.; Dragovitsch, P.; Dugger, M.; Dytman, S.; Eckhause, M.; Efremenko, Y.; Egiyan, H.; Egiyan, K. S.; Elouadrhiri, L.; Empl, A.; Farhi, L.; Feuerbach, R. J.; Ficenec, J.; Forest, T. A.; Frolov, V.; Funsten, H.; Gaff, S. J.; Gai, M.; Gavalian, G.; Gavrilov, V.; Gilad, S.; Gilfoyle, G. P.; Giovanetti, K. L.; Girard, P.; Griffioen, K.; Guidal, M.; Guillo, M.; Gyurjyan, V.; Hancock, D.; Hardie, J.; Heddle, D.; Heisenberg, J.; Hersman, F. W.; Hicks, K.; Hicks, R. S.; Holtrop, M.; Hu, J.; Fatemi, R.; Hyde-Wright, C. E.; Ito, M. M.; Jenkins, D.; Joo, K.; Kelley, J. H.; Khandaker, M.; Kim, K. Y.; Kim, K.; Kim, W.; Klein, A.; Klein, F. J.; Klusman, M.; Kossov, M.; Kramer, L. H.; Kuang, Y.; Kuhn, S. E.; Laget, J. M.; Lawrence, D.; Leksin, G. A.; Longhi, A.; Lucas, M.; Lukashin, K.; Major, R. W.; Manak, J. J.; Marchand, C.; Matthews, S. K.; McCarthy, J.; McNabb, J. W.; Mecking, B. A.; Mestayer, M. D.; Meyer, C. A.; Mikhailov, K.; Minehart, R.; Mirazita, M.; Miskimen, R.; Muccifora, V.; Mueller, J.; Murphy, L. Y.; Mutchler, G. S.; Napolitano, J.; Nelson, S. O.; Niculescu, G.; Niculescu, I.; Niyazov, R. A.; O'brien, J. T.; O'rielly, G. V.; Opper, A. K.; Park, K.; Paschke, K.; Pasyuk, E.; Patois, Y.; Peterson, G.; Philips, S. A.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Polli, E.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Qin, L. M.; Raue, B. A.; Reolon, A. R.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Ronchetti, F.; Rossi, P.; Rowntree, D.; Rubin, P. D.; Sabatié, F.; Sabourov, K.; Salgado, C.; Sanzone-Arenhovel, M.; Sapunenko, V.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Shaw, J.; Shuvalov, S.; Skabelin, A. V.; Smith, E. S.; Smith, T.; Smith, L. C.; Sober, D. I.; Spraker, M.; Stavinsky, A.; Stepanyan, S.; Stoler, P.; Taiuti, M.; Taylor, S.; Tedeschi, D. J.; Thompson, R.; Tung, T. Y.; Vineyard, M. F.; Vlassov, A. V.; Wang, K.; Weinstein, L. B.; Weisberg, A.; Weller, H.; Weygand, D. P.; Whisnant, C. S.; Witkowski, M.; Wolin, E.; Yegneswaran, A.; Yun, J.; Zhang, B.; Zhao, J.; Zhou, Z.

    2001-10-01

    The reaction ep-->e'K+Λ(1520) with Λ(1520)-->p'K- was studied at electron beam energies of 4.05, 4.25, and 4.46 GeV, using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The cos θK+, φK+, Q2, and W dependencies of Λ(1520) electroproduction are presented for the kinematic region 0.9electroproduction.

  14. The Onset of Quark-Hadron Duality in Pion Electroproduction

    SciTech Connect

    Tigran Navasardyan; Gary Adams; Abdellah Ahmidouch; Tatiana Angelescu; John Arrington; Razmik Asaturyan; O. Baker; Nawal Benmouna; Crystal Bertoncini; Henk Blok; Werner Boeglin; Peter Bosted; Herbert Breuer; Michael Christy; Simon Connell; Yonggang Cui; Mark Dalton; Samuel Danagoulian; Donal Day; T. Dodario; James Dunne; Dipangkar Dutta; Najib Elkhayari; Rolf Ent; Howard Fenker; Valera Frolov; Liping Gan; David Gaskell; Kawtar Hafidi; Wendy Hinton; Roy Holt; Tanja Horn; Garth Huber; Ed Hungerford; Xiaodong Jiang; Mark Jones; Kyungseon Joo; Narbe Kalantarians; James Kelly; Cynthia Keppel; Edward Kinney; V. Kubarovski; Ya Li; Yongguang Liang; Simona Malace; Pete Markowitz; Erin McGrath; Daniella Mckee; David Meekins; Hamlet Mkrtchyan; Brian Moziak; Gabriel Niculescu; Maria-Ioana Niculescu; Allena Opper; Tanya Ostapenko; Paul Reimer; Joerg Reinhold; Julie Roche; Stephen Rock; Elaine Schulte; Edwin Segbefia; C. Smith; G.R. Smith; Paul Stoler; Vardan Tadevosyan; Liguang Tang; Maurizio Ungaro; Alicia Uzzle; Sandra Vidakovic; Anthony Villano; William Vulcan; Miao Wang; Glen Warren; Frank Wesselmann; Bogdan Wojtsekhowski; Stephen Wood; Chuncheng Xu; Lulin Yuan; Xiaochao Zheng; Hong Guo Zhu

    2006-08-29

    A large data set of charged-pion electroproduction from both hydrogen and deuterium targets has been obtained spanning the low-energy residual-mass region. These data conclusively show the onset of the quark-hadron duality phenomenon, as predicted for high-energy hadron electroproduction. We construct several ratios from these data to exhibit the relation of this phenomenon to the high-energy factorization ansatz of electron-quark scattering and subsequent quark-to- pion production mechanisms.

  15. The onset of quark-hadron duality in pion electroproduction.

    SciTech Connect

    Navasardyan, T.; Adams, G. S.; Ahnidouch, A.; Angelescu, T.; Arrington, T.; Arrington, J.; Hafidi, K.; Holt, R. J.; Reimer, P.; Schulte, E.; Zheng, X.; Physics; Yerevan Physics Inst.; Rensselaer Polytechnic Inst.; North Carolina A & T Univ.; Bucharest Univ.

    2007-01-01

    A large data set of charged-pion ({pi}*) electroproduction from both hydrogen and deuterium targets has been obtained spanning the low-energy residual-mass region. These data conclusively show the onset of the quark-hadron duality phenomenon, as predicted for high-energy hadron electroproduction. We construct several ratios from these data to exhibit the relation of this phenomenon to the high-energy factorization ansatz of electron-quark scattering and subsequent quark {yields} pion production mechanisms.

  16. Exclusive Neutral Pion Electroproduction in the Deeply Virtual Regime

    SciTech Connect

    Fuchey, E; Camsonne, A; Mazouz, M; Gavalian, G; Kuchina, E; Amarian, M; Aniol, K A; Beaumel, M; Benaoum, H; Bertin, P; Brossard, M; Canan, M; Chen, J -P; Chudakov, E; Craver, B; Cusanno, F; de Jager, C W; Deur, A; Ferdi, C; Feuerbach, R; Fieschi, J -M; Frullani, S; Garcon, M; Garibaldi, F; Gayou, O; Gilman, R; Gomez, J; Gueye, P; Guichon, P.A.M.; Guillon, B; Hansen, O; Hayes, D; Higinbotham, D W; Homstrom, T; Hyde, C E; Ibrahim, H; Igarashi, R; Itard, F; Jiang, X; Jo, H S; Kaufman, L J; Kelleher, A; Kolarkar, A; Kumbartzki, G; Laveissiere, G; LeRose, J J; Lindgren, R; Liyanage, N; Lu, H -J; Margaziotis, D J; Meziani, Z -E; McCormick, K; Michaels, R; Michel, B; Moffit, B; Monaghan, P; Nanda, S; Nelyubin, V; Potokar, M; Qiang, Y; Ransome, R D; Real, J -S; Reitz, B; Roblin, Y; Roche, J; Sabatie, F; Saha, A; Sirca, S; Slifer, K; Solvignon, P; Subedi, R; Sulkosky, V; Ulmer, P E; Voutier, E; Wang, K; Weinstein, L B; Wojtsekhowski, B; Zheng, X; Zhu, L

    2011-02-01

    We present measurements of the ep->ep pi^0 cross section extracted at two values of four-momentum transfer Q^2=1.9 GeV^2 and Q^2=2.3 GeV^2 at Jefferson Lab Hall A. The kinematic range allows to study the evolution of the extracted hadronic tensor as a function of Q^2 and W. Results will be confronted with Regge inspired calculations and GPD predictions. An intepretation of our data within the framework of semi-inclusive deep inelastic scattering has also been attempted.

  17. Exclusive neutral pion electroproduction in the deeply virtual regime

    SciTech Connect

    Fuchey, E.; Camsonne, A.; Bertin, P.; Munoz Camacho, C.; Gavalian, G.; Amarian, M.; Canan, M.; Hayes, D.; Ibrahim, H.; Ulmer, P. E.; Weinstein, L. B.; Kuchina, E.; Gilman, R.; Jiang, X.; Kumbartzki, G.; McCormick, K.; Ransome, R. D.; Aniol, K. A.; Margaziotis, D. J.

    2011-02-15

    We present measurements of the ep{yields}ep{pi}{sup 0} cross section extracted at two values of four-momentum transfer Q{sup 2}=1.9 GeV{sup 2} and Q{sup 2}=2.3 GeV{sup 2} at Jefferson Lab Hall A. The kinematic range allows one to study the evolution of the extracted cross section as a function of Q{sup 2} and W. Results are confronted with Regge-inspired calculations and GPD predictions. An intepretation of our data within the framework of semi-inclusive deep inelastic scattering is also discussed.

  18. Electroproduction of kaons and light hypernuclei

    SciTech Connect

    Geesaman, D.F.; Jackson, H.E.; Jones, C.E.

    1995-08-01

    A detailed investigation of the basic hyperon-nucleon interactions in nuclei is one of the aims of Experiment 91-016, approved with high priority at CEBAF, to study the electroproduction of kaons on targets of deuterium, {sup 3}He, and {sup 4}He. Inasmuch as both the electron and K{sup +} are particles that interact relatively weakly with nucleons, electroproduction of light hypernuclei provides a low-distortion method for investigating the fundamental interactions between nucleons, {Alpha}`s, and {Epsilon}`s in few-body systems. In particular, the (e,e`K{sup +}) reactions on cryogenic targets of D, {sup 3}He, and {sup 4}He will be studied at incident electron energies near 3 GeV with coincident detection of the emergent e and K{sup +} in the HMS and SOS magnetic spectrometers in Hall C. Construction of the He target, operating at {approximately}10 atm, {approximately}50 K and capable of dissipating {approximately}30 W, is expected to be complete prior to commencement of production runs in Hall C. The first data runs for E91-016, expected to begin late in FY 1995, will also be the basis for a doctoral thesis at Hampton University. In addition to providing new information on the phases of hyperon-nucleon interactions, measurements of cross sections for hypernuclear formation, and interference phenomena, the data may provide evidence for the presence of bound {Epsilon}`s and strange di-baryonic states that are the subject of considerable theoretical discussion.

  19. Q{sup 2} Dependence of Nuclear Transparency for Incoherent {rho}{sup 0} Electroproduction

    SciTech Connect

    John Arrington; Frank Dohrmann; Ahmed El Alaoui; Don Geesaman; Kawtar Hafidi; Roy Holt; Harold Jackson; David Potterveld; Brahim Mustapha; Paul Reimer; Elaine Schulte; Krishni Wijesooriya; Maurik Holtrop; Jacques Ball; Michel Garcon; Jean Laget; Franck Sabatie; Michel Guidal; Latifa Elouadrhiri; A. Borissov; Wolfgang Lorenzon; Stepan Stepanyan; Lawrence Weinstein

    2002-05-01

    Measurements of exclusive incoherent electroproduction of {rho}{sup 0} (770) meson from {sup 2}D, {sup 12}C, and {sup 63}Cu targets up to Q{sup 2} = 4 GeV{sup 2} are proposed using the CLAS detector. The objective of these measurements is to determine the Q{sup 2} dependence of the nuclear transparency ratio for the two nuclear targets: {sup 12}C and {sup 63}Cu at fixed coherence length of quark-antiquark fluctuations of the virtual photon. A sizeable rise of the nuclear transparency is predicted and can be measured in this experiment. A relatively large increase of the nuclear transparency can be considered as a signature of the onset of color transparency.

  20. Kaon electro-production on protons at JLab in Hall A

    SciTech Connect

    Mauro Iodice

    2003-07-15

    The elementary reaction of kaon exclusive electro-production on protons has been studied in a broad kinematical range at Jefferson Lab in Hall A. Data have been taken at different values of the invariant center-of-mass energy W in the range W=1.8-2.2 GeV, for two values of the transferred 4-momentum Q2 =1.9 and 2.4 (GeV/c)2. Each kinematics was measured at different electron beam energies so as to separate the longitudinal (L) and transverse (T) contributions to the cross-section. The LT interference term has also been measured for a limited number of kinematics. The preliminary data are compared to results of different models developed in the framework of hadronic field and Regge theories.

  1. Electroproduction of pions at threshold in chiral perturbation theory

    SciTech Connect

    Lee, T.S.H.; Bernard, V.; Kaiser, N.; Meissner, U.G.

    1995-08-01

    The electroproduction of pions off protons close to threshold is studied within the framework of baryon chiral perturbation theory. The approach is based on the fundamental QCD property that at low energies the strong interactions are dictated by the spontaneously broken chiral symmetry. The calculation was done up to the 1-loop level by carrying out order-by-order renormalization procedures. A thorough study of the low-energy theorems related to electroproduction of pions was carried out. Our study showed how the axial radius of the nucleon can be related to the S-wave multipoles E{sub 0+}{sup (-)} and L{sub 0+}{sup (-)}.

  2. Onset of Quark-Hadron Duality in Pion Electroproduction

    SciTech Connect

    Navasardyan, T.; Asaturyan, R.; Mkrtchyan, H.; Tadevosyan, V.; Adams, G. S.; Kubarovski, V.; Moziak, B.; Stoler, P.; Ungaro, M.; Villano, A.; Ahmidouch, A.; Danagoulian, S.; Angelescu, T.; Malace, S.; Arrington, J.; Hafidi, K.; Holt, R. J.; Reimer, P.; Schulte, E.; Zheng, X.

    2007-01-12

    A large data set of charged-pion ({pi}{sup {+-}}) electroproduction from both hydrogen and deuterium targets has been obtained spanning the low-energy residual-mass region. These data conclusively show the onset of the quark-hadron duality phenomenon, as predicted for high-energy hadron electroproduction. We construct several ratios from these data to exhibit the relation of this phenomenon to the high-energy factorization ansatz of electron-quark scattering and subsequent quark{yields}pion production mechanisms.

  3. Longitudinal Electroproduction of Charged Pions from

    SciTech Connect

    David Gaskell; Abdellah Ahmidouch; Pawel Ambrozewicz; H. Anklin; John Arrington; K. Assamagan; Steven Avery; Kevin Bailey; Oliver K. Baker; Shelton Beedoe; Elizabeth Beise; Herbert Breuer; D. S. Brown; Roger Carlini; Jinseok Cha; Nicholas Chant; Anthony Cowley; Samuel Danagoulian; D. De Schepper; Jim Dunne; Dipangkar Dutta; Rolf Ent; Liping Gan; Ashot Gasparian; Donald Geesaman; Ron Gilman; Charles Glashausser; Paul Gueye; M. Harvey; O. Hashimoto; Wendy Hinton; G. Hofman; Ceasar Jackson; Hal Jackson; Cynthia Keppel; Ed Kinney; Doug Koltenuk; G. Kyle; Allison Lung; David Mack; D. McKee; Joseph Mitchell; Hamlet Mkrtchyan; B. Mueller; Gabriel Niculescu; Ioana Niculescu; Tom O'Neill; V. Papavassiliou; Dave Potterveld; Juerg Reinhold; Philip Roos; Reyad Sawafta; Ralph Segel; Stepan Stepanyan; Vardan Tadevosyan; T. Takahashi; Liguang Tang; B. Terburg; D. Van Westrum; J. Volmer; T. P. Welch; Stephen Wood; Lulin Yuan; Ben Zeidman; Beni Zihlmann

    2001-11-12

    Separated longitudinal and transverse cross sections for charged pion electroproduction from {sup 1}H, {sup 2}H, and {sup 3}He were measured at Q{sup 2} = 0.4 (GeV/c){sup 2} for two values of the invariant mass, {bar W} = 1.15 GeV and {bar W} = 1.60 GeV, in a search for a mass dependence which would signal the effect of nuclear pions. This is the first such study that includes recoil momenta significantly above the Fermi surface. The longitudinal cross section, if dominated by the pion-pole process, should be sensitive to nuclear pion currents. Comparisons of the longitudinal cross section target ratios to a quasifree calculation reveal a significant suppression in {sup 3>}He at {bar W} = 1.60 GeV. The {bar W} = 1.15 GeV results are consistent with simple estimates of the effect of nuclear pion currents, but are also consistent with pure quasifree production.

  4. Spin O decay angular distribution for interfering mesons in electroproduction

    SciTech Connect

    Funsten, H.; Gilfoyle, G.

    1994-04-01

    Self analyzing meson electroproduction experiments are currently being planned for the CEBAF CLAS detector. These experiments deduce the spin polarization of outgoing unstable spin s (?)0 mesons from their decay angular distribution, W({theta},{psi}). The large angular acceptance of the CLAS detector permits kinematic tracking of a sufficient number of these events to accurately determine electroproduction amplitudes from the deduced polarization. Maximum polarization information is obtained from W({theta},{psi}) for decay into spin 0 daughters. The helicity of the decaying meson is transferred to the daughter`s relative orbital angular momentum m-projection; none is {open_quotes}absorbed{close_quotes} into daughter helicities. The decaying meson`s helicity maximally appears in W({theta},{psi}). W({theta},{psi}) for spin 0 daughters has been derived for (1) vector meson electroproduction and (2) general interfering mesons produced by incident pions. This paper derives W({theta},{psi}) for electroproduction of two interfering mesons that decay into spin 0 daughters. An application is made to the case of interfering scalar and vector mesons. The derivation is an extension of work by Schil using the general decay formalism of Martin. The expressions can be easily extended to the case of N interfering mesons since interference occurs pairwise in the observable W ({theta},{psi}), a quadratic function of the meson amplitudes. The derivation uses the virtual photon density matrix of Schil which is transformed by a meson electroproduction transition operator, T. The resulting density matrix for the interfering mesons is then converted into a corresponding statistical tensor and contracted into the efficiency tensor for spin 0 daughters.

  5. Single spin asymmetries in electroproduction at CLAS

    SciTech Connect

    Harut Avakian; Latifa Elouadrhiri

    2004-06-02

    We present measurements of spin asymmetries in semi-inclusive processes in hard scattering kinematics using a 5.7 GeV electron beam and the CEBAF Large Acceptance Spectrometer (CLAS) at JLab. Scattering of longitudinally polarized electrons of an unpolarized liquid-hydrogen and off a polarized NH{sub 3} targets was studied over a wide range of kinematics. Non-zero single-beam and single-target spin asymmetries have been observed in semi-inclusive pion production in hard-scattering kinematics (Q{sup 2} > 1.2 GeV{sup 2}, W{sup 4} > 4 GeV{sup 2}). Systematic studies of factorization of x and z dependences have been done for different spin-dependent and spin-independent observables. No significant x/z dependence has been observed within statistical uncertainties, which is consistent with factorization of hard scattering and fragmentation processes.

  6. Scaling study of the pion electroproduction cross sections

    SciTech Connect

    Horn, T.; Bosted, P.; Bruell, A.; Chudakov, E.; Ent, R.; Fenker, H.; Gaskell, D.; Jones, M. K.; Lung, A. F.; Meekins, D.; Smith, G. R.; Vulcan, W.; Wood, S. A.; Qian, X.; Gao, H.; Kramer, K.; Arrington, J.; El Fassi, L.; Zheng, X. C.; Asaturyan, R.

    2008-11-15

    The {sup 1}H(e, e{sup '}{pi}{sup +})n cross section was measured for arange of four-momentum transfer up to Q{sup 2}=3.91 GeV{sup 2} at values of the invariant mass W above the resonance region. The Q{sup 2} dependence of the longitudinal component was found to be consistent with the Q{sup 2}-scaling prediction for hard exclusive processes. This suggests that the QCD factorization theorem is applicable at rather low values of Q{sup 2}. The transverse term falls off slower than the naive Q{sup -8} expectation and remains appreciable even at Q{sup 2}=3.91 GeV{sup 2}.

  7. Electroproduction of $\\phi(1020)$ Mesons at High $Q^2$ with CLAS

    SciTech Connect

    Santoro, Joseph; Smith, Elton; Garcon, Michel; Guidal, Michel; Laget, Jean; Weiss, Christian; Adams, Gary; Amaryan, Moscov; Amaryan, Moskov; Anghinolfi, Marco; Asryan, Gegham; Audit, Gerard; Avagyan, Harutyun; Baghdasaryan, Hovhannes; Baillie, Nathan; Ball, J.P.; Ball, Jacques; Ball, J.P.; Ball, Jacques; Ball, James; Baltzell, Nathan; Barrow, Steve; Battaglieri, Marco; Bedlinskiy, Ivan; Bektasoglu, Mehmet; Bellis, Matthew; Benmouna, Nawal; Berman, Barry; Biselli, Angela; Blaszczyk, Lukasz; Bonner, Billy; Bookwalter, Craig; Bouchigny, Sylvain; Bouchigny, Sylvain; Bradford, Robert; Branford, Derek; Briscoe, William; Brooks, William; Bultmann, S.; Bueltmann, Stephen; Bultmann, S.; Bueltmann, Stephen; Burkert, Volker; Butuceanu, Cornel; Calarco, John; Careccia, Sharon; Carman, Daniel; Casey, Liam; Cazes, Antoine; Chen, Shifeng; Cheng, Lu; Cole, Philip; Collins, Patrick; Coltharp, Philip; Cords, Dieter; Corvisiero, Pietro; Crabb, Donald; Crannell, Hall; Crede, Volker; Cummings, John; Dale, Daniel; Dashyan, Natalya; De Masi, Rita; De Sanctis, Enzo; De Vita, Raffaella; Degtiarenko, Pavel; Denizli, Haluk; Dennis, Lawrence; Deur, Alexandre; Dhamija, Seema; Dharmawardane, Kahanawita; Dhuga, Kalvir; Dickson, Richard; Djalali, Chaden; Dodge, Gail; Doughty, David; Dugger, Michael; Dytman, Steven; Dzyubak, Oleksandr; Egiyan, Hovanes; Egiyan, Kim; Elfassi, Lamiaa; Elouadrhiri, Latifa; Eugenio, Paul; Fatemi, Renee; Fedotov, Gleb; Feuerbach, Robert; Ficenec, John; Forest, Tony; Fradi, Ahmed; Funsten, Herbert; Gavalian, Gagik; Gevorgyan, Nerses; Gilfoyle, Gerard; Giovanetti, Kevin; Girod, Francois-Xavier; Goetz, John; Gohn, Wesley; Gordon, Christopher; Gothe, Ralf; Graham, Lewis; Griffioen, Keith; Guillo, Matthieu; Guler, Nevzat; Guo, Lei; Gyurjyan, Vardan; Hadjidakis, Cynthia; Hafidi, Kawtar; Hakobyan, Hayk; Hanretty, Charles; Hardie, John; Hassall, Neil; Heddle, David; Hersman, F.; Hicks, Kenneth; Hleiqawi, Ishaq; Holtrop, Maurik; Hyde, Charles; Ilieva, Yordanka; Ireland, David; Ishkhanov, Boris; Isupov, Evgeny; Ito, Mark; Jenkins, David; Jo, Hyon-Suk; Johnstone, John; Joo, Kyungseon; Juengst, Henry; Kalantarians, Narbe; Keller, Dustin; Kellie, James; Khandaker, Mahbubul; Kim, Wooyoung; Klein, Andreas; Klein, Franz; Klimenko, Alexei; Kossov, Mikhail; Krahn, Zebulun; Kramer, Laird; Kubarovsky, Valery; Kuhn, Joachim; Kuhn, Sebastian; Kuleshov, Sergey; Kuznetsov, Viacheslav; Lachniet, Jeff; Langheinrich, Jorn; Lawrence, David; Livingston, Kenneth; Lu, Haiyun; MacCormick, Marion; Marchand, Claude; Markov, Nikolai; Mattione, Paul; McAleer, Simeon; McKinnon, Bryan; McNabb, John; Mecking, Bernhard; Mehrabyan, Surik; Melone, Joseph; Mestayer, Mac; Meyer, Curtis; Mibe, Tsutomu; Mikhaylov, Konstantin; Minehart, Ralph; Mirazita, Marco; Miskimen, Rory; Mokeev, Viktor; Morand, Ludyvine; Moreno, Brahim; Moriya, Kei; Morrow, Steven; Moteabbed, Maryam; Mueller, James; Munevar Espitia, Edwin; Mutchler, Gordon; Nadel-Turonski, Pawel; Nasseripour, Rakhsha; Niccolai, Silvia; Niculescu, Gabriel; Niculescu, Maria-Ioana; Niczyporuk, Bogdan; Niroula, Megh; Niyazov, Rustam; Nozar, Mina; O'Rielly, Grant; Osipenko, Mikhail; Ostrovidov, Alexander; Park, Kijun; Park, Sungkyun; Pasyuk, Evgueni; Paterson, Craig; Pereira, Sergio; Philips, Sasha; Pierce, Joshua; Pivnyuk, Nikolay; Pocanic, Dinko; Pogorelko, Oleg; Popa, Iulian; Pozdnyakov, Sergey; Preedom, Barry; Price, John; Procureur, Sebastien; Prok, Yelena; Protopopescu, Dan; Qin, Liming; Raue, Brian; Riccardi, Gregory; Ricco, Giovanni; Ripani, Marco; Ritchie, Barry; Rosner, Guenther; Rossi, Patrizia; Sabatie, Franck; Saini, Mukesh; Salamanca, Julian; Salgado, Carlos; Sapunenko, Vladimir; Schott, Diane; Schumacher, Reinhard; Serov, Vladimir; Sharabian, Youri; Sharov, Dmitri; Shvedunov, Nikolay; Skabelin, Alexander; Smith, Lee; Sober, Daniel; Sokhan, Daria; Stavinsky, Aleksey; Stepanyan, Samuel; Stepanyan, Stepan; Stokes, Burnham; Stoler, Paul; Strakovski, Igor; Strauch, Steffen; Taiuti, Mauro; Tedeschi, David; Tkabladze, A

    2008-08-01

    http://dx.doi.org/10.1103/PhysRevC.78.025210
    Electroproduction of exclusive $\\phi$ vector mesons has been studied with the CLAS detector in the kinematical range $1.6\\leq Q^2\\leq 3.8$ GeV$^{2}$, $0.0\\leq t^{\\prime}\\leq 3.6$ GeV$^{2}$, and $2.0\\leq W\\leq 3.0$ GeV. The scaling exponent for the total cross section as $1/(Q^2+M_{\\phi}^2)^n$ was determined to be $n=2.49\\pm 0.33$. The slope of the four-momentum transfer $t'$ distribution is $b_{\\phi}=0.98 \\pm 0.17$ GeV$^{-2}$. The data are consistent with the assumption of s-channel helicity conservation (SCHC). Under this assumption, we determine the ratio of longitudinal to transverse cross sections to be $R=0.86 \\pm 0.24$. A 2-gluon exchange model is able to reproduce the main features of the data.

  8. High-energy electroproduction in an atomic field

    NASA Astrophysics Data System (ADS)

    Krachkov, P. A.; Milstein, A. I.

    2016-06-01

    The differential cross section of high-energy electroproduction in the electric field of heavy atoms is derived. The results are obtained with the exact account for the atomic field. We use the quasiclassical approximation to the wave functions in the external field. For heavy atoms, the Coulomb corrections substantially modify the differential cross section as compared with the Born result. They lead to the azimuth asymmetry in the differential cross section for the polarized incoming electron. The Coulomb corrections to the total cross section are obtained in the leading logarithmic approximation.

  9. First Observation of the {Lambda}(1405) Line Shape in Electroproduction

    SciTech Connect

    Lu, Haiyun; Schumacher, Reinhard A.

    2013-10-01

    We report the first observation of the line shape of the {Lambda}(1405) from electroproduction, and show that it is not a simple Breit-Wigner resonance. Electroproduction of K{sup +}{Lambda}(1405) off the proton was studied by using data from CLAS at Jefferson Lab in the range 1.0

  10. Strangeness suppression of qq creation observed in exclusive reactions.

    PubMed

    Mestayer, M D; Park, K; Adhikari, K P; Aghasyan, M; Pereira, S Anefalos; Ball, J; Battaglieri, M; Batourine, V; Bedlinskiy, I; Biselli, A S; Boiarinov, S; Briscoe, W J; Brooks, W K; Burkert, V D; Carman, D S; Celentano, A; Chandavar, S; Charles, G; Colaneri, L; Cole, P L; Contalbrigo, M; Cortes, O; Crede, V; D'Angelo, A; Dashyan, N; De Vita, R; Deur, A; Djalali, C; Doughty, D; Dupre, R; El Alaoui, A; El Fassi, L; Elouadrhiri, L; Eugenio, P; Fedotov, G; Fleming, J A; Forest, T A; Garillon, B; Garçon, M; Ghandilyan, Y; Gilfoyle, G P; Giovanetti, K L; Girod, F X; Goetz, J T; Golovatch, E; Gothe, R W; Griffioen, K A; Guegan, B; Guidal, M; Hakobyan, H; Hanretty, C; Hattawy, M; Holtrop, M; Hughes, S M; Hyde, C E; Ilieva, Y; Ireland, D G; Jiang, H; Jo, H S; Joo, K; Keller, D; Khandaker, M; Kim, A; Kim, W; Koirala, S; Kubarovsky, V; Kuleshov, S V; Lenisa, P; Levine, W I; Livingston, K; Lu, H Y; MacGregor, I J D; Mayer, M; McKinnon, B; Meyer, C A; Mirazita, M; Mokeev, V; Montgomery, R A; Moody, C I; Moutarde, H; Movsisyan, A; Camacho, C Munoz; Nadel-Turonski, P; Niccolai, S; Niculescu, G; Niculescu, I; Osipenko, M; Ostrovidov, A I; Pappalardo, L L; Paremuzyan, R; Peng, P; Phelps, W; Pisano, S; Pogorelko, O; Pozdniakov, S; Price, J W; Protopopescu, D; Puckett, A J R; Raue, B A; Rimal, D; Ripani, M; Rizzo, A; Rosner, G; Roy, P; Sabatié, F; Saini, M S; Schott, D; Schumacher, R A; Simonyan, A; Sokhan, D; Strauch, S; Sytnik, V; Tang, W; Tian, Ye; Ungaro, M; Vernarsky, B; Vlassov, A V; Voskanyan, H; Voutier, E; Walford, N K; Watts, D P; Wei, X; Weinstein, L B; Wood, M H; Zachariou, N; Zhang, J; Zhao, Z W; Zonta, I

    2014-10-10

    We measured the ratios of electroproduction cross sections from a proton target for three exclusive meson-baryon final states: ΛK(+), pπ(0), and nπ(+), with the CLAS detector at Jefferson Lab. Using a simple model of quark hadronization, we extract qq creation probabilities for the first time in exclusive two-body production, in which only a single qq pair is created. We observe a sizable suppression of strange quark-antiquark pairs compared to nonstrange pairs, similar to that seen in high-energy production.

  11. Strangeness suppression of qq creation observed in exclusive reactions.

    PubMed

    Mestayer, M D; Park, K; Adhikari, K P; Aghasyan, M; Pereira, S Anefalos; Ball, J; Battaglieri, M; Batourine, V; Bedlinskiy, I; Biselli, A S; Boiarinov, S; Briscoe, W J; Brooks, W K; Burkert, V D; Carman, D S; Celentano, A; Chandavar, S; Charles, G; Colaneri, L; Cole, P L; Contalbrigo, M; Cortes, O; Crede, V; D'Angelo, A; Dashyan, N; De Vita, R; Deur, A; Djalali, C; Doughty, D; Dupre, R; El Alaoui, A; El Fassi, L; Elouadrhiri, L; Eugenio, P; Fedotov, G; Fleming, J A; Forest, T A; Garillon, B; Garçon, M; Ghandilyan, Y; Gilfoyle, G P; Giovanetti, K L; Girod, F X; Goetz, J T; Golovatch, E; Gothe, R W; Griffioen, K A; Guegan, B; Guidal, M; Hakobyan, H; Hanretty, C; Hattawy, M; Holtrop, M; Hughes, S M; Hyde, C E; Ilieva, Y; Ireland, D G; Jiang, H; Jo, H S; Joo, K; Keller, D; Khandaker, M; Kim, A; Kim, W; Koirala, S; Kubarovsky, V; Kuleshov, S V; Lenisa, P; Levine, W I; Livingston, K; Lu, H Y; MacGregor, I J D; Mayer, M; McKinnon, B; Meyer, C A; Mirazita, M; Mokeev, V; Montgomery, R A; Moody, C I; Moutarde, H; Movsisyan, A; Camacho, C Munoz; Nadel-Turonski, P; Niccolai, S; Niculescu, G; Niculescu, I; Osipenko, M; Ostrovidov, A I; Pappalardo, L L; Paremuzyan, R; Peng, P; Phelps, W; Pisano, S; Pogorelko, O; Pozdniakov, S; Price, J W; Protopopescu, D; Puckett, A J R; Raue, B A; Rimal, D; Ripani, M; Rizzo, A; Rosner, G; Roy, P; Sabatié, F; Saini, M S; Schott, D; Schumacher, R A; Simonyan, A; Sokhan, D; Strauch, S; Sytnik, V; Tang, W; Tian, Ye; Ungaro, M; Vernarsky, B; Vlassov, A V; Voskanyan, H; Voutier, E; Walford, N K; Watts, D P; Wei, X; Weinstein, L B; Wood, M H; Zachariou, N; Zhang, J; Zhao, Z W; Zonta, I

    2014-10-10

    We measured the ratios of electroproduction cross sections from a proton target for three exclusive meson-baryon final states: ΛK(+), pπ(0), and nπ(+), with the CLAS detector at Jefferson Lab. Using a simple model of quark hadronization, we extract qq creation probabilities for the first time in exclusive two-body production, in which only a single qq pair is created. We observe a sizable suppression of strange quark-antiquark pairs compared to nonstrange pairs, similar to that seen in high-energy production. PMID:25375706

  12. Electroproduction of pions on the three-nucleon systems

    SciTech Connect

    Lee, T.S.H.; Chmielewski, C.; Sauer, P.U.

    1995-08-01

    The electroproduction of pions on {sup 3}He is being studied with the assumption that the basic pion production mechanisms can be described by the N(e,e{prime}{pi}) model developed by Nozawa and Lee. In the impulse approximation, the {sup 3}He(e,e{prime}{pi}) cross section is then determined from the N and {Delta} spectral functions generated from Hannover`s three-body calculation including the {Delta}. The objective is to investigate the effects due to the {Delta} components in {sup 3}He, as suggested by Lipkin and Lee. This is being investigated by calculating the ratio between {sup 3}He(e,e{prime}{pi}{sup +}p) and {sup 3}He(e,e{prime}{pi}{sup -}). In a calculation for {sup 3}He(e,e{prime}{pi}{sup +}p) at very high momentum transfer, questions concerning color transparency of {Delta}{sup ++} propagation can be addressed.

  13. Color transparency in incoherent electroproduction of {rho} mesons off nuclei

    SciTech Connect

    Nemchik, J.; Kopeliovich, B. Z.; Potashnikova, I. K.

    2013-04-15

    Color transparency (CT) phenomena in elastic electroproduction of vector mesons off nuclei are usually infected by the onset of coherence length (CL) effects. However, at low energies corresponding to the CLAS experiment at Jefferson Lab (JLab), one can study practically the net CT effects, since CL is much shorter than the nuclear radius. We investigate various manifestations of CT effects using rigorous quantum mechanical approach based on the path integral technique. We include also the effects of {rho} meson decay inside the nucleus leading to a rise of the nuclear suppression towards small values of Q{sup 2}. Motivated by the last CLAS data we predict the A, Q{sup 2} and l{sub c} dependence of nuclear transparency for {rho}{sup 0} mesons produced incoherently off nuclei. We also perform predictions for expected signal of CT corresponding to the planned JLab upgrade to 12 GeV electron beam.

  14. Transversity GPD in photo- and electroproduction of two vectormesons

    SciTech Connect

    Enberg, Rikard; Pire, Bernard; Szymanowski, Lech

    2006-01-17

    The chiral-odd generalized parton distribution (GPD), or transversity GPD, of the nucleon can be accessed experimentally through the photo- or electroproduction of two vector mesons on a polarized nucleon target, {gamma}{sup (*)}N {yields} {rho}{sub 1}{rho}{sub 2}N', where {rho}{sub 1} is produced at large transverse momentum, {rho}{sub 2} is transversely polarized, and the mesons are separated by a large rapidity gap. We predict the cross section for this process for both transverse and longitudinal {rho}{sub 2} production. To this end we propose a model for the transversity GPDH{sub T}(x,{zeta},t), and give an estimate of the relative sizes of the transverse and longitudinal {rho}{sub 2}cross sections. We show that a dedicated experiment at high energy should be able to measure the transversity content of the proton.

  15. Electroproduction of K+ Λ at JLab Hall-C

    NASA Astrophysics Data System (ADS)

    Gogami, T.; Achenbach, P.; Ahmidouch, A.; Albayrak, I.; Androic, D.; Asaturyan, A.; Asaturyan, R.; Ates, O.; Baturin, P.; Badui, R.; Boeglin, W.; Bono, J.; Brash, E.; Carter, P.; Chen, C.; Chiba, A.; Christy, E.; Dalton, M.; Danagoulian, S.; De Leo, R.; Doi, D.; Elaasar, M.; Ent, R.; Fujii, Y.; Furic, M.; Gabrielyan, M.; Gan, L.; Garibaldi, F.; Gaskell, D.; Gasparian, A.; Hashimoto, O.; Horn, T.; Hu, B.; Hungerford, Ed. V.; Jones, M.; Kanda, H.; Kaneta, M.; Kato, S.; Kawai, M.; Kawama, D.; Khanal, H.; Kohl, M.; Liyanage, A.; Luo, W.; Maeda, K.; Margaryan, A.; Markowitz, P.; Maruta, T.; Matsumura, A.; Maxwell, V.; Mkrtchyan, A.; Mkrtchyan, H.; Nagao, S.; Nakamura, S. N.; Narayan, A.; Neville, C.; Niculescu, G.; Niculescu, M. I.; Nunez, A.; Nuruzzaman; Okayasu, Y.; Petkovic, T.; Pochodzalla, J.; Qiu, X.; Reinhold, J.; Rodriguez, V. M.; Samanta, C.; Sawatzky, B.; Seva, T.; Shichijo, A.; Tadevosyan, V.; Tang, L.; Taniya, N.; Tsukada, K.; Veilleux, M.; Vulcan, W.; Wesselmann, F. R.; Wood, S. A.; Yamamoto, T.; Ya, L.; Ye, Z.; Yokota, K.; Yuan, L.; Zhamkochyan, S.; Zhu, L.

    2013-08-01

    A Λ hypernuclear spectroscopic experiment, JLab E05-115 was performed at JLab Hall-C in 2009 by the (e, e'K+) reaction. Data of Λ hypernuclei with mass numbers from A = 7 to A = 52 were successfully taken, and the analyses are in progress. A polyethylene (CH2) target was used as a proton target to calibrate energy scales, and to study elementary process of the p(e, e'K+) Λ, Σ0 reaction. A preliminary differential cross section of K+ Λ electro-production at low Q2 [~0.01 (GeV/c)2] and at small kaon angles is reported in the present article.

  16. Pion Electroproduction form Helium 3, Deuterium, and Hydrogen

    SciTech Connect

    S. Avery

    2002-05-01

    A series of measurements for pion electroproduction from helium-3, deuterium, and hydrogen were completed at the Thomas Jefferson National Accelerator Facility by the NucPi Collaboration. E91003 began taking data in February 1998 and was completed in April 1998. The longitudinal and transverse parts of the differential cross section were extracted, by means of a Rosenbluth type separation, in the direction parallel to the virtual photon, at Q 2 = 0.4 GeV 2 , for W = 1.15 and W = 1.6 GeV. The mass dependence of the longitudinal cross section should provide insight into the surprising apparent absence of any significant cross section enhancement due to excess pions in the nuclear medium.

  17. Electroproduction of. pi. sup 0 on the proton near threshold

    SciTech Connect

    Welch, T.P.; Karen, P.H.; Mitchell, J.H.; Norum, B.E. ); Blok, H.P.; van den Brink, H.B. ); de Jager, C.W.; Jans, E.; Lapikas, L.; de Vries, H.; Wesseling, J. , P. O. Box 41882, 1009 DB Amsterdam ); Bergstrom, J. ); Deady, M. )

    1992-11-09

    The electroproduction of {pi}{sup 0} on the proton was measured from 0 to 2.5 MeV above threshold for virtual-photon 4-momenta of {minus}0.05 and {minus}0.1 (GeV/{ital c}){sup 2}. The sum of the lowest-order contributing multipoles, {ital a}{sub 0}={vert bar}{ital E}{sub 0+}{vert bar}{sup 2}{minus}{epsilon}{sub {ital L}}{vert bar}{ital L}{sub 0+}{vert bar}{sup 2}, was determined with a precision an order of magnitude better than previously possible. Our results for {ital a}{sub 0} are consistent with present calculations. Our extracted value for {vert bar}{ital L}{sub 0+}{vert bar}{sup 2} at the photon point'' is in agreement with recent predictions.

  18. Recoil Polarization for Delta Excitation in Pion Electroproduction

    SciTech Connect

    J. J. Kelly; R. E. Roche; Z. Chai; M. K. Jones; O. Gayou; A. J. Sarty; S. Frullani; K. Aniol; E. J. Beise; F. Benmokhtar; W. Bertozzi; W. U. Boeglin; T. Botto; E. J. Brash; H. Breuer; E. Brown; E. Burtin; J. R. Calarco; C. Cavata; C. C. Chang; N. S. Chant; J.-P. Chen; M. Coman; D. Crovelli; R. De Leo; S. Dieterich; S. Escoffier; K. G. Fissum; V. Garde; F. Garibaldi; S. Georgakopoulus; S. Gilad; R. Gilman; C. Glashausser; J.-O. Hansen; D. W. Higinbotham; A. Hotta; G. M. Huber; H. Ibrahim; M. Iodice; C. W. de Jager; X. Jiang; A. Klimenko; A. Kozlov; G. Kumbartzki; M. Kuss; L. Lagamba; G. Laveissiere; J. J. LeRose; R. A. Lindgren; N. Liyanage; G. J. Lolos; R. W. Lourie; D. J. Margaziotis; F. Marie; P. Markowitz; S. McAleer; D. Meekins; R. Michaels; B. D. Milbrath; J. Mitchell; J. Nappa; D. Neyret; C. F. Perdrisat; M. Potokar; V. A. Punjabi; T. Pussieux; R. D. Ransome; P. G. Roos; M. Rvachev; A. Saha; S. Sirca; R. Suleiman; S. Strauch; J. A. Templon; L. Todor; P. E. Ulmer; G. M. Urciuoli; L. B. Weinstein; K. Wijesooriya; B. Wojtsekhowski; X. Zheng; and L. Zhu

    2005-08-01

    We measured angular distributions of recoil-polarization response functions for neutral pion electroproduction for W=1.23 GeV at Q{sup 2}=1.0 (GeV/c){sup 2}, obtaining 14 separated response functions plus 2 Rosenbluth combinations; of these, 12 have been observed for the first time. Dynamical models do not describe quantities governed by imaginary parts of interference products well, indicating the need for adjusting magnitudes and phases for nonresonant amplitudes. We performed a nearly model-independent multipole analysis and obtained values for Re(S1+/M1+)=-(6.84+/-0.15)% and Re(E1+/M1+)=-(2.91+/-0.19)% that are distinctly different from those from the traditional Legendre analysis based upon M1+ dominance and sp truncation.

  19. Deeply Virtual Exclusive Reactions with CLAS

    SciTech Connect

    Kubarovsky, Valery

    2011-03-01

    Deeply virtual exclusive reactions offer an unique opportunity to study the structure of the nucleon at the parton level as one has access to Bjorken xB and momentum transfer to the nucleon t at the same time. Such processes can reveal much more information about the structure of the nucleon than either inclusive electroproduction or elastic form factors alone. Dedicated experiments to study Deeply Virtual Compton Scattering (DVCS) and Deeply VirtualMeson Production (DVMP) have been carried out in Hall B at Jefferson Lab. DVCS helicity–dependent and helicity–independent cross sections and beam spin asymmetries have been measured with CLAS, as well as cross sections and asymmetries for the p 0, h, r 0, r+, w and f for exclusive electroproduction. The data were taken in a wide kinematic range in Q2=1–4.5 GeV2, xB=0.1–0.5, and |t| up to 2 GeV2. We will discuss the interpretation of these data in terms of traditional Regge and Generalized Parton Distributions models. We view the work presented in this report as leading into the program of the Jefferson Lab 12 GeV upgrade. The increased energy and luminosity will allow us to acquire data at much higher Q2 and xB, and perform Rosenbluth L/T separations of the cross sections.

  20. Scaling study of the pion electroproduction cross sections and the pion form factor

    SciTech Connect

    Tanja Horn; Xin Qian; John Arrington; Razmik Asaturyan; Fatiha Benmokthar; Werner Boeglin; Peter Bosted; Antje Bruell; Eric Christy; Eugene Chudakov; Ben Clasie; Mark Dalton; AJI Daniel; Donal Day; Dipangkar Dutta; Lamiaa El Fassi; Rolf Ent; Howard Fenker; J. Ferrer; Nadia Fomin; H. Gao; K Garrow; Dave Gaskell; C Gray; G. Huber; M. Jones; N Kalantarians; C. Keppel; K Kramer; Y Li; Y Liang; A. Lung; S Malace; P. Markowitz; A. Matsumura; D. Meekins; T Mertens; T Miyoshi; H. Mykrtchyan; R. Monson; T. Navasardyan; G. Niculescu; I. Niculescu; Y. Okayasu; A. Opper; C Perdrisat; V. Punjabi; A. Rauf; V. Rodriguez; D. Rohe; J Seely; E Segbefia; G. Smith; M. Sumihama; V. Tadevoyan; L Tang; V. Tvaskis; A. Villano; W. Vulcan; F. Wesselmann; S. Wood; L. Yuan; X. Zheng

    2007-07-12

    The $^{1}$H($e,e^\\prime \\pi^+$)n cross section was measured for a range of four-momentum transfer up to $Q^2$=3.91 GeV$^2$ at values of the invariant mass, $W$, above the resonance region. The $Q^2$-dependence of the longitudinal component is consistent with the $Q^2$-scaling prediction for hard exclusive processes. This suggests that perturbative QCD concepts are applicable at rather low values of $Q^2$. Pion form factor results, while consistent with the $Q^2$-scaling prediction, are inconsistent in magnitude with perturbative QCD calculations. The extraction of Generalized Parton Distributions from hard exclusive processes assumes the dominance of the longitudinal term. However, transverse contributions to the cross section are still significant at $Q^2$=3.91 GeV$^2$.

  1. Electroproduction of neutral pions in the Hall A at the Jefferson Laboratory; Electroproduction de pions neutres dans le Hall A au Jefferson Laboratory

    SciTech Connect

    Fuchey, Eric

    2010-06-01

    The past decade has seen a strong evolution of the study of the hadron structure through exclusive processes, allowing to access to a more complete description of this structure. Exclusive processes include DVCS (Deeply Virtual Compton Scattering) as well as hard exclusive meson production. This document is particularly focussed on the latter, and more particularly on exclusive neutral pion production. In this thesis is described the analysis of triple coincidence events H(e, e'γγ)X, which were a consequent by-product of the DVCS experiment which occured during Fall 2004 at Jefferson Lab Hall A, to extract the ep → epπ0 cross section. This cross section has been measured at two values of four-momentum transfer Q2 = 1.9 GeV2 and Q2 = 2.3 GeV2. The statistical precision for these measurements is achieved at better than 5 %. The kinematic range allows to study the evolution of the extracted cross section as a function of Q2 and W. Results are be confronted with Regge inspired calculations and Generalized (GPD) predictions. An intepretation of our

  2. Spectroscopy of LiΛ9 by electroproduction

    DOE PAGESBeta

    Urciuoli, G. M.; Cusanno, F.; Marrone, S.; Acha, A.; Ambrozewicz, P.; Aniol, K. A.; Baturin, P.; Bertin, P. Y.; Benaoum, H.; Blomqvist, K. I.; et al

    2015-03-01

    Background: In the absence of accurate data on the free two-body hyperon-nucleon interaction, the spectra of hypernuclei can provide information on the details of the effective hyperon-nucleon interaction. Purpose: To obtain a high-resolution spectrum for the 9Be(e,e'K+)9ΛLi reaction. Method: Electroproduction of the hypernucleus 9ΛLi has been studied for the first time with sub-MeV energy resolution in Hall A at Jefferson Lab on a 9Be target. In order to increase the counting rate and to provide unambiguous kaon identification, two superconducting septum magnets and a Ring Imaging CHerenkov detector (RICH) were added to the Hall A standard equipment. Results: The crossmore » section to low-lying states of 9ΛLi is concentrated within 3 MeV of the ground state and can be fitted with four peaks. The positions of the doublets agree with theory while a disagreement could exist with respect to the relative strengths of the peaks in the doublets. A Λ separation energy, BΛ, of 8.36±0.08 (stat.) ±0.08 (syst.) MeV was measured, in agreement with an earlier experiment.« less

  3. Semi-Inclusive Pion Electroproduction in Deep Inelastic Scattering

    NASA Astrophysics Data System (ADS)

    Gohn, Wesley; Avakian, Harut; Joo, Kyungseon; Ungaro, Maurizio

    2010-02-01

    Measurements of pion electro-production in semi-inclusive deep inelastic scattering (SIDIS) have been performed. Data were taken with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab using a 5.498 GeV longitudinally polarized electron beam and an unpolarized liquid hydrogen target during the E1-f run period in 2003. All three pion channels (&+circ;, 0̂ and &-circ;) were measured simultaneously over a large range of kinematics(Q^2 1-4 GeV^2 and x 0.1-0.5). Preliminary results from our study of single-spin azimuthal asymmetries from all three pion channels as functions of x, z, and PT, from which ALU^sinφ is extracted, will be presented, as will preliminary measurements of AUU^cosφ and AUU^cos2φ in the charged pion channels. This new high statistical data could provide access to transverse-momentum dependent parton distribution functions (TMD's), which are thought to be important in understanding of the physics underlying the spin structure of the nucleon. )

  4. Exclusive {rho}{sup 0} meson electroproduction from hydrogen at CLAS

    SciTech Connect

    Cynthia Hadjidakis; Michel Guidal; Michel Garcon; Jean Laget; Elton Smith; Marc Vanderhaeghen

    2004-08-01

    The longitudinal and transverse components of the cross section for the ep {yields} e{prime}pp{sup 0} reaction were measured in Hall B at Jefferson Laboratory using the CLAS detector. The data were taken with a 4.247 GeV electron beam and were analyzed in a range of x{sub B} from 0.2 to 0.6 and of Q{sup 2} from 1.5 to 3.0 GeV{sup 2}. The data are compared to a Regge model based on effective hadronic degrees of freedom and to a calculation based on Generalized Parton Distributions. It is found that the transverse part of the cross section is well described by the former approach while the longitudinal part can be reproduced by the latter.

  5. Cross Sections for the Exclusive Photon Electroproduction on the Proton and Generalized Parton Distributions.

    PubMed

    Jo, H S; Girod, F X; Avakian, H; Burkert, V D; Garçon, M; Guidal, M; Kubarovsky, V; Niccolai, S; Stoler, P; Adhikari, K P; Adikaram, D; Amaryan, M J; Anderson, M D; Anefalos Pereira, S; Ball, J; Baltzell, N A; Battaglieri, M; Batourine, V; Bedlinskiy, I; Biselli, A S; Boiarinov, S; Briscoe, W J; Brooks, W K; Carman, D S; Celentano, A; Chandavar, S; Charles, G; Colaneri, L; Cole, P L; Compton, N; Contalbrigo, M; Crede, V; D'Angelo, A; Dashyan, N; De Vita, R; De Sanctis, E; Deur, A; Djalali, C; Dupre, R; Alaoui, A El; Fassi, L El; Elouadrhiri, L; Fedotov, G; Fegan, S; Filippi, A; Fleming, J A; Garillon, B; Gevorgyan, N; Ghandilyan, Y; Gilfoyle, G P; Giovanetti, K L; Goetz, J T; Golovatch, E; Gothe, R W; Griffioen, K A; Guegan, B; Guler, N; Guo, L; Hafidi, K; Hakobyan, H; Harrison, N; Hattawy, M; Hicks, K; Hirlinger Saylor, N; Ho, D; Holtrop, M; Hughes, S M; Ilieva, Y; Ireland, D G; Ishkhanov, B S; Jenkins, D; Joo, K; Joosten, S; Keller, D; Khachatryan, G; Khandaker, M; Kim, A; Kim, W; Klein, A; Klein, F J; Kuhn, S E; Kuleshov, S V; Lenisa, P; Livingston, K; Lu, H Y; MacGregor, I J D; McKinnon, B; Meziani, Z E; Mirazita, M; Mokeev, V; Montgomery, R A; Moutarde, H; Movsisyan, A; Munevar, E; Munoz Camacho, C; Nadel-Turonski, P; Net, L A; Niculescu, G; Osipenko, M; Ostrovidov, A I; Paolone, M; Park, K; Pasyuk, E; Phillips, J J; Pisano, S; Pogorelko, O; Price, J W; Procureur, S; Prok, Y; Puckett, A J R; Raue, B A; Ripani, M; Rizzo, A; Rosner, G; Rossi, P; Roy, P; Sabatié, F; Salgado, C; Schott, D; Schumacher, R A; Seder, E; Simonyan, A; Skorodumina, Iu; Smith, G D; Sokhan, D; Sparveris, N; Stepanyan, S; Strakovsky, I I; Strauch, S; Sytnik, V; Tian, Ye; Tkachenko, S; Ungaro, M; Voskanyan, H; Voutier, E; Walford, N K; Watts, D P; Wei, X; Weinstein, L B; Wood, M H; Zachariou, N; Zana, L; Zhang, J; Zhao, Z W; Zonta, I

    2015-11-20

    Unpolarized and beam-polarized fourfold cross sections (d^{4}σ/dQ^{2}dx_{B}dtdϕ) for the ep→e^{'}p^{'}γ reaction were measured using the CLAS detector and the 5.75-GeV polarized electron beam of the Jefferson Lab accelerator, for 110 (Q^{2},x_{B},t) bins over the widest phase space ever explored in the valence-quark region. Several models of generalized parton distributions (GPDs) describe the data well at most of our kinematics. This increases our confidence that we understand the GPD H, expected to be the dominant contributor to these observables. Through a leading-twist extraction of Compton form factors, these results support the model predictions of a larger nucleon size at lower quark-momentum fraction x_{B}.

  6. Cross sections for the exclusive photon electroproduction on the proton and Generalized Parton Distributions

    DOE PAGESBeta

    Jo, Hyon -Suk

    2015-11-17

    Unpolarized and beam-polarized four-fold cross sectionsmore » $$\\frac{d^4 \\sigma}{dQ^2 dx_B dt d\\phi}$$ for the $$ep\\to e^\\prime p^\\prime \\gamma$$ reaction were measured using the CLAS detector and the 5.75-GeV polarized electron beam of the Jefferson Lab accelerator, for 110 ($Q^2,x_B,t$) bins over the widest phase space ever explored in the valence-quark region. Several models of Generalized Parton Distributions (GPDs) describe the data well at most of our kinematics. This increases our confidence that we understand the GPD $H$, expected to be the dominant contributor to these observables. Thus, through a leading-twist extraction of Compton Form Factors, these results reveal a tomographic image of the nucleon.« less

  7. Cross sections for the exclusive photon electroproduction on the proton and Generalized Parton Distributions

    SciTech Connect

    Jo, Hyon -Suk

    2015-11-17

    Unpolarized and beam-polarized four-fold cross sections $\\frac{d^4 \\sigma}{dQ^2 dx_B dt d\\phi}$ for the $ep\\to e^\\prime p^\\prime \\gamma$ reaction were measured using the CLAS detector and the 5.75-GeV polarized electron beam of the Jefferson Lab accelerator, for 110 ($Q^2,x_B,t$) bins over the widest phase space ever explored in the valence-quark region. Several models of Generalized Parton Distributions (GPDs) describe the data well at most of our kinematics. This increases our confidence that we understand the GPD $H$, expected to be the dominant contributor to these observables. Thus, through a leading-twist extraction of Compton Form Factors, these results reveal a tomographic image of the nucleon.

  8. Electron beam asymmetry measurements from exclusive pi0 electroproduction in the Delta(1232) resonance region

    SciTech Connect

    K. Joo

    2003-05-01

    The polarized longitudinal-transverse structure function sigma_LT'in the p(e,e'p)pi^0 reaction has been measured for the first time in the Delta(1232) resonance region for invariant mass W = 1.1 - 1.3 GeV and at four-momentum transfer Q^2 = 0.40 and 0.65 GeV^2. Data were taken at the Thomas Jefferson National Accelerator Facility with the CEBAF Large Acceptance Spectrometer (CLAS) using longitudinally polarized electrons at an energy of 1.515 GeV. This newly measured sigma_LT' provides new and unique information on the interference between resonant and non-resonant amplitudes in the Delta(1232) resonance region. The comparison to recent phenomenological calculations shows sensitivity to the description of non-resonant amplitudes and higher resonances.

  9. Deeply Virtual Exclusive Reactions with CLAS

    SciTech Connect

    Valery Kubarovsky

    2011-11-01

    Deeply virtual exclusive reactions offer an unique opportunity to study the structure of the nucleon at the parton level as one has access to Bjorken x{sub B} and momentum transfer to the nucleon t at the same time. Such processes can reveal much more information about the structure of the nucleon than either inclusive electroproduction or elastic form factors alone. Dedicated experiments to study Deeply Virtual Compton Scattering (DVCS) and Deeply Virtual Meson Production (DVMP) have been carried out in Hall B at Jefferson Lab. DVCS helicity–dependent and helicity–independent cross sections and beam spin asymmetries have been measured with CLAS, as well as cross sections and asymmetries for the {pi}{sup }0, {eta} , {rho}{sup }0, {rho}{sup +}, {omega} and {phi} for exclusive electroproduction. The data were taken in a wide kinematic range in Q{sup 2}=1–4.5 GeV{sup 2}, x{sub B}=0.1–0.5, and {absval t} up to 2 GeV{sup 2}. We will discuss the interpretation of these data in terms of traditional Regge and Generalized Parton Distributions (GPDs) models. The successful description of the recent CLAS pseudoscalar meson exclusive production data by GPD-based model provides a unique opportunity to access the transversity GPDs. We view the work presented in this report as leading into the program of the Jefferson Lab 12 GeV upgrade. The increased energy and luminosity will allow us to acquire data at much higher Q{sup 2} and x{sub B}, and perform Rosenbluth L/T separations of the cross sections.

  10. Semi-inclusive charged-pion electroproduction off protons and deuterons: Cross sections, ratios, and access to the quark-parton model at low energies

    DOE PAGESBeta

    Asaturyan, R.; Ent, R.; Mkrtchyan, H.; Navasardyan, T.; Tadevosyan, V.; Adams, G. S.; Ahmidouch, A.; Angelescu, T.; Arrington, J.; Asaturyan, A.; et al

    2012-01-01

    A large set of cross sections for semi-inclusive electroproduction of charged pions (π±) from both proton and deuteron targets was measured. The data are in the deep-inelastic scattering region with invariant mass squared W2 > 4 GeV2 and range in four-momentum transfer squared 2 < Q2 < 4 (GeV/c)2, and cover a range in the Bjorken scaling variable 0.2 < x < 0.6. The fractional energy of the pions spans a range 0.3 < z < 1, with small transverse momenta with respect to the virtual-photon direction, Pt2 < 0.2 (GeV/c)2. The invariant mass that goes undetected, Mx or W',more » is in the nucleon resonance region, W' < 2 GeV. The new data conclusively show the onset of quark-hadron duality in this process, and the relation of this phenomenon to the high-energy factorization ansatz of electron-quark scattering and subsequent quark → pion production mechanisms. The x, z and Pt2 dependences of several ratios (the ratios of favored-unfavored fragmentation functions, charged pion ratios, deuteron-hydrogen and aluminum-deuteron ratios for π+ and π-) have been studied. The ratios are found to be in good agreement with expectations based upon a high-energy quark-parton model description. We find the azimuthal dependences to be small, as compared to exclusive pion electroproduction, and consistent with theoretical expectations based on tree-level factorization in terms of transverse-momentum-dependent parton distribution and fragmentation functions. In the context of a simple model, the initial transverse momenta of d quarks are found to be slightly smaller than for u quarks, while the transverse momentum width of the favored fragmentation function is about the same as for the unfavored one, and both fragmentation widths are larger than the quark widths.« less

  11. Exclusive processes: Tests of coherent QCD phenomena and nucleon substructure at CEBAF

    SciTech Connect

    Brodsky, S.J.

    1994-07-01

    Measurements of exclusive processes such as electroproduction, photoproduction, and Compton scattering are among the most sensitive probes of proton structure and coherent phenomena in quantum chromodynamics. The continuous electron beam at CEBAF, upgraded in laboratory energy to 10--12 GeV, will allow a systematic study of exclusive, semi-inclusive, and inclusive reactions in a kinematic range well-tuned to the study of fundamental nucleon and nuclear substructure. I also discuss the potential at CEBAF for studying novel QCD phenomena at the charm production threshold, including the possible production of nuclear-bound quarkonium.

  12. Strangeness suppression of qq¯ creation observed in exclusive reactions

    DOE PAGESBeta

    Mestayer, M. D.; Park, K.; Adhikari, K. P.; Aghasyan, M.; Pereira, S. Anefalos; Ball, J.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; et al

    2014-10-10

    In this study, we measured the ratios of electroproduction cross sections from a proton target for three exclusive meson-baryon final states: ΛK+, pπ0, and nπ+, with the CLAS detector at Jefferson Lab. Using a simple model of quark hadronization, we extract qq¯ creation probabilities for the first time in exclusive two-body production, in which only a single qq¯ pair is created. We observe a sizable suppression of strange quark-antiquark pairs compared to nonstrange pairs, similar to that seen in high-energy production.

  13. Recent results on high resolution hypernuclear spectroscopy by electroproduction at Jefferson Lab, Hall A

    SciTech Connect

    F. Garibaldi; H. Breuer; P. Brindza; P. Bydzovski; G. Chang; E. Cisbani; S. Colilli; F. Cusanno; R. De Leo; G. De Cataldo; K. De Jager; R. Feuerbach; E. Folts; R. Fratoni; S. Frullani; F. Giuliani; M. Gricia; D. Higinbotham; M. Iodice; B. Kross; L. Lagamba; J.J.Le Rose; M. Lucentini; P. Markowitz; S. Marrone; R. Michaels; E. Nappi; Y. Qiang; B. Reitz; F. Santavenere; J. Segal; M. Sotona; G.M.Urciuoli; P. Veneroni; B.Wojtsekhowski; C. Zorn

    2005-12-01

    The first ''systematic'' study of 1 p shell hypernuclei with electromagnetic probes has started in Hall A at Jefferson Lab [?]. The aim is to perform hypernuclear high resolution spectroscopy by the electroproduction of strangeness on four 1p-shell targets: 12C, 9Be, 16O, 7Li. The first part of the experiment on 12C and 9Be has been performed in 2004, the second part (16O and 7Li) is scheduled for June 2005. To overcome the major experimental difficulties, namely the low counting rate and the challenging Particle IDentification (PID), two septum magnets and a Ring Imaging CHerenkov (RICH) detector had to be added to the existing apparatus. After underlining the particular role the electroproduction reaction plays in hypernuclear physics we describe the challenging modifications of the Hall A apparatus. Preliminary results on 12C and 9Be are presented.

  14. Monte Carlo simulation of polarization measurements in kaon electro-production

    SciTech Connect

    T. Angelescu; L. Teodorescu; O.Keith Baker; P. Gueye

    2000-05-01

    Kaon electro-production experiments with polarized electron beam are planed at the Thomas Jefferson National Accelerator Facility (Virginia, USA) in order to complete the information on polarization response functions for the kaon electro-production reactions. The experiment uses the self analyzing property of the L recoil. The scattered electrons will be detected in coincidence with the kaons and the decay protons. This paper presents the simulation of this experiment which takes into account the spectrometer acceptances, multiple scattering and radiative corrections. The phase space distribution of the decay protons in the L center-of-mass system are generated in order to extract information on the polarization on the three directions. An experimental test with an unpolarized beam has been performed to estimate the efficiency of the method.

  15. Electroproduction of [pi][sup 0]'s at threshold: Finding less than expected

    SciTech Connect

    Welch, T.P.

    1992-01-01

    Near-threshold electroproduction of [pi][sup 0]'s was measured at NIKHEF-K for virtual photon 4-momentum -0.05 and -0.1 (GeV/c)[sup 2]. The magnitude of the sum of the lowest order contributing multipoles, a[sub 0] = [vert bar]E[sub 0+][vert bar][sup 2] [minus] [epsilon]k[sup 2][vert bar]L[sub 0+][vert bar][sup 2]/k[sup *2[sub o

  16. Probing Nucleon Structure with Meson Electro-production in Hall C

    SciTech Connect

    Wood, Stephen

    2011-02-01

    Meson electro-production is used in Hall C at Jefferson Lab to probe nucleon, baryon and nuclear structure. The experimental program in Hall C includes studies of semi-inclusive pion production, p, d(e, e'π±)X, where low energy factorization has been observed, suggesting that these reactions can be used to probe nucleon structure, including transverse momentum distributions of quarks, at energies available at JLab after the upcoming 12 GeV upgrade.

  17. Electroproduction of strangeness on (Lambda)H-3,4 bound states on helium

    SciTech Connect

    F. Dohrmann; D. Abbott; A. Ahmidouch; P. Ambrozewicz; C. S. Armstrong; J. Arrington; R. Asaturyan; K. Assamagan; S. Avery; K. Bailey; S. Beedoe; H. Bitao; H. Breuer; D. S. Brown; R. Carlini; J. Cha; N. Chant; E. Christy; A. Cochran; L. Cole; G. Collins; C. Cothran; J. Crowder; W. J. Cummings; S. Danagoulian; F. Duncan; J. Dunne; D. Dutta; T. Eden; M. Elaasar; R. Ent; L. Ewell; H. Fenker; H. T. Fortune; Y. Fujii; L. Gan; H. Gao; K. Garrow; D. F. Geesaman; P. Gueye; K. Gustafsson; K. Hafidi; J. O. Hansen; W. Hinton; H. E. Jackson; H. Juengst; C. Keppel; A. Klein; D. Koltenuk; Y. Liang; J. H. Liu; A. Lung; D. Mack; R. Madey; P. Markowitz; C. J. Martoff; D. Meekins; J. Mitchell; T. Miyoshi; H. Mkrtchyan; R. Mohring; S. K. Mtingwa; B. Mueller; T. G. O'Neill; G. Niculescu; I. Niculescu; D. Potterveld; J. W. Price; B. A. Raue; P. E. Reimer; J. Reinhold; J. Roche; P. Roos; M. Sarsour; Y. Sato; G. Savage; R. Sawafta; R. E. Segel; A. Yu. Semenov; S. Stepanyan; V. Tadevosian; S. Tajima; L. Tang; B. Terburg; A. Uzzle; S. Wood; H. Yamaguchi; C. Yan; C. Yan; L. Yuan; M. Zeier; B. Zeidman; B. Zihlmann

    2005-05-01

    The A(e,eK+)X reaction has been investigated at Jefferson Laboratory. Data were taken for Q{sup 2} approx. 0.35 GeV{sup 2} at a beam energy of 3.245 GeV for 1H,3He and 4He targets. Evidence for Lambda-hypernuclear bound states is seen for 3,4He targets. This is the first time that the electroproduction of these hypernuclei has been observed.

  18. Electroproduction of strangeness on {sub {lambda}}{sup 3,4}H bound states on Helium

    SciTech Connect

    Dohrmann, F.; Abbott, D.; Carlini, R.; Dunne, J.; Ent, R.; Fenker, H.; Garrow, K.; Lung, A.; Mack, D.; Meekins, D.; Mitchell, J.; Wood, S.; Yan, C.; Ahmidouch, A.; Ambrozewicz, P.; Martoff, C.J.; Armstrong, C.S.; Arrington, J.; Bailey, K.; Cummings, W.J.

    2005-05-06

    The A(e,e'K+)X reaction has been investigated at Jefferson Laboratory. Data were taken for Q2 {approx_equal} 0.35 GeV2 at a beam energy of 3.245 GeV for 1H,3He and 4He targets. Evidence for {lambda}-hypernuclear bound states is seen for 3,4He targets. This is the first time that the electroproduction of these hypernuclei has been observed.

  19. Nucleon resonance electroproduction at high momentum transers: Results from SLAC and suggestions for CEBAF

    SciTech Connect

    Keppel, C.

    1994-04-01

    Nucleon resonance electroproduction results from SLAC Experiment E14OX are presented. A CEBAF facility with doubled energy would enable similar high momentum transfer measurements to be made with greater accuracy. Of particular interest are the Delta P{sub 33}(1232) resonance form factor and R = {sigma}{sub L}/{sigma}{sub T}, the ratio of the longitudinal and transverse components of the cross section. A suggestion is made to study these quantities in conjunction with Bloom-Gilman duality.

  20. Electroexcitation of nucleon resonances from CLAS data on single pion electroproduction

    SciTech Connect

    I. G. Aznauryan, V. D. Burkert

    2009-11-01

    We present results on the electroexcitation of the low mass resonances Delta(1232)P33, N(1440)P11, N(1520)D13, and N(1535)S11 in a wide range of Q2. The results were obtained in the comprehensive analysis of JLab-CLAS data on differential cross sections, longitudinally polarized beam asymmetries, and longitudinal target and beam-target asymmetries for pion electroproduction off the proton. The data were analysed using two conceptually different approaches, fixed-t dispersion relations and a unitary isobar model, allowing us to draw conclusions on the model sensitivity of the obtained electrocoupling amplitudes. The amplitudes for the Delta(1232)P33} show the importance of a meson-cloud contribution to quantitatively explain the magnetic dipole strength, as well as the electric and scalar quadrupole transitions. They do not show any tendency of approaching the pQCD regime for Q2<6 GeV2. For the Roper resonance, N(1440)P11, the data provide strong evidence for this state as a predominantly radial excitation of a 3-quark ground state. Measured in pion electroproduction, the transverse helicity amplitude for the N(1535)S11 allowed us to obtain the branching ratios of this state to the piN and etaN channels via comparison to the results extracted from eta electroproduction. The extensive CLAS data also enabled the extraction of the gamma*p -> N(1520)D13 and N(1535)S11 longitudinal helicity amplitudes with good precision.

  1. A study of longitudinal charged-pion electroproduction in D, {sup 3}He, and {sup 4}He

    SciTech Connect

    Jackson, H.E.; Coulter, K.P.; Geesaman, D.F.

    1995-08-01

    Recent studies of pion electroproduction on the deuteron carried out by the ANL group at ALS, Saclay, show that even in the weakly-bound deuteron, multinucleon processes alter the electroproduction amplitudes in the forward direction. The data provide the first experimental indications for a significant change in the pion-nucleon coupling for nucleons bound in nuclei. It is clear that forward-angle electroproduction may be a sensitive probe of the properties of the pion coupling in the nuclear medium. At CEBAF, we will study longitudinal charged-pion electroproduction (in the excitation region below the delta isobar) along the direction of the momentum transfer where the charge scattering process dominates. Direct comparison of the cross section per nucleon in deuterium and the helium isotopes with the experimental value for the free nucleon will provide estimates of the strength of the nuclear pion field. A Rosenbluth separation of the longitudinal and transverse cross sections will be performed for four-momentum transfers of 2.5 and 10 fm{sup -2}. Measurements for a number of light nuclei will provide useful data on the sensitivity of longitudinal electroproduction to nuclear binding effects. If current conceptions of pion-exchange currents in nuclei are correct, longitudinal electroproduction will be suppressed at the lower momentum transfer and enhanced at the higher momentum transfer by multinucleon processes. If on the other hand, as suggested by recent data from Drell-Yan studies of antiquark structure functions, there is no such enhancement, a reformulation of pion exchange models of the medium- and short-range properties of nuclear forces will be required. Our proposal to carry out such a series of measurements at CEBAF using the coincident-pair spectrometer system planned for Hall C was approved. Pions will be observed in the short-orbit spectrometer (SOS) which will serve as the second arm.

  2. Kaon electroproduction at large four-momentum transfer

    SciTech Connect

    Pete Markowitz

    2003-06-16

    Exclusive H(e,e'K)Y data were taken in January, March and April of 2001 at the Jefferson Lab Hall A. The electrons and kaons were detected in coincidence in the hall's two High Resolution Spectrometers (HRS). The kaon arm of the pair had been specifically outfitted with two aerogel Cerenkov threshold detectors, designed to separately provide pion and proton particle identification thus allowing kaon identification. Preliminary data show the cross section's dependence on the invariant mass, W, along with results of systematic studies. Ultimately the data will be used to perform a Rosenbluth Separation as well, separating the longitudinal from the transverse response functions.

  3. Nucleon resonance electrocouplings from the CLAS data on charged double pion electroproduction.

    NASA Astrophysics Data System (ADS)

    Mokeev, Victor

    2009-05-01

    Measurements of charged double pion (2π) electroproduction off protons with CLAS [1-3] provided the most extensive experimental data set of nine 1-fold differential cross sections. Phenomenological analysis of these data was carried out within the framework of model [4] in the kinematic range: 1.3 < W < 1.8 GeV and 0.25 < Q^2 < 1.5 GeV^2. A successful description of all observables was achieved, allowing us to establish all essential contributing mechanisms, consisting of various meson-baryon isobar channels, direct 2π production, and to isolate the resonant parts of the cross sections. For the first time electrocouplings of the P11(1440) and D13(1520) states were obtained in studies of 2π electroproduction. Good agreement with the previous results [5] obtained from studies of &+circ;n and 0̂p electroproduction channels show that these electrocouplings can be evaluated reliably. The CLAS 2π data allowed us to determine electrocouplings for several high lying N^* states (M > 1.65 GeV), that have major hadronic decays with 2π emission. The information on amplitudes of contributing non-resonant mechanisms will be used in future N^* studies in a global multi-channel analysis under development at EBAC [6]. [1] M. Ripani et al., Phys. Rev. Lett. 91, 022002 (2003). [2] G. V. Fedotov et al., (CLAS Collaboration), arXiv:0809.1562 [nucl-ex] accepted by Phys. Rev. C. [3] http://clasweb.jlab.org/physicsdb/ (CLAS Physics Data Base). [4] V. I. Mokeev et al., arXiv: 0809.4158[hep-ph]. [5] I.G.Aznauryan, et. al., Phys. Rev.,C71, 015201 (2005). [6] A.Matsuyama, et. al., Phys.Rep., 439, 193 (2007); B.Julia-Diaz, et.al., Phys. Rev., C76, 065201 (2007).

  4. High-Resolution Spectroscopy of NΛ16 by Electroproduction

    NASA Astrophysics Data System (ADS)

    Cusanno, F.; Urciuoli, G. M.; Acha, A.; Ambrozewicz, P.; Aniol, K. A.; Baturin, P.; Bertin, P. Y.; Benaoum, H.; Blomqvist, K. I.; Boeglin, W. U.; Breuer, H.; Brindza, P.; Bydžovský, P.; Camsonne, A.; Chang, C. C.; Chen, J.-P.; Choi, Seonho; Chudakov, E. A.; Cisbani, E.; Colilli, S.; Coman, L.; Craver, B. J.; de Cataldo, G.; de Jager, C. W.; de Leo, R.; Deur, A. P.; Ferdi, C.; Feuerbach, R. J.; Folts, E.; Fratoni, R.; Frullani, S.; Garibaldi, F.; Gayou, O.; Giuliani, F.; Gomez, J.; Gricia, M.; Hansen, J. O.; Hayes, D.; Higinbotham, D. W.; Holmstrom, T. K.; Hyde, C. E.; Ibrahim, H. F.; Iodice, M.; Jiang, X.; Kaufman, L. J.; Kino, K.; Kross, B.; Lagamba, L.; Lerose, J. J.; Lindgren, R. A.; Lucentini, M.; Margaziotis, D. J.; Markowitz, P.; Marrone, S.; Meziani, Z. E.; McCormick, K.; Michaels, R. W.; Millener, D. J.; Miyoshi, T.; Moffit, B.; Monaghan, P. A.; Moteabbed, M.; Muñoz Camacho, C.; Nanda, S.; Nappi, E.; Nelyubin, V. V.; Norum, B. E.; Okasyasu, Y.; Paschke, K. D.; Perdrisat, C. F.; Piasetzky, E.; Punjabi, V. A.; Qiang, Y.; Raue, B.; Reimer, P. E.; Reinhold, J.; Reitz, B.; Roche, R. E.; Rodriguez, V. M.; Saha, A.; Santavenere, F.; Sarty, A. J.; Segal, J.; Shahinyan, A.; Singh, J.; Širca, S.; Snyder, R.; Solvignon, P. H.; Sotona, M.; Subedi, R.; Sulkosky, V. A.; Suzuki, T.; Ueno, H.; Ulmer, P. E.; Veneroni, P.; Voutier, E.; Wojtsekhowski, B. B.; Zheng, X.; Zorn, C.

    2009-11-01

    An experimental study of the O16(e,e'K+)NΛ16 reaction has been performed at Jefferson Lab. A thin film of falling water was used as a target. This permitted a simultaneous measurement of the p(e,e'K+)Λ,Σ0 exclusive reactions and a precise calibration of the energy scale. A ground-state binding energy of 13.76±0.16MeV was obtained for NΛ16 with better precision than previous measurements on the mirror hypernucleus OΛ16. Precise energies have been determined for peaks arising from a Λ in s and p orbits coupled to the p1/2 and p3/2 hole states of the N15 core nucleus.

  5. High Resolution Spectroscopy of 16N_Lambda by Electroproduction

    SciTech Connect

    Cusanno, Francesco; Urciuoli, Guido; Acha Quimper, Armando; Ambrozewicz, Pawel; Aniol, Konrad; Baturin, Pavlo; Bertin, Pierre; Benaoum, Hachemi; Blomqvist, Ingvar; Boeglin, Werner; Breuer, Herbert; Brindza, Paul; Bydzovsky, Petr; Camsonne, Alexandre; Chang, C.; Chang, C.C.; Chang, C.; Chang, C.C.; Chang, C.; Chang, C.C.; Chang, C.; Chang, C.C.; Chen, Jian-Ping; Choi, Seonho; Chudakov, Eugene; Cisbani, Evaristo; Colilli, Stefano; Coman, Luminita; Craver, Brandon; de Cataldo, Giacinto; De Jager, Cornelis; De Leo, Raffaele; Deur, Alexandre; Ferdi, Catherine; Feuerbach, Robert; Folts, Edward; Frullani, Salvatore; Garibaldi, Franco; Gayou, Olivier; Giuliani, Fausto; Gomez, Javier; Gricia, Massimo; Hansen, Jens-Ole; Hayes, David; Higinbotham, Douglas; Holmstrom, Timothy; Hyde, Charles; Ibrahim, Hassan; Iodice, Mauro; Jiang, Xiaodong; Kaufman, Lisa; Kino, Kouichi; Kross, Brian; Lagamba, Luigi; LeRose, John; Lindgren, Richard; Lucentini, Maurizio; Margaziotis, Demetrius; Markowitz, Pete; Marrone, Stefano; Meziani, Zein-Eddine; McCormick, Kathy; Michaels, Robert; Millener, D.; Miyoshi, Toshinobu; Moffit, Bryan; Monaghan, Peter; Moteabbed, Maryam; Munoz Camacho, Carlos; Nanda, Sirish; Nappi, E.; Nelyubin, Vladimir; Norum, Blaine; Okasyasu, Y.; Paschke, Kent; Perdrisat, Charles; Piasetzky, Eliazer; Punjabi, Vina; Qiang, Yi; Raue, Brian; Reimer, Paul; Reinhold, Joerg; Reitz, Bodo; Roche, Rikki; Rodriguez, Victor; Saha, Arunava; Santavenere, Fabio; Sarty, Adam; Segal, John; Shahinyan, Albert; Singh, Jaideep; Sirca, Simon; Snyder, Ryan; Solvignon, Patricia; Sotona, M.; Sotona, Miloslav; Sotona, M.; Sotona, Miloslav; Sotona, M.; Sotona, Miloslav; Sotona, M.; Sotona, Miloslav; Subedi, Ramesh; Sulkosky, Vince; Sulkosky, Vincent; Sulkosky, Vince; Sulkosky, Vincent; Suzuki, Tomokazu; Ueno, Hiroaki; Ulmer, Paul; Veneroni, P.P.; Voutier, Eric; Wojtsekhowski, Bogdan; Zeng, X.; Zorn, Carl

    2009-01-01

    An experimental study of the 16O(e, e'K+)16N_Lambda reaction has been performed at Jefferson Lab. A thin film of falling water was used as a target. This permitted a simultaneous measurement of the p(e, e'K+)Lambda,Sigma_0 exclusive reactions and a precise calibration of the energy scale. A ground-state binding energy of 13.76 ± 0.16 MeV was obtained for 16N_Lambda with better precision than previous measurements on the mirror hypernucleus 16O_Lambda. Precise energies have been determined for peaks arising from a Lambda in s and p orbits coupled to the p1/2 and p3/2 hole states of the 15N core nucleus.

  6. Measurement of Beam-Spin Asymmetries for Deep Inelastic pi{sup +} Electroproduction

    SciTech Connect

    H. Avakian; Volker D. Burkert; Latifa Elouadrhiri; et. al.

    2002-12-01

    We report the first evidence for a non-zero beam-spin azimuthal asymmetry in the electroproduction of positive pions in the deep-inelastic region. Data have been obtained using a polarized electron beam of 4.3 GeV and with the CLAS detector at the Thomas Jefferson National Accelerator Facility (JLab). The amplitude of the sin phi modulation increases with the momentum of the pion relative to the virtual photon, z, with an average amplitude of 0.038+/-0.005+/-0.003 for 0.5

  7. New quark-model calculations of photo-and electroproduction of N* and and Delta * resonances

    SciTech Connect

    Capstick, Simon

    1992-06-01

    An introduction is given to the calculation of resonance electromagnetic coupling in the nonrelativistic quark model. Recent improvements brought about by the inclusion of relativistic corrections to the transition operator are described. We show how such calculations may be further improved by the use of relativized-model wave functions, a modestly increased effective quark mass, and an ab initio calculation of the signs of the N-pidecay amplitudes of the resonances. A summary is given of the results for the photocouplings of all nonstrage baryons, as well as for certain amplitude ratios in electroproduction.

  8. Diffractive electroproduction of s{bar s} mesons off nuclei at CEBAF energies

    SciTech Connect

    Benhar, O.; Nikolaev, N.N.; Zakharov, B.G.

    1994-04-01

    The authors discuss diffractive incoherent electroproduction of s{bar s} mesons off nuclear targets at beam energies that are expected to be available at CEBAF (5-8 GeV). The Q{sup 2} and target mass dependence of the {phi} and {phi}{prime} transparency ratios has been studied within a theoretical approach in which the propagation of the s{bar s} pair through the nuclear medium is described in terms of the quantum mechanical evolution operator. The authors predict a complex pattern of nuclear effects, whose experimental study may provide information on several issues relevant to the understanding of QCD, both in the perturbative and nonperturbative regimes.

  9. High Resolution Spectroscopy of {sub {lambda}}{sup 12}B by Electroproduction

    SciTech Connect

    Iodice, M.; Cusanno, F.; Urciuoli, G. M.; Acha, A.; Ambrozewicz, P.; Coman, L.; Markowitz, P.; Moteabbed, M.; Raue, B.; Reinhold, J.; Aniol, K. A.; Margaziotis, D. J.; Baturin, P.; Jiang, X.; McCormick, K.; Bertin, P. Y.; Camsonne, A.; Ferdi, C.; Blomqvist, K. I.

    2007-08-03

    An experiment measuring electroproduction of hypernuclei has been performed in hall A at Jefferson Lab on a {sup 12}C target. In order to increase counting rates and provide unambiguous kaon identification two superconducting septum magnets and a ring imaging Cherenkov detector were added to the hall A standard equipment. An unprecedented energy resolution of less than 700 keV FWHM has been achieved. Thus, the observed {sub {lambda}}{sup 12}B spectrum shows for the first time identifiable strength in the core-excited region between the ground-state s-wave {lambda} peak and the 11 MeV p-wave {lambda} peak.

  10. Semi-inclusive charged-pion electroproduction off protons and deuterons: Cross sections, ratios, and access to the quark-parton model at low energies

    SciTech Connect

    Asaturyan, R.; Ent, R.; Mkrtchyan, H.; Navasardyan, T.; Tadevosyan, V.; Adams, G. S.; Ahmidouch, A.; Angelescu, T.; Arrington, J.; Asaturyan, A.; Baker, O. K.; Benmouna, N.; Bertoncini, C.; Blok, H. P.; Boeglin, W. U.; Bosted, P. E.; Breuer, H.; Christy, M. E.; Connell, S. H.; Cui, Y.; Dalton, M. M.; Danagoulian, S.; Day, D.; Dunne, J. A.; Dutta, D.; El Khayari, N.; Fenker, H. C.; Frolov, V. V.; Gan, L.; Gaskell, D.; Hafidi, K.; Hinton, W.; Holt, R. J.; Horn, T.; Huber, G. M.; Hungerford, E.; Jiang, X.; Jones, M.; Joo, K.; Kalantarians, N.; Kelly, J. J.; Keppel, C. E.; Kubarovsky, V.; Li, Y.; Liang, Y.; Mack, D.; Malace, S. P.; Markowitz, P.; McGrath, E.; McKee, P.; Meekins, D. G.; Mkrtchyan, A.; Moziak, B.; Niculescu, G.; Niculescu, I.; Opper, A. K.; Ostapenko, T.; Reimer, P. E.; Reinhold, J.; Roche, J.; Rock, S. E.; Schulte, E.; Segbefia, E.; Smith, C.; Smith, G. R.; Stoler, P.; Tang, L.; Ungaro, M.; Uzzle, A.; Vidakovic, S.; Villano, A.; Vulcan, W. F.; Wang, M.; Warren, G.; Wesselmann, F. R.; Wojtsekhowski, B.; Wood, S. A.; Xu, C.; Yuan, L.; Zheng, X.

    2012-01-01

    A large set of cross sections for semi-inclusive electroproduction of charged pions (π±) from both proton and deuteron targets was measured. The data are in the deep-inelastic scattering region with invariant mass squared W2 > 4 GeV2 and range in four-momentum transfer squared 2 < Q2 < 4 (GeV/c)2, and cover a range in the Bjorken scaling variable 0.2 < x < 0.6. The fractional energy of the pions spans a range 0.3 < z < 1, with small transverse momenta with respect to the virtual-photon direction, Pt2 < 0.2 (GeV/c)2. The invariant mass that goes undetected, Mx or W', is in the nucleon resonance region, W' < 2 GeV. The new data conclusively show the onset of quark-hadron duality in this process, and the relation of this phenomenon to the high-energy factorization ansatz of electron-quark scattering and subsequent quark → pion production mechanisms. The x, z and Pt2 dependences of several ratios (the ratios of favored-unfavored fragmentation functions, charged pion ratios, deuteron-hydrogen and aluminum-deuteron ratios for π+ and π-) have been studied. The ratios are found to be in good agreement with expectations based upon a high-energy quark-parton model description. We find the azimuthal dependences to be small, as compared to exclusive pion electroproduction, and consistent with theoretical expectations based on tree-level factorization in terms of transverse-momentum-dependent parton distribution and fragmentation functions. In the context of a simple model, the initial transverse momenta of d quarks are found to be slightly smaller than for u quarks, while the transverse momentum width of the favored fragmentation function is about the same as for the unfavored one, and both fragmentation widths are larger than the quark widths.

  11. Transition nucleon resonance electrocouplings from CLAS data on pi+pi-p electroproduction off protons.

    SciTech Connect

    Victor Mokeev

    2011-10-01

    Electrocouplings of excited proton states with masses less than 1.8 GeV were determined for the first time from the CLAS data on {pi}{sup +}{pi}{sup -}p electroproduction at photon virtualities Q{sup 2} < 1.5 GeV {sup 2}. Electrocouplings were obtained from a combined fit of all available observables within the framework of a phenomenological reaction model. Accurate information on the Q{sup 2}-evolution of {gamma}{sub virt}NN* electrocouplings for many excited proton states with masses less than 1.8 GeV and at photon virtualities up to 1.5 GeV{sup 2} have become available from CLAS data on {pi}{sup +}{pi}{sup -}p electroproduction. These results open up new opportunities for theory to explore confinement mechanisms in the baryon sector through their manifestation in the structure of excited proton states of various quantum numbers, as it was outlined. The analysis reported here covers the range of photon virtualities, where both meson-baryon and quark degrees of freedom can be relevant. Our results on high lying N* electrocouplings for the first time make it possible to explore the transition from meson-baryon to quark degrees of freedom in the structure of excited proton states with masses above 1.6 GeV within the framework of dynamical coupled channel approaches under development in EBAC at Jefferson Lab.

  12. Precision Measurements of Neutral Pion Electroproduction Near Threshold: A Test of Chiral QCD Dynamics

    SciTech Connect

    Lindgren, Richard A.; Chirapatpimol, Khem; Smith, Lee Cole

    2013-08-01

    Preliminary results are presented from an experiment to measure {pi}{sup 0} electroproduction at and above threshold using the p(e;e' p){pi}{sup 0} reaction. The data were taken at a beam energy of 1192 MeV using a two-spectrometer setup in Hall A at Jefferson Lab. For the first time in {pi}{sup 0} threshold electroproduction, complete coverage of the {phi}{sub {pi}}* and {theta}{sub {pi}}* angles in the center-of-mass (C.M.) was obtained for the invariant mass region up to {Delta}W=18 MeV above the {pi}{sup 0} threshold. At the same time our invariant momentum transfer squared covers the range Q{sup 2} = 0.05-0.15 (GeV/c){sup 2} with twelve bins in Q{sup 2}. The improved kinematic coverage in C.M., W and Q{sup 2} will better constrain theoretical interpretations of the data using phenomenological models and QCD-inspired models such as Heavy Baryon Chiral Perturbation Theory.

  13. Beam spin asymmetries from semi-inclusive pion electroproduction in deep inelastic scattering

    SciTech Connect

    Gohn, W.; Joo, K.; Ungaro, M.; Avakian, H.

    2009-08-04

    Measurements of beam-spin asymmetries from semi-inclusive pion electro-production in deep inelastic scattering (DIS) have been performed. Data were taken with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab using a 5.7 GeV longitudinally polarized electron beam and an unpolarized liquid hydrogen target. All three pion channels ({pi}{sup +}, {pi}{sup 0} and {pi}{sup -}) were measured simultaneously over a large range of kinematics at the intermediate Q{sup 2} range (Q{sup 2}{approx_equal}1-3 GeV{sup 2}). We present our preliminary studies of single-spin azimuthal asymmetries of the two charged pion channels as functions of z and P{sub T}. This new high statistical data will provide important means of studying physics underlying the spin structure of the nucleon.

  14. Single pi0 electro-production in the resonance region with CLAS

    SciTech Connect

    Kyungseon Joo

    2009-12-01

    We report the analysis status of single π0 electroproduction in the resonance region to study the electromagnetic excitation of the nucleon resonances. The study is aimed at understanding of the internal structure and dynamics of the nucleon. The experiment was performed using an unpolarized cryogenic hydrogen target and 2.0 and 5.8 GeV polarized electron beam during the e1e and e1-6 run periods with CLAS at Jefferson Lab. The new measurements will produce a data base with high statistics and large kinematic coverage for the hadronic invariant mass (W) up to 2.0 GeV in the momentum transfer (Q2) range of 0.3—6.0 GeV2. Preliminary results will be presented and compared with the various model calculations.

  15. Exclusive and Semi-Exclusive Reactions at a Higher Energy CEBAF

    SciTech Connect

    Carl Carlson

    1998-06-01

    More energy at CEBAF provides more opportunity for studies of hadron and nuclear properties. Many of the experiments that could be done are extensions of things already done at lower energies. Others represent new initiatives that could not work or could not theoretically be interpreted at lower energies. The author concentrates on the new initiatives, but do not wish our thinking to neglect what can be learned from continuations of lower energy work. The author begins with a list of some things that should be continued into a new energy regime. (1) Baryon and meson spectroscopy of higher mass states. With 4 GeV incoming electron energy, strange mesons are limited to 1.8 GeV in mass and charm is not producible. (2) Exclusive reactions, including meson and baryon form factors and reactions on few nucleon systems. The latter includes deuteron photodisintegration, the A and B form factors of the deuteron, and the deuteron tensor polarization T{sub 20}. (And we should not forget T{sub 20} in inclusive scattering.) (3) Hadrons in the nuclear medium, with such topics as color transparency, electroproduction of {rho} mesons, virtual Compton scattering off nuclei, and backward hadrons from e-d reactions. The very last must be especially important, since it gives the logo used in the advertizing for this conference. In addition, there are new initiatives that this talk will call attention to, in particular: (1) semi-exclusive meson production; (2) duality in semi-exclusive reactions; and (3) new views of exclusive reactions and perturbative QCD (leading to ''off-forward parton distributions'').

  16. Strangeness suppression of qq¯ creation observed in exclusive reactions

    SciTech Connect

    Mestayer, M. D.; Park, K.; Adhikari, K. P.; Aghasyan, M.; Pereira, S. Anefalos; Ball, J.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; Boiarinov, S.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Colaneri, L.; Cole, P. L.; Contalbrigo, M.; Cortes, O.; Crede, V.; D’Angelo, A.; Dashyan, N.; De Vita, R.; Deur, A.; Djalali, C.; Doughty, D.; Dupre, R.; Alaoui, A. El; Fassi, L. El; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fleming, J. A.; Forest, T. A.; Garillon, B.; Garçon, M.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guegan, B.; Guidal, M.; Hakobyan, H.; Hanretty, C.; Hattawy, M.; Holtrop, M.; Hughes, S. M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Jiang, H.; Jo, H. S.; Joo, K.; Keller, D.; Khandaker, M.; Kim, A.; Kim, W.; Koirala, S.; Kubarovsky, V.; Kuleshov, S. V.; Lenisa, P.; Levine, W. I.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Mayer, M.; McKinnon, B.; Meyer, C. A.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Moody, C. I.; Moutarde, H.; Movsisyan, A.; Camacho, C. Munoz; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Pappalardo, L. L.; Paremuzyan, R.; Peng, P.; Phelps, W.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Protopopescu, D.; Puckett, A. J. R.; Raue, B. A.; Rimal, D.; Ripani, M.; Rizzo, A.; Rosner, G.; Roy, P.; Sabatié, F.; Saini, M. S.; Schott, D.; Schumacher, R. A.; Simonyan, A.; Sokhan, D.; Strauch, S.; Sytnik, V.; Tang, W.; Tian, Ye; Ungaro, M.; Vernarsky, B.; Vlassov, A. V.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Weinstein, L. B.; Wood, M. H.; Zachariou, N.; Zhang, J.; Zhao, Z. W.; Zonta, I.

    2014-10-10

    In this study, we measured the ratios of electroproduction cross sections from a proton target for three exclusive meson-baryon final states: ΛK+, pπ0, and nπ+, with the CLAS detector at Jefferson Lab. Using a simple model of quark hadronization, we extract qq¯ creation probabilities for the first time in exclusive two-body production, in which only a single qq¯ pair is created. We observe a sizable suppression of strange quark-antiquark pairs compared to nonstrange pairs, similar to that seen in high-energy production.

  17. Exclusive processes at JLab at 6 GeV

    SciTech Connect

    Kim, Andrey

    2015-01-01

    Deeply virtual exclusive reactions provide a unique opportunity to probe the complex internal structure of the nucleon. They allow to access information about the correlations between parton transverse spatial and longitudinal momentum distributions from experimental observables. Dedicated experiments to study Deeply Virtual Compton Scattering (DVCS) and Deeply Virtual Meson Production (DVMP) have been carried out at Jefferson Lab using continuous electron beam with energies up to 6 GeV. Unpolarized cross sections, beam, target and double spin asymmetries have been measured for DVCS as well as for π0 exclusive electroproduction. The data from Hall B provide a wide kinematic coverage with Q2=1-4.5 GeV2, xB=0.1-0.5, and -t up to 2 GeV2. Hall A data have limited kinematic range partially overlapping with Hall B kinematics but provide a high accuracy measurements. Scaling tests of the DVCS cross sections provide solid evidence of twist-2 dominance, which makes chiral-even GPDs accessible even at modest Q2. We will discuss the interpretation of these data in terms of Generalized Parton Distributions (GPDs) model. Successful description of the recent CLAS π0 exclusive production data within the framework of the GPD-based model provides a unique opportunity to access the chiral-odd GPDs.

  18. Omega Electroproduction

    SciTech Connect

    Unwuchola, A. D.; Connell, Simon H.; Aurousseau, M.; Dalton, Mark M.

    2013-08-01

    The differential cross section for p(e, e'ω)p has been studied at Q{sup 2} ~ 5.5 (GeV/c)2. Here Q{sup 2} represents the four momentum squared of the virtual photon in the excitation of baryonic resonances by an electron projectile. In order to extract the ω-meson differential cross section from the JLAB data, the data was compared to a full Monte Carlo simulation of the detector based on events generated for omega production in a way that the production cross section was varied to achieve a match to the data. The bin selected for this procedure takes into account the measure of robustness of the stripping of the ω peak from the multi-pion background as well as the statistics in the measured data and the Monte Carlo simulation of the signal and background physics. An error estimation technique for the cross section was based on determining the dependence of the extracted cross section parameters on the experimental set-up (including parameters for the spectrometer, target beam geometeries and performance). We compare our results with a Regge-based model for hadronic content in the t-channel exchange of a photon in Q{sup 2} region of overlap. There is an extension of this data into a completely new region, which is the highest yet measured.

  19. Precision Measurement of Electroproduction of pi0 near Threshold

    SciTech Connect

    Chirapatpimol, Khem

    2012-05-01

    Electromagnetic production of neutral pions near threshold is the most basic, lowest energy reaction in which a new hadron is created. The electromagnetic interaction is well understood so measurements of this reaction can yield direct insight into the hadronic production mechanism. During the past three decades there have been many developments in both the measurement and theory of threshold pion production, starting with measurements of photo-production at Saclay in 1986 and at Mainz in 1990. These measurements indicated a surprising discrepancy with so-called Low Energy Theorems (LETs) which are based on quite fundamental symmetries and considerations. Chiral Perturbation Theory (ChPT) is an effective field theoretic description of the nuclear force which contains the underlying symmetries of the force but deals with nucleons and pions rather than quarks and gluons. It has the advantage of being applicable at low energies but requires tuning some parameters to experimental data. Once these parameters have been determined ChPT predicts how the reaction should behave as a function of the kinematic variable. When applied to the reaction, p(γ,π0)p, near threshold it explained the discrepancy with the LETs and made predictions for electroproduction, p(e,e'p)π 0. Electroproduction measurements at Mainz in the 1990's showed a clear discrepancy with these predictions of ChPT; with parameters determined from one set of kinematics the data for a second set lay far from the predicted value. However, recently completed measurements at Mainz disagreed with their previous measurements. In the experiment presented here, measurements of neutral pion electroproduction,p(e,e'p)π0, were made in bins of momentum transfer, Q2, between Q2 = 0.05 [GeV/c]2 and Q2 = 0.15 [GeV/c]0 and of center-of-mass energy, W, between 0 ≤ W ≤ 30 MeV (above threshold). The experiment was performed in Hall A

  20. Consistent model for πN transition distribution amplitudes and backward pion electroproduction

    NASA Astrophysics Data System (ADS)

    Lansberg, J. P.; Pire, B.; Semenov-Tian-Shansky, K.; Szymanowski, L.

    2012-03-01

    The extension of the concept of generalized parton distributions leads to the introduction of baryon to meson transition distribution amplitudes (TDAs), nondiagonal matrix elements of the nonlocal three quark operator between a nucleon and a meson state. We present a general framework for modeling nucleon to pion (πN) TDAs. Our main tool is the spectral representation for πN TDAs in terms of quadruple distributions. We propose a factorized Ansatz for quadruple distributions with input from the soft-pion theorem for πN TDAs. The spectral representation is complemented with a D-term like contribution from the nucleon exchange in the cross channel. We then study backward pion electroproduction in the QCD collinear factorization approach in which the nonperturbative part of the amplitude involves πN TDAs. Within our two component model for πN TDAs, we update previous leading-twist estimates of the unpolarized cross section. Finally, we compute the transverse target single spin asymmetry as a function of skewness. We find it to be sizable in the valence region and sensitive to the phenomenological input of our πN TDA model.

  1. Single p+ Electroproduction in the First and Second Resonance Regions Using CLAS

    SciTech Connect

    Hovanes Egiyan

    2001-09-01

    The study of single pion electroproduction can provide valuable information on the structure of the nucleon and its excited states. Although these reactions have been studied for decades, never has the n pi{sup +} channel been measured over the complete phase space of the reaction. The CEBAF Large Acceptance Spectrometer (CLAS) located in Hall B of Jefferson Lab is well-suited for conducting these measurements. The CLAS data were taken using a 1.515 GeV electron beam incident on a liquid H{sub 2} target. The cross sections have been extracted, and their phi-dependence has been fit to obtain the sigma{sub TT}, sigma{sub TL} and the sigma{sub T} + epsilon sigma{sub L} linear combination of the structure functions. An analysis program based on the Mainz unitary isobar model was used to analyze the experimental data from the pi{sup +} channel only. The resonant amplitudes for P{sub 33}(1232), S{sub 11}(1535) and D{sub 13}(1520) were obtained from the fit.

  2. Electroproduction of the {phi}(1020) Vector Meson at 4 GeV

    SciTech Connect

    Konstantin Loukachine

    2000-02-01

    We studied the reaction ep {yields} e{prime}p{prime}{phi} with a 4.2 GeV incident electron beam in the region of the electroproduction variables Q{sup 2} from 0.7 to 2.2 GeV{sup 2} and W from 2.0 to 2.6 GeV. The data were taken and analyzed at the Thomas Jefferson National Accelerator Facility. For the first time, we observe the expected t-slope dependence on Q{sup 2} and {Delta}{tau} in {phi} vector meson production. We find that the width of the forward {phi}-meson diffraction peak increases rapidly as the interaction time decreases below c{Delta}{tau} of 1 fm. Within a simple optical model framework, the data show that {phi} meson has a smaller size than the {rho}. The measured {phi} cross-section dependence on Q{sup 2} is in a good agreement with previous measurements and well-described by the phenomenological Pomeron exchange model. Our cross-section data do not favor the standard Vector Meson Dominance and s{bar s}-knockout model predictions. From the angular distribution of the decay {phi} {yields} K{sup +} K{sup -}, assuming the s-channel helicity conservation, we extracted the longitudinal-to-transverse cross-section ratio, R, and Vector Meson Dominance scaling parameter, {xi}{sup 2}, which are consistent with the previous measurements and the model expectations.

  3. Pion structure function from leading neutron electroproduction and SU(2) flavor asymmetry

    DOE PAGESBeta

    McKenney, Joshua R.; Sato, Nobuo; Melnitchouk, Wally; Ji, Chueng-Ryong

    2016-03-07

    In this paper, we examine the efficacy of pion exchange models to simultaneously describe leading neutron electroproduction at HERA and themore » $$\\bar{d}-\\bar{u}$$ flavor asymmetry in the proton. A detailed $$\\chi^2$$ analysis of the ZEUS and H1 cross sections, when combined with constraints on the pion flux from Drell-Yan data, allows regions of applicability of one-pion exchange to be delineated. The analysis disfavors several models of the pion flux used in the literature, and yields an improved extraction of the pion structure function and its uncertainties at parton momentum fractions in the pion of $$4 \\times 10^{-4} \\lesssim x_\\pi \\lesssim 0.05$$ at a scale of $Q^2$=10 GeV$^2$. Also, we provide estimates for leading proton structure functions in upcoming tagged deep-inelastic scattering experiments on the deuteron with forward protons, based on the fit results, at Jefferson Lab.« less

  4. Measurement of unpolarized semi-inclusive pi+ electroproduction off the proton

    SciTech Connect

    Osipenko, Mikhail; Ripani, Marco; Ricco, Giovanni; Avagyan, Harutyun; De Vita, Raffaella; Adams, Gary; Amaryan, Moscov; Amaryan, Moskov; Ambrozewicz, Pawel; Anghinolfi, Marco; Asryan, Gegham; Audit, Gerard; Bagdasaryan, H.; Baillie, Nathan; Ball, J.P.; Ball, Jacques; Baltzell, Nathan; Barrow, Steve; Battaglieri, Marco; Bedlinskiy, Ivan; Bektasoglu, Mehmet; Bellis, Matthew; Benmouna, Nawal; Berman, Barry; Biselli, Angela; Blaszczyk, Lukasz; Bonner, Billy; Bouchigny, Sylvain; Boyarinov, Sergey; Bradford, Robert; Branford, Derek; Briscoe, Wilbert; Brooks, William; Bultmann, S.; Bueltmann, Stephen; Burkert, Volker; Butuceanu, Cornel; Calarco, John; Careccia, Sharon; Carman, Daniel; Cazes, Antoine; Ceccopieri, Federico; Chen, Shifeng; Cole, Philip; Collins, Patrick; Coltharp, Philip; Corvisiero, Pietro; Crabb, Donald; Crede, Volker; Cummings, John; Dashyan, Natalya; De Masi, Rita; De Sanctis, Enzo; Degtiarenko, Pavel; Denizli, Haluk; Dennis, Lawrence; Deur, Alexandre; Dharmawardane, Kahanawita; Dhuga, Kalvir; Dickson, Richard; Djalali, Chaden; Dodge, Gail; Donnelly, J.; Doughty, David; Drozdov, V.; Dugger, Michael; Dytman, Steven; Dzyubak, Oleksandr; Egiyan, Hovanes; Egiyan, Kim; Elfassi, Lamiaa; Elouadrhiri, Latifa; Eugenio, Paul; Fatemi, Renee; Fedotov, Gleb; Feldman, Gerald; Feuerbach, Robert; Funsten, Herbert; Garcon, Michel; Gavalian, Gagik; Gilfoyle, Gerard; Giovanetti, Kevin; Girod, Francois-Xavier; Goetz, John; Golovach, Evgeny; Gonenc, Atilla; Gordon, Christopher; Gothe, Ralf; Griffioen, Keith; Guidal, Michel; Guillo, Matthieu; Guler, Nevzat; Guo, Lei; Gyurjyan, Vardan; Hadjidakis, Cynthia; Hafidi, Kawtar; Hakobyan, Hayk; Hakobyan, Rafael; Hanretty, Charles; Hardie, John; Hassall, Neil; Heddle, David; Hersman, F.; Hicks, Kenneth; Hleiqawi, Ishaq; Holtrop, Maurik; Hyde, Charles; Ilieva, Yordanka; Ilyichev, Alexander; Ireland, David; Ishkhanov, Boris; Isupov, Evgeny; Ito, Mark; Jenkins, David; Jo, Hyon-Suk; Joo, Kyungseon; Juengst, Henry; Kalantarians, Narbe; Kellie, James; Khandaker, Mahbubul; Kim, Wooyoung; Klein, Andreas; Klein, Franz; Klimenko, Alexei; Kossov, Mikhail; Krahn, Zebulun; Kramer, Laird; Kubarovsky, Valery; Kuhn, Joachim; Kuhn, Sebastian; Kuleshov, Sergey; Lachniet, Jeff; Laget, Jean; Langheinrich, Jorn; Lawrence, David; Li, Ji; Livingston, Kenneth; Lu, Haiyun; MacCormick, Marion; Marchand, Claude; Markov, Nikolai; Mattione, Paul; McAleer, Simeon; McCracken, Michael; McKinnon, Bryan; McNabb, John; Mecking, Bernhard; Mehrabyan, Surik; Melone, Joseph; Mestayer, Mac; Meyer, Curtis; Mibe, Tsutomu; Mikhaylov, Konstantin; Minehart, Ralph; Mirazita, Marco; Miskimen, Rory; Mokeev, Viktor; Morand, Ludyvine; Moriya, Kei; Morrow, Steven; Moteabbed, Maryam; Mueller, James; Munevar Espitia, Edwin; Mutchler, Gordon; Nadel-Turonski, Pawel; Napolitano, James; Nasseripour, Rakhsha; Niccolai, Silvia; Niculescu, Gabriel; Niculescu, Maria-Ioana; Niczyporuk, Bogdan; Niroula, Megh; Niyazov, Rustam; Nozar, Mina; O'Rielly, Grant; Ostrovidov, Alexander; Park, Kijun; Pasyuk, Evgueni; Paterson, Craig; Pereira, Sergio; Philips, Sasha; Pierce, Joshua; Pivnyuk, Nikolay; Pocanic, Dinko; Pogorelko, Oleg; Polli, Ermanno; Popa, Iulian; Pozdnyakov, Sergey; Preedom, Barry; Price, John; Prok, Yelena; Protopopescu, Dan; Qin, Liming; Raue, Brian; Riccardi, Gregory; Ritchie, Barry; Rosner, Guenther; Rossi, Patrizia; Rubin, Philip; Sabatie, Franck; Salamanca, Julian; Salgado, Carlos; Santoro, Joseph; Sapunenko, Vladimir; Schumacher, Reinhard; Serov, Vladimir; Sharabian, Youri; Shvedunov, Nikolay; Skabelin, Alexander; Smith, Elton; Smith, Lee; Sober, Daniel; Sokhan, Daria; Stavinskiy, Aleksey; Stepanyan, Samuel; Stepanyan, Stepan; Stokes, Burnham; Stoler, Paul; Strakovski, Igor; Strauch, Steffen; Taiuti, Mauro; Tedeschi, David; Thoma, Ulrike; Tkabladze, Avtandil; Tkachenko, Svyatoslav; Todor, Luminita; Trentadue, L.; Tur, Clarisse; Ungaro, Maurizio; Vineyard, Michael; Vlassov, Alexander; Watts, Daniel; Weinstein, Lawrence; Weygand, Dennis; Williams,

    2008-01-01

    Semi-inclusive pi+ electroproduction on protons has been measured with the CLAS detector at Jefferson Lab. The measurement was performed on a liquid-hydrogen target using a 5.75 GeV electron beam. The complete five-fold differential cross sections were measured over a wide kinematic range in Q2, x, z, and pT and over the complete range of azimuthal angles, phi, enabling us to separate the different structure functions, H2+eps*H1, H3 and H4. Our measurements of H2 at low-x were found to be in fairly good agreement with pQCD calculations, suggesting a precocious factorization of the process. Indeed, the conventional f(x)*D(z) term can account for almost all of the observed cross section, even at small z. The measured xF-distributions are in qualitative agreement with high energy data, which suggests a surprising numerical similarity between the spectator diquark fragmentation in the present reaction and the anti-quark fragmentation measured in e+e- collisions. We have observed that the p

  5. Session: Hard Rock Penetration

    SciTech Connect

    Tennyson, George P. Jr.; Dunn, James C.; Drumheller, Douglas S.; Glowka, David A.; Lysne, Peter

    1992-01-01

    This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of five presentations: ''Hard Rock Penetration - Summary'' by George P. Tennyson, Jr.; ''Overview - Hard Rock Penetration'' by James C. Dunn; ''An Overview of Acoustic Telemetry'' by Douglas S. Drumheller; ''Lost Circulation Technology Development Status'' by David A. Glowka; ''Downhole Memory-Logging Tools'' by Peter Lysne.

  6. Hardness Tester for Polyur

    NASA Technical Reports Server (NTRS)

    Hauser, D. L.; Buras, D. F.; Corbin, J. M.

    1987-01-01

    Rubber-hardness tester modified for use on rigid polyurethane foam. Provides objective basis for evaluation of improvements in foam manufacturing and inspection. Typical acceptance criterion requires minimum hardness reading of 80 on modified tester. With adequate correlation tests, modified tester used to measure indirectly tensile and compressive strengths of foam.

  7. The hard metal diseases

    SciTech Connect

    Cugell, D.W. )

    1992-06-01

    Hard metal is a mixture of tungsten carbide and cobalt, to which small amounts of other metals may be added. It is widely used for industrial purposes whenever extreme hardness and high temperature resistance are needed, such as for cutting tools, oil well drilling bits, and jet engine exhaust ports. Cobalt is the component of hard metal that can be a health hazard. Respiratory diseases occur in workers exposed to cobalt--either in the production of hard metal, from machining hard metal parts, or from other sources. Adverse pulmonary reactions include asthma, hypersensitivity pneumonitis, and interstitial fibrosis. A peculiar, almost unique form of lung fibrosis, giant cell interstitial pneumonia, is closely linked with cobalt exposure.66 references.

  8. The hard metal diseases.

    PubMed

    Cugell, D W

    1992-06-01

    Hard metal is a mixture of tungsten carbide and cobalt, to which small amounts of other metals may be added. It is widely used for industrial purposes whenever extreme hardness and high temperature resistance are needed, such as for cutting tools, oil well drilling bits, and jet engine exhaust ports. Cobalt is the component of hard metal that can be a health hazard. Respiratory diseases occur in workers exposed to cobalt--either in the production of hard metal, from machining hard metal parts, or from other sources. Adverse pulmonary reactions include asthma, hypersensitivity pneumonitis, and interstitial fibrosis. A peculiar, almost unique form of lung fibrosis, giant cell interstitial pneumonia, is closely linked with cobalt exposure.

  9. The hard metal diseases.

    PubMed

    Cugell, D W

    1992-06-01

    Hard metal is a mixture of tungsten carbide and cobalt, to which small amounts of other metals may be added. It is widely used for industrial purposes whenever extreme hardness and high temperature resistance are needed, such as for cutting tools, oil well drilling bits, and jet engine exhaust ports. Cobalt is the component of hard metal that can be a health hazard. Respiratory diseases occur in workers exposed to cobalt--either in the production of hard metal, from machining hard metal parts, or from other sources. Adverse pulmonary reactions include asthma, hypersensitivity pneumonitis, and interstitial fibrosis. A peculiar, almost unique form of lung fibrosis, giant cell interstitial pneumonia, is closely linked with cobalt exposure. PMID:1511554

  10. Hard Photodisintegration of Proton Pairs in {sup 3}He

    SciTech Connect

    Piasetzky, Eli; Pomerantz, Ishay; Higinbotham, D.; Strauch, S.; Gilman, R.

    2008-10-13

    Hard deuteron photodisintegration has been investigated for 20 years, as its cross section follows the constituent counting rule and it provides insight into the interplay between hadronic and quark-gluon degrees of freedom in high-momentum transfer exclusive reactions. We have now measured for the first time hard pp-pair disintegration in the reaction {gamma}{sup 3}He{yields}pp+n, using kinematics corresponding to a spectator neutron. Cross sections were measured for 90 deg. c.m. at 8 beam energies, from 0.8 to 4.7 GeV. Preliminary results will be presented and compared to the hard deuteron photodisintegration data.

  11. Hard exclusive neutral pion production at Jefferson Lab Hall A

    SciTech Connect

    Fuchey, E.

    2011-10-24

    We present measurements of the ep{yields}ep{pi}{sup 0} cross section extracted at two values of four-momentum transfer Q{sup 2} = 1.9 GeV{sup 2} and Q{sup 2} = 2.3 GeV{sup 2} at Jefferson Lab Hall A. The kinematic range allows to study the evolution of the cross section as a function of Q{sup 2} and W. Results will be confronted with Regge inspired calculations and GPD predictions. An intepretation of our data within the framework of semi-inclusive deep inelastic scattering has also been attempted.

  12. Hard diffractive results and prospects at the Tevatron

    SciTech Connect

    Peters, Krisztian; /Manchester U.

    2006-01-01

    We review hard diffractive results and prospects at the Tevatron with an emphasis on factorization breaking in diffractive processes. Upper limits on the exclusive di-jet and {chi}{sub c}{sup 0} production cross sections at CDF and the status of the D0 Forward Proton Detectors are discussed.

  13. Organizing Your Hard Disk.

    ERIC Educational Resources Information Center

    Stocker, H. Robert; Hilton, Thomas S. E.

    1991-01-01

    Suggests strategies that make hard disk organization easy and efficient, such as making, changing, and removing directories; grouping files by subject; naming files effectively; backing up efficiently; and using PATH. (JOW)

  14. Measurement of the polarized structure function sigma_LT^' for pion electroproduction in the Roper-resonance region

    SciTech Connect

    K. Joo; L. C. Smith

    2005-11-01

    The polarized longitudinal-transverse structure function sigma{sub LT'} measures the interference between real and imaginary amplitudes in pion electroproduction and can be used to probe the coupling between resonant and nonresonant processes. We report new measurements of sigma{sub LT'} in the N(1440)1/2+ (Roper) resonance region at Q2=0.40 and 0.65GeV2 for both the pi0p and pi+n channels. The experiment was performed at Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS) using longitudinally polarized electrons at a beam energy of 1.515 GeV. Complete angular distributions were obtained and are compared to recent phenomenological models. The sigma{sub LT'}(pi+n) channel shows a large sensitivity to the Roper-resonance multipoles M1- and S1- and provides new constraints on models of resonance formation.

  15. Model of reversible vesicular transport with exclusion

    NASA Astrophysics Data System (ADS)

    Bressloff, Paul C.; Karamched, Bhargav R.

    2016-08-01

    A major question in neurobiology concerns the mechanics behind the motor-driven transport and delivery of vesicles to synaptic targets along the axon of a neuron. Experimental evidence suggests that the distribution of vesicles along the axon is relatively uniform and that vesicular delivery to synapses is reversible. A recent modeling study has made explicit the crucial role that reversibility in vesicular delivery to synapses plays in achieving uniformity in vesicle distribution, so called synaptic democracy (Bressloff et al 2015 Phys. Rev. Lett. 114 168101). In this paper we generalize the previous model by accounting for exclusion effects (hard-core repulsion) that may occur between molecular motor-cargo complexes (particles) moving along the same microtubule track. The resulting model takes the form of an exclusion process with four internal states, which distinguish between motile and stationary particles, and whether or not a particle is carrying vesicles. By applying a mean field approximation and an adiabatic approximation we reduce the system of ODEs describing the evolution of occupation numbers of the sites on a 1D lattice to a system of hydrodynamic equations in the continuum limit. We find that reversibility in vesicular delivery allows for synaptic democracy even in the presence of exclusion effects, although exclusion does exacerbate nonuniform distributions of vesicles in an axon when compared with a model without exclusion. We also uncover the relationship between our model and other models of exclusion processes with internal states.

  16. Exclusive processes and the fundamental structure of hadrons

    DOE PAGESBeta

    Brodsky, Stanley J.

    2015-01-20

    I review the historical development of QCD predictions for exclusive hadronic processes, beginning with constituent counting rules and the quark interchange mechanism, phenomena which gave early validation for the quark structure of hadrons. The subsequent development of pQCD factorization theorems for hard exclusive amplitudes and the development of evolution equations for the hadron distribution amplitudes provided a rigorous framework for calculating hadronic form factors and hard scattering exclusive scattering processes at high momentum transfer. I also give a brief introduction to the field of "light-front holography" and the insights it brings to quark confinement, the behavior of the QCD couplingmore » in the nonperturbative domain, as well as hadron spectroscopy and the dynamics of exclusive processes.« less

  17. Exclusive processes and the fundamental structure of hadrons

    SciTech Connect

    Brodsky, Stanley J.

    2015-01-20

    I review the historical development of QCD predictions for exclusive hadronic processes, beginning with constituent counting rules and the quark interchange mechanism, phenomena which gave early validation for the quark structure of hadrons. The subsequent development of pQCD factorization theorems for hard exclusive amplitudes and the development of evolution equations for the hadron distribution amplitudes provided a rigorous framework for calculating hadronic form factors and hard scattering exclusive scattering processes at high momentum transfer. I also give a brief introduction to the field of "light-front holography" and the insights it brings to quark confinement, the behavior of the QCD coupling in the nonperturbative domain, as well as hadron spectroscopy and the dynamics of exclusive processes.

  18. Budgeting in Hard Times.

    ERIC Educational Resources Information Center

    Parrino, Frank M.

    2003-01-01

    Interviews with school board members and administrators produced a list of suggestions for balancing a budget in hard times. Among these are changing calendars and schedules to reduce heating and cooling costs; sharing personnel; rescheduling some extracurricular activities; and forming cooperative agreements with other districts. (MLF)

  19. Hard (and Soft) Facts.

    ERIC Educational Resources Information Center

    Kennedy, Mike

    1999-01-01

    Provides guidelines to help schools maintain hard floors and carpets, including special areas in schools and colleges that need attention and the elements needed to have a successful carpet-maintenance program. The importance of using heavy equipment to lessen time and effort is explained as are the steps maintenance workers can take to make the…

  20. CSI: Hard Drive

    ERIC Educational Resources Information Center

    Sturgeon, Julie

    2008-01-01

    Acting on information from students who reported seeing a classmate looking at inappropriate material on a school computer, school officials used forensics software to plunge the depths of the PC's hard drive, searching for evidence of improper activity. Images were found in a deleted Internet Explorer cache as well as deleted file space.…

  1. Running in Hard Times

    ERIC Educational Resources Information Center

    Berry, John N., III

    2009-01-01

    Roberta Stevens and Kent Oliver are campaigning hard for the presidency of the American Library Association (ALA). Stevens is outreach projects and partnerships officer at the Library of Congress. Oliver is executive director of the Stark County District Library in Canton, Ohio. They have debated, discussed, and posted web sites, Facebook pages,…

  2. Hard Times Hit Schools

    ERIC Educational Resources Information Center

    McNeil, Michele

    2008-01-01

    Hard-to-grasp dollar amounts are forcing real cuts in K-12 education at a time when the cost of fueling buses and providing school lunches is increasing and the demands of the federal No Child Left Behind Act still loom larger over states and districts. "One of the real challenges is to continue progress in light of the economy," said Gale Gaines,…

  3. Hard Diffraction at CDF

    SciTech Connect

    Melese, P.; CDF Collaboration

    1997-06-01

    We present results on diffractive production of hard processes in {anti p}p collisions at {radical}s = 1.8 TeV at the Tevatron using the CDF detector. The signatures used to identify diffractive events are the forward rapidity gap and/or the detection of a recoil antiproton with high forward momentum. We have observed diffractive W- boson, dijet, and heavy quark production. We also present results on double-pomeron production of dijets.

  4. Work Hard. Be Nice

    ERIC Educational Resources Information Center

    Mathews, Jay

    2009-01-01

    In 1994, fresh from a two-year stint with Teach for America, Mike Feinberg and Dave Levin inaugurated the Knowledge Is Power Program (KIPP) in Houston with an enrollment of 49 5th graders. By this Fall, 75 KIPP schools will be up and running, setting children from poor and minority families on a path to college through a combination of hard work,…

  5. SUPER HARD SURFACED POLYMERS

    SciTech Connect

    Mansur, Louis K; Bhattacharya, R; Blau, Peter Julian; Clemons, Art; Eberle, Cliff; Evans, H B; Janke, Christopher James; Jolly, Brian C; Lee, E H; Leonard, Keith J; Trejo, Rosa M; Rivard, John D

    2010-01-01

    High energy ion beam surface treatments were applied to a selected group of polymers. Of the six materials in the present study, four were thermoplastics (polycarbonate, polyethylene, polyethylene terephthalate, and polystyrene) and two were thermosets (epoxy and polyimide). The particular epoxy evaluated in this work is one of the resins used in formulating fiber reinforced composites for military helicopter blades. Measures of mechanical properties of the near surface regions were obtained by nanoindentation hardness and pin on disk wear. Attempts were also made to measure erosion resistance by particle impact. All materials were hardness tested. Pristine materials were very soft, having values in the range of approximately 0.1 to 0.5 GPa. Ion beam treatment increased hardness by up to 50 times compared to untreated materials. For reference, all materials were hardened to values higher than those typical of stainless steels. Wear tests were carried out on three of the materials, PET, PI and epoxy. On the ion beam treated epoxy no wear could be detected, whereas the untreated material showed significant wear.

  6. Measurement of the photon electroproduction cross section at JLAB with the goal of performing a Rosenbluth separation of the DVCS contribution

    SciTech Connect

    Jimenez-Arguello, Alejandro Marti

    2014-07-11

    The study of the inner structure of hadrons allows us to understand the nature of the interactions between partons, quarks and gluons, described by Quantum Chromodynamics. The elastic scattering reactions, which have been studied in order to measure the nucleon form factors, are included in this frame. The inelastic scattering reactions are also included in this frame, they allow us to obtain information about the nucleon structure thanks to the development of the parton distribution functions (PDFs). While through elastic scattering we can obtain information about the charge distribution of the nucleon, and hence, about the spatial distribution of the partons, through inelastic scattering we obtain information about the momentum distributions of partons, by employing the PDFs. However, we can study the exclusive inelastic scattering reactions, such as the Deeply Virtual Compton Scattering (DVCS), wich allow us to access to the spatial and momentum distributions simultaneously. This is possible thanks to the generalized parton distributions (GPDs), which allow us to correlate both types of distributions. The process known as DVCS is the easiest way to access the GPDs. This process can be expressed as the scattering of an electron by a proton by means of a virtual photon with the result of the scattered initial particles plus a real photon. We find a process competing with DVCS known as Bethe-Heitler (BH), in which the real photon is radiated by the lepton rather than the quark. Due to the small cross section of DVCS, of the order of nb, in order to conduct these kind of experiments it is necessary to make use of facilities capable of providing high beam intensities. One of these facilities is the Thomas Jefferson National Accelerator Facility , where the experiment JLab E07-007, "Complete Separation of Virtual Photon and π⁰ Electroproduction Observables of Unpolarized Protons", took place during the months of October to December of 2010. The main goal of this

  7. Ultrasonic characterization of materials hardness

    PubMed

    Badidi Bouda A; Benchaala; Alem

    2000-03-01

    In this paper, an experimental technique has been developed to measure velocities and attenuation of ultrasonic waves through a steel with a variable hardness. A correlation between ultrasonic measurements and steel hardness was investigated.

  8. ''Follow that quarkexclamation'' (and other exclusive stories)

    SciTech Connect

    Carroll, A.S.

    1987-06-17

    Quarks are considered to be the basic constituents of matter. In a series of recent experiments, Carroll studied exclusive reactions as a means of determining the interactions between quarks. Quantum Chromo-dynamics (QCD) is the modern theory of the interaction of quarks. This theory explains how quarks are held together via the strong interaction in particles known as hadrons. Hadrons consisting of three quarks are called baryons. Hadrons made up of a quark and an antiquark are called mesons. In his lecture, Carroll describes what happens when two hadrons collide and scatter to large angles. The violence of the collision causes the gluons that bind the quarks in a particular hadron to temporarily lose their grip on particular quarks. Quarks scramble toward renewed unity with other quarks, and they undergo rearrangement, which generally results in additional new particles. A two-body exclusive reaction has occurred when the same number of particles exist before and after the collisions. At large angles these exclusive reactions are very rare. The labels on the quarks known as flavor enable the experimenter to follow the history of individual quarks in detail during these exclusive reactions. Carroll describes the equipment used in the experiment to measure short distance, hard collisions at large angles. The collisions he discusses occur when a known beam of mesons or protons collide with a stationary proton target. Finally, Carroll summarizes what the experiments have shown from the study of exclusive reactions and what light some of their results shed on the theory of QCD.

  9. Hard metal composition

    DOEpatents

    Sheinberg, H.

    1983-07-26

    A composition of matter having a Rockwell A hardness of at least 85 is formed from a precursor mixture comprising between 3 and 10 wt % boron carbide and the remainder a metal mixture comprising from 70 to 90% tungsten or molybdenum, with the remainder of the metal mixture comprising nickel and iron or a mixture thereof. The composition has a relatively low density of between 7 and 14 g/cc. The precursor is preferably hot pressed to yield a composition having greater than 100% of theoretical density.

  10. Hard metal composition

    DOEpatents

    Sheinberg, Haskell

    1986-01-01

    A composition of matter having a Rockwell A hardness of at least 85 is formed from a precursor mixture comprising between 3 and 10 weight percent boron carbide and the remainder a metal mixture comprising from 70 to 90 percent tungsten or molybdenum, with the remainder of the metal mixture comprising nickel and iron or a mixture thereof. The composition has a relatively low density of between 7 to 14 g/cc. The precursor is preferably hot pressed to yield a composition having greater than 100% of theoretical density.

  11. Dihadron Electroproduction in DIS with Transversely Polarized 3He Target at 12 GeV Jefferson Lab

    NASA Astrophysics Data System (ADS)

    Zhang, Jixie; SoLID Collaboration

    2013-10-01

    The transversity distribution function is one of the important and least known parton distribution functions (PDFs) of the nucleon. It can be studied via both single-hadron and double-hadron electro-production from a transversely polarized target in the deep inelastic scattering (DIS) region. Due to the low cross section, the data for the transversity distribution functions are very scarce. After 12 GeV upgrade, the high intensity 12 GeV electron accelerator at Jefferson Lab (JLab), togather with tThe large acceptance of the proposed Solenoidal Large Intensity Device (SoLID) in Hall A, will provide very good opportunities to study the transversity distribution functions in high precision. In this talk, we will present the dihadron program with SoLID. We plan to measure the single target spin asymmetries (SSA) of dihadron production in DIS region using 11 and 8.8 GeV electron beam on a transversely polarized 3He target. We will map the SSA in a 4-D space of x, Q2, zh and Mh. Assuming leading twist dominance, the transversity distribution, h1, can be extracted by combine with the world data on dihadron fragmentation functions (DiFF). These data will provide crucial inputs to the flavor separation of the transversity, especially the d quark distribution.

  12. Measurement of the unpolarized kaon(+)Lambda and kaon(+)Sigma(0) electroproduction cross sections and interference terms from the proton with the CLAS detector

    NASA Astrophysics Data System (ADS)

    Feuerbach, Robert J.

    Using the CLAS detector, we measure the K+Λ and K+Sigma0 electroproduction response functions over the continuous kinematic range from threshold to W = 2.05 GeV and for Q2 between 0.5 and 1.5 (GeV/c)2, with nearly complete angular coverage in the center-of-momentum frame angles. The sigmaT + epsilonsigmaL, sigmaTT and sigmaLT terms are extracted and compared to recent theoretical calculations based upon a hadrodynamic effective-Lagrangian framework. From examining the W-dependence of the response functions for the K+Λ final state, we find features in the (sigmaT + epsilonsigma L) term in the W = 1.75 to 1.90 GeV region, similar to features seen in recent photoproduction results. In general, the sigma TT and sigmaLT response-functions for Λ production are of the same order of magnitude as the (sigma T + epsilonsigmaL) term, suggesting that both sigmaT and sigmaL contribute significantly. For the K+Sigma 0 final state the W-dependence of the (sigma T + epsilonsigmaL) and sigma TT terms have large, resonant-like features near W = 1.9 GeV. Unlike in Λ electroproduction, the sigma LT interference term for Sigma0 electroproduction is found to be consistent with zero across nearly the entire kinematic range, while sigmaTT is comparable in magnitude to the sigmaT + epsilonsigmaL differential cross-section. The models, while achieving some qualitative agreement with the data, fail to both describe the details of the angular distributions and reproduce the resonant-like behavior observed.

  13. Deeply Virtual Pseudoscalar Meson Production with CLAS

    SciTech Connect

    Valery Kubarovsky; Paul Stoler; Ivan Bedlinsky

    2007-09-03

    Deeply virtual Compton scattering, cross sections and asymmetries for the pi^0 and eta exclusive electroproduction in a very wide kinematic range of Q^2, t and x_B have been measured with CLAS (Jlab). Initial analyzes already are showing remarkable results. These data will help us to better understand the transition from soft to hard mechanisms.

  14. Electroproduction of Eta Mesons in the S11(1535) Resonance Region at High Momentum Transfer

    SciTech Connect

    Dalton, Mark; Adams, Gary; Ahmidouch, Abdellah; Angelescu, Tatiana; Arrington, John; Asaturyan, Razmik; Baker, Keith; Benmouna, Nawal; Bertoncini, Crystal; Boeglin, Werner; Bosted, Peter; Breuer, Herbert; Christy, Michael; Connell, S.; Cui, Y.; Danagoulian, Samuel; Day, Donal; Dodario, T.; Dunne, James; Dutta, Dipangkar; Khayari, N.El; Ent, R.; Fenker, Howard; Frolov, Valera; Gan, Liping; Gaskell, David; Hafidi, Kawtar; Hinton, Wendy; Holt, Roy; Horn, Tanja; Huber, Garth; Hungerford, Ed; Jiang, Xiaodong; Jones, Mark; Joo, Kyungseon; Kalantarians, Narbe; Kelly, J.J.; Keppel, Cynthia; Koubarovski, Valeri; Kubarovsky, Valery; Kubarovsky, Valery; Kubarovsky, Valery; Li, Y.; Liang, Y.; Malace, S.; Markowitz, Pete; McKee, Paul; Meekins, David; Mkrtchyan, Hamlet; Moziak, B.; Navasardyan, Tigran; Niculescu, Gabriel; Niculescu, Maria-Ioana; Opper, Allena; Ostapenko, Tanya; Reimer, Paul; Reinhold, Joerg; Roche, Julie; ROCK, S.E.; Schulte, Elaine; Segbefia, Edwin; Smith, C.; Smith, Gregory; Stoler, Paul; Tadevosyan, Vardan; Tang, Liguang; Tvaskis, Vladas; Ungaro, Maurizio; Uzzle, Alicia; Vidakovic, S.; Villano, A.; Vulcan, William; WANG, M.; Warren, Glen; Wesselmann, Frank; Wojtsekhowski, Bogdan; Wood, Stephen; Xu, C.; Yuan, Lulin; Zheng, Xiaochao; Guo Zhu, Hong

    2009-01-01

    The differential cross-section for the process p(e,e'p)eta has been measured at Q2 ~ 5.7 and 7.0 (GeV/c)2 for centre-of-mass energies from threshold to 1.8 GeV, encompassing the S11(1535) resonance, which dominates the channel. This is the highest momentum transfer measurement of this exclusive process to date. The helicity-conserving transition amplitude A_1/2, for the production of the S11(1535) resonance, is extracted from the data. This quantity appears to begin scaling as 1/Q3, a predicted signal of the dominance of perturbative QCD, at Q2 ~ 5 (GeV/c)2.

  15. High-Resolution Spectroscopy of {sub L}AMBDA{sup 16}N by Electroproduction

    SciTech Connect

    Cusanno, F.; Urciuoli, G. M.; Acha, A.; Ambrozewicz, P.; Boeglin, W. U.; Coman, L.; Markowitz, P.; Moteabbed, M.; Raue, B.; Reinhold, J.; Aniol, K. A.; Margaziotis, D. J.; Baturin, P.; Jiang, X.; McCormick, K.; Bertin, P. Y.; Camsonne, A.; Ferdi, C.; Blomqvist, K. I.

    2009-11-13

    An experimental study of the {sup 16}O(e,e{sup '}K{sup +}){sub L}AMBDA{sup 16}N reaction has been performed at Jefferson Lab. A thin film of falling water was used as a target. This permitted a simultaneous measurement of the p(e,e{sup '}K{sup +})LAMBDA,SIGMA{sup 0} exclusive reactions and a precise calibration of the energy scale. A ground-state binding energy of 13.76+-0.16 MeV was obtained for {sub L}AMBDA{sup 16}N with better precision than previous measurements on the mirror hypernucleus {sub L}AMBDA{sup 16}O. Precise energies have been determined for peaks arising from a LAMBDA in s and p orbits coupled to the p{sub 1/2} and p{sub 3/2} hole states of the {sup 15}N core nucleus.

  16. Induced Proton Polarization for pi0 Electroproduction at Q2 = 0.126 GeV2/c2 Around the Delta(1232) Resonance

    SciTech Connect

    Glen Warren; Ricardo Alarcon; Christopher Armstrong; Burin Asavapibhop; David Barkhuff; William Bertozzi; Volker Burkert; J. Chen; Jian-Ping Chen; Joseph Comfort; Daniel Dale; George Dodson; S. Dolfini; K. Dow; Martin Epstein; Manouchehr Farkhondeh; John Finn; Shalev Gilad; Ralf Gothe; Xiaodong Jiang; Mark Jones; Kyungseon Joo; A. Karabarbounis; James Kelly; Stanley Kowalski; C. Kunz; D. Liu; R.W. Lourie; Richard Madey; Demetrius Margaziotis; Pete Markowitz; Justin McIntyre; C. Mertz; Brian Milbrath; Rory Miskimen; Joseph Mitchell; S. Mukhopadhyay; Costas Papanicolas; Charles Perdrisat; Vina Punjabi; Liming Qin; Paul Rutt; Adam Sarty; Jeffrey Shaw; S.B. Soong; D. Tieger; Christoph Tschalaer; William Turchinetz; Paul Ulmer; Scott Van Verst; C. Vellidis; Lawrence Weinstein; Steven Williamson; Rhett Woo; Alaen Young

    1998-12-01

    We present a measurement of the induced proton polarization P{sub n} in {pi}{sup 0} electroproduction on the proton around the {Delta} resonance. The measurement was made at a central invariant mass and a squared four-momentum transfer of W = 1231 MeV and Q{sup 2} = 0.126 GeV{sup 2}/c{sup 2}, respectively. We measured a large induced polarization, P{sub n} = -0.397 {+-} 0.055 {+-} 0.009. The data suggest that the scalar background is larger than expected from a recent effective Hamiltonian model.

  17. Incoherent $J/\\psi$ electroproduction from the deuteron at energies available at Jefferson Laboratory and the elastic$J/\\psi$-nucleon scattering amplitude

    SciTech Connect

    Howell, Gary T.; Miller, Gerald A.

    2013-07-01

    Calculations are presented for incoherent $J/\\psi$ electroproduction from the deuteron at JLab energies, including the effects of $J/\\psi$-nucleon rescattering in the final state, in order to determine the feasibility of measuring the $J/\\psi$-nucleon scattering length, or the $J/\\psi$-nucleon scattering amplitude at lower relative energies than in previous measurements. It is shown that for a scattering length of the size predicted by existing theoretical calculations, it would not be possible to determine the scattering length. However, it may be possible to determine the scattering amplitude at significantly lower relative energies than the only previous measurements.

  18. Combinatorics of bicubic maps with hard particles

    NASA Astrophysics Data System (ADS)

    Bouttier, J.; Di Francesco, P.; Guitter, E.

    2005-05-01

    We present a purely combinatorial solution of the problem of enumerating planar bicubic maps with hard particles. This is done by the use of a bijection with a particular class of blossom trees with particles, obtained by an appropriate cutting of the maps. Although these trees have no simple local characterization, we prove that their enumeration may be performed upon introducing a larger class of 'admissible' trees with possibly doubly occupied edges and summing them with appropriate signed weights. The proof relies on an extension of the cutting procedure allowing for the presence on the maps of special non-sectile edges. The admissible trees are characterized by simple local rules, allowing eventually for an exact enumeration of planar bicubic maps with hard particles. We also discuss generalizations for maps with particles subject to more general exclusion rules and show how to re-derive the enumeration of quartic maps with Ising spins in the present framework of admissible trees. We finally comment on a possible interpretation in terms of branching processes.

  19. Enhanced Information Exclusion Relations

    NASA Astrophysics Data System (ADS)

    Xiao, Yunlong; Jing, Naihuan; Li-Jost, Xianqing

    2016-07-01

    In Hall’s reformulation of the uncertainty principle, the entropic uncertainty relation occupies a core position and provides the first nontrivial bound for the information exclusion principle. Based upon recent developments on the uncertainty relation, we present new bounds for the information exclusion relation using majorization theory and combinatoric techniques, which reveal further characteristic properties of the overlap matrix between the measurements.

  20. Central Exclusive Dijet Production

    SciTech Connect

    Dechambre, A.; Cudell, J. R.; Ivanov, I. P.; Hernandez, O.

    2008-08-29

    The ingredients of central exclusive production cross section include large perturbative corrections and soft quantities that must be parametrized and fitted to data. In this talk, we summarize the results of a study of the uncertainties coming from these ingredients, in the case of exclusive dijet production.

  1. Enhanced Information Exclusion Relations.

    PubMed

    Xiao, Yunlong; Jing, Naihuan; Li-Jost, Xianqing

    2016-01-01

    In Hall's reformulation of the uncertainty principle, the entropic uncertainty relation occupies a core position and provides the first nontrivial bound for the information exclusion principle. Based upon recent developments on the uncertainty relation, we present new bounds for the information exclusion relation using majorization theory and combinatoric techniques, which reveal further characteristic properties of the overlap matrix between the measurements. PMID:27460975

  2. Generalized parton distributions and exclusive processes

    SciTech Connect

    Guzey, Vadim

    2013-10-01

    In last fifteen years, GPDs have emerged as a powerful tool to reveal such aspects of the QCD structure of the nucleon as: - 3D parton correlations and distributions; - spin content of the nucleon. Further advances in the field of GPDs and hard exclusive processes rely on: - developments in theory and new methods in phenomenology such as new flexible parameterizations, neural networks, global QCD fits - new high-precision data covering unexplored kinematics: JLab at 6 and 12 GeV, Hermes with recoil detector, Compass, EIC. This slide-show presents: Nucleon structure in QCD, particularly hard processes, factorization and parton distributions; and a brief overview of GPD phenomenology, including basic properties of GPDs, GPDs and QCD structure of the nucleon, and constraining GPDs from experiments.

  3. Overview: Hard Rock Penetration

    SciTech Connect

    Dunn, J.C.

    1992-01-01

    The Hard Rock Penetration program is developing technology to reduce the costs of drilling and completing geothermal wells. Current projects include: lost circulation control, rock penetration mechanics, instrumentation, and industry/DOE cost shared projects of the Geothermal Drilling organization. Last year, a number of accomplishments were achieved in each of these areas. A new flow meter being developed to accurately measure drilling fluid outflow was tested extensively during Long Valley drilling. Results show that this meter is rugged, reliable, and can provide useful measurements of small differences in fluid inflow and outflow rates. By providing early indications of fluid gain or loss, improved control of blow-out and lost circulation problems during geothermal drilling can be expected. In the area of downhole tools for lost circulation control, the concept of a downhole injector for injecting a two-component, fast-setting cementitious mud was developed. DOE filed a patent application for this concept during FY 91. The design criteria for a high-temperature potassium, uranium, thorium logging tool featuring a downhole data storage computer were established, and a request for proposals was submitted to tool development companies. The fundamental theory of acoustic telemetry in drill strings was significantly advanced through field experimentation and analysis. A new understanding of energy loss mechanisms was developed.

  4. Overview: Hard Rock Penetration

    SciTech Connect

    Dunn, J.C.

    1992-08-01

    The Hard Rock Penetration program is developing technology to reduce the costs of drilling and completing geothermal wells. Current projects include: lost circulation control, rock penetration mechanics, instrumentation, and industry/DOE cost shared projects of the Geothermal Drilling organization. Last year, a number of accomplishments were achieved in each of these areas. A new flow meter being developed to accurately measure drilling fluid outflow was tested extensively during Long Valley drilling. Results show that this meter is rugged, reliable, and can provide useful measurements of small differences in fluid inflow and outflow rates. By providing early indications of fluid gain or loss, improved control of blow-out and lost circulation problems during geothermal drilling can be expected. In the area of downhole tools for lost circulation control, the concept of a downhole injector for injecting a two-component, fast-setting cementitious mud was developed. DOE filed a patent application for this concept during FY 91. The design criteria for a high-temperature potassium, uranium, thorium logging tool featuring a downhole data storage computer were established, and a request for proposals was submitted to tool development companies. The fundamental theory of acoustic telemetry in drill strings was significantly advanced through field experimentation and analysis. A new understanding of energy loss mechanisms was developed.

  5. Overview - Hard Rock Penetration

    SciTech Connect

    Dunn, James C.

    1992-03-24

    The Hard Rock Penetration program is developing technology to reduce the costs of drilling and completing geothermal wells. Current projects include: lost circulation control, rock penetration mechanics, instrumentation, and industry/DOE cost shared projects of the Geothermal Drilling Organization. Last year, a number of accomplishments were achieved in each of these areas. A new flow meter being developed to accurately measure drilling fluid outflow was tested extensively during Long Valley drilling. Results show that this meter is rugged, reliable, and can provide useful measurements of small differences in fluid inflow and outflow rates. By providing early indications of fluid gain or loss, improved control of blow-out and lost circulation problems during geothermal drilling can be expected. In the area of downhole tools for lost circulation control, the concept of a downhole injector for injecting a two-component, fast-setting cementitious mud was developed. DOE filed a patent application for this concept during FY 91. The design criteria for a high-temperature potassium, uranium, thorium logging tool featuring a downhole data storage computer were established, and a request for proposals was submitted to tool development companies. The fundamental theory of acoustic telemetry in drill strings was significantly advanced through field experimentation and analysis. A new understanding of energy loss mechanisms was developed.

  6. Measuring the Hardness of Minerals

    ERIC Educational Resources Information Center

    Bushby, Jessica

    2005-01-01

    The author discusses Moh's hardness scale, a comparative scale for minerals, whereby the softest mineral (talc) is placed at 1 and the hardest mineral (diamond) is placed at 10, with all other minerals ordered in between, according to their hardness. Development history of the scale is outlined, as well as a description of how the scale is used…

  7. Enhanced Information Exclusion Relations

    PubMed Central

    Xiao, Yunlong; Jing, Naihuan; Li-Jost, Xianqing

    2016-01-01

    In Hall’s reformulation of the uncertainty principle, the entropic uncertainty relation occupies a core position and provides the first nontrivial bound for the information exclusion principle. Based upon recent developments on the uncertainty relation, we present new bounds for the information exclusion relation using majorization theory and combinatoric techniques, which reveal further characteristic properties of the overlap matrix between the measurements. PMID:27460975

  8. Beta Backscatter Measures the Hardness of Rubber

    NASA Technical Reports Server (NTRS)

    Morrissey, E. T.; Roje, F. N.

    1986-01-01

    Nondestructive testing method determines hardness, on Shore scale, of room-temperature-vulcanizing silicone rubber. Measures backscattered beta particles; backscattered radiation count directly proportional to Shore hardness. Test set calibrated with specimen, Shore hardness known from mechanical durometer test. Specimen of unknown hardness tested, and radiation count recorded. Count compared with known sample to find Shore hardness of unknown.

  9. Melting of polydisperse hard disks.

    PubMed

    Pronk, Sander; Frenkel, Daan

    2004-06-01

    The melting of a polydisperse hard-disk system is investigated by Monte Carlo simulations in the semigrand canonical ensemble. This is done in the context of possible continuous melting by a dislocation-unbinding mechanism, as an extension of the two-dimensional hard-disk melting problem. We find that while there is pronounced fractionation in polydispersity, the apparent density-polydispersity gap does not increase in width, contrary to 3D polydisperse hard spheres. The point where the Young's modulus is low enough for the dislocation unbinding to occur moves with the apparent melting point, but stays within the density gap, just like for the monodisperse hard-disk system. Additionally, we find that throughout the accessible polydispersity range, the bound dislocation-pair concentration is high enough to affect the dislocation-unbinding melting as predicted by Kosterlitz, Thouless, Halperin, Nelson, and Young.

  10. Spin Density Matrix Elements in Exclusive Production of Omega Mesons at HERMES

    NASA Astrophysics Data System (ADS)

    Marukyan, Hrachya

    2016-02-01

    Exclusive electroproduction of ω mesons on unpolarized hydrogen and deuterium targets is studied at HERMES in the kinematic region of Q2 > 1.0GeV2, 3.0GeV < W < 6.3GeV, and ‑ t‧ < 0.2GeV2. The data were accumulated during the 1996-2007 running period using the 27.6GeV longitudinally polarized electron or positron beams at HERA. The determination of the virtual-photon longitudinal-to-transverse cross-section ratio shows that a considerable part of the cross section arises from transversely polarized photons. Spin density matrix elements are derived and presented in projections of Q2 or ‑ t‧. Violation of s-channel helicity conservation is observed for some of these elements. A sizable contribution from unnatural-parity-exchange amplitudes is found and the phase shift between those amplitudes that describe transverse ω production by longitudinal and transverse virtual photons is determined for the first time. Good agreement is found between the HERMES proton data and results of a pQCD-inspired phenomenological model that includes pion-pole contributions.

  11. Inference by Exclusion in Goffin Cockatoos (Cacatua goffini)

    PubMed Central

    O’Hara, Mark; Auersperg, Alice M. I.; Bugnyar, Thomas; Huber, Ludwig

    2015-01-01

    Inference by exclusion, the ability to base choices on the systematic exclusion of alternatives, has been studied in many nonhuman species over the past decade. However, the majority of methodologies employed so far are hard to integrate into a comparative framework as they rarely use controls for the effect of neophilia. Here, we present an improved approach that takes neophilia into account, using an abstract two-choice task on a touch screen, which is equally feasible for a large variety of species. To test this approach we chose Goffin cockatoos (Cacatua goffini), a highly explorative Indonesian parrot species, which have recently been reported to have sophisticated cognitive skills in the technical domain. Our results indicate that Goffin cockatoos are able to solve such abstract two-choice tasks employing inference by exclusion but also highlight the importance of other response strategies. PMID:26244692

  12. Probing the perturbative dynamics of exclusive meson pair production

    NASA Astrophysics Data System (ADS)

    Harland-Lang, L. A.; Khoze, V. A.; Ryskin, M. G.; Stirling, W. J.

    2013-10-01

    We present the results of a recent novel application of the 'hard exclusive' perturbative formalism to the process gg → MMbar at large angles, where M (Mbar) is a light meson (anti-meson). As well as discussing the important theoretical features of the relevant leading-order gg → qqbar (gg) qqbar (gg) 6-parton amplitudes, we also comment on their phenomenological implications. In particular, we consider the central exclusive production of meson pairs at comparatively large transverse momentum k⊥, which is expected to proceed via this mechanism. We show that this leads to various non-trivial predictions for a range of exclusive processes, and that the cross sections for the η‧ and η mesons display significant sensitivity to any valence gg component of the meson wavefunctions.

  13. Inclusive and Exclusive |Vub|

    SciTech Connect

    Petrella, Antonio; /Ferrara U. /INFN, Ferrara

    2011-11-17

    The current status of the determinations of CKM matrix element |V{sub ub}| via exclusive and inclusive charmless semileptonic B decays is reviewed. The large datasets collected at the B-Factories, and the increased precision of theoretical calculations have allowed an improvement in the determination of |V{sub ub}|. However, there are still significant uncertainties. In the exclusive approach, the most precise measurement of the pion channel branching ratio is obtained by an untagged analysis. This very good precision can be reached by tagged analyses with more data. The problem with exclusive decays is that the strong hadron dynamics can not be calculated from first principles and the determination of the form factor has to rely on light-cone sum rules or lattice QCD calculations. The current data samples allow a comparison of different FF models with data distributions. With further developments on lattice calculations, the theoretical error should shrink to reach the experimental one. The inclusive approach still provides the most precise |V{sub ub}| determinations. With new theoretical calculations, the mild (2.5{sigma}) discrepancy with respect to the |V{sub ub}| value determined from the global UT fit has been reduced. As in the exclusive approach, theoretical uncertainties represent the limiting factor to the precision of the measurement. Reducing the theoretical uncertainties to a level comparable with the statistical error is challenging. New measurements in semileptonic decays of charm mesons could increase the confidence in theoretical calculations and related uncertainties.

  14. Mutually Exclusive, Complementary, or . . .

    ERIC Educational Resources Information Center

    Schloemer, Cathy G.

    2016-01-01

    Whether students are beginning their study of probability or are well into it, distinctions between complementary sets and mutually exclusive sets can be confusing. Cathy Schloemer writes in this article that for years she used typical classroom examples but was not happy with the student engagement or the level of understanding they produced.…

  15. Hard Facts and Soft Skills

    ERIC Educational Resources Information Center

    Terego, Alex

    2009-01-01

    The argument now raging in academic circles pits those who espouse teaching 21st century skills against those who believe that schools should be teaching explicit and well-sequenced content. This debate has largely been framed as an either-or proposition. In this author's view, portraying this debate as one between two mutually exclusive sides…

  16. Hard diffraction in Pythia 8

    NASA Astrophysics Data System (ADS)

    Overgaard Rasmussen, Christine

    2016-07-01

    We present an overview of the options for diffraction implemented in the general-purpose event generator Pythia 8 [1]. We review the existing model for soft diffraction and present a new model for hard diffraction. Both models use the Pomeron approach pioneered by Ingelman and Schlein, factorising the diffractive cross section into a Pomeron flux and a Pomeron PDF, with several choices for both implemented in Pythia 8. The model of hard diffraction is implemented as a part of the multiparton interactions (MPI) framework, thus introducing a dynamical gap survival probability that explicitly breaks factorisation.

  17. Hardness of ion implanted ceramics

    SciTech Connect

    Oliver, W.C.; McHargue, C.J.; Farlow, G.C.; White, C.W.

    1985-01-01

    It has been established that the wear behavior of ceramic materials can be modified through ion implantation. Studies have been done to characterize the effect of implantation on the structure and composition of ceramic surfaces. To understand how these changes affect the wear properties of the ceramic, other mechanical properties must be measured. To accomplish this, a commercially available ultra low load hardness tester has been used to characterize Al/sub 2/O/sub 3/ with different implanted species and doses. The hardness of the base material is compared with the highly damaged crystalline state as well as the amorphous material.

  18. Structure of hard particle fluids near a hard wall. II. yw(z) for hard spheres

    NASA Astrophysics Data System (ADS)

    Labik, S.; Smith, William R.; Speedy, Robin J.

    1988-02-01

    Predictions of the wall-cavity correlation function yw(z) for hard spheres against a hard wall are tested using the treatment that Smith and Speedy developed and examined for the case of hard disks in part I of this series, as well as an extension of this approach using an alternative procedure. yw(z) in the range 0≤z≤1 may be accurately predicted using only the thermodynamic properties of the bulk fluid, for which precise expressions are available. These predictions are tested by determining yw(z) and the cavity concentration profile nwo(z) in a computer simulation study. We also derive a new integral equation relating yw(z) near the wall to its values just outside the wall and illustrate this in examining the consistency of our computer simulation results.

  19. FATIGUE OF BIOMATERIALS: HARD TISSUES.

    PubMed

    Arola, D; Bajaj, D; Ivancik, J; Majd, H; Zhang, D

    2010-09-01

    The fatigue and fracture behavior of hard tissues are topics of considerable interest today. This special group of organic materials comprises the highly mineralized and load-bearing tissues of the human body, and includes bone, cementum, dentin and enamel. An understanding of their fatigue behavior and the influence of loading conditions and physiological factors (e.g. aging and disease) on the mechanisms of degradation are essential for achieving lifelong health. But there is much more to this topic than the immediate medical issues. There are many challenges to characterizing the fatigue behavior of hard tissues, much of which is attributed to size constraints and the complexity of their microstructure. The relative importance of the constituents on the type and distribution of defects, rate of coalescence, and their contributions to the initiation and growth of cracks, are formidable topics that have not reached maturity. Hard tissues also provide a medium for learning and a source of inspiration in the design of new microstructures for engineering materials. This article briefly reviews fatigue of hard tissues with shared emphasis on current understanding, the challenges and the unanswered questions.

  20. FATIGUE OF BIOMATERIALS: HARD TISSUES

    PubMed Central

    Arola, D.; Bajaj, D.; Ivancik, J.; Majd, H.; Zhang, D.

    2009-01-01

    The fatigue and fracture behavior of hard tissues are topics of considerable interest today. This special group of organic materials comprises the highly mineralized and load-bearing tissues of the human body, and includes bone, cementum, dentin and enamel. An understanding of their fatigue behavior and the influence of loading conditions and physiological factors (e.g. aging and disease) on the mechanisms of degradation are essential for achieving lifelong health. But there is much more to this topic than the immediate medical issues. There are many challenges to characterizing the fatigue behavior of hard tissues, much of which is attributed to size constraints and the complexity of their microstructure. The relative importance of the constituents on the type and distribution of defects, rate of coalescence, and their contributions to the initiation and growth of cracks, are formidable topics that have not reached maturity. Hard tissues also provide a medium for learning and a source of inspiration in the design of new microstructures for engineering materials. This article briefly reviews fatigue of hard tissues with shared emphasis on current understanding, the challenges and the unanswered questions. PMID:20563239

  1. 75 FR 80798 - Availability for Exclusive, Non-Exclusive, or Partially-Exclusive Licensing of Inventions...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-23

    ... Department of the Army Availability for Exclusive, Non-Exclusive, or Partially-Exclusive Licensing of... AGENCY: Department of the Army, DoD. ACTION: Notice. SUMMARY: Announcement is made of the availability... of the Army, has rights to this invention. ADDRESSES: Commander, U.S. Army Medical Research...

  2. Hard processes in hadronic interactions

    SciTech Connect

    Satz, H. |; Wang, X.N.

    1995-07-01

    Quantum chromodynamics is today accepted as the fundamental theory of strong interactions, even though most hadronic collisions lead to final states for which quantitative QCD predictions are still lacking. It therefore seems worthwhile to take stock of where we stand today and to what extent the presently available data on hard processes in hadronic collisions can be accounted for in terms of QCD. This is one reason for this work. The second reason - and in fact its original trigger - is the search for the quark-gluon plasma in high energy nuclear collisions. The hard processes to be considered here are the production of prompt photons, Drell-Yan dileptons, open charm, quarkonium states, and hard jets. For each of these, we discuss the present theoretical understanding, compare the resulting predictions to available data, and then show what behaviour it leads to at RHIC and LHC energies. All of these processes have the structure mentioned above: they contain a hard partonic interaction, calculable perturbatively, but also the non-perturbative parton distribution within a hadron. These parton distributions, however, can be studied theoretically in terms of counting rule arguments, and they can be checked independently by measurements of the parton structure functions in deep inelastic lepton-hadron scattering. The present volume is the work of Hard Probe Collaboration, a group of theorists who are interested in the problem and were willing to dedicate a considerable amount of their time and work on it. The necessary preparation, planning and coordination of the project were carried out in two workshops of two weeks` duration each, in February 1994 at CERn in Geneva andin July 1994 at LBL in Berkeley.

  3. Social exclusion in finite populations.

    PubMed

    Li, Kun; Cong, Rui; Wu, Te; Wang, Long

    2015-04-01

    Social exclusion, keeping free riders from benefit sharing, plays an important role in sustaining cooperation in our world. Here we propose two different exclusion regimes, namely, peer exclusion and pool exclusion, to investigate the evolution of social exclusion in finite populations. In the peer exclusion regime, each excluder expels all the defectors independently, and thus bears the total cost on his own, while in the pool exclusion regime, excluders spontaneously form an institution to carry out rejection of the free riders, and each excluder shares the cost equally. In a public goods game containing only excluders and defectors, it is found that peer excluders outperform pool excluders if the exclusion costs are small, and the situation is converse once the exclusion costs exceed some critical points, which holds true for all the selection intensities and different update rules. Moreover, excluders can dominate the whole population under a suitable parameters range in the presence of second-order free riders (cooperators), showing that exclusion has prominent advantages over common costly punishment. More importantly, our finding indicates that the group exclusion mechanism helps the cooperative union to survive under unfavorable conditions. Our results may give some insights into better understanding the prevalence of such a strategy in the real world and its significance in sustaining cooperation. PMID:25974550

  4. Social exclusion in finite populations.

    PubMed

    Li, Kun; Cong, Rui; Wu, Te; Wang, Long

    2015-04-01

    Social exclusion, keeping free riders from benefit sharing, plays an important role in sustaining cooperation in our world. Here we propose two different exclusion regimes, namely, peer exclusion and pool exclusion, to investigate the evolution of social exclusion in finite populations. In the peer exclusion regime, each excluder expels all the defectors independently, and thus bears the total cost on his own, while in the pool exclusion regime, excluders spontaneously form an institution to carry out rejection of the free riders, and each excluder shares the cost equally. In a public goods game containing only excluders and defectors, it is found that peer excluders outperform pool excluders if the exclusion costs are small, and the situation is converse once the exclusion costs exceed some critical points, which holds true for all the selection intensities and different update rules. Moreover, excluders can dominate the whole population under a suitable parameters range in the presence of second-order free riders (cooperators), showing that exclusion has prominent advantages over common costly punishment. More importantly, our finding indicates that the group exclusion mechanism helps the cooperative union to survive under unfavorable conditions. Our results may give some insights into better understanding the prevalence of such a strategy in the real world and its significance in sustaining cooperation.

  5. Social exclusion in finite populations

    NASA Astrophysics Data System (ADS)

    Li, Kun; Cong, Rui; Wu, Te; Wang, Long

    2015-04-01

    Social exclusion, keeping free riders from benefit sharing, plays an important role in sustaining cooperation in our world. Here we propose two different exclusion regimes, namely, peer exclusion and pool exclusion, to investigate the evolution of social exclusion in finite populations. In the peer exclusion regime, each excluder expels all the defectors independently, and thus bears the total cost on his own, while in the pool exclusion regime, excluders spontaneously form an institution to carry out rejection of the free riders, and each excluder shares the cost equally. In a public goods game containing only excluders and defectors, it is found that peer excluders outperform pool excluders if the exclusion costs are small, and the situation is converse once the exclusion costs exceed some critical points, which holds true for all the selection intensities and different update rules. Moreover, excluders can dominate the whole population under a suitable parameters range in the presence of second-order free riders (cooperators), showing that exclusion has prominent advantages over common costly punishment. More importantly, our finding indicates that the group exclusion mechanism helps the cooperative union to survive under unfavorable conditions. Our results may give some insights into better understanding the prevalence of such a strategy in the real world and its significance in sustaining cooperation.

  6. Diffractive and exclusive measurements at CDF

    SciTech Connect

    Gallinaro, Michele; /Rockefeller U.

    2006-06-01

    Experimental results from the CDF experiment at the Tevatron in p{bar p} collisions at {radical}s = 1.96 TeV are presented on the diffractive structure function at different values of the exchanged momentum transfer squared in the range 0 < Q{sup 2} < 10,000 GeV{sup 2}, on the four-momentum transfer |t| distribution in the region 0 < |t| < 1 GeV{sup 2} for both soft and hard diffractive events up to Q{sup 2} {approx} 4,500 GeV{sup 2}, and on the first experimental evidence of exclusive production in both dijet and diphoton events. A novel technique to align the Roman Pot detectors is also presented.

  7. Enthalpy versus Entropy: the Thermodynamic Origin of Hard Particle Ordering

    NASA Astrophysics Data System (ADS)

    Anthamatten, Mitchell; Chen, Shaw; Ou, Jane; Weinfeld, Jeffrey; Department of Chemical Engineering Team

    The topic of hard particle ordering transitions is important in the development of molecular to mesoscale materials with potential applications in biomedicine, catalysis, optoelectronics, and renewable energy. The first step toward deterministic materials design rests on understanding the thermodynamic nature of ordering transitions involving two phases in equilibrium. We apply classical thermodynamics to show that (i) first-order, hard particle ordering transitions are forbidden at constant volume; and that (ii) hard-particle ordering is driven by a loss in enthalpy through volume reduction that outweighs a concomitant entropy loss upon ordering. The traditional approach considers minimization of Helmholtz energy, at constant volume, whereas the current study exclusively focuses on equilibrium phase transitions and, therefore, targets minimization of Gibbs energy at constant pressure. The Gibbs energy platform offers physically intuitive interpretations consistent with existing computation and experiments. The prevalent idea of entropy-driven ordering at constant V is restricted to transitions from non-equilibrium initial states that have yet to be properly defined for quantification. Laboratory of Laser Energetics, DE-FC52-08NA28302.

  8. Probing young drinking water biofilms with hard and soft particles.

    PubMed

    Paris, Tony; Skali-Lami, Salaheddine; Block, Jean-Claude

    2009-01-01

    The aim of our study was to investigate, through the use of soft (Escherichia coli) and hard (polystyrene microspheres) particles, the distribution and persistence of allochthonous particles inoculated in drinking water flow chambers. Biofilms were allowed to grow for 7-10 months in tap water from Nancy's drinking water network and were composed of bacterial aggregates and filamentous fungi. Both model particles adhered almost exclusively on the biofilms (i.e. on the bacterial aggregates and on the filamentous structures) and not directly on the uncolonized walls (glass or Plexiglas). Biofilm age (i.e. bacterial density and biofilm properties) and convective-diffusion were found to govern particle accumulation: older biofilms and higher wall shear rates both increased the velocity and the amount of particle deposition on the biofilm. Persistence of the polystyrene particles was measured over a two-month period after inoculation. Accumulation amounts were found to be very different between hard and soft particles as only 0.03 per thousand of the soft particles inoculated accumulated in the biofilm against 0.3-0.8% for hard particles.

  9. Ultrasonic material hardness depth measurement

    DOEpatents

    Good, Morris S.; Schuster, George J.; Skorpik, James R.

    1997-01-01

    The invention is an ultrasonic surface hardness depth measurement apparatus and method permitting rapid determination of hardness depth of shafts, rods, tubes and other cylindrical parts. The apparatus of the invention has a part handler, sensor, ultrasonic electronics component, computer, computer instruction sets, and may include a display screen. The part handler has a vessel filled with a couplant, and a part rotator for rotating a cylindrical metal part with respect to the sensor. The part handler further has a surface follower upon which the sensor is mounted, thereby maintaining a constant distance between the sensor and the exterior surface of the cylindrical metal part. The sensor is mounted so that a front surface of the sensor is within the vessel with couplant between the front surface of the sensor and the part.

  10. Overview-hard rock penetration

    SciTech Connect

    Dunn, J.C. )

    1993-01-01

    The Hard Rock Penetration program is developing technology to reduce the costs of drilling and completing geothermal wells. Current projects include: lost circulation control, borehole instrumentation, acoustic telemetry, slimhole drilling, geothermal heat pumps. A new project to improve synthetic diamond drill bits for hard rock drilling was initiated during the year. Accomplishments during the year include completion of important acoustic telemetry tests in the Long Valley Well. These tests produced the first set of reliable, repeatable data in a drill hole. The results indicate the promise of acoustic transmission through drill pipe for great distances without repeaters. The rolling float meter for measuring drilling fluid outflow was duplicated and sent to six different companies for evaluation in the field. A new slimhole spectral gamma tool for operation at temperatures up to 300 C was fabricated and evaluated in the laboratory. Slimhole drilling for exploration and reservoir characterization was begun with several projects jointly completed with industry.

  11. Ultrasonic material hardness depth measurement

    DOEpatents

    Good, M.S.; Schuster, G.J.; Skorpik, J.R.

    1997-07-08

    The invention is an ultrasonic surface hardness depth measurement apparatus and method permitting rapid determination of hardness depth of shafts, rods, tubes and other cylindrical parts. The apparatus of the invention has a part handler, sensor, ultrasonic electronics component, computer, computer instruction sets, and may include a display screen. The part handler has a vessel filled with a couplant, and a part rotator for rotating a cylindrical metal part with respect to the sensor. The part handler further has a surface follower upon which the sensor is mounted, thereby maintaining a constant distance between the sensor and the exterior surface of the cylindrical metal part. The sensor is mounted so that a front surface of the sensor is within the vessel with couplant between the front surface of the sensor and the part. 12 figs.

  12. Microwave assisted hard rock cutting

    DOEpatents

    Lindroth, David P.; Morrell, Roger J.; Blair, James R.

    1991-01-01

    An apparatus for the sequential fracturing and cutting of subsurface volume of hard rock (102) in the strata (101) of a mining environment (100) by subjecting the volume of rock to a beam (25) of microwave energy to fracture the subsurface volume of rock by differential expansion; and , then bringing the cutting edge (52) of a piece of conventional mining machinery (50) into contact with the fractured rock (102).

  13. Results on hard diffractive production

    SciTech Connect

    Goulianos, K.

    1995-07-01

    The results of experiments at hadron colliders probing the structure of the pomeron through hard diffraction are reviewed. Some results on deep inelastic diffractive scattering obtained a HERA are also discussed and placed in perspective. By using a properly normalized pomeron flux factor in single diffraction dissociation, as dictated by unitarity, the pomeron emerges as a combination of valence quark and gluon color singlets in a ratio suggested by asymptopia.

  14. Schwannoma of the hard palate

    PubMed Central

    Sahoo, Pradyumna Kumar; Mandal, Palash Kumar; Ghosh, Saradindu

    2014-01-01

    Schwannomas are benign encapsulated perineural tumors. The head and neck region is the most common site. Intraoral origin is seen in only 1% of cases, tongue being the most common site; its location in the palate is rare. We report a case of hard-palate schwannoma with bony erosion which was immunohistochemically confirmed. The tumor was excised completely intraorally. After two months of follow-up, the defect was found to be completely covered with palatal mucosa. PMID:25298716

  15. Exclusion performance and learning by exclusion in dogs.

    PubMed

    Zaine, Isabela; Domeniconi, Camila; de Rose, Julio C

    2016-05-01

    Responding by exclusion is a type of emergent repertoire in which an individual chooses an alternative by the apparent exclusion of other available alternatives. In this case it is possible to respond appropriately to an undefined stimulus (one that has not previously acquired discriminative functions) by excluding the defined alternatives. There is evidence of exclusion in humans and nonhuman animals, although learning as an outcome of exclusion does not always occur. This study aimed to investigate exclusion in visual simple discriminations and learning of new simple discriminations resulting from exclusion in four border collies. Subjects were trained to perform simple simultaneous discriminations between pairs of tridimensional objects, and were then tested for exclusion, novelty control and learning of new simple discriminations. All dogs successfully responded by exclusion, choosing an undefined stimulus displayed with an S-. For three dogs, it was possible to conclude that these previously undefined stimuli acquired S+ functions, documenting learning of new simple discriminations. However, this required up to four exposures to exclusion trials with each pair of stimuli.

  16. Mutual exclusivity and exclusion: Converging evidence from two contrasting traditions

    PubMed Central

    Huntley, Kenneth R.; Ghezzi, Patrick M.

    1993-01-01

    Mutual exclusivity and exclusion are two terms used by cognitive psychologists and behavior analysts, respectively, to identify essentially the same phenomenon. While cognitive psychologists view mutual exclusivity in terms of a hypothesis that individuals use intuitively while acquiring language, behavior analysts regard exclusion as a derived stimulus relation that bears upon the acquisition and elaboration of verbal behavior. Each research tradition, though at odds with respect to accounting for the phenomenon, employs similar procedures to answer comparable questions. Insofar as both cognitive and behavioral psychologists are studying the same phenomenon, the ground work is established for collaboration between them. PMID:22477081

  17. kT factorization of exclusive processes

    NASA Astrophysics Data System (ADS)

    Nagashima, Makiko; Li, Hsiang-Nan

    2003-02-01

    We prove the kT factorization theorem in perturbative QCD (PQCD) for exclusive processes by considering πγ*→γ(π) and B→γ(π)lν¯. The relevant form factors are expressed as the convolution of hard amplitudes with two-parton meson wave functions in the impact parameter b space, b being conjugate to the parton transverse momenta kT. The point is that on-shell valence partons carry longitudinal momenta initially, and acquire kT through collinear gluon exchanges. The b-dependent two-parton wave functions with an appropriate path for the Wilson links are gauge-invariant. The hard amplitudes, defined as the difference between the parton-level diagrams of on-shell external particles and their collinear approximation, are also gauge-invariant. We compare the predictions for two-body nonleptonic B meson decays derived from kT factorization (the PQCD approach) and from collinear factorization (the QCD factorization approach).

  18. Virial coefficients and equations of state for mixtures of hard discs, hard spheres and hard hyperspheres

    NASA Astrophysics Data System (ADS)

    Santos, A.; Yuste, S. B.; López de Haro, M.

    The composition-independent virial coefficients of a d-dimensional binary mixture of (additive) hard hyperspheres following from a recent proposal for the equation of state of the mixture (SANTOS, A., YUSTE, S. B., and LÓPEZ DE HARO, M., 1999, Molec. Phys., 96 , 1) are examined. Good agreement between theoretical estimates and available exact or numerical results is found for d = 2, 3, 4 and 5, except for mixtures whose components are very disparate in size. A slight modification that remedies this deficiency is introduced and the resummation of the associated virial series is carried out, leading to a new proposal for the equation of state. The case of binary hard sphere mixtures (d = 3) is analysed in some detail.

  19. Exclusive Processes in Quantum Chromodynamics

    NASA Astrophysics Data System (ADS)

    Brodsky, Stanley J.; Peter Lepage, G.

    The following sections are included: * INTRODUCTION * NONRELATIVISTIC FORM FACTORS FOR HEAVY-QUARK MESONS * HADRONIC WAVEFUNCTIONS * DEFINITIONS * LIGHT-CONE BOUND-STATE EQUATIONS * GENERAL PROPERTIES OF LIGHT-CONE WAVEFUNCTIONS * RENORMALIZATION * CALCULATING * A PERTURBATIVE ANALYSIS * FACTORIZATION—LEADING ORDER ANALYSIS * THE QUARK DISTRIBUTION AMPLITUDE * DETERMINATION OF DISTRIBUTION AMPLITUDES * HIGHER ORDER ANALYSIS * COMPLICATIONS * How LARGE IS ASYMPTOTIC Q? * APPLICATIONS OF QCD TO THE PHENOMENOLOGY OF EXCLUSIVE REACTIONS * GENERAL FEATURES OF EXCLUSIVE PROCESSES IN QCD * ELECTROMAGNETIC FORM FACTORS * COMPARISON OF QCD SCALING WITH EXPERIMENT * EXCLUSIVE ANTI-PROTON PROTON ANNIHILATION PROCESSES * ADDITIONAL TESTS OF GLUON SPIN IN EXCLUSIVE PROCESSES * HADRONIC WAVEFUNCTION PHENOMENOLOGY * CALCULATING TH * THE PRE-QCD DEVELOPMENT OF EXCLUSIVE REACTIONS * EXCLUSIVE e+ e- ANNIHILATION PROCESSES * J/ψ DECAY TO HADRON PAIRS * THE π-ρ PUZZLE * FORM FACTOR ZEROS IN QCD * EXCLUSIVE γγ REACTIONS * QCD PROCESSES IN NUCLEI * EXCLUSIVE NUCLEAR REACTIONS - REDUCED AMPLITUDES * COLOR TRANSPARENCY * SPIN CORRELATIONS IN PROTON-PROTON SCATTERING * CONCLUSIONS * APPENDIX I BARYON FORM FACTORS AND EVOLUTION EQUATIONS * APPENDIX II LIGHT CONE QUANTIZATION AND PERTURBATION THEORY * APPENDIX III A NONPERTURBATIVE ANALYSIS OF EXCLUSIVE REACTIONS-DISCRETIZED LIGHT-CONE QUANTIZATION * ACKNOWLEDGEMENTS * REFERENCES

  20. 7 CFR 201.57 - Hard seeds.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... REGULATIONS Germination Tests in the Administration of the Act § 201.57 Hard seeds. Seeds which remain hard at..., are to be counted as “hard seed.” If at the end of the germination period provided for legumes, okra... percentage of germination. For flatpea, continue the swollen seed in test for 14 days when germinating at...

  1. 7 CFR 201.57 - Hard seeds.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... REGULATIONS Germination Tests in the Administration of the Act § 201.57 Hard seeds. Seeds which remain hard at..., are to be counted as “hard seed.” If at the end of the germination period provided for legumes, okra... percentage of germination. For flatpea, continue the swollen seed in test for 14 days when germinating at...

  2. 7 CFR 201.57 - Hard seeds.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... REGULATIONS Germination Tests in the Administration of the Act § 201.57 Hard seeds. Seeds which remain hard at..., are to be counted as “hard seed.” If at the end of the germination period provided for legumes, okra... percentage of germination. For flatpea, continue the swollen seed in test for 14 days when germinating at...

  3. 7 CFR 201.57 - Hard seeds.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... REGULATIONS Germination Tests in the Administration of the Act § 201.57 Hard seeds. Seeds which remain hard at..., are to be counted as “hard seed.” If at the end of the germination period provided for legumes, okra... percentage of germination. For flatpea, continue the swollen seed in test for 14 days when germinating at...

  4. 7 CFR 201.57 - Hard seeds.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... REGULATIONS Germination Tests in the Administration of the Act § 201.57 Hard seeds. Seeds which remain hard at..., are to be counted as “hard seed.” If at the end of the germination period provided for legumes, okra... percentage of germination. For flatpea, continue the swollen seed in test for 14 days when germinating at...

  5. 7 CFR 201.30 - Hard seed.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Hard seed. 201.30 Section 201.30 Agriculture..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Vegetable Seeds § 201.30 Hard seed. The label shall show the percentage of hard seed,...

  6. 7 CFR 201.30 - Hard seed.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Hard seed. 201.30 Section 201.30 Agriculture..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Vegetable Seeds § 201.30 Hard seed. The label shall show the percentage of hard seed,...

  7. 7 CFR 201.21 - Hard seed.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Hard seed. 201.21 Section 201.21 Agriculture..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.21 Hard seed. The label shall show the percentage of hard...

  8. 7 CFR 201.21 - Hard seed.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Hard seed. 201.21 Section 201.21 Agriculture..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.21 Hard seed. The label shall show the percentage of hard...

  9. 7 CFR 201.30 - Hard seed.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Hard seed. 201.30 Section 201.30 Agriculture..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Vegetable Seeds § 201.30 Hard seed. The label shall show the percentage of hard seed,...

  10. 7 CFR 201.21 - Hard seed.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Hard seed. 201.21 Section 201.21 Agriculture..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.21 Hard seed. The label shall show the percentage of hard...

  11. 7 CFR 201.30 - Hard seed.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Hard seed. 201.30 Section 201.30 Agriculture..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Vegetable Seeds § 201.30 Hard seed. The label shall show the percentage of hard seed,...

  12. 7 CFR 201.21 - Hard seed.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Hard seed. 201.21 Section 201.21 Agriculture..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.21 Hard seed. The label shall show the percentage of hard...

  13. 7 CFR 201.21 - Hard seed.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Hard seed. 201.21 Section 201.21 Agriculture..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.21 Hard seed. The label shall show the percentage of hard...

  14. 7 CFR 201.30 - Hard seed.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Hard seed. 201.30 Section 201.30 Agriculture..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Vegetable Seeds § 201.30 Hard seed. The label shall show the percentage of hard seed,...

  15. 30 CFR 56.15002 - Hard hats.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Hard hats. 56.15002 Section 56.15002 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Personal Protection § 56.15002 Hard hats. All persons shall wear suitable hard hats when in or around a mine or plant where falling...

  16. 30 CFR 57.15002 - Hard hats.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Hard hats. 57.15002 Section 57.15002 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Underground § 57.15002 Hard hats. All persons shall wear suitable hard hats when in or around a mine or...

  17. Measurement of the cross-section ratio σψ(2S)/σJ/ψ(1S) in deep inelastic exclusive ep scattering at HERA

    NASA Astrophysics Data System (ADS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Antonelli, S.; Aushev, V.; Aushev, Y.; Behnke, O.; Behrens, U.; Bertolin, A.; Bloch, I.; Boos, E. G.; Borras, K.; Brock, I.; Brook, N. H.; Brugnera, R.; Bruni, A.; Bussey, P. J.; Caldwell, A.; Capua, M.; Catterall, C. D.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cooper-Sarkar, A. M.; Corradi, M.; Corriveau, F.; Dementiev, R. K.; Devenish, R. C. E.; Dolinska, G.; Dusini, S.; Figiel, J.; Foster, B.; Gach, G.; Gallo, E.; Garfagnini, A.; Geiser, A.; Gizhko, A.; Gladilin, L. K.; Golubkov, Yu. A.; Grebenyuk, J.; Gregor, I.; Grzelak, G.; Gueta, O.; Guzik, M.; Hain, W.; Hochman, D.; Hori, R.; Ibrahim, Z. A.; Iga, Y.; Ishitsuka, M.; Iudin, A.; Januschek, F.; Jomhari, N. Z.; Kadenko, I.; Kananov, S.; Karshon, U.; Kaur, M.; Kaur, P.; Kisielewska, D.; Klanner, R.; Klein, U.; Kondrashova, N.; Kononenko, O.; Korol, Ie.; Korzhavina, I. A.; Kotański, A.; Kötz, U.; Kovalchuk, N.; Kowalski, H.; Krupa, B.; Kuprash, O.; Kuze, M.; Levchenko, B. B.; Levy, A.; Libov, V.; Limentani, S.; Lisovyi, M.; Lobodzinska, E.; Löhr, B.; Lohrmann, E.; Longhin, A.; Lontkovskyi, D.; Lukina, O. Yu.; Makarenko, I.; Malka, J.; Mergelmeyer, S.; Mohamad Idris, F.; Mohammad Nasir, N.; Myronenko, V.; Nagano, K.; Nobe, T.; Notz, D.; Nowak, R. J.; Onishchuk, Yu.; Paul, E.; Perlański, W.; Pokrovskiy, N. S.; Przybycień, M.; Roloff, P.; Rubinsky, I.; Ruspa, M.; Saxon, D. H.; Schioppa, M.; Schmidke, W. B.; Schneekloth, U.; Schörner-Sadenius, T.; Shcheglova, L. M.; Shevchenko, R.; Shkola, O.; Shyrma, Yu.; Singh, I.; Skillicorn, I. O.; Słomiński, W.; Solano, A.; Stanco, L.; Stefaniuk, N.; Stern, A.; Stopa, P.; Sztuk-Dambietz, J.; Szuba, D.; Szuba, J.; Tassi, E.; Tokushuku, K.; Tomaszewska, J.; Trofymov, A.; Tsurugai, T.; Turcato, M.; Turkot, O.; Tymieniecka, T.; Verbytskyi, A.; Viazlo, O.; Walczak, R.; Wan Abdullah, W. A. T.; Wichmann, K.; Wing, M.; Wolf, G.; Yamada, S.; Yamazaki, Y.; Zakharchuk, N.; Żarnecki, A. F.; Zawiejski, L.; Zenaiev, O.; Zhautykov, B. O.; Zhmak, N.; Zotkin, D. S.

    2016-08-01

    The exclusive deep inelastic electroproduction of ψ (2 S) and J / ψ (1 S) at an ep centre-of-mass energy of 317 GeV has been studied with the ZEUS detector at HERA in the kinematic range 2 exclusive vector-meson production.

  18. The Hard Problem of Cooperation

    PubMed Central

    Eriksson, Kimmo; Strimling, Pontus

    2012-01-01

    Based on individual variation in cooperative inclinations, we define the “hard problem of cooperation” as that of achieving high levels of cooperation in a group of non-cooperative types. Can the hard problem be solved by institutions with monitoring and sanctions? In a laboratory experiment we find that the answer is affirmative if the institution is imposed on the group but negative if development of the institution is left to the group to vote on. In the experiment, participants were divided into groups of either cooperative types or non-cooperative types depending on their behavior in a public goods game. In these homogeneous groups they repeatedly played a public goods game regulated by an institution that incorporated several of the key properties identified by Ostrom: operational rules, monitoring, rewards, punishments, and (in one condition) change of rules. When change of rules was not possible and punishments were set to be high, groups of both types generally abided by operational rules demanding high contributions to the common good, and thereby achieved high levels of payoffs. Under less severe rules, both types of groups did worse but non-cooperative types did worst. Thus, non-cooperative groups profited the most from being governed by an institution demanding high contributions and employing high punishments. Nevertheless, in a condition where change of rules through voting was made possible, development of the institution in this direction was more often voted down in groups of non-cooperative types. We discuss the relevance of the hard problem and fit our results into a bigger picture of institutional and individual determinants of cooperative behavior. PMID:22792282

  19. Making Nozzles From Hard Materials

    NASA Technical Reports Server (NTRS)

    Wells, Dennis L.

    1989-01-01

    Proposed method of electrical-discharge machining (EDM) cuts hard materials like silicon carbide into smoothly contoured parts. Concept developed for fabrication of interior and exterior surfaces and internal cooling channels of convergent/divergent nozzles. EDM wire at skew angle theta creates hyperboloidal cavity in tube. Wire offset from axis of tube and from axis of rotation by distance equal to throat radius. Maintaining same skew angle as that used to cut hyperboloidal inner surface but using larger offset, cooling channel cut in material near inner hyperboloidal surface.

  20. Radiation Hardness Assurance (RHA) Guideline

    NASA Technical Reports Server (NTRS)

    Campola, Michael J.

    2016-01-01

    Radiation Hardness Assurance (RHA) consists of all activities undertaken to ensure that the electronics and materials of a space system perform to their design specifications after exposure to the mission space environment. The subset of interests for NEPP and the REAG, are EEE parts. It is important to register that all of these undertakings are in a feedback loop and require constant iteration and updating throughout the mission life. More detail can be found in the reference materials on applicable test data for usage on parts.

  1. Hard and Soft Safety Verifications

    NASA Technical Reports Server (NTRS)

    Wetherholt, Jon; Anderson, Brenda

    2012-01-01

    The purpose of this paper is to examine the differences between and the effects of hard and soft safety verifications. Initially, the terminology should be defined and clarified. A hard safety verification is datum which demonstrates how a safety control is enacted. An example of this is relief valve testing. A soft safety verification is something which is usually described as nice to have but it is not necessary to prove safe operation. An example of a soft verification is the loss of the Solid Rocket Booster (SRB) casings from Shuttle flight, STS-4. When the main parachutes failed, the casings impacted the water and sank. In the nose cap of the SRBs, video cameras recorded the release of the parachutes to determine safe operation and to provide information for potential anomaly resolution. Generally, examination of the casings and nozzles contributed to understanding of the newly developed boosters and their operation. Safety verification of SRB operation was demonstrated by examination for erosion or wear of the casings and nozzle. Loss of the SRBs and associated data did not delay the launch of the next Shuttle flight.

  2. Hardness correlation for uranium and its alloys

    SciTech Connect

    Humphreys, D L; Romig, Jr, A D

    1983-03-01

    The hardness of 16 different uranium-titanium (U-Ti) alloys was measured on six (6) different hardness scales (R/sub A/, R/sub B/, R/sub C/, R/sub D/, Knoop, and Vickers). The alloys contained between 0.75 and 2.0 wt % Ti. All of the alloys were solutionized (850/sup 0/C, 1 h) and ice-water quenched to produce a supersaturated martensitic phase. A range of hardnesses was obtained by aging the samples for various times and temperatures. The correlation of various hardness scales was shown to be virtually identical to the hardness-scale correlation for steels. For more-accurate conversion from one hardness scale to another, least-squares-curve fits were determined for the various hardness-scale correlations. 34 figures, 5 tables.

  3. Spectroscopy of LiΛ9 by electroproduction

    SciTech Connect

    Urciuoli, G. M.; Cusanno, F.; Marrone, S.; Acha, A.; Ambrozewicz, P.; Aniol, K. A.; Baturin, P.; Bertin, P. Y.; Benaoum, H.; Blomqvist, K. I.; Boeglin, W. U.; Breuer, H.; Brindza, P.; Bydžovský, P.; Camsonne, A.; Chang, C. C.; Chen, J.-P.; Choi, Seonho; Chudakov, E. A.; Cisbani, E.; Colilli, S.; Coman, L.; Craver, B. J.; De Cataldo, G.; de Jager, C. W.; De Leo, R.; Deur, A. P.; Ferdi, C.; Feuerbach, R. J.; Folts, E.; Fratoni, R.; Frullani, S.; Garibaldi, F.; Gayou, O.; Giuliani, F.; Gomez, J.; Gricia, M.; Hansen, J. O.; Hayes, D.; Higinbotham, D. W.; Holmstrom, T. K.; Hyde, C. E.; Ibrahim, H. F.; Iodice, M.; Jiang, X.; Kaufman, L. J.; Kino, K.; Kross, B.; Lagamba, L.; LeRose, J. J.; Lindgren, R. A.; Lucentini, M.; Margaziotis, D. J.; Markowitz, P.; Meziani, Z. E.; McCormick, K.; Michaels, R. W.; Millener, D. J.; Miyoshi, T.; Moffit, B.; Monaghan, P. A.; Moteabbed, M.; Camacho, C. Muñoz; Nanda, S.; Nappi, E.; Nelyubin, V. V.; Norum, B. E.; Okasyasu, Y.; Paschke, K. D.; Perdrisat, C. F.; Piasetzky, E.; Punjabi, V. A.; Qiang, Y.; Reimer, P. E.; Reinhold, J.; Reitz, B.; Roche, R. E.; Rodriguez, V. M.; Saha, A.; Santavenere, F.; Sarty, A. J.; Segal, J.; Shahinyan, A.; Singh, J.; Širca, S.; Snyder, R.; Solvignon, P. H.; Sotona, M.; Subedi, R.; Sulkosky, V. A.; Suzuki, T.; Ueno, H.; Ulmer, P. E.; Veneroni, P.; Voutier, E.; Wojtsekhowski, B. B.; Zheng, X.; Zorn, C.

    2015-03-01

    Background: In the absence of accurate data on the free two-body hyperon-nucleon interaction, the spectra of hypernuclei can provide information on the details of the effective hyperon-nucleon interaction. Purpose: To obtain a high-resolution spectrum for the 9Be(e,e'K+)9ΛLi reaction. Method: Electroproduction of the hypernucleus 9ΛLi has been studied for the first time with sub-MeV energy resolution in Hall A at Jefferson Lab on a 9Be target. In order to increase the counting rate and to provide unambiguous kaon identification, two superconducting septum magnets and a Ring Imaging CHerenkov detector (RICH) were added to the Hall A standard equipment. Results: The cross section to low-lying states of 9ΛLi is concentrated within 3 MeV of the ground state and can be fitted with four peaks. The positions of the doublets agree with theory while a disagreement could exist with respect to the relative strengths of the peaks in the doublets. A Λ separation energy, BΛ, of 8.36±0.08 (stat.) ±0.08 (syst.) MeV was measured, in agreement with an earlier experiment.

  4. Induced polarization of Λ(1116) in kaon electroproduction

    SciTech Connect

    Gabrielyan, M.; Raue, B. A.; Carman, D. S.; Park, K.; Adhikari, K. P.; Adikaram, D.; Amaryan, M. J.; Anefalos Pereira, S.; Avakian, H.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Baturin, V.; Bedlinskiy, I.; Biselli, A. S.; Bono, J.; Boiarinov, S.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Cao, T.; Celentano, A.; Chandavar, S.; Charles, G.; Colaneri, L.; Cole, P. L.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Doughty, D.; Dupre, R.; El Fassi, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Fleming, J. A.; Forest, T. A.; Garillon, B.; Gevorgyan, N.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hattawy, M.; Hicks, K.; Ho, D.; Holtrop, M.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Jenkins, D.; Jiang, H.; Jo, H. S.; Joo, K.; Keller, D.; Khandaker, M.; Kim, W.; Klein, F. J.; Koirala, S.; Kubarovsky, V.; Kuhn, S. E.; Kuleshov, S. V.; Lenisa, P.; Levine, W. I.; Livingston, K.; MacGregor, I. J. D.; Mayer, M.; McKinnon, B.; Meyer, C. A.; Mestayer, M. D.; Mirazita, M.; Mokeev, V.; Moody, C. I.; Moutarde, H.; Movsisyan, A.; Munevar, E.; Munoz Camacho, C.; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Osipenko, M.; Pappalardo, L. L.; Paremuzyan, R.; Pasyuk, E.; Peng, P.; Phelps, W.; Phillips, J. J.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Protopopescu, D.; Rimal, D.; Ripani, M.; Rizzo, A.; Sabatié, F.; Salgado, C.; Schott, D.; Schumacher, R. A.; Simonyan, A.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Stepanyan, S. S.; Stepanyan, S.; Strakovsky, I. I.; Strauch, S.; Sytnik, V.; Tang, W.; Ungaro, M.; Vlassov, A. V.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Weinstein, L. B.; Zachariou, N.; Zana, L.; Zhang, J.; Zonta, I.

    2014-09-01

    We have measured the induced polarization of the Λ(1116) in the reaction ep→e'K+Λ, detecting the scattered e' and K+ in the final state along with the proton from the decay Λ→pπ-.The present study used the CEBAF Large Acceptance Spectrometer (CLAS), which allowed for a large kinematic acceptance in invariant energy W (1.6≤W≤2.7 GeV) and covered the full range of the kaon production angle at an average momentum transfer Q2=1.90 GeV2.In this experiment a 5.50 GeV electron beam was incident upon an unpolarized liquid-hydrogen target. We have mapped out the W and kaon production angle dependencies of the induced polarization and found striking differences from photoproduction data over most of the kinematic range studied. However, we also found that the induced polarization is essentially Q2 independent in our kinematic domain, suggesting that somewhere below the Q2 covered here there must be a strong Q2 dependence. Along with previously published photo- and electroproduction cross sections and polarization observables, these data are needed for the development of models, such as effective field theories, and as input to coupled-channel analyses that can provide evidence of previously unobserved s-channel resonances.

  5. Exclusion processes with avalanches.

    PubMed

    Bhat, Uttam; Krapivsky, P L

    2014-07-01

    In an exclusion process with avalanches, when a particle hops to a neighboring empty site which is adjacent to an island the particle on the other end of the island immediately hops, and if it joins another island this triggers another hop. There are no restrictions on the length of the islands and the duration of the avalanche. This process is well defined in the low-density region ρ < 1/2. We describe the nature of steady states (on a ring) and determine all correlation functions. For the asymmetric version of the process, we compute the steady state current, and we describe shock and rarefaction waves which arise in the evolution of the step-function initial profile. For the symmetric version, we determine the diffusion coefficient and examine the evolution of a tagged particle.

  6. Inclusive and Exclusive Compton Processes in Quantum Chromodynamics

    SciTech Connect

    Ales Psaker

    2005-12-31

    In our work, we describe two types of Compton processes. As an example of an inclusive process, we consider the high-energy photoproduction of massive muon pairs off the nucleon. We analyze the process in the framework of the QCD parton model, in which the usual parton distributions emerge as a tool to describe the nucleon in terms of quark and gluonic degrees of freedom. To study its exclusive version, a new class of phenomenological functions is required, namely, generalized parton distributions. They can be considered as a generalization of the usual parton distributions measured in deeply inelastic lepton-nucleon scattering. Generalized parton distributions (GPDs) may be observed in hard exclusive reactions such as deeply virtual Compton scattering. We develop an extension of this particular process into the weak interaction sector. We also investigate a possible application of the GPD formalism to wide-angle real Compton scattering.

  7. NONFUEL MINERAL RESOURCES OF THE PACIFIC EXCLUSIVE ECONOMIC ZONE.

    USGS Publications Warehouse

    Clague, David; Bischoff, James; Howell, David

    1984-01-01

    The Pacific Exclusive Economic Zone contains a variety of hard mineral resources. Sand and gravel and their associated placer deposits of heavy minerals are the most likely to be developed in the near future, but offshore and deep water deposits of phosphorite, abyssal manganese nodules, ferromanganese crusts enriched in cobalt, and massive sulfide deposits all represent future resources. The distribution, extent, and formation of these deposits are poorly understood and will be clarified only with additional exploration, framework geologic mapping, and study of the processes by which these resources form. It is pointed out that the initial discovery of most hard-mineral resources in the EEZ was made during routine scientific marine-geologic surveys aimed at understanding the framework geology and geologic processes of an offshore region.

  8. Development of radiation hard scintillators

    SciTech Connect

    Markley, F.; Woods, D.; Pla-Dalmau, A.; Foster, G. ); Blackburn, R. )

    1992-05-01

    Substantial improvements have been made in the radiation hardness of plastic scintillators. Cylinders of scintillating materials 2.2 cm in diameter and 1 cm thick have been exposed to 10 Mrads of gamma rays at a dose rate of 1 Mrad/h in a nitrogen atmosphere. One of the formulations tested showed an immediate decrease in pulse height of only 4% and has remained stable for 12 days while annealing in air. By comparison a commercial PVT scintillator showed an immediate decrease of 58% and after 43 days of annealing in air it improved to a 14% loss. The formulated sample consisted of 70 parts by weight of Dow polystyrene, 30 pbw of pentaphenyltrimethyltrisiloxane (Dow Corning DC 705 oil), 2 pbw of p-terphenyl, 0.2 pbw of tetraphenylbutadiene, and 0.5 pbw of UVASIL299LM from Ferro.

  9. Hard X-ray astrophysics

    NASA Technical Reports Server (NTRS)

    Rothschild, R. E.

    1981-01-01

    Past hard X-ray and lower energy satellite instruments are reviewed and it is shown that observation above 20 keV and up to hundreds of keV can provide much valuable information on the astrophysics of cosmic sources. To calculate possible sensitivities of future arrays, the efficiencies of a one-atmosphere inch gas counter (the HEAO-1 A-2 xenon filled HED3) and a 3 mm phoswich scintillator (the HEAO-1 A-4 Na1 LED1) were compared. Above 15 keV, the scintillator was more efficient. In a similar comparison, the sensitivity of germanium detectors did not differ much from that of the scintillators, except at high energies where the sensitivity would remain flat and not rise with loss of efficiency. Questions to be addressed concerning the physics of active galaxies and the diffuse radiation background, black holes, radio pulsars, X-ray pulsars, and galactic clusters are examined.

  10. Electroproduction of {eta} mesons in the S{sub 11} (1535) resonance region at high momentum transfer.

    SciTech Connect

    Dalton, M. M.; Adams, G. S.; Ahmidouch, A.; Angelescu, T.; Arrington, J.; Holt, R. J.; Hafidi, K.; Reimer, P.; Schulte, E.; Zheng, X.; Physics; Univ. of Witwatersrand; Rensselaer Polytechnic Inst.; North Carolina A & T State Univ.; Bucharest Univ.; Yerevan Physics Inst.

    2009-07-01

    The differential cross section for the process p(e,e{prime}p) {eta} has been measured at Q{sup 2} {approx} 5.7 and 7.0(GeV/c){sup 2} for center-of-mass energies from threshold to 1.8 GeV, encompassing the S{sub 11}(1535) resonance, which dominates the channel. This is the highest momentum-transfer measurement of this exclusive process to date. The helicity-conserving transition amplitude A{sub 1/2}, for the production of the S{sub 11}(1535) resonance, is extracted from the data. Within the limited Q{sup 2} now measured, this quantity appears to begin scaling as Q{sup -3} - a predicted, but not definitive, signal of the dominance of perturbative QCD at Q{sup 2} {approx} 5 (GeV/c){sup 2}.

  11. Electroproduction of {eta} mesons in the S{sub 11}(1535) resonance region at high momentum transfer

    SciTech Connect

    Dalton, M. M.; Adams, G. S.; Moziak, B.; Stoler, P.; Villano, A.; Ahmidouch, A.; Danagoulian, S.; Angelescu, T.; Malace, S.; Arrington, J.; Hafidi, K.; Holt, R. J.; Reimer, P. E.; Schulte, E.; Zheng, X.; Asaturyan, R.; Mkrtchyan, H.; Navasardyan, T.; Tadevosyan, V.; Baker, O. K.

    2009-07-15

    The differential cross section for the process p(e,e{sup '}p){eta} has been measured at Q{sup 2}{approx}5.7 and 7.0(GeV/c){sup 2} for center-of-mass energies from threshold to 1.8 GeV, encompassing the S{sub 11}(1535) resonance, which dominates the channel. This is the highest momentum-transfer measurement of this exclusive process to date. The helicity-conserving transition amplitude A{sub 1/2}, for the production of the S{sub 11}(1535) resonance, is extracted from the data. Within the limited Q{sup 2} now measured, this quantity appears to begin scaling as Q{sup -3}--a predicted, but not definitive, signal of the dominance of perturbative QCD at Q{sup 2}{approx}5 (GeV/c){sup 2}.

  12. Habitat Suitability Index Models: Hard clam

    USGS Publications Warehouse

    Mulholland, Rosemarie

    1984-01-01

    Two species of hard clams occur along the Atlantic and Gulf of Mexico coasts of North America: the southern hard clam, Mercenaria campechiensis Gmelin 1791, and the northern hard clam, ~lercenaria mercenaria Linne 1758 (Wells 1957b). The latter species, also commonly kno\\'m as the quahog, was formerly named Venus mercenaria. The two species are closely related, produce viable hybrids (Menzel and Menzel 1965), and may be a single species.

  13. Results from CLAS and Outlook to CLAS12

    SciTech Connect

    Marco Ripani

    2010-12-01

    In this paper I will illustrate examples of progress in the five main avenues of nucleon structure research in Hall B at JLab: elastic and resonance transition form factors, polarized inelastic scattering, semi-inclusive meson electroproduction, hard exclusive reactions and non-strange baryon spectroscopy. The 12 GeV machine and detector upgrade will offer an unprecedented opportunity to study all these topics in a broader kinematic domain.

  14. Reggeometry of lepton- and hadron-induced reactions

    SciTech Connect

    Fiore, Roberto; Jenkovszky, Laszlo; Lavorini, Adelmo; Salii, Andrii

    2013-04-15

    We append a simple Pomeron pole amplitude by t and Q{sup 2}, MV dependencies inspired by geometrical ideas. The experimentally transition from soft to hard dynamics is realized by the introduction of a two-component Pomeron with different Q{sup 2} and M{sub V}-dependent residues. A unified description of deeply virtual Compton scattering (DVCS), of exclusive electroproduction of all vector mesons as well as of elastic pp scattering is suggested.

  15. 30 CFR 75.1720-1 - Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Distinctively colored hard hats, or hard caps... STANDARDS-UNDERGROUND COAL MINES Miscellaneous § 75.1720-1 Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in...

  16. 30 CFR 77.1710-1 - Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Distinctively colored hard hats or hard caps... Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color from those worn by experienced miners shall be worn...

  17. Tale of two hard Pomerons

    SciTech Connect

    Berera, Arjun

    2000-07-01

    Two mechanisms are examined for hard double ''pomeron'' exchange dijet production, the factorized model of Ingelman-Schlein, and the nonfactorized model of lossless jet production which exhibits the Collins-Frankfurt-Strikman mechanism. Comparisons between these two mechanisms are made of the total cross section, E{sub T} spectra, and mean rapidity spectra. For both mechanisms, several specific models are examined with the cuts of the collider detector at Fermilab (CDF), DOe, and representative cuts of CERN LHC. Distinct qualitative differences are predicted by the two mechanisms for the CDF y{sub +} spectra and for the E{sub T} spectra for all three experimental cuts. The preliminary CDF and DOe experimental data for this process are interpreted in terms of these two mechanisms. The y{sub +} spectra of the CDF data are suggestive of domination by the factorized Ingelman-Schlein mechanism, whereas the DOe data show no greater preference for either mechanism. An inconsistency is found among all the theoretical models in attempting to explain the ratio of the cross sections given by the data from these two experiments. (c) 2000 The American Physical Society.

  18. Radiation Hardness of Trigger Electronics

    NASA Astrophysics Data System (ADS)

    Zawisza, Irene; Safonov, Alexei; Gilmore, Jason; Khotilovich, Vadim

    2011-10-01

    As the maximum intensity of particle accelerators increases, probing the most basic questions of the Universe, detectors and electronics must be designed to insure reliability in high-radiation environments. As the Large Hadron Collider (LHC) beam intensity is increased, it is necessary to upgrade the electronics in the Compact Muon Solenoid (CMS). To select interesting events, CMS utilizes fast electronics, which are installed in the experimental cavern. However, much higher post-upgrade levels of radiation in the cavern set tight requirements on the radiation hardness of the new electronics. Damaging effects of high and low energy radiation leads to disruption of digital circuits and accumulated degradation of silicon components. Quantifying the radiation exposure is required for the design of a radiation-tolerant system, but current simulation studies suffer from large uncertainties. We compare simulation predictions with measured performance in two different experimental studies, which evaluate component performance for pre and post irradiation determining the survivability of electronics in the harsh CMS environment. Funded by DOE and NSF-REU Program.

  19. Recoil Polarization Measurements for Neutral Pion Electroproduction at Q^2=1 (GeV/c)^2 Near the Delta Resonance

    SciTech Connect

    James Kelly; et. Al.

    2005-09-01

    We measured angular distributions of differential cross section, beam analyzing power, and recoil polarization for neutral pion electroproduction at Q{sup 2} = 1.0 (GeV/c){sup 2} in 10 bins of W across the Delta resonance. A total of 16 independent response functions were extracted, of which 12 were observed for the first time. Comparisons with recent model calculations show that response functions governed by real parts of interference products are determined relatively well near 1.232 GeV, but variations among models is large for response functions governed by imaginary parts and for both increases rapidly with W. We performed a nearly model-independent multipole analysis that adjusts complex multipoles with high partial waves constrained by baseline models. Parabolic fits to the W dependence of the multipole analysis around the Delta mass gives values for SMR = (-6.61 +/- 0.18)% and EMR = (-2.87 +/- 0.19)% that are distinctly larger than those from Legendre analysis of the same data. Similarly, the multipole analysis gives Re(S0+/M1+) = (+7.1 +/- 0.8)% at W=1.232 GeV, consistent with recent models, while the traditional Legendre analysis gives the opposite sign because its truncation errors are quite severe. Finally, using a unitary isobar model (UIM), we find that excitation of the Roper resonance is dominantly longitudinal with S1/2 = (0.05 +/- 0.01) GeV{sup (-1/2)} at Q{sup 2}=1. The ReS0+ and ReE0+ multipoles favor pseudovector coupling over pseudoscalar coupling or a recently proposed mixed-coupling scheme, but the UIM does not reproduce the imaginary parts of 0+ multipoles well.

  20. Virtual Compton scattering and neutral pion electroproduction in the resonance region up to the deep inelastic region at backward angles

    NASA Astrophysics Data System (ADS)

    Laveissière, G.; Degrande, N.; Jaminion, S.; Jutier, C.; Todor, L.; Salvo, R. Di; Hoorebeke, L. Van; Alexa, L. C.; Anderson, B. D.; Aniol, K. A.; Arundell, K.; Audit, G.; Auerbach, L.; Baker, F. T.; Baylac, M.; Berthot, J.; Bertin, P. Y.; Bertozzi, W.; Bimbot, L.; Boeglin, W. U.; Brash, E. J.; Breton, V.; Breuer, H.; Burtin, E.; Calarco, J. R.; Cardman, L. S.; Cavata, C.; Chang, C.-C.; Chen, J.-P.; Chudakov, E.; Cisbani, E.; Dale, D. S.; de Jager, C. W.; de Leo, R.; Deur, A.; D'Hose, N.; Dodge, G. E.; Domingo, J. J.; Elouadrhiri, L.; Epstein, M. B.; Ewell, L. A.; Finn, J. M.; Fissum, K. G.; Fonvieille, H.; Fournier, G.; Frois, B.; Frullani, S.; Furget, C.; Gao, H.; Gao, J.; Garibaldi, F.; Gasparian, A.; Gilad, S.; Gilman, R.; Glamazdin, A.; Glashausser, C.; Gomez, J.; Gorbenko, V.; Grenier, P.; Guichon, P. A. M.; Hansen, J. O.; Holmes, R.; Holtrop, M.; Howell, C.; Huber, G. M.; Hyde, C. E.; Incerti, S.; Iodice, M.; Jardillier, J.; Jones, M. K.; Kahl, W.; Kamalov, S.; Kato, S.; Katramatou, A. T.; Kelly, J. J.; Kerhoas, S.; Ketikyan, A.; Khayat, M.; Kino, K.; Kox, S.; Kramer, L. H.; Kumar, K. S.; Kumbartzki, G.; Kuss, M.; Leone, A.; Lerose, J. J.; Liang, M.; Lindgren, R. A.; Liyanage, N.; Lolos, G. J.; Lourie, R. W.; Madey, R.; Maeda, K.; Malov, S.; Manley, D. M.; Marchand, C.; Marchand, D.; Margaziotis, D. J.; Markowitz, P.; Marroncle, J.; Martino, J.; McCormick, K.; McIntyre, J.; Mehrabyan, S.; Merchez, F.; Meziani, Z. E.; Michaels, R.; Miller, G. W.; Mougey, J. Y.; Nanda, S. K.; Neyret, D.; Offermann, E. A. J. M.; Papandreou, Z.; Perdrisat, C. F.; Perrino, R.; Petratos, G. G.; Platchkov, S.; Pomatsalyuk, R.; Prout, D. L.; Punjabi, V. A.; Pussieux, T.; Quémenér, G.; Ransome, R. D.; Ravel, O.; Real, J. S.; Renard, F.; Roblin, Y.; Rowntree, D.; Rutledge, G.; Rutt, P. M.; Saha, A.; Saito, T.; Sarty, A. J.; Serdarevic, A.; Smith, T.; Smirnov, G.; Soldi, K.; Sorokin, P.; Souder, P. A.; Suleiman, R.; Templon, J. A.; Terasawa, T.; Tiator, L.; Tieulent, R.; Tomasi-Gustaffson, E.; Tsubota, H.; Ueno, H.; Ulmer, P. E.; Urciuoli, G. M.; de Vyver, R. Van; der Meer, R. L. J. Van; Vernin, P.; Vlahovic, B.; Voskanyan, H.; Voutier, E.; Watson, J. W.; Weinstein, L. B.; Wijesooriya, K.; Wilson, R.; Wojtsekhowski, B. B.; Zainea, D. G.; Zhang, W.-M.; Zhao, J.; Zhou, Z.-L.

    2009-01-01

    We have made the first measurements of the virtual Compton scattering (VCS) process via the H(e, e'p)γ exclusive reaction in the nucleon resonance region, at backward angles. Results are presented for the W-dependence at fixed Q2=1GeV2 and for the Q2 dependence at fixed W near 1.5 GeV. The VCS data show resonant structures in the first and second resonance regions. The observed Q2 dependence is smooth. The measured ratio of H(e, e'p)γ to H(e, e'p)π0 cross sections emphasizes the different sensitivity of these two reactions to the various nucleon resonances. Finally, when compared to real Compton scattering (RCS) at high energy and large angles, our VCS data at the highest W (1.8-1.9 GeV) show a striking Q2 independence, which may suggest a transition to a perturbative scattering mechanism at the quark level.

  1. Electroproduction of η Mesons in the S11(1535) Resonance Region at High Momentum Transfer

    SciTech Connect

    Dalton, Mark Macrae

    2008-08-01

    The differential cross-section for the exclusive process p(e, e0p) has been measured at Q2 5.7 and 7.0 (GeV/c)2, which represents the highest momentum transfer measurement of this to date, significantly higher than the previous highest at Q2 3.6 (GeV/c)2. Data was taken for centre-of-mass energies from threshold to 1.8 GeV, encompassing the S11(1535) resonance, which dominates the pη channel. The total cross section is obtained, from which is extracted the helicity-conserving transition amplitude A1/2, for the production of the S11(1535) resonance. This quantity appears to begin scaling as Q-3, a predicted signal of the dominance of perturbative QCD, within the Q2 range of this measurement. No currently available theoretical predictions can account for the behaviour of this quantity over the full measured range of Q2.

  2. Virtual Compton scattering and neutral pion electroproduction in the resonance region up to the deep inelastic region at backward angles

    SciTech Connect

    Laveissiere, Geraud; Degrande, Natalie; Jaminion, Stephanie; Jutier, Christophe; Todor, Luminita; Di Salvo, Rachele; Van Hoorebeke, L.; Alexa, L.C.; Anderson, Brian; Aniol, Konrad; Arundell, Kathleen; Audit, Gerard; Auerbach, Leonard; Baker, F.; Baylac, Maud; Berthot, J.; Bertin, Pierre; Bertozzi, William; Bimbot, Louis; Boeglin, Werner; Brash, Edward; Breton, Vincent; Breuer, Herbert; Burtin, Etienne; Calarco, John; Cardman, Lawrence; Cavata, Christian; Chang, C.; Chang, C.C.; Chang, C.; Chang, C.C.; Chang, C.; Chang, C.C.; Chang, C.; Chang, C.C.; Chen, Jian-Ping; Chudakov, Eugene; Cisbani, Evaristo; Dale, Daniel; De Jager, Cornelis; De Leo, Raffaele; Deur, Alexandre; D'Hose, Nicole; Dodge, Gail; Domingo, John; Elouadrhiri, Latifa; Epstein, Martin; Ewell, Lars; Finn, John; Fissum, Kevin; Fonvieille, Helene; Fournier, Guy; Frois, Bernard; Frullani, Salvatore; Furget, Christophe; Gao, Haiyan; Gao, Juncai; Garibaldi, Franco; Gasparian, Ashot; Gilad, Shalev; Gilman, Ronald; Glamazdin, Oleksandr; Glashausser, Charles; Gomez, Javier; Gorbenko, Viktor; Grenier, Philippe; Guichon, Pierre; Hansen, Jens-Ole; Holmes, Richard; Holtrop, Maurik; Howell, Calvin; Huber, Garth; Hyde, Charles; Incerti, Sebastien; Iodice, Mauro; Jardillier, Johann; Jones, Mark; Kahl, William; Kamalov, Sabit; Kato, Seigo; Katramatou, A.T.; Kelly, James; Kerhoas, Sophie; Ketikyan, Armen; Khayat, Mohammad; Kino, Kouichi; Kox, Serge; Kramer, Laird; Kumar, Krishna; Kumbartzki, Gerfried; Kuss, Michael; Leone, Antonio; LeRose, John; Liang, Meihua; Lindgren, Richard; Liyanage, Nilanga; Lolos, George; Lourie, Robert; Madey, Richard; Maeda, Kazushige; Malov, Sergey; Manley, D.; Marchand, Claude; Marchand, Dominique; Margaziotis, Demetrius; Markowitz, Pete; Marroncle, Jacques; Martino, Jacques; McCormick, Kathy; McIntyre, Justin; Mehrabyan, Surik; Merchez, Fernand; Meziani, Zein-Eddine; Michaels, Robert; Miller, Gerald; Mougey, Jean; Nanda, Sirish; Neyret, Damien; Offermann, Edmond; Papandreou, Zisis; Perdrisat, Charles; Perrino, R.; Petratos, Gerassimos; Platchkov, Stephane; Pomatsalyuk, Roman; Prout, David; Punjabi, Vina; Pussieux, Thierry; Quemener, Gilles; Ransome, Ronald; Ravel, Oliver; Real, Jean-Sebastien; Renard, F.; Roblin, Yves; Rowntree, David; Rutledge, Gary; Rutt, Paul; Saha, Arunava; Saito, Teijiro; Sarty, Adam; Serdarevic, A.; Smith, T.; Smirnov, G.; Soldi, K.; Sorokin, Pavel; Souder, Paul; Suleiman, Riad; Templon, Jeffrey; Terasawa, Tatsuo; Tiator, Lothar; Tieulent, Raphael; Tomasi-Gustaffson, E.; Tsubota, Hiroaki; Ueno, Hiroaki; Ulmer, Paul; Urciuoli, Guido; Van De Vyver, R.; van der Meer, Rob; Vernin, Pascal; Vlahovic, B.; Voskanyan, Hakob; Voutier, Eric; Watson, J.W.; Weinstein, Lawrence; Wijesooriya, Krishni; Wilson, R.; Wojtsekhowski, Bogdan; Zainea, Dan; Zhang, Wei-Ming; Zhao, Jie; Zhou, Z.-L.

    2009-01-01

    We have made the first measurements of the virtual Compton scattering (VCS) process via the H(e,e'p)? exclusive reaction in the nucleon resonance region, at backward angles. Results are presented for the W-dependence at fixed Q2=1 GeV2, and for the Q2-dependence at fixed W near 1.5 GeV. The VCS data show resonant structures in the first and second resonance regions. The observed Q2-dependence is smooth. The measured ratio of H(e,e'p)? to H(e,e'p)?0 cross sections emphasizes the different sensitivity of these two reactions to the various nucleon resonances. Finally, when compared to Real Compton Scattering (RCS) at high energy and large angles, our VCS data at the highest W (1.8-1.9 GeV) show a striking Q2-independence, which may suggest a transition to a perturbative scattering mechanism at the quark level.

  3. Virtual Compton scattering and neutral pion electroproduction in the resonance region up to the deep inelastic region at backward angles

    SciTech Connect

    Laveissiere, G.; Jaminion, S.; Salvo, R. Di; Berthot, J.; Bertin, P. Y.; Breton, V.; Fonvieille, H.; Grenier, P.; Ravel, O.; Roblin, Y.; Smirnov, G.; Jutier, C.; Hyde, C. E.; Todor, L.; Dodge, G. E.; McCormick, K.; Ulmer, P. E.

    2009-01-15

    We have made the first measurements of the virtual Compton scattering (VCS) process via the H(e, e{sup '}p){gamma} exclusive reaction in the nucleon resonance region, at backward angles. Results are presented for the W-dependence at fixed Q{sup 2}=1 GeV{sup 2} and for the Q{sup 2} dependence at fixed W near 1.5 GeV. The VCS data show resonant structures in the first and second resonance regions. The observed Q{sup 2} dependence is smooth. The measured ratio of H(e, e{sup '}p){gamma} to H(e, e{sup '}p){pi}{sup 0} cross sections emphasizes the different sensitivity of these two reactions to the various nucleon resonances. Finally, when compared to real Compton scattering (RCS) at high energy and large angles, our VCS data at the highest W (1.8-1.9 GeV) show a striking Q{sup 2} independence, which may suggest a transition to a perturbative scattering mechanism at the quark level.

  4. "Hard Science" for Gifted 1st Graders

    ERIC Educational Resources Information Center

    DeGennaro, April

    2006-01-01

    "Hard Science" is designed to teach 1st grade gifted students accurate and high level science concepts. It is based upon their experience of the world and attempts to build a foundation for continued love and enjoyment of science. "Hard Science" provides field experiences and opportunities for hands-on discovery working beside experts in the field…

  5. 21 CFR 133.150 - Hard cheeses.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Hard cheeses. 133.150 Section 133.150 Food and... CONSUMPTION CHEESES AND RELATED CHEESE PRODUCTS Requirements for Specific Standardized Cheese and Related Products § 133.150 Hard cheeses. (a) The cheeses for which definitions and standards of identity...

  6. Retraction of Hard, Lozano, and Tversky (2006)

    ERIC Educational Resources Information Center

    Hard, B. M.; Lozano, S. C.; Tversky, B.

    2008-01-01

    Reports a retraction of "Hierarchical encoding of behavior: Translating perception into action" by Bridgette Martin Hard, Sandra C. Lozano and Barbara Tversky (Journal of Experimental Psychology: General, 2006[Nov], Vol 135[4], 588-608). All authors retract this article. Co-author Tversky and co-author Hard believe that the research results cannot…

  7. Hardness Evolution of Gamma-Irradiated Polyoxymethylene

    NASA Astrophysics Data System (ADS)

    Hung, Chuan-Hao; Harmon, Julie P.; Lee, Sanboh

    2016-04-01

    This study focuses on analyzing hardness evolution in gamma-irradiated polyoxymethylene (POM) exposed to elevated temperatures after irradiation. Hardness increases with increasing annealing temperature and time, but decreases with increasing gamma ray dose. Hardness changes are attributed to defects generated in the microstructure and molecular structure. Gamma irradiation causes a decrease in the glass transition temperature, melting point, and extent of crystallinity. The kinetics of defects resulting in hardness changes follow a first-order structure relaxation. The rate constant adheres to an Arrhenius equation, and the corresponding activation energy decreases with increasing dose due to chain scission during gamma irradiation. The structure relaxation of POM has a lower energy barrier in crystalline regions than in amorphous ones. The hardness evolution in POM is an endothermic process due to the semi-crystalline nature of this polymer.

  8. Conclusive exclusion of quantum states

    NASA Astrophysics Data System (ADS)

    Bandyopadhyay, Somshubhro; Jain, Rahul; Oppenheim, Jonathan; Perry, Christopher

    2014-02-01

    In the task of quantum state exclusion, we consider a quantum system prepared in a state chosen from a known set. The aim is to perform a measurement on the system which can conclusively rule that a subset of the possible preparation procedures cannot have taken place. We ask what conditions the set of states must obey in order for this to be possible and how well we can complete the task when it is not. The task of quantum state discrimination forms a subclass of this set of problems. Within this paper, we formulate the general problem as a semidefinite program (SDP), enabling us to derive sufficient and necessary conditions for a measurement to be optimal. Furthermore, we obtain a necessary condition on the set of states for exclusion to be achievable with certainty, and we give a construction for a lower bound on the probability of error. This task of conclusively excluding states has gained importance in the context of the foundations of quantum mechanics due to a result from Pusey, Barrett, and Rudolph (PBR). Motivated by this, we use our SDP to derive a bound on how well a class of hidden variable models can perform at a particular task, proving an analog of Tsirelson's bound for the PBR experiment and the optimality of a measurement given by PBR in the process. We also introduce variations of conclusive exclusion, including unambiguous state exclusion, and state exclusion with worst-case error.

  9. Intrapersonal and interpersonal processes of social exclusion

    PubMed Central

    Kawamoto, Taishi; Ura, Mitsuhiro; Nittono, Hiroshi

    2015-01-01

    People have a fundamental need to belong with others. Social exclusion impairs this need and has various effects on cognition, affect, and the behavior of excluded individuals. We have previously reported that activity in the dorsal anterior cingulate cortex (dACC) and right ventrolateral prefrontal cortex (rVLPFC) could be a neurocognitive index of social exclusion (Kawamoto et al., 2012). In this article, we provide an integrative framework for understanding occurrences during and after social exclusion, by reviewing neuroimaging, electrophysiological, and behavioral studies of dACC and rVLPFC, within the framework of intrapersonal and interpersonal processes of social exclusion. As a result, we have indicated directions for future studies to further clarify the phenomenon of social exclusion from the following perspectives: (1) constructional elements of social exclusion, (2) detection sensitivity and interpretation bias in social exclusion, (3) development of new methods to assess the reactivity to social exclusion, and (4) sources of social exclusion. PMID:25798081

  10. Effects of Hard Water on Hair

    PubMed Central

    Srinivasan, Gautham; Srinivas, Chakravarthi Rangachari; Mathew, Anil C; Duraiswami, Divakar

    2013-01-01

    Background: Hardness of water is determined by the amount of salts (calcium carbonate [CaCO3] and magnesium sulphate [MgSO4]) present in water. The hardness of the water used for washing hair may cause fragility of hair. Objective: The objective of the following study is to compare the tensile strength and elasticity of hair treated in hard water and hair treated in distilled water. Materials and Methods: 10-15 strands of hair of length 15-20 cm, lost during combing were obtained from 15 volunteers. Each sample was cut in the middle to obtain 2 sets of hair per volunteer. One set of 15 samples was immersed in hard water and the other set in distilled water for 10 min on alternate days. Procedure was repeated for 30 days. The tensile strength and elasticity of the hair treated in hard water and distilled water was determined using INSTRON universal strength tester. Results: The CaCO3 and MgSO4 content of hard water and distilled water were determined as 212.5 ppm of CaCO3 and 10 ppm of CaCO3 respectively. The tensile strength and elasticity in each sample was determined and the mean values were compared using t-test. The mean (SD) of tensile strength of hair treated in hard water was 105.28 (27.59) and in distilled water was 103.66 (20.92). No statistical significance was observed in the tensile strength, t = 0.181, P = 0.858. The mean (SD) of elasticity of hair treated in hard water was 37.06 (2.24) and in distilled water was 36.84 (4.8). No statistical significance was observed in the elasticity, t = 0.161, P = 0.874. Conclusion: The hardness of water does not interfere with the tensile strength and elasticity of hair. PMID:24574692

  11. Analysis of Hard Thin Film Coating

    NASA Technical Reports Server (NTRS)

    Shen, Dashen

    1998-01-01

    MSFC is interested in developing hard thin film coating for bearings. The wearing of the bearing is an important problem for space flight engine. Hard thin film coating can drastically improve the surface of the bearing and improve the wear-endurance of the bearing. However, many fundamental problems in surface physics, plasma deposition, etc, need further research. The approach is using electron cyclotron resonance chemical vapor deposition (ECRCVD) to deposit hard thin film an stainless steel bearing. The thin films in consideration include SiC, SiN and other materials. An ECRCVD deposition system is being assembled at MSFC.

  12. Analysis of Hard Thin Film Coating

    NASA Technical Reports Server (NTRS)

    Shen, Dashen

    1998-01-01

    Marshall Space Flight Center (MSFC) is interested in developing hard thin film coating for bearings. The wearing of the bearing is an important problem for space flight engine. Hard thin film coating can drastically improve the surface of the bearing and improve the wear-endurance of the bearing. However, many fundamental problems in surface physics, plasma deposition, etc, need further research. The approach is using Electron Cyclotron Resonance Chemical Vapor Deposition (ECRCVD) to deposit hard thin film on stainless steel bearing. The thin films in consideration include SiC, SiN and other materials. An ECRCVD deposition system is being assembled at MSFC.

  13. Differential cross-sections with hard targets

    NASA Astrophysics Data System (ADS)

    Brun, J. L.; Pacheco, A. F.

    2005-09-01

    When the concept of scattering differential cross-section is introduced in classical mechanics textbooks, usually it is first supposed that the target is a fixed, hard sphere. In this paper we calculate the scattering differential cross-section in the case of the hard target being a fixed figure of revolution of any shape. When the target is a paraboloid of revolution, we find the well-known formula corresponding to Rutherford's scattering. In addition, we analyse the inverse problem, i.e. given a differential cross-section, what is the profile of the corresponding hard target?

  14. [Methods for evaluation of penile erection hardness].

    PubMed

    Yuan, Yi-Ming; Zhou, Su; Zhang, Kai

    2010-07-01

    Penile erection hardness is one of the key factors for successful sexual intercourse, as well as an important index in the diagnosis and treatment of erectile dysfunction (ED). This article gives an overview on the component and impact factors of erection hardness, summarizes some commonly used evaluation methods, including those for objective indexes, such as Rigiscan, axial buckling test and color Doppler ultrasonography, and those for subjective indexes of ED patients, such as IIEF, the Erectile Function Domain of IIEF (IIEF-EF), and Erection Hardness Score (EHS), and discusses the characteristics of these methods.

  15. Generalized parton distributions and rapidity gap survival in exclusive diffractive pp scattering

    SciTech Connect

    Frankfurt, L.; Hyde, C. E.; Strikman, M.; Weiss, C.

    2007-03-01

    We study rapidity gap survival (RGS) in the production of high-mass systems (H=dijet, heavy quarkonium, Higgs boson) in double-gap exclusive diffractive pp scattering, pp{yields}p+(gap)+H+(gap)+p. Our approach is based on the idea that hard and soft interactions are approximately independent because they proceed over widely different time and distance scales. We implement this idea in a partonic description of proton structure, which allows for a model-independent treatment of the interplay of hard and soft interactions. The high-mass system is produced in a hard scattering process with exchange of two gluons between the protons, whose amplitude is calculable in terms of the gluon generalized parton distribution (GPD), measured in exclusive ep scattering. The hard scattering process is modified by soft spectator interactions, which we calculate neglecting correlations between hard and soft interactions (independent interaction approximation). We obtain an analytic expression for the RGS probability in terms of the phenomenological pp elastic scattering amplitude, without reference to the eikonal approximation. Contributions from inelastic intermediate states are suppressed. The onset of the black-disk limit in pp scattering at TeV energies strongly suppresses diffraction at small impact parameters and is the main factor in determining the RGS probability. Correlations between hard and soft interactions (e.g. due to scattering from the long-range pion field of the proton or due to possible short-range transverse correlations between partons) further decrease the RGS probability. We also investigate the dependence of the diffractive cross section on the transverse momenta of the final-state protons ('diffraction pattern'). By measuring this dependence one can perform detailed tests of the interplay of hard and soft interactions and even extract information about the gluon GPD in the proton. Such studies appear to be feasible with the planned forward detectors at the

  16. Novel hard compositions and methods of preparation

    DOEpatents

    Sheinberg, H.

    1981-02-03

    Novel very hard compositions of matter are prepared by using in all embodiments only a minor amount of a particular carbide (or materials which can form the carbide in situ when subjected to heat and pressure); and no strategic cobalt is needed. Under a particular range of conditions, densified compositions of matter of the invention are prepared having hardnesses on the Rockwell A test substantially equal to the hardness of pure tungsten carbide and to two of the hardest commercial cobalt-bonded tungsten carbides. Alternately, other compositions of the invention which have slightly lower hardnesses than those described above in one embodiment also possess the advantage of requiring no tungsten and in another embodiment possess the advantage of having a good fracture toughness value.

  17. Automated radiation hard ASIC design tool

    NASA Technical Reports Server (NTRS)

    White, Mike; Bartholet, Bill; Baze, Mark

    1993-01-01

    A commercial based, foundry independent, compiler design tool (ChipCrafter) with custom radiation hardened library cells is described. A unique analysis approach allows low hardness risk for Application Specific IC's (ASIC's). Accomplishments, radiation test results, and applications are described.

  18. Financial Incentives for Staffing Hard Places.

    ERIC Educational Resources Information Center

    Prince, Cynthia D.

    2002-01-01

    Describes examples of financial incentives used to recruit teachers for low-achieving and hard-to-staff schools. Includes targeted salary increases, housing incentives, tuition assistance, and tax credits. (PKP)

  19. Electronic Teaching: Hard Disks and Networks.

    ERIC Educational Resources Information Center

    Howe, Samuel F.

    1984-01-01

    Describes floppy-disk and hard-disk based networks, electronic systems linking microcomputers together for the purpose of sharing peripheral devices, and presents points to remember when shopping for a network. (MBR)

  20. Density functional theory for hard polyhedra.

    PubMed

    Marechal, Matthieu; Löwen, Hartmut

    2013-03-29

    Using the framework of geometry-based fundamental-measure theory, we develop a classical density functional for hard polyhedra and their mixtures and apply it to inhomogeneous fluids of Platonic solids near a hard wall. As revealed by Monte Carlo simulations, the faceted shape of the polyhedra leads to complex layering and orientational ordering near the wall, which is excellently reproduced by our theory. These effects can be verified in real-space experiments on polyhedral colloids.

  1. Breakdown of QCD factorization in hard diffraction

    NASA Astrophysics Data System (ADS)

    Kopeliovich, B. Z.

    2016-07-01

    Factorization of short- and long-distance interactions is severely broken in hard diffractive hadronic collisions. Interaction with the spectator partons leads to an interplay between soft and hard scales, which results in a leading twist behavior of the cross section, on the contrary to the higher twist predicted by factorization. This feature is explicitly demonstrated for diffractive radiation of abelian (Drell-Yan, gauge bosons, Higgs) and non-abelian (heavy flavors) particles.

  2. A Novel Approach to Hardness Testing

    NASA Technical Reports Server (NTRS)

    Spiegel, F. Xavier; West, Harvey A.

    1996-01-01

    This paper gives a description of the application of a simple rebound time measuring device and relates the determination of relative hardness of a variety of common engineering metals. A relation between rebound time and hardness will be sought. The effect of geometry and surface condition will also be discussed in order to acquaint the student with the problems associated with this type of method.

  3. Laser Ablatin of Dental Hard Tissue

    SciTech Connect

    Seka, W.; Rechmann, P.; Featherstone, J.D.B.; Fried, D.

    2007-07-31

    This paper discusses ablation of dental hard tissue using pulsed lasers. It focuses particularly on the relevant tissue and laser parameters and some of the basic ablation processes that are likely to occur. The importance of interstitial water and its phase transitions is discussed in some detail along with the ablation processes that may or may not directly involve water. The interplay between tissue parameters and laser parameters in the outcome of the removal of dental hard tissue is discussed in detail.

  4. The AdS/QCD Correspondence and Exclusive Processes

    SciTech Connect

    Brodsky, Stanley J.; de Teramond, Guy F.; Deur, Alexandre; /Jefferson Lab

    2010-08-25

    The AdS/CFT correspondence between theories in AdS space and conformal field theories in physical space-time provides an analytic, semi-classical, color-confining model for strongly-coupled QCD. The soft-wall AdS/QCD model modified by a positive-sign dilaton metric leads to a remarkable one-parameter description of nonperturbative hadron dynamics at zero quark mass, including a zero-mass pion and a Regge spectrum of linear trajectories with the same slope in orbital angular momentum L and radial quantum number n for both mesons and baryons. One also predicts the form of the non-perturbative effective coupling {alpha}{sub s}{sup AdS}(q) and its {beta}-function which agrees with the effective coupling {alpha}{sub ga} extracted from the Bjorken sum rule. Light-front holography, which connects the fifth-dimensional coordinate of AdS space z to an invariant impact separation variable {zeta}, allows one to compute the analytic form of the frame-independent light-front wavefunctions, the fundamental entities which encode hadron properties as well as decay constants, form factors, deeply virtual Compton scattering, exclusive heavy hadron decays and other exclusive scattering amplitudes. One thus obtains a relativistic description of hadrons in QCD at the amplitude level with dimensional counting for hard exclusive reactions at high momentum transfer. As specific examples we discuss the behavior of the pion and nucleon form factors in the space-like and time-like regions. We also review the phenomenology of exclusive processes including some anomalous empirical results.

  5. Measurement of the Unpolarized K{sup +} {Lambda} and K{sup +} {Sigma}{sup 0} Electroproduction Cross Sections and Interference Terms from the Proton with the CLAS Detector

    SciTech Connect

    Robert Feuerbach

    2002-12-01

    Using the CLAS detector, we measure the K{sup +}{Lambda} and K{sup +}{Sigma}{sup 0} electroproduction response functions over the continuous kinematic range from threshold to W = 2.05 GeV and for Q{sup 2} between 0.5 and 1.5 (GeV/c){sup 2}, with nearly complete angular coverage in the center-of-momentum frame angles. The {sigma}{sub T} + {epsilon}{sigma}{sub L}, {sigma}{sub TT} terms are extracted and compared to recent theoretical calculations based upon a hadrodynamic effective-Lagrangian framework. From examining the W-dependence of the response functions for the K{sup +}{Lambda} final state, we find features in the ({sigma}{sub T} + {epsilon}{sigma}{sub L}) term in the W = 1.75 to 1.90GeV region, similar to features seen in recent photoproduction results. In general, the {sigma}{sub TT} and {sigma}{sub LT} response-functions for {Lambda} production are of the same order of magnitude as the ({sigma}{sub T} + {epsilon}{sigma}{sub L}) term, suggesting that both {sigma}{sub T} and {sigma}{sub L} contribute significantly. For the K{sup +} {Sigma}{sup 0} final state the W-dependence of the ({sigma}{sub T} + {epsilon}{sigma}{sub L}) and {sigma}{sub TT} terms have large, resonant-like features near W = 1.9GeV. Unlike in {Lambda} electroproduction, the {sigma}{sub LT} interference term for {Sigma}{sup 0} electroproduction is found to be consistent with zero across nearly the entire kinematic range, while {sigma}{sub TT} is comparable in magnitude to the {sigma}{sub T} + {epsilon}{sigma}{sub L} differential cross-section. The models, while achieving some qualitative agreement with the data, fail to both describe the details of the angular distributions and reproduce the resonant-like behavior observed.

  6. 78 FR 55687 - Notice of Intent To Grant an Exclusive, Partially Exclusive or Non-Exclusive License of the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-11

    ... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF DEFENSE Department of the Army Notice of Intent To Grant an Exclusive, Partially Exclusive or Non-Exclusive License of the United States Patent Application No. 13/ 543,217 Filed July 06, 2012 Entitled ''Tie-Down...

  7. 76 FR 38122 - Notice of Availability for Exclusive, Non-Exclusive, or Partially-Exclusive Licensing of an...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-29

    ... Department of the Army Notice of Availability for Exclusive, Non-Exclusive, or Partially-Exclusive Licensing... Agents, Synthesis of and Methods of Use Thereof AGENCY: Department of the Army, DoD. ACTION: Notice... United States Government, as represented by the Secretary of the Army, has rights to this...

  8. 78 FR 6814 - Notice of Availability for Exclusive, Non-Exclusive, or Partially-Exclusive Licensing of an...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-31

    ... Department of the Army Notice of Availability for Exclusive, Non-Exclusive, or Partially-Exclusive Licensing... Epitopes AGENCY: Department of the Army, DoD. ACTION: Notice. SUMMARY: Announcement is made of the... September 22, 2006. The United States Government as represented by the Secretary of the Army has rights...

  9. 76 FR 38122 - Notice of Availability for Exclusive, Non-Exclusive, or Partially-Exclusive Licensing of an...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-29

    ... Department of the Army Notice of Availability for Exclusive, Non-Exclusive, or Partially-Exclusive Licensing..., Synthesis of and Methods of Use Thereof AGENCY: Department of the Army, DoD. ACTION: Notice. SUMMARY... represented by the Secretary of the Army, has rights to this invention. ADDRESSES: Commander, U.S....

  10. Exclusive processes in quantum chromodynamics

    SciTech Connect

    Brodsky, S.J.; Lepage, G.P.

    1981-06-01

    Large momentum transfer exclusive processes and the short distance structure of hadronic wave functions can be systematically analyzed within the context of perturbative QCD. Predictions for meson form factors, two-photon processes ..gamma gamma.. ..-->.. M anti M, hadronic decays of heavy quark systems, and a number of other related QCD phenomena are reviewed.

  11. University Ranking as Social Exclusion

    ERIC Educational Resources Information Center

    Amsler, Sarah S.; Bolsmann, Chris

    2012-01-01

    In this article we explore the dual role of global university rankings in the creation of a new, knowledge-identified, transnational capitalist class and in facilitating new forms of social exclusion. We examine how and why the practice of ranking universities has become widely defined by national and international organisations as an important…

  12. 5 CFR 551.214 - Statutory exclusion.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... ADMINISTRATION UNDER THE FAIR LABOR STANDARDS ACT Exemptions and Exclusions § 551.214 Statutory exclusion. A....S.C. 267 and under 19 CFR 24.16 for time worked may not receive pay or other compensation for...

  13. 5 CFR 551.214 - Statutory exclusion.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... ADMINISTRATION UNDER THE FAIR LABOR STANDARDS ACT Exemptions and Exclusions § 551.214 Statutory exclusion. A....S.C. 267 and under 19 CFR 24.16 for time worked may not receive pay or other compensation for...

  14. 5 CFR 551.214 - Statutory exclusion.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... ADMINISTRATION UNDER THE FAIR LABOR STANDARDS ACT Exemptions and Exclusions § 551.214 Statutory exclusion. A....S.C. 267 and under 19 CFR 24.16 for time worked may not receive pay or other compensation for...

  15. 5 CFR 551.214 - Statutory exclusion.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... ADMINISTRATION UNDER THE FAIR LABOR STANDARDS ACT Exemptions and Exclusions § 551.214 Statutory exclusion. A....S.C. 267 and under 19 CFR 24.16 for time worked may not receive pay or other compensation for...

  16. 5 CFR 551.214 - Statutory exclusion.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... ADMINISTRATION UNDER THE FAIR LABOR STANDARDS ACT Exemptions and Exclusions § 551.214 Statutory exclusion. A....S.C. 267 and under 19 CFR 24.16 for time worked may not receive pay or other compensation for...

  17. When 1+1>2: Nanostructured composites for hard tissue engineering applications.

    PubMed

    Uskoković, Vuk

    2015-12-01

    Multicomponent, synergistic and multifunctional nanostructures have taken over the spotlight in the realm of biomedical nanotechnologies. The most prospective materials for bone regeneration today are almost exclusively composites comprising two or more components that compensate for the shortcomings of each one of them alone. This is quite natural in view of the fact that all hard tissues in the human body, except perhaps the tooth enamel, are composite nanostructures. This review article highlights some of the most prospective breakthroughs made in this research direction, with the hard tissues in main focus being those comprising bone, tooth cementum, dentin and enamel. The major obstacles to creating collagen/apatite composites modeled after the structure of bone are mentioned, including the immunogenicity of xenogeneic collagen and continuously failing attempts to replicate the biomineralization process in vitro. Composites comprising a polymeric component and calcium phosphate are discussed in light of their ability to emulate the soft/hard composite structure of bone. Hard tissue engineering composites created using hard material components other than calcium phosphates, including silica, metals and several types of nanotubes, are also discoursed on, alongside additional components deliverable using these materials, such as cells, growth factors, peptides, antibiotics, antiresorptive and anabolic agents, pharmacokinetic conjugates and various cell-specific targeting moieties. It is concluded that a variety of hard tissue structures in the body necessitates a similar variety of biomaterials for their regeneration. The ongoing development of nanocomposites for bone restoration will result in smart, theranostic materials, capable of acting therapeutically in direct feedback with the outcome of in situ disease monitoring at the cellular and subcellular scales. Progress in this research direction is expected to take us to the next generation of biomaterials

  18. When 1+1>2: Nanostructured composites for hard tissue engineering applications.

    PubMed

    Uskoković, Vuk

    2015-12-01

    Multicomponent, synergistic and multifunctional nanostructures have taken over the spotlight in the realm of biomedical nanotechnologies. The most prospective materials for bone regeneration today are almost exclusively composites comprising two or more components that compensate for the shortcomings of each one of them alone. This is quite natural in view of the fact that all hard tissues in the human body, except perhaps the tooth enamel, are composite nanostructures. This review article highlights some of the most prospective breakthroughs made in this research direction, with the hard tissues in main focus being those comprising bone, tooth cementum, dentin and enamel. The major obstacles to creating collagen/apatite composites modeled after the structure of bone are mentioned, including the immunogenicity of xenogeneic collagen and continuously failing attempts to replicate the biomineralization process in vitro. Composites comprising a polymeric component and calcium phosphate are discussed in light of their ability to emulate the soft/hard composite structure of bone. Hard tissue engineering composites created using hard material components other than calcium phosphates, including silica, metals and several types of nanotubes, are also discoursed on, alongside additional components deliverable using these materials, such as cells, growth factors, peptides, antibiotics, antiresorptive and anabolic agents, pharmacokinetic conjugates and various cell-specific targeting moieties. It is concluded that a variety of hard tissue structures in the body necessitates a similar variety of biomaterials for their regeneration. The ongoing development of nanocomposites for bone restoration will result in smart, theranostic materials, capable of acting therapeutically in direct feedback with the outcome of in situ disease monitoring at the cellular and subcellular scales. Progress in this research direction is expected to take us to the next generation of biomaterials

  19. Transverse nucleon structure and diagnostics of hard parton-parton processes at LHC

    SciTech Connect

    L. Frankfurt, M. Strikman, C. Weiss

    2011-03-01

    We propose a new method to determine at what transverse momenta particle production in high-energy pp collisions is governed by hard parton-parton processes. Using information on the transverse spatial distribution of partons obtained from hard exclusive processes in ep/\\gamma p scattering, we evaluate the impact parameter distribution of pp collisions with a hard parton-parton process as a function of p_T of the produced parton (jet). We find that the average pp impact parameters in such events depend very weakly on p_T in the range 2 < p_T < few 100 GeV, while they are much smaller than those in minimum-bias inelastic collisions. The impact parameters in turn govern the observable transverse multiplicity in such events (in the direction perpendicular to the trigger particle or jet). Measuring the transverse multiplicity as a function of p_T thus provides an effective tool for determining the minimum p_T for which a given trigger particle originates from a hard parton-parton process.

  20. Developing and Studying the Methods of Hard-Facing with Heat-Resisting High-Hardness Steels

    NASA Astrophysics Data System (ADS)

    Malushin, N. N.; Kovalev, A. P.; Valuev, D. V.; Shats, E. A.; Borovikov, I. F.

    2016-08-01

    The authors develop the methods of hard-facing of mining-metallurgic equipment parts with heat-resisting high-hardness steels on the base of plasma-jet hard-facing in the shielding-alloying nitrogen atmosphere.

  1. 40 CFR 122.3 - Exclusions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 22 2014-07-01 2013-07-01 true Exclusions. 122.3 Section 122.3... § 122.3 Exclusions. The following discharges do not require NPDES permits: (a) Any discharge of sewage... wastes, or any other discharge incidental to the normal operation of a vessel. This exclusion does...

  2. Novel hard compositions and methods of preparation

    DOEpatents

    Sheinberg, H.

    1983-08-23

    Novel very hard compositions of matter are prepared by using in all embodiments only a minor amount of a particular carbide (or materials which can form the carbide in situ when subjected to heat and pressure); and no strategic cobalt is needed. Under a particular range of conditions, densified compositions of matter of the invention are prepared having hardnesses on the Rockwell A test substantially equal to the hardness of pure tungsten carbide and to two of the hardest commercial cobalt-bonded tungsten carbides. Alternately, other compositions of the invention which have slightly lower hardnesses than those described above in one embodiment also possess the advantage of requiring no tungsten and in another embodiment possess the advantage of having a good fracture toughness value. Photomicrographs show that the shapes of the grains of the alloy mixture with which the minor amount of carbide (or carbide-formers) is mixed are radically altered from large, rounded to small, very angular by the addition of the carbide. Superiority of one of these hard compositions of matter over cobalt-bonded tungsten carbide for ultra-high pressure anvil applications was demonstrated. 3 figs.

  3. Novel hard compositions and methods of preparation

    DOEpatents

    Sheinberg, Haskell

    1983-08-23

    Novel very hard compositions of matter are prepared by using in all embodiments only a minor amount of a particular carbide (or materials which can form the carbide in situ when subjected to heat and pressure); and no strategic cobalt is needed. Under a particular range of conditions, densified compositions of matter of the invention are prepared having hardnesses on the Rockwell A test substantially equal to the hardness of pure tungsten carbide and to two of the hardest commercial cobalt-bonded tungsten carbides. Alternately, other compositions of the invention which have slightly lower hardnesses than those described above in one embodiment also possess the advantage of requiring no tungsten and in another embodiment possess the advantage of having a good fracture toughness value. Photomicrographs show that the shapes of the grains of the alloy mixture with which the minor amount of carbide (or carbide-formers) is mixed are radically altered from large, rounded to small, very angular by the addition of the carbide. Superiority of one of these hard compositions of matter over cobalt-bonded tungsten carbide for ultra-high pressure anvil applications was demonstrated.

  4. Exclusive Dijet production from CDF2LHC

    SciTech Connect

    Gallinaro, Michele; /Rockefeller U.

    2005-04-01

    Exclusive dijet production at the Tevatron can be used as a benchmark to establish predictions on exclusive diffractive Higgs production, a process with a much smaller cross section. Exclusive dijet production in Double Pomeron Exchange processes, including diffractive Higgs production with measurements at the Tevatron and predictions for the Large Hadron Collider are presented. Using new data from the Tevatron and dedicated diffractive triggers, no excess over a smooth falling distribution for exclusive dijet events could be found. Upper limits on the exclusive dijet production cross section are presented and compared to current theoretical predictions.

  5. "We Can Get Everything We Want if We Try Hard": Young People, Celebrity, Hard Work

    ERIC Educational Resources Information Center

    Mendick, Heather; Allen, Kim; Harvey, Laura

    2015-01-01

    Drawing on 24 group interviews on celebrity with 148 students aged 14-17 across six schools, we show that "hard work" is valued by young people in England. We argue that we should not simply celebrate this investment in hard work. While it opens up successful subjectivities to previously excluded groups, it reproduces neoliberal…

  6. Research in the Hard Sciences, and in Very Hard "Softer" Domains

    ERIC Educational Resources Information Center

    Phillips, D. C.

    2014-01-01

    The author of this commentary argues that physical scientists are attempting to advance knowledge in the so-called hard sciences, whereas education researchers are laboring to increase knowledge and understanding in an "extremely hard" but softer domain. Drawing on the work of Popper and Dewey, this commentary highlights the relative…

  7. Hard Water and Soft Soap: Dependence of Soap Performance on Water Hardness

    ERIC Educational Resources Information Center

    Osorio, Viktoria K. L.; de Oliveira, Wanda; El Seoud, Omar A.; Cotton, Wyatt; Easdon, Jerry

    2005-01-01

    The demonstration of the performance of soap in different aqueous solutions, which is due to water hardness and soap formulation, is described. The demonstrations use safe, inexpensive reagents and simple glassware and equipment, introduce important everyday topics, stimulates the students to consider the wider consequences of water hardness and…

  8. [Mothers' knowledge about exclusive breastfeeding].

    PubMed

    da Silva, Nichelle Monique; Waterkemper, Roberta; da Silva, Eveline Franco; Cordova, Fernanda Peixoto; Bonilha, Ana Lucia de Lourenzi

    2014-01-01

    This is a descriptive study, with a qualitative approach, aimed to identify the knowledge of puerperal women on exclusive breastfeeding. Data were collected between September-October 2011, through semi-structured interview. Thirteen puerperal women, interned in a rooming unit of a public institution in the city of Caxias do Sul-RS, participated in the study. Data analysis was performed using thematic analysis. From the interpretation of information three categories emerged: the knowledge about exclusive breastfeeding, the breastfeeding process and the influences of received information. Even getting information from health professionals in the prenatal period, it is possible to understand that there is a need to improve communication and monitoring of mothers, as a continuity of professional care in the postpartum period, and also later, in the remote.

  9. Potential Health Impacts of Hard Water

    PubMed Central

    Sengupta, Pallav

    2013-01-01

    In the past five decades or so evidence has been accumulating about an environmental factor, which appears to be influencing mortality, in particular, cardiovascular mortality, and this is the hardness of the drinking water. In addition, several epidemiological investigations have demonstrated the relation between risk for cardiovascular disease, growth retardation, reproductive failure, and other health problems and hardness of drinking water or its content of magnesium and calcium. In addition, the acidity of the water influences the reabsorption of calcium and magnesium in the renal tubule. Not only, calcium and magnesium, but other constituents also affect different health aspects. Thus, the present review attempts to explore the health effects of hard water and its constituents. PMID:24049611

  10. Erosion testing of hard materials and coatings

    SciTech Connect

    Hawk, Jeffrey A.

    2005-04-29

    Erosion is the process by which unconstrained particles, usually hard, impact a surface, creating damage that leads to material removal and component failure. These particles are usually very small and entrained in fluid of some type, typically air. The damage that occurs as a result of erosion depends on the size of the particles, their physical characteristics, the velocity of the particle/fluid stream, and their angle of impact on the surface of interest. This talk will discuss the basics of jet erosion testing of hard materials, composites and coatings. The standard test methods will be discussed as well as alternative approaches to determining the erosion rate of materials. The damage that occurs will be characterized in genera1 terms, and examples will be presented for the erosion behavior of hard materials and coatings (both thick and thin).

  11. Potential health impacts of hard water.

    PubMed

    Sengupta, Pallav

    2013-08-01

    In the past five decades or so evidence has been accumulating about an environmental factor, which appears to be influencing mortality, in particular, cardiovascular mortality, and this is the hardness of the drinking water. In addition, several epidemiological investigations have demonstrated the relation between risk for cardiovascular disease, growth retardation, reproductive failure, and other health problems and hardness of drinking water or its content of magnesium and calcium. In addition, the acidity of the water influences the reabsorption of calcium and magnesium in the renal tubule. Not only, calcium and magnesium, but other constituents also affect different health aspects. Thus, the present review attempts to explore the health effects of hard water and its constituents.

  12. Incorporating cultural beliefs in promoting exclusive breastfeeding

    PubMed Central

    Reinsma, Kathryn; Bolima, Nancy; Fonteh, Florence; Okwen, Patrick; Yota, Daniel; Montgomery, Susanne

    2015-01-01

    Introduction Since 2003, the World Health Organization has recommended exclusive breastfeeding for the first 6 months of life. In the Northwest region of Cameroon approximately 90% of women initiate breastfeeding, yet only 34% of these women exclusively breastfeed for the recommended six months. Aim To determine influences on women’s exclusive breastfeeding practices. Methods Semi-structured interviews were conducted with six women and six men followed by focus group discussions with three groups of women and three groups of men in the Kumbo West Health District, Northwest region, Cameroon. All participants were selected using theoretical sampling to assure triangulation. Results Three themes emerged that influence exclusive breastfeeding practices: woman’s readiness to exclusively breastfeed; cultural influences towards exclusive breastfeeding; and perceived constraints to exclusive breastfeeding. Conclusion These emergent themes were used to create a theoretical framework that is useful for developing a breastfeeding health education intervention in non-Western settings. PMID:26973717

  13. Equation of state for fluid mixtures of hard spheres and heteronuclear hard dumbbells

    NASA Astrophysics Data System (ADS)

    Barrio, C.; Solana, J. R.

    1999-09-01

    A theoretically founded equation of state is developed for mixtures of hard spheres with heteronuclear hard dumbbells. It is based on a model previously developed for hard-convex-body fluid mixtures, and further extended to fluid mixtures of homonuclear hard dumbbells. The equation scales the excess compressibility factor for an equivalent hard-sphere fluid mixture to obtain that corresponding to the true mixture. The equivalent mixture is one in which the averaged volume of a sphere is the same as the effective molecular volume of a molecule in the real mixture. Thus, the theory requires two parameters, namely the averaged effective molecular volume of the molecules in the mixture and the scaling factor, which is the effective nonsphericity parameter. Expressions to determine these parameters are derived in terms of the geometrical characteristics of the molecules that form the mixture. The overall results are in closer agreement with simulation data than those obtained with other theories developed for these kinds of mixtures.

  14. Novel Aspects of Hard Diffraction in QCD

    SciTech Connect

    Brodsky, Stanley J.; /SLAC

    2005-12-14

    Initial- and final-state interactions from gluon-exchange, normally neglected in the parton model have a profound effect in QCD hard-scattering reactions, leading to leading-twist single-spin asymmetries, diffractive deep inelastic scattering, diffractive hard hadronic reactions, and nuclear shadowing and antishadowing--leading-twist physics not incorporated in the light-front wavefunctions of the target computed in isolation. I also discuss the use of diffraction to materialize the Fock states of a hadronic projectile and test QCD color transparency.

  15. UV curable hard coatings on polyesters

    NASA Astrophysics Data System (ADS)

    Datashvili, Tea; Brostow, Witold; Kao, David

    2006-10-01

    UV curable, hard and transparent hybrid inorganic-organic coatings with covalent links between the inorganic and the organic networks were prepared using organically crosslinked heteropolysiloxanes based on the sol-gel process. The materials were applied onto polyester sheets and UV cured. The deposition was followed by a thermal treatment to improve mechanical properties of the coatings. High light transmission and the resulting thermophysical properties indicate the presence of a nanoscale hybrid composition. The coatings show excellent adhesion to polyesters even without using primers. Further mechanical characterization shows that the coatings provide high hardness and good abrasion resistance.

  16. Radiation-hard static induction transistor

    SciTech Connect

    Hanes, M.H.; Bartko, J.; Hwang, J.M.; Rai-Choudhury, P.; Leslie, S.G.

    1988-12-01

    The static induction transistor (SIT) has been proposed as a preferred power switching device for applications in military and space environments because of its potential for radiation hardness, high-frequency operation, and the incorporation of on-chip smart power sensor and logic functions. Design, fabrication, and characteristics of a 350 V, 100 A buried gate SIT are described. The potential radiation hardness of this class of devices was evaluated by measurement of SIT characteristics after irradiation with 100 Mrad electrons (2 MeV), and up to 10%16% fission neutrons/cm/sup 2/. High-temperature operation and the possibility of radiation damage self-annealing are discussed.

  17. [Necrotizing sialometaplasia of the hard palate].

    PubMed

    Topstad, T K; Olofsson, J; Myking, A

    1991-11-30

    Necrotizing sialometaplasia is a benign, self-healing disease of salivary gland tissue and is usually confined to the minor salivary glands of the hard palate. It has clinical and histological features that simulate malignancies such as mucoepidermoid and squamous cell carcinomas. Wrong diagnosis has led to unnecessary mutilating surgical procedures. The etiology of the disease is unknown, but an ischaemic process is considered most likely. We describe two patients with necrotizing sialometaplasia, one with midline and one with bilateral symmetrical affection of the hard palate.

  18. Ototraumatic effects of hard rock music.

    PubMed

    Reddell, R C; Lebo, C P

    1972-01-01

    Temporary and permanent shifts in auditory thresholds were found in 43 hard rock musicians and temporary shifts were also observed in some listeners. The threshold shifts involved all of the conventional puretone test frequencies. Custom-fitted polyvinyl chloride ear protectors were found to be effective in prevention of these noise-induced hearing losses.

  19. Sustaining Transformation: "Resiliency in Hard Times"

    ERIC Educational Resources Information Center

    Guarasci, Richard; Lieberman, Devorah

    2009-01-01

    The strategic, systemic, and encompassing evolution of a college or university spans a number of years, and the vagaries of economic cycles inevitably catch transforming institutions in mid-voyage. "Sustaining Transformation: Resiliency in Hard Times" presents a study of Wagner College as it moves into its second decade of purposeful institutional…

  20. Hard Times: Philosophy and the Fundamentalist Imagination

    ERIC Educational Resources Information Center

    Allsup, Randall Everett

    2005-01-01

    A close reading of Gradgrind's opening monologue of Hard Times by Charles Dickens will provide the starting off point for an examination of the role and place of philosophy in the music curriculum. The Gradgrind philosophy finds easy parallel to current thinking in American education. In the fundamentalist imagination, sources of ambiguity must be…

  1. Registration of 'Advance' Hard Red Spring Wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grower and end-user acceptance of new hard red spring wheat (HRSW; Triticum aestivum L.) cultivars is largely contingent on satisfactory agronomic performance, end-use quality potential, and disease resistance levels. Additional characteristics, such as desirable plant height, can also help to maxi...

  2. Hard thermal loops in static external fields

    SciTech Connect

    Frenkel, J.; Takahashi, N.; Pereira, S. H.

    2009-04-15

    We examine, in the imaginary-time formalism, the high temperature behavior of n-point thermal loops in static Yang-Mills and gravitational fields. We show that in this regime, any hard thermal loop gives the same leading contribution as the one obtained by evaluating the loop integral at zero external energies and momenta.

  3. Classic and Hard-Boiled Detective Fiction.

    ERIC Educational Resources Information Center

    Reilly, John M.

    Through an analysis of several stories, this paper defines the similarities and differences between classic and hard-boiled detective fiction. The characters and plots of three stories are discussed: "The Red House" by A. A. Milne; "I, The Jury" by Mickey Spillane; and "League of Frightened Men" by Rex Stout. The classic detective story is defined…

  4. PROTEIN TEMPLATES IN HARD TISSUE ENGINEERING

    PubMed Central

    George, Anne; Ravindran, Sriram

    2010-01-01

    Biomineralization processes such as formation of bones and teeth require controlled mineral deposition and self-assembly into hierarchical biocomposites with unique mechanical properties. Ideal biomaterials for regeneration and repair of hard tissues must be biocompatible, possess micro and macroporosity for vascular invasion, provide surface chemistry and texture that facilitate cell attachment, proliferation, differentiation of lineage specific progenitor cells, and induce deposition of calcium phosphate mineral. To expect in-vivo like cellular response several investigators have used extracellular matrix proteins as templates to recreate in-vivo microenvironment for regeneration of hard tissues. Recently, several novel methods of designing tissue repair and restoration materials using bioinspired strategies are currently being formulated. Nanoscale structured materials can be fabricated via the spontaneous organization of self-assembling proteins to construct hierarchically organized nanomaterials. The advantage of such a method is that polypeptides can be specifically designed as building blocks incorporated with molecular recognition features and spatially distributed bioactive ligands that would provide a physiological environment for cells in-vitro and in-vivo. This is a rapidly evolving area and provides a promising platform for future development of nanostructured templates for hard tissue engineering. In this review we try to highlight the importance of proteins as templates for regeneration and repair of hard tissues as well as the potential of peptide based nanomaterials for regenerative therapies. PMID:20802848

  5. Registration of 'Prevail' hard red spring wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grower and end-user acceptance of new Hard Red Spring Wheat (HRSW; Triticum aestivum L.) cultivars is largely contingent upon satisfactory agronomic performance, end-use quality potential, and disease resistance levels. Additional characteristics, such as desirable plant height, can also contribute...

  6. Radiation-Hardness Data For Semiconductor Devices

    NASA Technical Reports Server (NTRS)

    Price, W. E.; Nichols, D. K.; Brown, S. F.; Gauthier, M. K.; Martin, K. E.

    1984-01-01

    Document presents data on and analysis of radiation hardness of various semiconductor devices. Data specifies total-dose radiation tolerance of devices. Volume 1 of report covers diodes, bipolar transistors, field effect transistors, silicon controlled rectifiers and optical devices. Volume 2 covers integrated circuits. Volume 3 provides detailed analysis of data in volumes 1 and 2.

  7. Posttranscriptional control is a strong factor enabling exclusive expression of surface antigens in Paramecium tetraurelia.

    PubMed

    Simon, Martin C; Marker, Simone; Schmidt, Helmut J

    2006-01-01

    Variable antigens are large proteins located on the outer membrane of parasitic but also of free-living protists. Multigene families encoding surface antigens demonstrate an exclusive expression of proteins. The resulting presence of just one protein species on the cell surface is required for surface antigen function; therefore, the molecular mechanism of exclusive expression is of main interest. Regulation of gene expression and mechanisms establishing switching of antigens are hardly understood in any organism. Here we report on the reaction of Paramecium to the artificial knock down of surface antigen 51A expression by bacteria-mediated RNAi. This technique involves the feeding of dsRNA-producing bacteria. We analyzed different fragments of the target gene for dsRNA template regarding their specific knock down efficiency and found great differences. Treatment of Paramecia with RNAi against the 51A antigen demonstrated that although a massive amount of mRNA was present, the protein was not detected on the cell surface. Moreover, a minor abundance of 51D transcripts resulted in an exclusive presence of 51D proteins on the cell surface. This posttranscriptional regulation was confirmed by the transcript ratio (51A/51D) determined by real-time (RT) PCR of single cells. Because we were able to document unexclusive transcription also in wild-type cells our results indicate that this posttranscriptional regulation is a main factor of enabling exclusive gene expression. The comparison of serotype shifts, caused by efficient and inefficient knock down, indicates an involvement of full-length transcripts in regulation of gene expression. Thus, our study gives new insights into the mechanism of exclusive expression on the molecular level: (i) exclusive transcription does not occur, (ii) posttranscriptional regulation is a powerful factor enabling exclusive antigen expression, and (iii) surface antigen mRNA is shown to be involved in this mechanism in a regulating way.

  8. Remember Hard But Think Softly: Metaphorical Effects of Hardness/Softness on Cognitive Functions.

    PubMed

    Xie, Jiushu; Lu, Zhi; Wang, Ruiming; Cai, Zhenguang G

    2016-01-01

    Previous studies have found that bodily stimulation, such as hardness biases social judgment and evaluation via metaphorical association; however, it remains unclear whether bodily stimulation also affects cognitive functions, such as memory and creativity. The current study used metaphorical associations between "hard" and "rigid" and between "soft" and "flexible" in Chinese, to investigate whether the experience of hardness affects cognitive functions whose performance depends prospectively on rigidity (memory) and flexibility (creativity). In Experiment 1, we found that Chinese-speaking participants performed better at recalling previously memorized words while sitting on a hard-surface stool (the hard condition) than a cushioned one (the soft condition). In Experiment 2, participants sitting on a cushioned stool outperformed those sitting on a hard-surface stool on a Chinese riddle task, which required creative/flexible thinking, but not on an analogical reasoning task, which required both rigid and flexible thinking. The results suggest the hardness experience affects cognitive functions that are metaphorically associated with rigidity or flexibility. They support the embodiment proposition that cognitive functions and representations can be grounded in bodily states via metaphorical associations. PMID:27672373

  9. Remember Hard But Think Softly: Metaphorical Effects of Hardness/Softness on Cognitive Functions.

    PubMed

    Xie, Jiushu; Lu, Zhi; Wang, Ruiming; Cai, Zhenguang G

    2016-01-01

    Previous studies have found that bodily stimulation, such as hardness biases social judgment and evaluation via metaphorical association; however, it remains unclear whether bodily stimulation also affects cognitive functions, such as memory and creativity. The current study used metaphorical associations between "hard" and "rigid" and between "soft" and "flexible" in Chinese, to investigate whether the experience of hardness affects cognitive functions whose performance depends prospectively on rigidity (memory) and flexibility (creativity). In Experiment 1, we found that Chinese-speaking participants performed better at recalling previously memorized words while sitting on a hard-surface stool (the hard condition) than a cushioned one (the soft condition). In Experiment 2, participants sitting on a cushioned stool outperformed those sitting on a hard-surface stool on a Chinese riddle task, which required creative/flexible thinking, but not on an analogical reasoning task, which required both rigid and flexible thinking. The results suggest the hardness experience affects cognitive functions that are metaphorically associated with rigidity or flexibility. They support the embodiment proposition that cognitive functions and representations can be grounded in bodily states via metaphorical associations.

  10. QCD and hard diffraction at the LHC

    SciTech Connect

    Albrow, Michael G.; /Fermilab

    2005-09-01

    As an introduction to QCD at the LHC the author gives an overview of QCD at the Tevatron, emphasizing the high Q{sup 2} frontier which will be taken over by the LHC. After describing briefly the LHC detectors the author discusses high mass diffraction, in particular central exclusive production of Higgs and vector boson pairs. The author introduces the FP420 project to measure the scattered protons 420m downstream of ATLAS and CMS.

  11. The unconstrained local hardness: an intriguing quantity, beset by problems.

    PubMed

    Cuevas-Saavedra, Rogelio; Rabi, Nataly; Ayers, Paul W

    2011-11-21

    Developing a mathematical approach to the local hard/soft acid/base principle requires an unambiguous definition for the local hardness. One such quantity, which has aroused significant interest in recent years, is the unconstrained local hardness. Key identities are derived for the unconstrained local hardness, δμ/δρ(r). Several identities are presented which allow one to determine the unconstrained local hardness either explicitly using the hardness kernel and the inverse-linear response function, or implicitly by solving a system of linear equations. One result of this analysis is that the problem of determining the unconstrained local hardness is infinitely ill-conditioned because arbitrarily small changes in electron density can cause enormous changes in the chemical potential. This is manifest in the exponential divergence of the unconstrained local hardness as one moves away from the system. This suggests that one should be very careful when using the unconstrained local hardness for chemical interpretation. PMID:21984043

  12. Hard-on-Hard Lubrication in the Artificial Hip under Dynamic Loading Conditions

    PubMed Central

    Sonntag, Robert; Reinders, Jörn; Rieger, Johannes S.; Heitzmann, Daniel W. W.; Kretzer, J. Philippe

    2013-01-01

    The tribological performance of an artificial hip joint has a particularly strong influence on its success. The principle causes for failure are adverse short- and long-term reactions to wear debris and high frictional torque in the case of poor lubrication that may cause loosening of the implant. Therefore, using experimental and theoretical approaches models have been developed to evaluate lubrication under standardized conditions. A steady-state numerical model has been extended with dynamic experimental data for hard-on-hard bearings used in total hip replacements to verify the tribological relevance of the ISO 14242-1 gait cycle in comparison to experimental data from the Orthoload database and instrumented gait analysis for three additional loading conditions: normal walking, climbing stairs and descending stairs. Ceramic-on-ceramic bearing partners show superior lubrication potential compared to hard-on-hard bearings that work with at least one articulating metal component. Lubrication regimes during the investigated activities are shown to strongly depend on the kinematics and loading conditions. The outcome from the ISO gait is not fully confirmed by the normal walking data and more challenging conditions show evidence of inferior lubrication. These findings may help to explain the differences between the in vitro predictions using the ISO gait cycle and the clinical outcome of some hard-on-hard bearings, e.g., using metal-on-metal. PMID:23940772

  13. Hard-on-hard lubrication in the artificial hip under dynamic loading conditions.

    PubMed

    Sonntag, Robert; Reinders, Jörn; Rieger, Johannes S; Heitzmann, Daniel W W; Kretzer, J Philippe

    2013-01-01

    The tribological performance of an artificial hip joint has a particularly strong influence on its success. The principle causes for failure are adverse short- and long-term reactions to wear debris and high frictional torque in the case of poor lubrication that may cause loosening of the implant. Therefore, using experimental and theoretical approaches models have been developed to evaluate lubrication under standardized conditions. A steady-state numerical model has been extended with dynamic experimental data for hard-on-hard bearings used in total hip replacements to verify the tribological relevance of the ISO 14242-1 gait cycle in comparison to experimental data from the Orthoload database and instrumented gait analysis for three additional loading conditions: normal walking, climbing stairs and descending stairs. Ceramic-on-ceramic bearing partners show superior lubrication potential compared to hard-on-hard bearings that work with at least one articulating metal component. Lubrication regimes during the investigated activities are shown to strongly depend on the kinematics and loading conditions. The outcome from the ISO gait is not fully confirmed by the normal walking data and more challenging conditions show evidence of inferior lubrication. These findings may help to explain the differences between the in vitro predictions using the ISO gait cycle and the clinical outcome of some hard-on-hard bearings, e.g., using metal-on-metal.

  14. Remember Hard But Think Softly: Metaphorical Effects of Hardness/Softness on Cognitive Functions

    PubMed Central

    Xie, Jiushu; Lu, Zhi; Wang, Ruiming; Cai, Zhenguang G.

    2016-01-01

    Previous studies have found that bodily stimulation, such as hardness biases social judgment and evaluation via metaphorical association; however, it remains unclear whether bodily stimulation also affects cognitive functions, such as memory and creativity. The current study used metaphorical associations between “hard” and “rigid” and between “soft” and “flexible” in Chinese, to investigate whether the experience of hardness affects cognitive functions whose performance depends prospectively on rigidity (memory) and flexibility (creativity). In Experiment 1, we found that Chinese-speaking participants performed better at recalling previously memorized words while sitting on a hard-surface stool (the hard condition) than a cushioned one (the soft condition). In Experiment 2, participants sitting on a cushioned stool outperformed those sitting on a hard-surface stool on a Chinese riddle task, which required creative/flexible thinking, but not on an analogical reasoning task, which required both rigid and flexible thinking. The results suggest the hardness experience affects cognitive functions that are metaphorically associated with rigidity or flexibility. They support the embodiment proposition that cognitive functions and representations can be grounded in bodily states via metaphorical associations. PMID:27672373

  15. Remember Hard But Think Softly: Metaphorical Effects of Hardness/Softness on Cognitive Functions

    PubMed Central

    Xie, Jiushu; Lu, Zhi; Wang, Ruiming; Cai, Zhenguang G.

    2016-01-01

    Previous studies have found that bodily stimulation, such as hardness biases social judgment and evaluation via metaphorical association; however, it remains unclear whether bodily stimulation also affects cognitive functions, such as memory and creativity. The current study used metaphorical associations between “hard” and “rigid” and between “soft” and “flexible” in Chinese, to investigate whether the experience of hardness affects cognitive functions whose performance depends prospectively on rigidity (memory) and flexibility (creativity). In Experiment 1, we found that Chinese-speaking participants performed better at recalling previously memorized words while sitting on a hard-surface stool (the hard condition) than a cushioned one (the soft condition). In Experiment 2, participants sitting on a cushioned stool outperformed those sitting on a hard-surface stool on a Chinese riddle task, which required creative/flexible thinking, but not on an analogical reasoning task, which required both rigid and flexible thinking. The results suggest the hardness experience affects cognitive functions that are metaphorically associated with rigidity or flexibility. They support the embodiment proposition that cognitive functions and representations can be grounded in bodily states via metaphorical associations.

  16. Hard-on-hard lubrication in the artificial hip under dynamic loading conditions.

    PubMed

    Sonntag, Robert; Reinders, Jörn; Rieger, Johannes S; Heitzmann, Daniel W W; Kretzer, J Philippe

    2013-01-01

    The tribological performance of an artificial hip joint has a particularly strong influence on its success. The principle causes for failure are adverse short- and long-term reactions to wear debris and high frictional torque in the case of poor lubrication that may cause loosening of the implant. Therefore, using experimental and theoretical approaches models have been developed to evaluate lubrication under standardized conditions. A steady-state numerical model has been extended with dynamic experimental data for hard-on-hard bearings used in total hip replacements to verify the tribological relevance of the ISO 14242-1 gait cycle in comparison to experimental data from the Orthoload database and instrumented gait analysis for three additional loading conditions: normal walking, climbing stairs and descending stairs. Ceramic-on-ceramic bearing partners show superior lubrication potential compared to hard-on-hard bearings that work with at least one articulating metal component. Lubrication regimes during the investigated activities are shown to strongly depend on the kinematics and loading conditions. The outcome from the ISO gait is not fully confirmed by the normal walking data and more challenging conditions show evidence of inferior lubrication. These findings may help to explain the differences between the in vitro predictions using the ISO gait cycle and the clinical outcome of some hard-on-hard bearings, e.g., using metal-on-metal. PMID:23940772

  17. Further links between the maximum hardness principle and the hard/soft acid/base principle: insights from hard/soft exchange reactions.

    PubMed

    Chattaraj, Pratim K; Ayers, Paul W; Melin, Junia

    2007-08-01

    Ayers, Parr, and Pearson recently showed that insight into the hard/soft acid/base (HSAB) principle could be obtained by analyzing the energy of reactions in hard/soft exchange reactions, i.e., reactions in which a soft acid replaces a hard acid or a soft base replaces a hard base [J. Chem. Phys., 2006, 124, 194107]. We show, in accord with the maximum hardness principle, that the hardness increases for favorable hard/soft exchange reactions and decreases when the HSAB principle indicates that hard/soft exchange reactions are unfavorable. This extends the previous work of the authors, which treated only the "double hard/soft exchange" reaction [P. K. Chattaraj and P. W. Ayers, J. Chem. Phys., 2005, 123, 086101]. We also discuss two different approaches to computing the hardness of molecules from the hardness of the composing fragments, and explain how the results differ. In the present context, it seems that the arithmetic mean of fragment softnesses is the preferable definition.

  18. How strange is pion electroproduction?

    NASA Astrophysics Data System (ADS)

    Gorchtein, Mikhail; Spiesberger, Hubert; Zhang, Xilin

    2016-01-01

    We consider pion production in parity-violating electron scattering (PVES) in the presence of nucleon strangeness in the framework of partial wave analysis with unitarity. Using the experimental bounds on the strange form factors obtained in elastic PVES, we study the sensitivity of the parity-violating asymmetry to strange nucleon form factors. For forward kinematics and electron energies above 1 GeV, we observe that this sensitivity may reach about 20% in the threshold region. With parity-violating asymmetries being as large as tens p.p.m., this study suggests that threshold pion production in PVES can be used as a promising way to better constrain strangeness contributions. Using this model for the neutral current pion production, we update the estimate for the dispersive γZ-box correction to the weak charge of the proton. In the kinematics of the Qweak experiment, our new prediction reads Re □γZV (E = 1.165 GeV) = (5.58 ± 1.41) ×10-3, an improvement over the previous uncertainty estimate of ± 2.0 ×10-3. Our new prediction in the kinematics of the upcoming MESA/P2 experiment reads Re □γZV (E = 0.155 GeV) = (1.1 ± 0.2) ×10-3.

  19. Spin effects in hard collision processes

    SciTech Connect

    Ranft, G.; Ranft, J.

    1984-05-01

    Questions of conservation and nonconservation of parity in phenomena associated with particle spin are reviewed. The main attention is concentrated on the production of hadrons, jets, and photons with large momentum transfer and the production of lepton pairs. The mechanisms of the hard-scattering subprocess include exchange of W/sup + -/ and Z/sup 0/ mesons, QCD and QED, and also interference between QCD and the weak interactions and between QED and the weak interactions. Effective cross sections of hard scattering processes are calculated, a factorization of the hadron--hadron scattering cross section is proposed, and the possible types of spin effects manifested in the hadronic subprocesses are classified and discussed. The properties of the polarized proton distributions and polarized structure functions are given in two appendices.

  20. Superhard material comparable in hardness to diamond

    SciTech Connect

    Badzian, A.R.

    1988-12-19

    Superhard boron suboxides, with hardness close to that of diamond, were synthesized from boron/boron oxide mixtures. Such hardness is expected when a material's molar volume approaches the value characteristic for diamond. These materials consist of boron-rich phases belonging to the boron-oxygen system. The phase which contains 4 at. % oxygen and a crystal structure related to ..beta..rhombohedral boron can scratch diamond faces. During scratching of diamond the suboxide is worn also, and the wear debris is amorphized. Wear on the lt. slash/100/ diamond faces results from a cleavage mechanism which leaves a rough surface covered with cleaved lt. slash/111/ microfaces. The lt. slash/100/ faces are more easily abraded than the lt. slash/111/ diamond faces. Wear on lt. slash/111/ faces consumes much more energy and leaves grooves of plastically deformed diamond.

  1. Superhard material comparable in hardness to diamond

    NASA Astrophysics Data System (ADS)

    Badzian, Andrzej R.

    1988-12-01

    Superhard boron suboxides, with hardness close to that of diamond, were synthesized from boron/boron oxide mixtures. Such hardness is expected when a material's molar volume approaches the value characteristic for diamond. These materials consist of boron-rich phases belonging to the boron-oxygen system. The phase which contains 4 at. % oxygen and a crystal structure related to β-rhombohedral boron can scratch diamond faces. During scratching of diamond the suboxide is worn also, and the wear debris is amorphized. Wear on the {100} diamond faces results from a cleavage mechanism which leaves a rough surface covered with cleaved {111} microfaces. The {100} faces are more easily abraded than the {111} diamond faces. Wear on {111} faces consumes much more energy and leaves grooves of plastically deformed diamond.

  2. Laser ablated hard coating for microtools

    DOEpatents

    McLean, W. II; Balooch, M.; Siekhaus, W.J.

    1998-05-05

    Wear-resistant coatings composed of laser ablated hard carbon films, are deposited by pulsed laser ablation using visible light, on instruments such as microscope tips and micro-surgical tools. Hard carbon, known as diamond-like carbon (DLC), films produced by pulsed laser ablation using visible light enhances the abrasion resistance, wear characteristics, and lifetimes of small tools or instruments, such as small, sharp silicon tips used in atomic probe microscopy without significantly affecting the sharpness or size of these devices. For example, a 10--20 nm layer of diamond-like carbon on a standard silicon atomic force microscope (AFM) tip, enables the useful operating life of the tip to be increased by at least twofold. Moreover, the low inherent friction coefficient of the DLC coating leads to higher resolution for AFM tips operating in the contact mode. 12 figs.

  3. Laser ablated hard coating for microtools

    DOEpatents

    McLean, II, William; Balooch, Mehdi; Siekhaus, Wigbert J.

    1998-05-05

    Wear-resistant coatings composed of laser ablated hard carbon films, are deposited by pulsed laser ablation using visible light, on instruments such as microscope tips and micro-surgical tools. Hard carbon, known as diamond-like carbon (DLC), films produced by pulsed laser ablation using visible light enhances the abrasion resistance, wear characteristics, and lifetimes of small tools or instruments, such as small, sharp silicon tips used in atomic probe microscopy without significantly affecting the sharpness or size of these devices. For example, a 10-20 nm layer of diamond-like carbon on a standard silicon atomic force microscope (AFM) tip, enables the useful operating life of the tip to be increased by at least twofold. Moreover, the low inherent friction coefficient of the DLC coating leads to higher resolution for AFM tips operating in the contact mode.

  4. Hard diffraction with dynamic gap survival

    NASA Astrophysics Data System (ADS)

    Rasmussen, Christine O.; Sjöstrand, Torbjörn

    2016-02-01

    We present a new framework for the modelling of hard diffraction in pp and poverline{p} collisions. It starts from the the approach pioneered by Ingelman and Schlein, wherein the single diffractive cross section is factorized into a Pomeron flux and a Pomeron PDF. To this it adds a dynamically calculated rapidity gap survival factor, derived from the modelling of multiparton interactions. This factor is not relevant for diffraction in ep collisions, giving non-universality between HERA and Tevatron diffractive event rates. The model has been implemented in P ythia 8 and provides a complete description of the hadronic state associated with any hard single diffractive process. Comparisons with poverline{p} and pp data reveal improvement in the description of single diffractive events.

  5. Hardness/intensity correlations among BATSE bursts

    NASA Technical Reports Server (NTRS)

    Paciesas, William S.; Pendleton, Geoffrey N.; Kouveliotou, Chryssa; Fishman, Gerald J.; Meegan, Charles A.; Wilson, Robert B.

    1992-01-01

    Conclusions about the nature of gamma-ray bursts derived from the size-frequency distribution may be altered if a significant correlation exists between burst intensity and spectral shape. Moreover, if gamma-ray bursts have a cosmological origin, such a correlation may be expected to result from the expansion of the universe. We have performed a rudimentary search of the BATSE bursts for hardness/intensity correlations. The range of spectral shapes was determined for each burst by computing the ratio of the intensity in the range 100-300 keV to that in 55-300 keV. We find weak evidence for the existence of a correlation, the strongest effect being present when comparing the maximum hardness ratio for each burst with its maximum rate.

  6. Exclusion and Education in South Africa: An Education Law Perspective of Emerging Alternative Understandings of Exclusion

    ERIC Educational Resources Information Center

    Beckmann, Johan

    2016-01-01

    The new democratic dispensation in South Africa (1994) was accompanied by law and policy aimed at preventing unfair exclusion from educational opportunities and promoting equal access to educational opportunities. However, feelings of unfair exclusion remain and new understandings of exclusion are emerging. This paper examines the new policy and…

  7. Rad-Hard/HI-REL FPGA

    NASA Technical Reports Server (NTRS)

    Wang, Jih-Jong; Cronquist, Brian E.; McGowan, John E.; Katz, Richard B.

    1997-01-01

    The goals for a radiation hardened (RAD-HARD) and high reliability (HI-REL) field programmable gate array (FPGA) are described. The first qualified manufacturer list (QML) radiation hardened RH1280 and RH1020 were developed. The total radiation dose and single event effects observed on the antifuse FPGA RH1280 are reported on. Tradeoffs and the limitations in the single event upset hardening are discussed.

  8. Radiation Hardness Assurance for Space Systems

    NASA Technical Reports Server (NTRS)

    Poivey, Christian; Day, John H. (Technical Monitor)

    2002-01-01

    The space radiation environment can lead to extremely harsh operating conditions for on-board electronic box and systems. The characteristics of the radiation environment are highly dependent on the type of mission (date, duration and orbit). Radiation accelerates the aging of the electronic parts and material and can lead to a degradation of electrical performance; it can also create transient phenomena on parts. Such damage at the part level can induce damage or functional failure at electronic box, subsystem, and system levels. A rigorous methodology is needed to ensure that the radiation environment does not compromise the functionality and performance of the electronics during the system life. This methodology is called hardness assurance. It consists of those activities undertaken to ensure that the electronic piece parts placed in the space system perform to their design specifications after exposure to the space environment. It deals with system requirements, environmental definitions, part selection, part testing, shielding and radiation tolerant design. All these elements should play together in order to produce a system tolerant to.the radiation environment. An overview of the different steps of a space system hardness assurance program is given in section 2. In order to define the mission radiation specifications and compare these requirements to radiation test data, a detailed knowledge of the space environment and the corresponding electronic device failure mechanisms is required. The presentation by J. Mazur deals with the Earth space radiation environment as well as the internal environment of a spacecraft. The presentation by J. Schwank deals with ionization effects, and the presentation by T. Weatherford deals with Single particle Event Phenomena (SEP) in semiconductor devices and microcircuits. These three presentations provide more detailed background to complement the sections 3 and 4. Part selection and categorization are discussed in section

  9. The PASCO Half-Byte Hard Drive

    NASA Astrophysics Data System (ADS)

    Anderson, Peter S.

    2005-03-01

    To provide an interesting application of Faraday's law, Brad Hinaus and Mick Veum created an experiment constructing a scaled-up model of a computer hard drive. They mounted permanent magnets on a wooden disk. When the disk was spun, an emf was induced in a "read" head (solenoid) and recorded by a computer. I have found a way to do a similar experiment using only PASCO equipment.2

  10. Nanotwinned diamond with unprecedented hardness and stability.

    PubMed

    Huang, Quan; Yu, Dongli; Xu, Bo; Hu, Wentao; Ma, Yanming; Wang, Yanbin; Zhao, Zhisheng; Wen, Bin; He, Julong; Liu, Zhongyuan; Tian, Yongjun

    2014-06-12

    Although diamond is the hardest material for cutting tools, poor thermal stability has limited its applications, especially at high temperatures. Simultaneous improvement of the hardness and thermal stability of diamond has long been desirable. According to the Hall-Petch effect, the hardness of diamond can be enhanced by nanostructuring (by means of nanograined and nanotwinned microstructures), as shown in previous studies. However, for well-sintered nanograined diamonds, the grain sizes are technically limited to 10-30 nm (ref. 3), with degraded thermal stability compared with that of natural diamond. Recent success in synthesizing nanotwinned cubic boron nitride (nt-cBN) with a twin thickness down to ∼3.8 nm makes it feasible to simultaneously achieve smaller nanosize, ultrahardness and superior thermal stability. At present, nanotwinned diamond (nt-diamond) has not been fabricated successfully through direct conversions of various carbon precursors (such as graphite, amorphous carbon, glassy carbon and C60). Here we report the direct synthesis of nt-diamond with an average twin thickness of ∼5 nm, using a precursor of onion carbon nanoparticles at high pressure and high temperature, and the observation of a new monoclinic crystalline form of diamond coexisting with nt-diamond. The pure synthetic bulk nt-diamond material shows unprecedented hardness and thermal stability, with Vickers hardness up to ∼200 GPa and an in-air oxidization temperature more than 200 °C higher than that of natural diamond. The creation of nanotwinned microstructures offers a general pathway for manufacturing new advanced carbon-based materials with exceptional thermal stability and mechanical properties.

  11. Nanotwinned diamond with unprecedented hardness and stability

    NASA Astrophysics Data System (ADS)

    Huang, Quan; Yu, Dongli; Xu, Bo; Hu, Wentao; Ma, Yanming; Wang, Yanbin; Zhao, Zhisheng; Wen, Bin; He, Julong; Liu, Zhongyuan; Tian, Yongjun

    2014-06-01

    Although diamond is the hardest material for cutting tools, poor thermal stability has limited its applications, especially at high temperatures. Simultaneous improvement of the hardness and thermal stability of diamond has long been desirable. According to the Hall-Petch effect, the hardness of diamond can be enhanced by nanostructuring (by means of nanograined and nanotwinned microstructures), as shown in previous studies. However, for well-sintered nanograined diamonds, the grain sizes are technically limited to 10-30 nm (ref. 3), with degraded thermal stability compared with that of natural diamond. Recent success in synthesizing nanotwinned cubic boron nitride (nt-cBN) with a twin thickness down to ~3.8 nm makes it feasible to simultaneously achieve smaller nanosize, ultrahardness and superior thermal stability. At present, nanotwinned diamond (nt-diamond) has not been fabricated successfully through direct conversions of various carbon precursors (such as graphite, amorphous carbon, glassy carbon and C60). Here we report the direct synthesis of nt-diamond with an average twin thickness of ~5 nm, using a precursor of onion carbon nanoparticles at high pressure and high temperature, and the observation of a new monoclinic crystalline form of diamond coexisting with nt-diamond. The pure synthetic bulk nt-diamond material shows unprecedented hardness and thermal stability, with Vickers hardness up to ~200 GPa and an in-air oxidization temperature more than 200 °C higher than that of natural diamond. The creation of nanotwinned microstructures offers a general pathway for manufacturing new advanced carbon-based materials with exceptional thermal stability and mechanical properties.

  12. Dynamic Hardness Tester and Cure Meter

    NASA Technical Reports Server (NTRS)

    Madigosky, Walter M.; Fiorito, Ralph B.

    1993-01-01

    The Shore hardness tester is used extensively throughout industry to determine the static modulus of materials. The new apparatus described here extends the capability of an indentor-type tester into the dynamic regime, and provides a measurement of the dynamic shear or Young's modulus and loss factor as a function of frequency. The instrument, model and data of typical rubber samples are given and compared to other dynamic measurements.

  13. Experiments on asteroids using hard landers

    NASA Technical Reports Server (NTRS)

    Turkevich, A.; Economou, T.

    1978-01-01

    Hard lander missions to asteroids are examined using the Westphal penetrator study as a basis. Imagery and chemical information are considered to be the most significant science to be obtained. The latter, particularly a detailed chemical analysis performed on an uncontaminated sample, may answer questions about the relationships of asteroids to meteorites and the place of asteroids in theories of the formation of the solar system.

  14. Hard and soft spectral states of ULXs

    NASA Astrophysics Data System (ADS)

    Soria, R.

    2011-05-01

    I discuss some differences between the observed spectral states of ultraluminous X-ray sources (ULXs) and the canonical scheme of spectral states defined in Galactic black holes. The standard interpretation of ULXs with a curved spectrum, or a moderately steep power-law with soft excess and high-energy downturn, is that they are an extension of the very high state, up to luminosities {≈ 1}-3 L_Edd. Two competing models are Comptonization in a warm corona, and slim disk; I suggest bulk motion Comptonization in the radiatively-driven outflow as another possibility. The interpretation of ULXs with a hard power-law spectrum is more problematic. Some of them remain in that state over a large range of luminosities; others switch directly to a curved state without going through a canonical high/soft state. I suggest that those ULXs are in a high/hard state not seen in Galactic black holes; that state may overlap with the low/hard state at lower accretion rates, and extend all the way to Eddington accretion rates. If some black holes can reach Eddington accretion rates without switching to a standard-disk-dominated state, it is also possible that they never quench their steady jets.

  15. Hard Constraints in Optimization Under Uncertainty

    NASA Technical Reports Server (NTRS)

    Crespo, Luis G.; Giesy, Daniel P.; Kenny, Sean P.

    2008-01-01

    This paper proposes a methodology for the analysis and design of systems subject to parametric uncertainty where design requirements are specified via hard inequality constraints. Hard constraints are those that must be satisfied for all parameter realizations within a given uncertainty model. Uncertainty models given by norm-bounded perturbations from a nominal parameter value, i.e., hyper-spheres, and by sets of independently bounded uncertain variables, i.e., hyper-rectangles, are the focus of this paper. These models, which are also quite practical, allow for a rigorous mathematical treatment within the proposed framework. Hard constraint feasibility is determined by sizing the largest uncertainty set for which the design requirements are satisfied. Analytically verifiable assessments of robustness are attained by comparing this set with the actual uncertainty model. Strategies that enable the comparison of the robustness characteristics of competing design alternatives, the description and approximation of the robust design space, and the systematic search for designs with improved robustness are also proposed. Since the problem formulation is generic and the tools derived only require standard optimization algorithms for their implementation, this methodology is applicable to a broad range of engineering problems.

  16. Hardness variability in commercial and hardened technologies

    SciTech Connect

    Shaneyfelt, M.R.; Winokur, P.S.; Meisenheimer, T.L.; Sexton, F.W.; Roeske, S.B.; Knoll, M.G.

    1994-03-01

    Over the past 10 years, there have been a number of advances in methods to assess and assure the radiation hardness of microelectronics in military and space applications. At the forefront of these is the Qualified Manufacturers List (QML) methodology, in which the hardness of product is ``built-in`` through statistical process control (SPC) of technology parameters relevant to the radiation response, test structure to integrated circuit (IC) correlations, and techniques for extrapolating laboratory test results to varying radiation scenarios. At the same time, there has been renewed interest in the use of commercial technology -- with its enhanced performance, reduced cost, and higher reliability -- in military and space systems. In this paper, we initially demonstrate the application of QML techniques to assure and control the radiation response of hardened technologies. Through several examples, we demonstrate intra-die, wafer-to-wafer, and lot-to-lot variations in a hardened technology. We observe 10 to 30% variations in key technology parameters that result from variability in geometry, process, and design layout. Radiation-induced degradation is seen to mirror preirradiation characteristics. We then evaluate commercial technologies and report considerably higher variability in radiation hardness, i.e., variations by a factor of two to five. This variability is shown to arise from a lack of control of technology parameters relevant to the radiation response, which a commercial manufacturer has no interest in controlling in a normal process flow.

  17. Hardness variability in commercial and hardened technologies

    NASA Astrophysics Data System (ADS)

    Shaneyfelt, M. R.; Winokur, P. S.; Meisenheimer, T. L.; Sexton, F. W.; Roeske, S. B.; Knoll, M. G.

    1994-01-01

    Over the past 10 years, there have been a number of advances in methods to assess and assure the radiation hardness of microelectronics in military and space applications. At the forefront of these is the Qualified Manufacturers List (QML) methodology, in which the hardness of product is 'built-in' through statistical process control (SPC) of technology parameters relevant to the radiation response, test structure to integrated circuit (IC) correlations, and techniques for extrapolating laboratory test results to varying radiation scenarios. At the same time, there has been renewed interest in the use of commercial technology -- with its enhanced performance, reduced cost, and higher reliability -- in military and space systems. In this paper, we initially demonstrate the application of QML techniques to assure and control the radiation response of hardened technologies. Through several examples, we demonstrate intra-die, wafer-to-wafer, and lot-to-lot variations in a hardened technology. We observe 10 to 30% variations in key technology parameters that result from variability in geometry, process, and design layout. Radiation-induced degradation is seen to mirror preirradiation characteristics. We then evaluate commercial technologies and report considerably higher variability in radiation hardness, i.e., variations by a factor of two to five. This variability is shown to arise from a lack of control of technology parameters relevant to the radiation response, which a commercial manufacturer has no interest in controlling in a normal process flow.

  18. Beam-Recoil Polarization Transfer in the Nucleon Resonance Region in the Exclusive $\\vec{e}p \\to e'K^+\\vec{\\Lambda}$ and $\\vec{e}p \\to e'K^+\\vec{\\Sigma}^0$ Reactions at CLAS

    SciTech Connect

    D.S. Carman, B.A. Raue, for the CLAS Collaboration

    2009-06-01

    Beam-recoil transferred polarizations for the exclusive $\\vec{e}p \\to e'K^+ \\vec{\\Lambda},\\vec{\\Sigma}^0$ reactions have been measured using the CLAS spectrometer at Jefferson Laboratory. New measurements have been completed at beam energies of 4.261 and 5.754~GeV that span a range of momentum transfer $Q^2$ from 0.7 to 5.4~GeV$^2$, invariant energy $W$ from 1.6 to 2.6~GeV, and the full center-of-mass angular range of the $K^+$ meson. These new data add to the existing CLAS $K^+\\Lambda$ measurements at 2.567~GeV, and provide the first-ever data for the $K^+\\Sigma^0$ channel in electroproduction. Comparisons of the data with several theoretical models are used to study the sensitivity to $s$-channel resonance contributions and the underlying reaction mechanism. Interpretations within two semi-classical partonic models are made to probe the underlying reaction mechanism and the $s\\bar{s}$ quark-pair creation dynamics.

  19. The electronic structure of hard materials

    NASA Astrophysics Data System (ADS)

    Winarski, Robert Paul

    This research dissertation involves an experimental as well as a theoretical examination of the electronic structure of hard materials. The materials that are presented in this dissertation cover a wide class of materials, consisting of transition metal borides, irradiated polymer films, theoretically predicted superhard semiconductors, doped intermetallic alloys, and transition metal carbides. The borides are traditionally used in high temperature, hard coating applications, such as rocket nozzle linings, extreme wear surfaces, and corrosion coatings. Measurements of the borides appear to show that the bonding in these hard materials is primarily between the boron atoms in these systems. Also of note are the remarkably short interatomic distances between the boron atoms and between the boron and metal atoms in these materials. Irradiated polymer films are being developed for electronic applications, in the hopes that circuits can be developed that can benefit from the high thermal stability, dielectric properties, and mechanical properties provided by these materials. C3N4 is a theoretically predicted superhard material, and some of the first soft x-ray emission measurements of well-characterized samples of this compound are discussed in this work. Intermetallic alloys, in particular Ni3Al, are rather hard, but brittle metallic alloys. It has been found that the addition of boron atoms, in rather low concentrations, can increase the ductility of these alloys, allowing them to be utilized in a wider variety of applications. Measurements of this system have examined a question regarding the positioning of the boron atoms in the structures of this alloy. Finally, the transition metal carbides are used extensively as coatings in industrial applications such as cutting and grinding tools, and polishing compounds. Measurements of these materials suggest that the high degree of covalency between the metal and carbon atoms is primarily responsible for the hardness of

  20. Fault-Tolerant, Radiation-Hard DSP

    NASA Technical Reports Server (NTRS)

    Czajkowski, David

    2011-01-01

    Commercial digital signal processors (DSPs) for use in high-speed satellite computers are challenged by the damaging effects of space radiation, mainly single event upsets (SEUs) and single event functional interrupts (SEFIs). Innovations have been developed for mitigating the effects of SEUs and SEFIs, enabling the use of very-highspeed commercial DSPs with improved SEU tolerances. Time-triple modular redundancy (TTMR) is a method of applying traditional triple modular redundancy on a single processor, exploiting the VLIW (very long instruction word) class of parallel processors. TTMR improves SEU rates substantially. SEFIs are solved by a SEFI-hardened core circuit, external to the microprocessor. It monitors the health of the processor, and if a SEFI occurs, forces the processor to return to performance through a series of escalating events. TTMR and hardened-core solutions were developed for both DSPs and reconfigurable field-programmable gate arrays (FPGAs). This includes advancement of TTMR algorithms for DSPs and reconfigurable FPGAs, plus a rad-hard, hardened-core integrated circuit that services both the DSP and FPGA. Additionally, a combined DSP and FPGA board architecture was fully developed into a rad-hard engineering product. This technology enables use of commercial off-the-shelf (COTS) DSPs in computers for satellite and other space applications, allowing rapid deployment at a much lower cost. Traditional rad-hard space computers are very expensive and typically have long lead times. These computers are either based on traditional rad-hard processors, which have extremely low computational performance, or triple modular redundant (TMR) FPGA arrays, which suffer from power and complexity issues. Even more frustrating is that the TMR arrays of FPGAs require a fixed, external rad-hard voting element, thereby causing them to lose much of their reconfiguration capability and in some cases significant speed reduction. The benefits of COTS high

  1. Disciplinary Exclusion: The Influence of School Ethos

    ERIC Educational Resources Information Center

    Hatton, Lucy Ann

    2013-01-01

    Disciplinary exclusion is a strategy used by some schools in response to challenging behaviour. While some studies have explored interventions that can be implemented to reduce the exclusion of "at risk" pupils, others have considered how the underlying school ethos influences how challenging behaviour is understood and managed. The current study…

  2. 40 CFR 763.99 - Exclusions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Exclusions. 763.99 Section 763.99... Asbestos-Containing Materials in Schools § 763.99 Exclusions. (a) A local education agency shall not be required to perform an inspection under § 763.85(a) in any sampling area as defined in 40 CFR 763.103...

  3. 12 CFR 229.42 - Exclusions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 3 2010-01-01 2010-01-01 false Exclusions. 229.42 Section 229.42 Banks and Banking FEDERAL RESERVE SYSTEM (CONTINUED) BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM AVAILABILITY OF FUNDS AND COLLECTION OF CHECKS (REGULATION CC) Collection of Checks § 229.42 Exclusions....

  4. 10 CFR 830.2 - Exclusions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Exclusions. 830.2 Section 830.2 Energy DEPARTMENT OF ENERGY NUCLEAR SAFETY MANAGEMENT § 830.2 Exclusions. This part does not apply to: (a) Activities that are... 1974, as amended; and (e) Activities related to the launch approval and actual launch of nuclear...

  5. 10 CFR 830.2 - Exclusions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Exclusions. 830.2 Section 830.2 Energy DEPARTMENT OF ENERGY NUCLEAR SAFETY MANAGEMENT § 830.2 Exclusions. This part does not apply to: (a) Activities that are... 1974, as amended; and (e) Activities related to the launch approval and actual launch of nuclear...

  6. 10 CFR 830.2 - Exclusions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Exclusions. 830.2 Section 830.2 Energy DEPARTMENT OF ENERGY NUCLEAR SAFETY MANAGEMENT § 830.2 Exclusions. This part does not apply to: (a) Activities that are... 1974, as amended; and (e) Activities related to the launch approval and actual launch of nuclear...

  7. 10 CFR 830.2 - Exclusions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Exclusions. 830.2 Section 830.2 Energy DEPARTMENT OF ENERGY NUCLEAR SAFETY MANAGEMENT § 830.2 Exclusions. This part does not apply to: (a) Activities that are... 1974, as amended; and (e) Activities related to the launch approval and actual launch of nuclear...

  8. 10 CFR 830.2 - Exclusions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Exclusions. 830.2 Section 830.2 Energy DEPARTMENT OF ENERGY NUCLEAR SAFETY MANAGEMENT § 830.2 Exclusions. This part does not apply to: (a) Activities that are... 1974, as amended; and (e) Activities related to the launch approval and actual launch of nuclear...

  9. Strategic Alternatives to Exclusion from School

    ERIC Educational Resources Information Center

    Parsons, Carl

    2009-01-01

    This original study shows that local authorities, working collaboratively with their schools and clusters, can dramatically reduce exclusions and make permanent exclusions unnecessary. And through research in three low excluding local authorities and five high excluding local authorities, it shows how this is done. The challenges and barriers are…

  10. 12 CFR 367.5 - Exclusions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... EXCLUSION OF CONTRACTOR AND TERMINATION OF CONTRACTS § 367.5 Exclusions. (a) The Ethics Counselor may... also prohibited from conducting business with FDIC as agents or representatives of other contractors... Ethics Counselor's decision to exclude the contractor pursuant to § 367.16. Provided further, that...

  11. 48 CFR 19.1504 - Exclusions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Exclusions. 19.1504 Section 19.1504 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS Women-Owned Small Business (WOSB) Program 19.1504 Exclusions. This...

  12. 48 CFR 19.1504 - Exclusions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Exclusions. 19.1504 Section 19.1504 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS Women-Owned Small Business (WOSB) Program 19.1504 Exclusions. This...

  13. 47 CFR 76.107 - Exclusivity contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Exclusivity contracts. 76.107 Section 76.107 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Network Non-duplication Protection, Syndicated Exclusivity and Sports...

  14. 48 CFR 32.404 - Exclusions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Exclusions. 32.404 Section 32.404 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Advance Payments for Non-Commercial Items 32.404 Exclusions. (a) This subpart does not apply to advance...

  15. 12 CFR 229.42 - Exclusions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 3 2013-01-01 2013-01-01 false Exclusions. 229.42 Section 229.42 Banks and Banking FEDERAL RESERVE SYSTEM (CONTINUED) BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM (CONTINUED) AVAILABILITY OF FUNDS AND COLLECTION OF CHECKS (REGULATION CC) Collection of Checks § 229.42 Exclusions....

  16. 12 CFR 229.42 - Exclusions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 3 2012-01-01 2012-01-01 false Exclusions. 229.42 Section 229.42 Banks and Banking FEDERAL RESERVE SYSTEM (CONTINUED) BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM AVAILABILITY OF FUNDS AND COLLECTION OF CHECKS (REGULATION CC) Collection of Checks § 229.42 Exclusions....

  17. 12 CFR 229.42 - Exclusions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 3 2014-01-01 2014-01-01 false Exclusions. 229.42 Section 229.42 Banks and Banking FEDERAL RESERVE SYSTEM (CONTINUED) BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM (CONTINUED) AVAILABILITY OF FUNDS AND COLLECTION OF CHECKS (REGULATION CC) Collection of Checks § 229.42 Exclusions....

  18. 12 CFR 229.42 - Exclusions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 3 2011-01-01 2011-01-01 false Exclusions. 229.42 Section 229.42 Banks and Banking FEDERAL RESERVE SYSTEM (CONTINUED) BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM AVAILABILITY OF FUNDS AND COLLECTION OF CHECKS (REGULATION CC) Collection of Checks § 229.42 Exclusions....

  19. Exclusion from School: The Public Cost. Revised.

    ERIC Educational Resources Information Center

    Parsons, Carl; Castle, Frances; Howlett, Keith; Worrall, John

    The true expense, in cash terms, of exclusion from school in England is investigated. Data were gathered in six English local education authorities (LEAs): two in London, two metropolitan authorities, and two country authorities. Permanent exclusion is a matter of concern to the Commission for Racial Equality because some ethnic minorities are…

  20. 7 CFR 1b.3 - Categorical exclusions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 1 2013-01-01 2013-01-01 false Categorical exclusions. 1b.3 Section 1b.3 Agriculture Office of the Secretary of Agriculture NATIONAL ENVIRONMENTAL POLICY ACT § 1b.3 Categorical exclusions... individual or cumulative effect on the human environment and are excluded from the preparation...

  1. 7 CFR 1b.3 - Categorical exclusions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 1 2010-01-01 2010-01-01 false Categorical exclusions. 1b.3 Section 1b.3 Agriculture Office of the Secretary of Agriculture NATIONAL ENVIRONMENTAL POLICY ACT § 1b.3 Categorical exclusions... individual or cumulative effect on the human environment and are excluded from the preparation...

  2. 33 CFR 87.3 - Exclusive use.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Exclusive use. 87.3 Section 87.3 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INLAND NAVIGATION RULES ANNEX IV: DISTRESS SIGNALS § 87.3 Exclusive use. The use or exhibition of any of the foregoing signals except for...

  3. 47 CFR 76.107 - Exclusivity contracts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 4 2012-10-01 2012-10-01 false Exclusivity contracts. 76.107 Section 76.107 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Network Non-duplication Protection, Syndicated Exclusivity and Sports...

  4. 47 CFR 76.107 - Exclusivity contracts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false Exclusivity contracts. 76.107 Section 76.107 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Network Non-duplication Protection, Syndicated Exclusivity and Sports...

  5. 47 CFR 76.107 - Exclusivity contracts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 4 2013-10-01 2013-10-01 false Exclusivity contracts. 76.107 Section 76.107 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Network Non-duplication Protection, Syndicated Exclusivity and Sports...

  6. 47 CFR 76.107 - Exclusivity contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Exclusivity contracts. 76.107 Section 76.107 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Network Non-duplication Protection, Syndicated Exclusivity and Sports...

  7. CMS results on exclusive and diffractive production

    SciTech Connect

    Alves, Gilvan A.

    2015-04-10

    We present recent CMS measurements of diffractive and exclusive processes, using data collected at 7 TeV at the LHC. Measurements of soft single- and double-diffractive cross sections are presented, as well as measurements of photon-induced processes including studies of exclusive WW production via photon-photon exchange.

  8. Exclusion from School and Recognition of Difference

    ERIC Educational Resources Information Center

    McCluskey, Gillean; Riddell, Sheila; Weedon, Elisabet; Fordyce, Mariela

    2016-01-01

    There has been an overall decrease in exclusion rates and numbers in recent years across the UK. This change has often been heralded as evidence that national inclusion policies are "working" and that schools themselves are becoming increasingly inclusive. This article examines findings from a recent study on school exclusion in Wales,…

  9. Hard Times May Exact a Toll on Brain Health

    MedlinePlus

    ... https://medlineplus.gov/news/fullstory_161283.html Hard Times May Exact a Toll on Brain Health Poverty ... a cause-and-effect relationship between hard economic times and brain health and aging. The findings were ...

  10. Roles of hardness in the sliding behavior of materials

    NASA Astrophysics Data System (ADS)

    Rigney, D. A.

    1994-06-01

    It is generally recognized that hardness is one of the key factors which influence the sliding behavior of different materials combinations. However, in many discussions the only hardness value considered is that of the softer of the two materials in a tribological pair. This is usually the case when a simple linear wear equation (Holm, Archard, Khruschov) is cited. Observations on many materials combinations demonstrate that the effects of hardness are much more complex. Hardness varies with position and time. It can depend on temperature, sliding speed and the chemical environment. The sign of hardness gradients adjacent to the sliding surface affects sliding behavior. Transfer and subsequent mechanical mixing strongly influence local hardness. Changes in hardness can affect transitions in friction and wear. Relative hardness values can help to explain differences in debris and in smooth and rough sliding. They can also help us to understand geometric effects such as those noted when materials are interchanged in a test system. Examples are described.

  11. Evidence for high mass exclusive dijet production in the D0 experiment

    SciTech Connect

    Hubacek, Zdenek; /Prague, Tech. U.

    2010-10-01

    Exclusive diffractive Higgs boson production is an interesting process which could be studied at the Large Hadron Collider. While the cross section for the Higgs boson production at the Fermilab Tevatron Collider is too low for this channel, it is important to check if the class of exclusive diffraction events exists. We present the evidence for the high mass exclusive dijet production in the D0 experiment. Hard diffractive processes are usually described by the exchange of a colorless object called Pomeron. In diffractive hadron hadron collisions, the hadrons will exchange the Pomeron and either one or both hadrons will not dissolve. The events are identified by either a presence of a large forward region of the detector devoid of any activity (rapidity gap) or by a tagging of the intact beam hadron(s). A subset of diffractive events is called exclusive when the whole Pomeron energy is used to produce the diffractive state, i.e there are no Pomeron remnants. Exclusive diffractive production (EDP) of the Higgs boson or any other new final state X pp {yields} p + X + p has been recently proposed as a search channel at the LHC. The cross section for the Higgs boson production is too low at the Tevatron (0.2fb is predicted for a Higgs boson mass of 120 GeV), but it is important to check if this class of events exists in this kinematic region. The CDF Collaboration has recently confirmed the existence of EDP in several channels. In this report, we present the evidence for the exclusive production of high dijet invariant mass events, i.e. a dijet event accompanied by large rapidity gaps on both sides of the calorimeter.

  12. Central exclusive production at RHIC

    NASA Astrophysics Data System (ADS)

    Adamczyk, Leszek; Guryn, Włodek; Turnau, Jacek

    2014-11-01

    The present status and future plans of the physics program of Central Exclusive Production (CEP) at RHIC are described. The measurements are based on the detection of the forward protons from the Double Pomeron Exchange (DPE) process in the Roman Pot system and of the recoil system of charged particles from the DPE process measured in the STAR experiment's Time Projection Chamber (TPC). The data described here were taken using polarized proton-proton collisions at √ {s} = 200 GeV. The preliminary spectra of two-pion mass reconstructed by STAR TPC in central region of pseudorapidity |η| < 1, are presented. Near future plans to take data with the current system at center-of-mass energy √ {s} = 200 GeV and plans to upgrade the forward proton tagging system are presented. Also a possible addition of the RPs to the sPHENIX detector is discussed.

  13. Central exclusive production at RHIC

    SciTech Connect

    Adamczyk, Leszek; Guryn, Włodek; Turnau, Jacek

    2014-11-10

    The present status and future plans of the physics program of Central Exclusive Production (CEP) at RHIC are described. The measurements are based on the detection of the forward protons from the Double Pomeron Exchange (DPE) process in the Roman Pot system and of the recoil system of charged particles from the DPE process measured in the STAR experiment’s Time Projection Chamber (TPC). The data described here were taken using polarized proton-proton collisions at ps = 200 GeV. The preliminary spectra of two pion and four pion invariant mass reconstructed by STAR TPC in central region of pseudo-rapidity | | < 1, are presented. Near future plans to take data with the current system at center-of-mass energy ps = 200 GeV and plans to upgrade the forward proton tagging sys- tem are presented. Also a possible addition of the Roman Pots to the sPHENIX detector is discussed.

  14. Central exclusive production at the Tevatron

    SciTech Connect

    Albrow, Michael G.; /Fermilab

    2008-12-01

    In CDF we have observed several exclusive processes: 2-photon {yields} e{sup +}e{sup -} and {mu}{sup +}{mu}{sup -}, photon+pomeron {yields} J/{psi} and {psi}(2S), and pomeron+pomeron {yields} {chi}{sub c}. The cross sections agree with QED, HERA photoproduction data, and theoretical estimates of gg {yields} {chi}{sub c} with another gluon exchanged to screen the color. This observation of exclusive {chi}{sub c}, together with earlier observations of exclusive dijets and exclusive 2-photon candidates, support some theoretical predictions for p+p {yields} p+H+p at the LHC. Exclusive dileptons offer the best means of precisely calibrating forward proton spectrometers.

  15. Central Exclusive Production at the Tevatron

    SciTech Connect

    Albrow, Michael

    2009-03-23

    In CDF we have observed several exclusive processes: {gamma}{gamma}{yields}e{sup +}e{sup -} and {mu}{sup +}{mu}{sup -}, {gamma}+IP{yields}J/{psi}, {psi}(2S) and IP+IP{yields}{chi}{sub c}. The cross sections agree with QED, HERA photoproduction data, and theoretical estimates of gg{yields}{chi}{sub c} with another gluon exchanged to screen the color. This observation of exclusive {chi}{sub c}, together with earlier observations of exclusive dijets and exclusive {gamma}{gamma} candidates, support some theoretical predictions for p+p{yields}p+SMH+p at the LHC. Exclusive dileptons offer the best means of precisely calibrating forward proton spectrometers.

  16. 42 CFR 402.308 - Waivers of exclusions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... PROVISIONS CIVIL MONEY PENALTIES, ASSESSMENTS, AND EXCLUSIONS Exclusions § 402.308 Waivers of exclusions. (a... authorization to obtain information from private health insurers, peer review organizations (including, but...

  17. Construal Level and Social Exclusion: Concrete Thinking Impedes Recovery From Social Exclusion.

    PubMed

    Pfundmair, Michaela; Lermer, Eva; Frey, Dieter; Aydin, Nilüfer

    2015-01-01

    Social exclusion is a painful experience. Recent research has shown, however, that coping with exclusion can be facilitated by favorable conditions. In the current research, we investigated whether construal level affects recovery from social exclusion. We hypothesized that an abstract vs. concrete mindset would moderate coping with exclusion. Indeed, lower compared to higher concrete thinking (Study 1) and abstract compared to concrete thinking (Study 2) bolstered the basic need of belonging when excluded. Priming of abstract thinking, moreover, increased participants' sense of belonging both in response to exclusion and inclusion relative to no priming (Study 3). Our results are the first to establish a relationship between construal level and social exclusion, thereby suggesting an alleviating "abstraction discount" effect for the consequences of social exclusion.

  18. Equation of state for hard convex body fluid mixtures

    NASA Astrophysics Data System (ADS)

    Barrio, C.; Solana, J. R.

    A model previously developed for the equation of state of pure fluids consisting of hard convex body molecules is extended to mixtures. The parameters of the model can be determined from the geometrical characteristics of the molecules which form the mixture. The equation of state is in excellent agreement with simulation data for mixtures of hard spheres with hard spherocylinders.

  19. 21 CFR 133.148 - Hard grating cheeses.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Hard grating cheeses. 133.148 Section 133.148 Food... Related Products § 133.148 Hard grating cheeses. (a) The cheeses for which definitions and standards of identity are prescribed by this section are hard grating cheeses for which specifically...

  20. 75 FR 4031 - Streamlining Hard-Copy Postage Statement Processing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-26

    ... 111 Streamlining Hard-Copy Postage Statement Processing AGENCY: Postal Service\\TM\\. ACTION: Proposed... Postal Service, Domestic Mail Manual (DMM ), to reflect changes in the processing of hard-copy postage... complete the ``USPS Use Only'' section of, or round date, hard-copy postage statements...

  1. Study of hot hardness characteristics of tool steels

    NASA Technical Reports Server (NTRS)

    Chevalier, J. L.; Dietrich, M. W.; Zaretsky, E. V.

    1972-01-01

    Hardness measurements of tool steel materials in electric furnace at elevated temperatures and low oxygen environment are discussed. Development of equation to predict short term hardness as function of intial room temperature hardness of steel is reported. Types of steel involved in the process are identified.

  2. Traceability in hardness measurements: from the definition to industry

    NASA Astrophysics Data System (ADS)

    Germak, Alessandro; Herrmann, Konrad; Low, Samuel

    2010-04-01

    The measurement of hardness has been and continues to be of significant importance to many of the world's manufacturing industries. Conventional hardness testing is the most commonly used method for acceptance testing and production quality control of metals and metallic products. Instrumented indentation is one of the few techniques available for obtaining various property values for coatings and electronic products in the micrometre and nanometre dimensional scales. For these industries to be successful, it is critical that measurements made by suppliers and customers agree within some practical limits. To help assure this measurement agreement, a traceability chain for hardness measurement traceability from the hardness definition to industry has developed and evolved over the past 100 years, but its development has been complicated. A hardness measurement value not only requires traceability of force, length and time measurements but also requires traceability of the hardness values measured by the hardness machine. These multiple traceability paths are needed because a hardness measurement is affected by other influence parameters that are often difficult to identify, quantify and correct. This paper describes the current situation of hardness measurement traceability that exists for the conventional hardness methods (i.e. Rockwell, Brinell, Vickers and Knoop hardness) and for special-application hardness and indentation methods (i.e. elastomer, dynamic, portables and instrumented indentation).

  3. CO2 laser milling of hard tissue

    NASA Astrophysics Data System (ADS)

    Werner, Martin; Ivanenko, Mikhail; Harbecke, Daniela; Klasing, Manfred; Steigerwald, Hendrik; Hering, Peter

    2007-02-01

    Drilling of bone and tooth tissue belongs to recurrent medical procedures (screw- and pin-bores, bores for implant inserting, trepanation etc.). Small round bores can be in general quickly produced with mechanical drills. Problems arise however by angled drilling, by the necessity to fulfill the drilling without damaging of sensitive soft tissue beneath the bone, or by the attempt to mill precisely noncircular small cavities. We present investigations on laser hard tissue "milling", which can be advantageous for solving these problems. The "milling" is done with a CO2 laser (10.6 μm) with pulse duration of 50 - 100 μs, combined with a PC-controlled galvanic beam scanner and with a fine water-spray, which helps to avoid thermal side-effects. The damaging of underlying soft tissue can be prevented through control of the optical or acoustical ablation signal. The ablation of hard tissue is accompanied with a strong glowing, which is absent during the laser beam action on soft tissue. The acoustic signals from the diverse tissue types exhibit distinct differences in the spectral composition. Also computer image analysis could be a useful tool to control the operation. Laser "milling" of noncircular cavities with 1 - 4 mm width and about 10 mm depth is particularly interesting for dental implantology. In ex-vivo investigations we found conditions for fast laser "milling" of the cavities without thermal damage and with minimal tapering. It included exploration of different filling patterns (concentric rings, crosshatch, parallel lines and their combinations), definition of maximal pulse duration, repetition rate and laser power, optimal position of the spray. The optimized results give evidences for the applicability of the CO2 laser for biologically tolerable "milling" of deep cavities in the hard tissue.

  4. Results on hard diffraction from CDF

    SciTech Connect

    Goulianos, K.

    1997-05-01

    We present results from studies of hard diffractive processes in {anti p}p collisions at {radical}s=1.8 TeV at the Tevatron using the CDF detector. Diffractive events are identified by the characteristic signature of a rapidity gap and/or by detecting a recoil antiproton with high forward momentum. Reactions studied include the diffractive production of W-bosons and of two-jet (dijet) events, diffractive heavy quark production, and dijet production by double-pomeron exchange.

  5. Justified hard paternalism: a response to Ten.

    PubMed

    Rainbolt, George W

    1989-04-01

    In a brief response to C.L. Ten's critique in the same issue of Bioethics of an earlier article by Rainbolt, Rainbolt defends his thesis that prescription drug laws are examples of permissible hard paternalism. They are not justifiable by soft paternalism, which permits interference with people's conduct only when their choices are insufficiently voluntary, because people who buy prescription drugs have good metaknowledge, i.e., they know that they do not know much about drugs and are making a decision based on this knowledge. PMID:11649244

  6. Arching in tapped deposits of hard disks.

    PubMed

    Pugnaloni, Luis A; Valluzzi, Marcos G; Valluzzi, Lucas G

    2006-05-01

    We simulate the tapping of a bed of hard disks in a rectangular box by using a pseudodynamic algorithm. In these simulations, arches are unambiguously defined and we can analyze their properties as a function of the tapping amplitude. We find that an order-disorder transition occurs within a narrow range of tapping amplitudes as has been seen by others. Arches are always present in the system although they exhibit regular shapes in the ordered regime. Interestingly, an increase in the number of arches does not always correspond to a reduction in the packing fraction. This is in contrast with what is found in three-dimensional systems.

  7. Nonvolatile Rad-Hard Holographic Memory

    NASA Technical Reports Server (NTRS)

    Chao, Tien-Hsin; Zhou, Han-Ying; Reyes, George; Dragoi, Danut; Hanna, Jay

    2001-01-01

    We are investigating a nonvolatile radiation-hardened (rad-hard) holographic memory technology. Recently, a compact holographic data storage (CHDS) breadboard utilizing an innovative electro-optic scanner has been built and demonstrated for high-speed holographic data storage and retrieval. The successful integration of this holographic memory breadboard has paved the way for follow-on radiation resistance test of the photorefractive (PR) crystal, Fe:LiNbO3. We have also started the investigation of using two-photon PR crystals that are doubly doped with atoms of iron group (Ti, Cr, Mn, Cu) and of rare-earth group (Nd, Tb) for nonvolatile holographic recordings.

  8. Exclusive meson pair production in {gamma}*{gamma} scattering at small momentum transfer

    SciTech Connect

    Lansberg, J.P.; Pire, B.; Szymanowski, L.

    2006-04-01

    We study the exclusive production of {pi}{pi} and {rho}{pi} in hard {gamma}*{gamma} scattering in the forward kinematical region where the virtuality of one photon provides us with a hard scale in the process. The newly introduced concept of Transition Distribution Amplitudes (TDA) is used to perform a QCD calculation of these reactions thanks to two simple models for TDAs. Cross sections for {rho}{pi} and {pi}{pi} production are evaluated and compared to the possible background from the Bremsstrahlung process. This picture may be tested at intense electron-positron colliders such as CLEO and B factories. The cross section e{gamma}{yields}e{sup '}{pi}{sup 0}{pi}{sup 0} is finally shown to provide a possible determination of the {pi}{sup 0} axial form factor, F{sub A}{sup {pi}{sup 0}}, at small t, which seems not to be measurable elsewhere.

  9. Density functional theory for nearest-neighbor exclusion lattice gases in two and three dimensions

    NASA Astrophysics Data System (ADS)

    Lafuente, Luis; Cuesta, José A.

    2003-12-01

    To speak about fundamental measure theory obliges us to mention dimensional crossover. This feature, inherent to the systems themselves, was incorporated in the theory almost from the beginning. Although at first it was thought to be a consistency check for the theory, it rapidly became its fundamental pillar, thus becoming the only density functional theory which possesses such a property. It is straightforward that dimensional crossover connects, for instance, the parallel hard cube system (three dimensional) with that of squares (two dimensional) and rods (one dimensional). We show here that there are many more connections which can be established in this way. Through them we deduce from the functional for parallel hard (hyper)cubes in the simple (hyper)cubic lattice the corresponding functionals for the nearest-neighbor exclusion lattice gases in the square, triangular, simple cubic, face-centered-cubic, and body-centered-cubic lattices. As an application, the bulk phase diagram for all these systems is obtained.

  10. Rapidity gap survival in central exclusive diffraction: Dynamical mechanisms and uncertainties

    SciTech Connect

    Strikman, Mark; Weiss, Christian

    2009-01-01

    We summarize our understanding of the dynamical mechanisms governing rapidity gap survival in central exclusive diffraction, pp -> p + H + p (H = high-mass system), and discuss the uncertainties in present estimates of the survival probability. The main suppression of diffractive scattering is due to inelastic soft spectator interactions at small pp impact parameters and can be described in a mean-field approximation (independent hard and soft interactions). Moderate extra suppression results from fluctuations of the partonic configurations of the colliding protons. At LHC energies absorptive interactions of hard spectator partons associated with the gg -> H process reach the black-disk regime and cause substantial additional suppression, pushing the survival probability below 0.01.

  11. Equation of state for fluid mixtures of hard spheres and linear homonuclear fused hard spheres

    NASA Astrophysics Data System (ADS)

    Largo, J.; Solana, J. R.

    1998-08-01

    This paper develops a theoretically based equation of state for fluid mixtures consisting of hard spheres and linear homonuclear fused hard spheres. The procedure is based on the equation of state previously developed for monocomponent athermal fluids. The equation of state only requires two parameters, namely the averaged effective molecular volume of the molecules in the mixture and the corresponding effective nonsphericity parameter. These parameters can be obtained from the geometry of the molecules forming the mixture. The results are in excellent agreement with simulation data and compare favorably with those obtained from other theories for athermal fluid mixtures.

  12. Searches for the θ5(1540)+ Strange-Pentaquark Candidate in e+e- Annihilation, Hadroproduction and Electroproduction with the BaBar Detector

    SciTech Connect

    Coleman, Jonathan P

    2009-05-01

    Since early in 2003, several experiments have presented evidence for the existence of a positive strangeness baryon state of mass around 1540 MeV/c2 and width <8 MeV, the θ(1540), which decays to K+n and K0p. Such a state has minimum quark content udud$\\bar{s}$ and consequently has been interpreted as the S = +1 member of the anti-decuplet of pentaquark states proposed by Diakonov et al. Subsequently, the NA49 experiment presented evidence for the S = -2 member of the anti-decuplet, the Ξ5 (1860) --, but this has yet to be observed in any other experiment. Results from the search for the production of the θ(1540) memember of the anti-decuplet of pentaquark states using data from e+e - collisions obtained with the BABAR detector at the PEP-II Collider are presented. No signal is observed, and cross section limits for the θ(1540) are given; these prove to be well below the cross section values for ordinary baryons of similar mass. In addition, a search has been carried out for the electroproduction of the θ(1540) in the material of the BABAR detector. Event selection procedures are discussed in detail, the results of this search are presented, and are discussed in the light of several other experiments.

  13. Influence of Gene Expression on Hardness in Wheat

    PubMed Central

    Nirmal, Ravi C.; Wrigley, Colin

    2016-01-01

    Puroindoline (Pina and Pinb) genes control grain texture or hardness in wheat. Wild-type/soft alleles lead to softer grain while a mutation in one or both of these genes results in a hard grain. Variation in hardness in genotypes with identical Pin alleles (wild-type or mutant) is known but the molecular basis of this is not known. We now report the identification of wheat genotypes with hard grain texture and wild-type/soft Pin alleles indicating that hardness in wheat may be controlled by factors other than mutations in the coding region of the Pin genes. RNA-Seq analysis was used to determine the variation in the transcriptome of developing grains of thirty three diverse wheat genotypes including hard (mutant Pin) and soft (wild type) and those that were hard without having Pin mutations. This defined the role of pin gene expression and identified other candidate genes associated with hardness. Pina was not expressed in hard wheat with a mutation in the Pina gene. The ratio of Pina to Pinb expression was generally lower in the hard non mutant genotypes. Hardness may be associated with differences in Pin expression and other factors and is not simply associated with mutations in the PIN protein coding sequences. PMID:27741295

  14. Statistical Physics of Hard Optimization Problems

    NASA Astrophysics Data System (ADS)

    Zdeborová, Lenka

    2008-06-01

    Optimization is fundamental in many areas of science, from computer science and information theory to engineering and statistical physics, as well as to biology or social sciences. It typically involves a large number of variables and a cost function depending on these variables. Optimization problems in the NP-complete class are particularly difficult, it is believed that the number of operations required to minimize the cost function is in the most difficult cases exponential in the system size. However, even in an NP-complete problem the practically arising instances might, in fact, be easy to solve. The principal question we address in this thesis is: How to recognize if an NP-complete constraint satisfaction problem is typically hard and what are the main reasons for this? We adopt approaches from the statistical physics of disordered systems, in particular the cavity method developed originally to describe glassy systems. We describe new properties of the space of solutions in two of the most studied constraint satisfaction problems - random satisfiability and random graph coloring. We suggest a relation between the existence of the so-called frozen variables and the algorithmic hardness of a problem. Based on these insights, we introduce a new class of problems which we named "locked" constraint satisfaction, where the statistical description is easily solvable, but from the algorithmic point of view they are even more challenging than the canonical satisfiability.

  15. Statistical physics of hard optimization problems

    NASA Astrophysics Data System (ADS)

    Zdeborová, Lenka

    2009-06-01

    Optimization is fundamental in many areas of science, from computer science and information theory to engineering and statistical physics, as well as to biology or social sciences. It typically involves a large number of variables and a cost function depending on these variables. Optimization problems in the non-deterministic polynomial (NP)-complete class are particularly difficult, it is believed that the number of operations required to minimize the cost function is in the most difficult cases exponential in the system size. However, even in an NP-complete problem the practically arising instances might, in fact, be easy to solve. The principal question we address in this article is: How to recognize if an NP-complete constraint satisfaction problem is typically hard and what are the main reasons for this? We adopt approaches from the statistical physics of disordered systems, in particular the cavity method developed originally to describe glassy systems. We describe new properties of the space of solutions in two of the most studied constraint satisfaction problems - random satisfiability and random graph coloring. We suggest a relation between the existence of the so-called frozen variables and the algorithmic hardness of a problem. Based on these insights, we introduce a new class of problems which we named "locked" constraint satisfaction, where the statistical description is easily solvable, but from the algorithmic point of view they are even more challenging than the canonical satisfiability.

  16. Solving the hard problem of Bertrand's paradox

    SciTech Connect

    Aerts, Diederik; Sassoli de Bianchi, Massimiliano

    2014-08-15

    Bertrand's paradox is a famous problem of probability theory, pointing to a possible inconsistency in Laplace's principle of insufficient reason. In this article, we show that Bertrand's paradox contains two different problems: an “easy” problem and a “hard” problem. The easy problem can be solved by formulating Bertrand's question in sufficiently precise terms, so allowing for a non-ambiguous modelization of the entity subjected to the randomization. We then show that once the easy problem is settled, also the hard problem becomes solvable, provided Laplace's principle of insufficient reason is applied not to the outcomes of the experiment, but to the different possible “ways of selecting” an interaction between the entity under investigation and that producing the randomization. This consists in evaluating a huge average over all possible “ways of selecting” an interaction, which we call a universal average. Following a strategy similar to that used in the definition of the Wiener measure, we calculate such universal average and therefore solve the hard problem of Bertrand's paradox. The link between Bertrand's problem of probability theory and the measurement problem of quantum mechanics is also briefly discussed.

  17. A Modified Theoretical Model of Intrinsic Hardness of Crystalline Solids

    PubMed Central

    Dai, Fu-Zhi; Zhou, Yanchun

    2016-01-01

    Super-hard materials have been extensively investigated due to their practical importance in numerous industrial applications. To stimulate the design and exploration of new super-hard materials, microscopic models that elucidate the fundamental factors controlling hardness are desirable. The present work modified the theoretical model of intrinsic hardness proposed by Gao. In the modification, we emphasize the critical role of appropriately decomposing a crystal to pseudo-binary crystals, which should be carried out based on the valence electron population of each bond. After modification, the model becomes self-consistent and predicts well the hardness values of many crystals, including crystals composed of complex chemical bonds. The modified model provides fundamental insights into the nature of hardness, which can facilitate the quest for intrinsic super-hard materials. PMID:27604165

  18. A Modified Theoretical Model of Intrinsic Hardness of Crystalline Solids

    NASA Astrophysics Data System (ADS)

    Dai, Fu-Zhi; Zhou, Yanchun

    2016-09-01

    Super-hard materials have been extensively investigated due to their practical importance in numerous industrial applications. To stimulate the design and exploration of new super-hard materials, microscopic models that elucidate the fundamental factors controlling hardness are desirable. The present work modified the theoretical model of intrinsic hardness proposed by Gao. In the modification, we emphasize the critical role of appropriately decomposing a crystal to pseudo-binary crystals, which should be carried out based on the valence electron population of each bond. After modification, the model becomes self-consistent and predicts well the hardness values of many crystals, including crystals composed of complex chemical bonds. The modified model provides fundamental insights into the nature of hardness, which can facilitate the quest for intrinsic super-hard materials.

  19. A Modified Theoretical Model of Intrinsic Hardness of Crystalline Solids.

    PubMed

    Dai, Fu-Zhi; Zhou, Yanchun

    2016-01-01

    Super-hard materials have been extensively investigated due to their practical importance in numerous industrial applications. To stimulate the design and exploration of new super-hard materials, microscopic models that elucidate the fundamental factors controlling hardness are desirable. The present work modified the theoretical model of intrinsic hardness proposed by Gao. In the modification, we emphasize the critical role of appropriately decomposing a crystal to pseudo-binary crystals, which should be carried out based on the valence electron population of each bond. After modification, the model becomes self-consistent and predicts well the hardness values of many crystals, including crystals composed of complex chemical bonds. The modified model provides fundamental insights into the nature of hardness, which can facilitate the quest for intrinsic super-hard materials. PMID:27604165

  20. Monitoring and manipulation of a sublittoral hard bottom biocoenosis in Balsfjord, northern Norway

    NASA Astrophysics Data System (ADS)

    Sandnes, O. K.; Gulliksen, B.

    1980-03-01

    Sublittoral hard bottom biocoenoses in Balsfjord, Norway (69°31' N, 19°1' E), were monitored using underwater stereophotogrammetry. The study includes manipulation of natural densities of organisms and testing the importance of biological interactions and “key species ” for the structure of biocoenoses. Underwater photography has the advantages of being a non-destructive method, but it is selective because small or hidden organisms cannot always be observed. Field experiments with exclusion of organisms from cages seem suitable for testing hypotheses concerning which animals are “key species ” in certain biocoenoses. Sea-urchins (Strongylocentrotus droebachiensis, S. pallidus) were suspected to be “key species ” in the present study, and their removal from cages caused an increase in abundance of barnacles (Balanus balanoides), the limpet Acmaea testudinalis and algal cover.

  1. Microstructure of dental hard tissues in fossil and recent xenarthrans (Mammalia: Folivora and Cingulata).

    PubMed

    Kalthoff, Daniela C

    2011-06-01

    A striking difference between xenarthrans and other mammals is the complete loss of tooth enamel in all members but the earliest armadillos. However, sloth and armadillo teeth show structured wear facets, which in all other mammals are formed by tooth enamel. How is that possible? Here, I report about an analysis of fossil and recent xenarthran dental hard tissue microstructure. It shows that osteodentine is not exclusive to fossil Cingulata, but also occurs in some recent taxa. Furthermore, I found profound modifications of orthodentine architecture in comparison to other mammals. Remarkable features are (a) a larger proportion of the highly mineralized, collagen-free peritubular dentine, and (b) a modified architecture of the odontoblastic process with frequent interconnections between the extensions and unusually intensive branching of the extensions forming a complex meshwork, penetrating the intertubular dentine matrix. The orthodentine microstructural build-up is unique in Folivora and Cingulata. PMID:21456028

  2. Fractions, Decimals, Ratios, & Percents: Hard To Teach and Hard To Learn? Mathematics Teaching Cases.

    ERIC Educational Resources Information Center

    Barnett, Carne, Ed.; And Others

    This book presents teacher-written cases relating stories, insights, and experiences about the teaching of fractions, decimals, ratios, and percents. The cases were written to stimulate colleagues to examine their own practice, to think hard about the mathematics they teach and would like to teach, and to initiate inquiries and discussions that…

  3. Hard-Boiled for Hard Times in Leonardo Padura Fuentes's Detective Fiction

    ERIC Educational Resources Information Center

    Song, H. Rosi

    2009-01-01

    Focusing on Leonardo Padura Fuentes's hard-boiled fiction, this essay traces the origin and evolution of the genre in Cuba. Padura Fuentes has challenged the officially sanctioned socialist "literatura policial" that became popular in the 1970s and 1980s. creating a new model of criticism that is not afraid to confront the island's socio-economic…

  4. Central exclusive production at RHIC

    DOE PAGESBeta

    Adamczyk, Leszek; Guryn, Włodek; Turnau, Jacek

    2014-11-10

    The present status and future plans of the physics program of Central Exclusive Production (CEP) at RHIC are described. The measurements are based on the detection of the forward protons from the Double Pomeron Exchange (DPE) process in the Roman Pot system and of the recoil system of charged particles from the DPE process measured in the STAR experiment’s Time Projection Chamber (TPC). The data described here were taken using polarized proton-proton collisions at ps = 200 GeV. The preliminary spectra of two pion and four pion invariant mass reconstructed by STAR TPC in central region of pseudo-rapidity | |more » < 1, are presented. Near future plans to take data with the current system at center-of-mass energy ps = 200 GeV and plans to upgrade the forward proton tagging sys- tem are presented. Also a possible addition of the Roman Pots to the sPHENIX detector is discussed.« less

  5. Hard-on-Hard Total Hip Impingement Causes Extreme Contact Stress Concentrations

    PubMed Central

    Elkins, Jacob M.; O’Brien, Megan K.; Stroud, Nicholas J.; Pedersen, Douglas R.; Callaghan, John J.

    2010-01-01

    Background Impingement events, in addition to their role immediately proximate to frank dislocation, hold the potential to damage new-generation hard-on-hard bearings as a result of the relatively unforgiving nature of the materials and designs. Because of the higher stiffness and tighter design tolerances of metal-on-metal and ceramic implants, surgical positioning plausibly has become even more important. Questions/purposes We asked (1) whether, and under what cup orientation conditions, hard-on-hard impingements might challenge implant material failure strength; and (2) whether particle generation propensity at impingement and egress sites would show similar dependence on cup orientation. Methods Realistic computational simulations were enabled by multistage finite element analyses, addressing both global construct motion and loading, and focal stress concentrations at neck impingement and rim egress sites. The global model, validated by a cadaveric simulation in a servohydraulic hip simulator, included both hardware components and advanced anisotropic capsule characterization. Parametric computational runs explored the effect of cup orientation for both ceramic-on-ceramic and metal-on-metal bearing couples for two distinct motion sequences associated with dislocation. Results Stress concentrations from impingement increased nearly linearly with increased cup tilt and with cup anteversion. In some situations, peak values of stress approached or exceeded 1 GPa, levels challenging the yield strength of cobalt-chromium implants, and potentially the fracture strength of ceramics. The tendency for impingement events to generate debris, indexed in terms of a new scraping severity metric, showed orientation dependences similar to that for bulk material failure. Conclusions Damage propensity arising from impingement events in hard total hip bearings is highly orientation-dependent. PMID:20953853

  6. 40 CFR 113.5 - Exclusions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 23 2012-07-01 2012-07-01 false Exclusions. 113.5 Section 113.5 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS LIABILITY LIMITS FOR... capacity. (b) Vehicles and rolling stock....

  7. 40 CFR 113.5 - Exclusions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 23 2013-07-01 2013-07-01 false Exclusions. 113.5 Section 113.5 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS LIABILITY LIMITS FOR... capacity. (b) Vehicles and rolling stock....

  8. 40 CFR 113.5 - Exclusions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 22 2014-07-01 2013-07-01 true Exclusions. 113.5 Section 113.5 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS LIABILITY LIMITS FOR... capacity. (b) Vehicles and rolling stock....

  9. Exclusion of pneumothorax by radionuclide lung scan

    SciTech Connect

    Weiss, P.E.

    1986-05-01

    A case is reported in which ventilation lung imaging was useful in excluding a large pneumothorax. This technique may be helpful in patients with emphysema in whom exclusion of pneumothorax by radiographic criteria might be difficult.

  10. 48 CFR 37.202 - Exclusions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... CONTRACTING SERVICE CONTRACTING Advisory and Assistance Services 37.202 Exclusions. The following activities...) Routine information technology services unless they are an integral part of a contract for the acquisition... research involving medical, biological, physical, social, psychological, or other phenomena....

  11. 48 CFR 832.404 - Exclusions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... REQUIREMENTS CONTRACT FINANCING Advance Payments for Non-Commercial Items 832.404 Exclusions. (a) Under 31 U.S.... 3324(a). The term “other publications” includes any publication printed, microfilmed, photocopied...

  12. Definition of Exclusion Zones Using Seismic Data

    NASA Astrophysics Data System (ADS)

    Bartal, Y.; Villagran, M.; Ben Horin, Y.; Leonard, G.; Joswig, M.

    - In verifying compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT), there is a motivation to be effective, efficient and economical and to prevent abuse of the right to conduct an On-site Inspection (OSI) in the territory of a challenged State Party. In particular, it is in the interest of a State Party to avoid irrelevant search in specific areas. In this study we propose several techniques to determine `exclusion zones', which are defined as areas where an event could not have possibly occurred. All techniques are based on simple ideas of arrival time differences between seismic stations and thus are less prone to modeling errors compared to standard event location methods. The techniques proposed are: angular sector exclusion based on a tripartite micro array, half-space exclusion based on a station pair, and closed area exclusion based on circumferential networks.

  13. 7 CFR 520.5 - Categorical exclusions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...) Department of Agriculture categorical exclusions (7 CFR 1b.3). (1) Policy development, planning and... environment; (iii) Testing outside of the laboratory, such as in small isolated field plots, which does...

  14. 7 CFR 520.5 - Categorical exclusions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...) Department of Agriculture categorical exclusions (7 CFR 1b.3). (1) Policy development, planning and... environment; (iii) Testing outside of the laboratory, such as in small isolated field plots, which does...

  15. Exclusive processes in strong and weak interactions

    SciTech Connect

    Tsokos, K.

    1983-01-01

    Evolution equations for flavor singlet mesons are derived; these are solved in terms of Gegenbauer polynomials. These results have been applied to exclusive processes at large momentum transfer which involve flavor singlet mesons and glueballs - two glueball decays of the Upsilon, radiative psi decays and two-photon processes involving the eta. Exclusive, weak decays of heavy mesons are examined and the heavy mass scaling behavior of decay rates is obtained.

  16. Exclusive Reactions Involving Pions and Nucleons

    NASA Technical Reports Server (NTRS)

    Norbury, John W.; Blattnig, Steve R.; Tripathi, R. K.

    2002-01-01

    The HZETRN code requires inclusive cross sections as input. One of the methods used to calculate these cross sections requires knowledge of all exclusive processes contributing to the inclusive reaction. Conservation laws are used to determine all possible exclusive reactions involving strong interactions between pions and nucleons. Inclusive particle masses are subsequently determined and are needed in cross-section calculations for inclusive pion production.

  17. Hard implant coatings with antimicrobial properties.

    PubMed

    Moseke, Claus; Gbureck, Uwe; Elter, Patrick; Drechsler, Peter; Zoll, Andreas; Thull, Roger; Ewald, Andrea

    2011-12-01

    Infection of orthopaedic implants often leads to inflammation immediately after surgery and increases patient morbidity due to repetitive operations. Silver ions have been shown to combine good biocompatibility with a low risk of inducing bacterial resistance. In this study a physical vapour deposition system using both arc deposition and magnetron sputtering has been utilized to produce silver ion doped TiN coatings on Ti substrates. This biphasic system combines the advantages of silver induced bactericidity with the good mechanical properties of TiN. Crystallographic analysis by X-ray diffraction showed that silver was deposited as well in its elementary form as it was incorporated into the crystal lattice of TiN, which resulted in increasing hardness of the TiN-coatings. Elution experiments revealed a continuous release of Ag ions in phosphate buffered saline. The coatings showed significant inhibitory effects on the growth of Staphylococcus epidermidis and Staphylococcus aureus and practically no cell-toxicity in cytocompatibility tests.

  18. Hard turning micro-machine tool

    DOEpatents

    DeVor, Richard E; Adair, Kurt; Kapoor, Shiv G

    2013-10-22

    A micro-scale apparatus for supporting a tool for hard turning comprises a base, a pivot coupled to the base, an actuator coupled to the base, and at least one member coupled to the actuator at one end and rotatably coupled to the pivot at another end. A tool mount is disposed on the at least one member. The at least one member defines a first lever arm between the pivot and the tool mount, and a second lever arm between the pivot and the actuator. The first lever arm has a length that is less than a length of the second lever arm. The actuator moves the tool mount along an arc.

  19. Peripheral osteoma of the hard palate

    PubMed Central

    Prabhuji, M. L. V.; Kishore, H. C.; Sethna, Gulnar; Moghe, Ameya G.

    2012-01-01

    Osteomas are benign slow growing, osteogenic lesions which may arise from proliferation of either cancellous or compact bone. They are usually sessile tumours composed of dense sclerotic, well formed bone projecting out from the cortical surface, most often of the skull and facial bones. This paper reports a case of a peripheral osteoma in the hard palate of a 45-year-old man, which was treated by periodontal flap surgery with surgical excision of the bony lesion. Peripheral osteomas of jaw bone are uncommon and usually associated with Gardner's syndrome. Histological examination confirmed the clinical impression of a peripheral osteoma. Patient was reviewed after one year and was asymptomatic with no recurrence of the lesion. PMID:22628981

  20. Nanomechanics of hard films on compliant substrates.

    SciTech Connect

    Reedy, Earl David, Jr.; Emerson, John Allen; Bahr, David F.; Moody, Neville Reid; Zhou, Xiao Wang; Hales, Lucas; Adams, David Price; Yeager,John; Nyugen, Thao D.; Corona, Edmundo; Kennedy, Marian S.; Cordill, Megan J.

    2009-09-01

    a result, our understanding of the critical relationship between adhesion, properties, and fracture for hard films on compliant substrates is limited. To address this issue, we integrated nanomechanical testing and mechanics-based modeling in a program to define the critical relationship between deformation and fracture of nanoscale films on compliant substrates. The approach involved designing model film systems and employing nano-scale experimental characterization techniques to isolate effects of compliance, viscoelasticity, and plasticity on deformation and fracture of thin hard films on substrates that spanned more than two orders of compliance magnitude exhibit different interface structures, have different adhesion strengths, and function differently under stress. The results of this work are described in six chapters. Chapter 1 provides the motivation for this work. Chapter 2 presents experimental results covering film system design, sample preparation, indentation response, and fracture including discussion on the effects of substrate compliance on fracture energies and buckle formation from existing models. Chapter 3 describes the use of analytical and finite element simulations to define the role of substrate compliance and film geometry on the indentation response of thin hard films on compliant substrates. Chapter 4 describes the development and application of cohesive zone model based finite element simulations to determine how substrate compliance affects debond growth. Chapter 5 describes the use of molecular dynamics simulations to define the effects of substrate compliance on interfacial fracture of thin hard tungsten films on silicon substrates. Chapter 6 describes the Workshops sponsored through this program to advance understanding of material and system behavior.

  1. Radiation Hardness Assurance (RHA) for Space Systems

    NASA Technical Reports Server (NTRS)

    Poivey, Christian; Buchner, Stephen

    2007-01-01

    This presentation discusses radiation hardness assurance (RHA) for space systems, providing both the programmatic aspects of RHA and the RHA procedure. RHA consists of all activities undertaken to ensure that the electronics and materials of a space system perform to their design specifications after exposure to the space radiation environment. RHA also pertains to environment definition, part selection, part testing, spacecraft layout, radiation tolerant design, and mission/system/subsystems requirements. RHA procedure consists of establishing mission requirements, defining and evaluating the radiation hazard, selecting and categorizing the appropriate parts, and evaluating circuit response to hazard. The RHA approach is based on risk management and is confined only to parts, it includes spacecraft layout, system/subsystem/circuit design, and system requirements and system operations. RHA should be taken into account in the early phases of a program including the proposal and feasibility analysis phases.

  2. Aging dynamics of colloidal hard sphere glasses.

    PubMed

    Martinez, V A; Bryant, G; van Megen, W

    2010-09-21

    We report the results of dynamic light scattering measurements of the coherent intermediate scattering function (ISF) of glasses of colloidal hard spheres for several volume fractions and a range of scattering vectors around the primary peak of the static structure factor. The ISF shows a clear crossover from an initial fast decay to a slower nonstationary decay. Aging is quantified in several different ways. However, regardless of the method chosen, the perfect "aged" glass is approached in a power law fashion. In particular the coupling between the fast and slow decays, as measured by the degree of stretching of the ISF at the crossover, also decreases algebraically with waiting time. The nonstationarity of this coupling implies that even the fastest detectable processes are themselves nonstationary. PMID:20866156

  3. Using Cell Phone Keyboards Is (NP) Hard

    NASA Astrophysics Data System (ADS)

    Boothe, Peter

    Sending text messages on cell phones which only contain the keys 0 through 9 and # and * can be a painful experience. We consider the problem of designing an optimal mapping of numbers to sets of letters to act as an alternative to the standard {2→{abc}, 3→{def}...}. Our overall goal is to minimize the expected number of buttons that must be pressed to enter a message in English. Some variations of the problem are efficiently solvable, either by being small instances or by being in P, but the most realistic version of the problem is NP hard. To prove NP-completeness, we describe a new graph coloring problem UniquePathColoring. We also provide numerical results for the English language on a standard corpus which describe several mappings that improve upon the standard one. With luck, one of these new mappings will achieve success similar to that of the Dvorak layout for computer keyboards.

  4. Shock compression synthesis of hard materials

    SciTech Connect

    Willson, C.G.

    1999-03-01

    The purpose of this research was to adapt the high explosives technology that was developed in conjunction with nuclear weapons programs to subjecting materials to ultra-high pressures and to explore the utility of this technique for the synthesis of hard materials. The research was conducted in collaboration with researchers at the University of Texas, Texas Tech University and Pantex (Mason and Hanger Corp.). The group designed, modeled, built, and tested a new device that allows quantitative recovery of grams of material that have been subjected to unprecedented pressures. The modeling work was done at Texas Tech and Pantex. The metal parts and material samples were made at the University of Texas, and Pantex machined the explosives, assembled the devices and conducted the detonations. Sample characterization was carried out at the University of Texas and Texas Tech.

  5. Coendangered hard-ticks: threatened or threatening?

    PubMed

    Mihalca, Andrei Daniel; Gherman, Călin Mircea; Cozma, Vasile

    2011-01-01

    The overwhelming majority of animal conservation projects are focused on vertebrates, despite most of the species on Earth being invertebrates. Estimates state that about half of all named species of invertebrates are parasitic in at least one stage of their development. The dilemma of viewing parasites as biodiversity or pest has been discussed by several authors. However, ticks were omitted. The latest taxonomic synopses of non-fossil Ixodidae consider valid 700 species. Though, how many of them are still extant is almost impossible to tell, as many of them are known only from type specimens in museums and were never collected since their original description. Moreover, many hosts are endangered and as part of conservation efforts of threatened vertebrates, a common practice is the removal of, and treatment for external parasites, with devastating impact on tick populations. There are several known cases when the host became extinct with subsequent coextinction of their ectoparasites. For our synoptic approach we have used the IUCN status of the host in order to evaluate the status of specifically associated hard-ticks. As a result, we propose a number of 63 coendangered and one extinct hard-tick species. On the other side of the coin, the most important issue regarding tick-host associations is vectorial transmission of microbial pathogens (i.e. viruses, bacteria, protozoans). Tick-borne diseases of threatened vertebrates are sometimes fatal to their hosts. Mortality associated with pathogens acquired from ticks has been documented in several cases, mostly after translocations. Are ticks a real threat to their coendangered host and should they be eliminated? Up to date, there are no reliable proofs that ticks listed by us as coendangered are competent vectors for pathogens of endangered animals. PMID:21554736

  6. The hard side of change management.

    PubMed

    Sirkin, Harold L; Keenan, Perry; Jackson, Alan

    2005-10-01

    Everyone agrees that managing change is tough, but few can agree on how to do it. Most experts are obsessed with "soft" issues, such as culture and motivation, but, say the authors, focusing on these issues alone won't bring about change. Companies also need to consider the hard factors-like the time it takes to complete a change initiative, the number of people required to execute it, and so forth. When the authors studied change initiatives at 225 companies, they found a consistent correlation between the outcomes of change programs (success versus failure) and four hard factors, which they called DICE: project duration, particularly the time between project reviews; integrity of performance, or the capabilities of project teams; the level of commitment of senior executives and staff; and the additional effort required of employees directly affected by the change. The DICE framework is a simple formula for calculating how well a company is implementing, or will be able to implement, its change initiatives. The framework comprises a set of simple questions that help executives score their projects on each of the four factors; the lower the score, the more likely the project will succeed. Companies can use DICE assessments to force conversations a bout projects, to gauge whether projects are on track or in trouble, and to manage project portfolios. The authors have used these four factors to predict the outcomes and guide the execution of more than 1,000 change management programs worldwide. Not only has the correlation held, but no other factors (or combination of factors) have predicted outcomes as successfully.

  7. 27 CFR 8.52 - Practices which result in exclusion.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Practices which result in..., DEPARTMENT OF THE TREASURY ALCOHOL EXCLUSIVE OUTLETS Exclusion § 8.52 Practices which result in exclusion. The practices specified in this section result in exclusion under section 105(a) of the Act....

  8. 27 CFR 8.53 - Practice not resulting in exclusion.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Practice not resulting in..., DEPARTMENT OF THE TREASURY ALCOHOL EXCLUSIVE OUTLETS Exclusion § 8.53 Practice not resulting in exclusion. The practice specified in this section is deemed not to result in exclusion under section 105(a)...

  9. 27 CFR 8.53 - Practice not resulting in exclusion.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Practice not resulting in..., DEPARTMENT OF THE TREASURY LIQUORS EXCLUSIVE OUTLETS Exclusion § 8.53 Practice not resulting in exclusion. The practice specified in this section is deemed not to result in exclusion under section 105(a)...

  10. 27 CFR 8.52 - Practices which result in exclusion.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Practices which result in..., DEPARTMENT OF THE TREASURY LIQUORS EXCLUSIVE OUTLETS Exclusion § 8.52 Practices which result in exclusion. The practices specified in this section result in exclusion under section 105(a) of the Act....

  11. 27 CFR 8.53 - Practice not resulting in exclusion.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Practice not resulting in..., DEPARTMENT OF THE TREASURY LIQUORS EXCLUSIVE OUTLETS Exclusion § 8.53 Practice not resulting in exclusion. The practice specified in this section is deemed not to result in exclusion under section 105(a)...

  12. 27 CFR 8.52 - Practices which result in exclusion.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Practices which result in..., DEPARTMENT OF THE TREASURY LIQUORS EXCLUSIVE OUTLETS Exclusion § 8.52 Practices which result in exclusion. The practices specified in this section result in exclusion under section 105(a) of the Act....

  13. 27 CFR 8.53 - Practice not resulting in exclusion.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Practice not resulting in..., DEPARTMENT OF THE TREASURY LIQUORS EXCLUSIVE OUTLETS Exclusion § 8.53 Practice not resulting in exclusion. The practice specified in this section is deemed not to result in exclusion under section 105(a)...

  14. 27 CFR 8.52 - Practices which result in exclusion.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Practices which result in..., DEPARTMENT OF THE TREASURY LIQUORS EXCLUSIVE OUTLETS Exclusion § 8.52 Practices which result in exclusion. The practices specified in this section result in exclusion under section 105(a) of the Act....

  15. 27 CFR 8.52 - Practices which result in exclusion.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Practices which result in..., DEPARTMENT OF THE TREASURY ALCOHOL EXCLUSIVE OUTLETS Exclusion § 8.52 Practices which result in exclusion. The practices specified in this section result in exclusion under section 105(a) of the Act....

  16. 27 CFR 8.53 - Practice not resulting in exclusion.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Practice not resulting in..., DEPARTMENT OF THE TREASURY ALCOHOL EXCLUSIVE OUTLETS Exclusion § 8.53 Practice not resulting in exclusion. The practice specified in this section is deemed not to result in exclusion under section 105(a)...

  17. 49 CFR 1542.111 - Exclusive area agreements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... exclusive area. (b) An exclusive area agreement must be in writing, signed by the airport operator and... 49 Transportation 9 2010-10-01 2010-10-01 false Exclusive area agreements. 1542.111 Section 1542... § 1542.111 Exclusive area agreements. (a) TSA may approve an amendment to an airport security...

  18. 21 CFR 316.34 - FDA recognition of exclusive approval.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (CONTINUED) DRUGS FOR HUMAN USE ORPHAN DRUGS Orphan-drug Exclusive Approval § 316.34 FDA recognition of... written notice recognizing exclusive approval once the marketing application for a designated orphan-drug... orphan-drug exclusive approval for the full 7-year term of exclusive approval. (b) When a...

  19. Revisiting the definition of the electronic chemical potential, chemical hardness, and softness at finite temperatures.

    PubMed

    Franco-Pérez, Marco; Gázquez, José L; Ayers, Paul W; Vela, Alberto

    2015-10-21

    We extend the definition of the electronic chemical potential (μe) and chemical hardness (ηe) to finite temperatures by considering a reactive chemical species as a true open system to the exchange of electrons, working exclusively within the framework of the grand canonical ensemble. As in the zero temperature derivation of these descriptors, the response of a chemical reagent to electron-transfer is determined by the response of the (average) electronic energy of the system, and not by intrinsic thermodynamic properties like the chemical potential of the electron-reservoir which is, in general, different from the electronic chemical potential, μe. Although the dependence of the electronic energy on electron number qualitatively resembles the piecewise-continuous straight-line profile for low electronic temperatures (up to ca. 5000 K), the introduction of the temperature as a free variable smoothens this profile, so that derivatives (of all orders) of the average electronic energy with respect to the average electron number exist and can be evaluated analytically. Assuming a three-state ensemble, well-known results for the electronic chemical potential at negative (-I), positive (-A), and zero values of the fractional charge (-(I + A)/2) are recovered. Similarly, in the zero temperature limit, the chemical hardness is formally expressed as a Dirac delta function in the particle number and satisfies the well-known reciprocity relation with the global softness.

  20. Revisiting the definition of the electronic chemical potential, chemical hardness, and softness at finite temperatures

    SciTech Connect

    Franco-Pérez, Marco E-mail: jlgm@xanum.uam.mx; Gázquez, José L. E-mail: jlgm@xanum.uam.mx; Ayers, Paul W.; Vela, Alberto

    2015-10-21

    We extend the definition of the electronic chemical potential (μ{sub e}) and chemical hardness (η{sub e}) to finite temperatures by considering a reactive chemical species as a true open system to the exchange of electrons, working exclusively within the framework of the grand canonical ensemble. As in the zero temperature derivation of these descriptors, the response of a chemical reagent to electron-transfer is determined by the response of the (average) electronic energy of the system, and not by intrinsic thermodynamic properties like the chemical potential of the electron-reservoir which is, in general, different from the electronic chemical potential, μ{sub e}. Although the dependence of the electronic energy on electron number qualitatively resembles the piecewise-continuous straight-line profile for low electronic temperatures (up to ca. 5000 K), the introduction of the temperature as a free variable smoothens this profile, so that derivatives (of all orders) of the average electronic energy with respect to the average electron number exist and can be evaluated analytically. Assuming a three-state ensemble, well-known results for the electronic chemical potential at negative (−I), positive (−A), and zero values of the fractional charge (−(I + A)/2) are recovered. Similarly, in the zero temperature limit, the chemical hardness is formally expressed as a Dirac delta function in the particle number and satisfies the well-known reciprocity relation with the global softness.

  1. Water hardness and sodium trends in Texas aquifers.

    PubMed

    Hudak, P F

    2001-05-01

    Median hardness and sodium levels in groundwater were calculated for 244 Texas counties from measurements at 7728 water wells. The data were mapped and analyzed with a geographic information system (GIS). County median hardness levels varied widely, from 4-2304 mg L-1. More than 60% of the counties had hardness medians above 180 mg L-1. County medium sodium concentrations ranged from 6-1170 mg L-1, with more than 90% of those values exceeding 20 mg L-1. There was a significant positive correlation between hardness and sodium concentrations in six of Texas' nine major aquifers. A significant negative correlation between hardness and sodium was observed in two aquifers. Several factors control hardness and sodium variations in Texas aquifers including rock/sediment composition, groundwater chemical evolution, and seepage from nearby formations. Probable human controls include agricultural return flow and pumping-induced saltwater intrusion. PMID:11411143

  2. Volume exclusion and soft interaction effects on protein stability under crowded conditions.

    PubMed

    Miklos, Andrew C; Li, Conggang; Sharaf, Naima G; Pielak, Gary J

    2010-08-24

    Most proteins function in nature under crowded conditions, and crowding can change protein properties. Quantification of crowding effects, however, is difficult because solutions containing hundreds of grams of macromolecules per liter often interfere with the observation of the protein being studied. Models for macromolecular crowding tend to focus on the steric effects of crowders, neglecting potential chemical interactions between the crowder and the test protein. Here, we report the first systematic, quantitative, residue-level study of crowding effects on the equilibrium stability of a globular protein. We used a system comprising poly(vinylpyrrolidone)s (PVPs) of varying molecular weights as crowding agents and chymotrypsin inhibitor 2 (CI2) as a small globular test protein. Stability was quantified with NMR-detected amide (1)H exchange. We analyzed the data in terms of hard particle exclusion, confinement, and soft interactions. For all crowded conditions, nearly every observed residue experiences a stabilizing effect. The exceptions are residues for which stabilities are unchanged. At a PVP concentration of 100 g/L, the data are consistent with theories of hard particle exclusion. At higher concentrations, the data are more consistent with confinement. The data show that the crowder also stabilizes the test protein by weakly binding its native state. We conclude that the role of native-state binding and other soft interactions needs to be seriously considered when applying both theory and experiment to studies of macromolecular crowding.

  3. Factorization and non-factorization in diffractive hard scattering

    SciTech Connect

    Berera, Arjun

    1997-04-20

    Factorization, in the sense defined for inclusive hard scattering, is discussed for diffractive hard scattering. A factorization theorem similar to its inclusive counterpart is presented for diffractive DIS. For hadron-hadron diffractive hard scattering, in contrast to its inclusive counterpart, the expected breakdown of factorization is discussed. Cross section estimates are given from a simple field theory model for non-factorizing double-pomeron-exchange (DPE) dijet production with and without account for Sudakov suppression.

  4. Radiation Hard AlGaN Detectors and Imager

    SciTech Connect

    2012-05-01

    Radiation hardness of AlGaN photodiodes was tested using a 65 MeV proton beam with a total proton fluence of 3x10{sup 12} protons/cm{sup 2}. AlGaN Deep UV Photodiode have extremely high radiation hardness. These new devices have mission critical applications in high energy density physics (HEDP) and space explorations. These new devices satisfy radiation hardness requirements by NIF. NSTec is developing next generation AlGaN optoelectronics and imagers.

  5. Generalized parton distributions: Status and perspectives

    SciTech Connect

    Weiss, Christian

    2009-01-01

    We summarize recent developments in understanding the concept of generalized parton distributions (GPDs), its relation to nucleon structure, and its application to high-Q^2 electroproduction processes. Following a brief review of QCD factorization and transverse nucleon structure, we discuss (a) new theoretical methods for the analysis of deeply-virtual Compton scattering (t-channel-based GPD parametrizations, dispersion relations); (b) the phenomenology of hard exclusive meson production (experimental tests of dominance of small-size configurations, model-independent comparative studies); (c) the role of GPDs in small-x physics and pp scattering (QCD dipole model, central exclusive diffraction). We emphasize the usefulness of the transverse spatial (or impact parameter) representation for both understanding the reaction mechanism in hard exclusive processes and visualizing the physical content of the GPDs.

  6. Hard and soft acids and bases: structure and process.

    PubMed

    Reed, James L

    2012-07-01

    Under investigation is the structure and process that gives rise to hard-soft behavior in simple anionic atomic bases. That for simple atomic bases the chemical hardness is expected to be the only extrinsic component of acid-base strength, has been substantiated in the current study. A thermochemically based operational scale of chemical hardness was used to identify the structure within anionic atomic bases that is responsible for chemical hardness. The base's responding electrons have been identified as the structure, and the relaxation that occurs during charge transfer has been identified as the process giving rise to hard-soft behavior. This is in contrast the commonly accepted explanations that attribute hard-soft behavior to varying degrees of electrostatic and covalent contributions to the acid-base interaction. The ability of the atomic ion's responding electrons to cause hard-soft behavior has been assessed by examining the correlation of the estimated relaxation energies of the responding electrons with the operational chemical hardness. It has been demonstrated that the responding electrons are able to give rise to hard-soft behavior in simple anionic bases.

  7. Efficacy and food safety considerations of poultry competitive exclusion products.

    PubMed

    Wagner, Robert Doug

    2006-11-01

    Competitive exclusion (CE) products are anaerobic cultures of bacteria that are applied to poultry hatchlings to establish a protective enteric microbiota that excludes intestinal colonization by human food-borne pathogens. For safety of the poultry flock and human consumers, the identities of bacteria in CE products need to be known. A CE product is a culture of intestinal contents from adult chickens. It may be microbiologically defined by analysis of bacteria isolated from the culture, but many bacteria are hard to reliably isolate, identify, and characterize with conventional techniques. Sequence analysis of 16S ribosomal RNA (rRNA) genes may be more reliable than conventional techniques to identify CE bacteria. Bacteria in CE products may contain antimicrobial drug resistance and virulence mechanisms that could be transferred to the enteric bacteria of the food animal and to the human consumer. Detection methods for specific antimicrobial drug resistance and virulence genes and the integrase genes of conjugative transposons, mostly utilizing PCR technology, are being developed that can be applied to assess these risks in CE bacteria. With improvements in efficacy, bacterial identification, and detection and control of the possible risks of gene transfer, CE product technology can be made a more effective food safety tool.

  8. Mapping a hard-sphere fluid mixture onto a single component hard-sphere fluid

    NASA Astrophysics Data System (ADS)

    Barrio, C.; Solana, J. R.

    2005-06-01

    The possibility of obtaining the thermodynamic and structural properties of a binary additive hard-sphere fluid mixture on the basis of the corresponding properties of a suitable single-component hard-sphere fluid is analyzed. To this end, Monte Carlo simulations have been performed for binary mixtures of hard spheres for different densities, compositions and diameter ratios in order to obtain the compressibility factor Z and the partial radial distribution functions gij(r) for pairs ij of the mixtures. These data are used to test the reliability of different proposals available in the literature for mapping the thermodynamic and structural properties of conformal mixtures onto those of a single-component fluid. It is found that, while the averaged radial distribution function and the equation of state of the mixture can be reasonably well reproduced by means of those of an equivalent single-component fluid, the partial radial distribution functions cannot be obtained with enough accuracy from the radial distribution function of the equivalent fluid. A possible explanation for this fact is suggested.

  9. Peroxide interactions with hard tissues: effects on surface hardness and surface/subsurface ultrastructural properties.

    PubMed

    White, Donald J; Kozak, Kathy M; Zoladz, James R; Duschner, Heinz; Götz, Hermann

    2002-01-01

    Laboratory studies were performed to assess the impact of peroxide bleaching on enamel surface and subsurface physical and ultrastructural properties. Human enamel blocks were prepared, polished, and measured for native color. Cyclic bleaching treatments were carried out with soaks in whole stimulated saliva interspersed with bleaching treatments using bulk bleaching gels from commercial bleaching systems including Opalescence (20% and 10% carbamide peroxide systems) and Crest Whitestrips, a hydrogen peroxide gel formula, at doses of 5.3% and 6.5% hydrogen peroxide. Treatments ranged from conditions of normal use (14 hours as recommended for Crest Whitestrips) to excessive bleaching (70 hours). Controls included nontreated as well as treatments with placebo (not containing peroxide) gels. Surface hardness and confocal laser scanning microscopy (CLSM) techniques were used to characterize the effects of bleaching on the physical properties and ultrastructure of the teeth. Tooth color measurements revealed dose-response bleaching in vitro with the increases in L* and decreases in b* normally expected with effective bleaching. Placebo control treatments did not bleach. Surface hardness measurements showed no decreases associated with tooth bleaching. CLSM measurements also showed no effects from tooth bleaches on the surface or subsurface prism architecture of enamel. This was opposed to significant changes seen with even moderate levels of demineralization associated with the caries process. These studies support: (1) the safety of Crest Whitestrips formulas for enamel surfaces and tooth subsurfaces; and (2) the generic safety of peroxide bleaching of hard tissues associated with conditions of both recommended use and overuse.

  10. 75 FR 65614 - Availability for Non-Exclusive or Partially-Exclusive Licensing of Invention Concerning...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-26

    ... Department of the Army Availability for Non-Exclusive or Partially-Exclusive Licensing of Invention Concerning Obstetrics Simulation and Training Method System AGENCY: Department of the Army, DoD. ACTION... States Government, as represented by the Secretary of the Army, has rights to this invention....

  11. Cooperation induced by random sequential exclusion

    NASA Astrophysics Data System (ADS)

    Li, Kun; Cong, Rui; Wang, Long

    2016-06-01

    Social exclusion is a common and powerful tool to penalize deviators in human societies, and thus to effectively elevate collaborative efforts. Current models on the evolution of exclusion behaviors mostly assume that each peer excluder independently makes the decision to expel the defectors, but has no idea what others in the group would do or how the actual punishment effect will be. Thus, a more realistic model, random sequential exclusion, is proposed. In this mechanism, each excluder has to pay an extra scheduling cost and then all the excluders are arranged in a random order to implement the exclusion actions. If one free rider has already been excluded by an excluder, the remaining excluders will not participate in expelling this defector. We find that this mechanism can help stabilize cooperation under more unfavorable conditions than the normal peer exclusion can do, either in well-mixed population or on social networks. However, too large a scheduling cost may undermine the advantage of this mechanism. Our work validates the fact that collaborative practice among punishers plays an important role in further boosting cooperation.

  12. Plasticity characteristics obtained through hardness measurement

    SciTech Connect

    Milman, Y.V.; Galanov, B.A.; Chugunova, S.I. )

    1993-09-01

    A characteristic of material plasticity [delta][sub H] is proposed. [delta][sub H] is determined as a part of plastic deformation in the total deformation during indentation. The following analytic expressions for the elastic deformation [epsilon][sub e] and for the total deformation [epsilon] on the contact area indenter-specimen in the direction of loading force are obtained, [epsilon][sub e] = 1.08(1 [minus] v [minus] 2v[sup 2])H[sub V/E], [epsilon] [approx] 0.076, where H[sub V] is the Vickers hardness, E is Young's modulus, v is the Poisson ratio, and [delta][sub H] = 1 [minus] ([epsilon][sub e]/[epsilon]). The [delta][sub H] value is calculated for various crystalline materials at different temperatures and in different structural states. [delta][sub H] is consistent with the concept of plasticity established before, and to characterize the influence of temperature, alloying and strain hardening on plasticity. The necessary condition for revealing ductility at tension and bending is [delta][sub H] [>=] 0.9. [delta][sub H] can be used as a plasticity characteristic of brittle materials.

  13. Revisiting the phase diagram of hard ellipsoids

    NASA Astrophysics Data System (ADS)

    Odriozola, Gerardo

    2012-04-01

    In this work, the well-known Frenkel-Mulder phase diagram of hard ellipsoids of revolution [D. Frenkel and B. M. Mulder, Mol. Phys. 55, 1171 (1985), 10.1080/00268978500101971] is revisited by means of replica exchange Monte Carlo simulations. The method provides good sampling of dense systems and so, solid phases can be accessed without the need of imposing a given structure. At high densities, we found plastic solids and fcc-like crystals for semi-spherical ellipsoids (prolates and oblates), and SM2 structures [P. Pfleiderer and T. Schilling, Phys. Rev. E 75, 020402 (2007)] for x : 1-prolates and 1 : x-oblates with x ≥ 3. The revised fluid-crystal and isotropic-nematic transitions reasonably agree with those presented in the Frenkel-Mulder diagram. An interesting result is that, for small system sizes (100 particles), we obtained 2:1- and 1.5:1-prolate equations of state without transitions, while some order is developed at large densities. Furthermore, the symmetric oblate cases are also reluctant to form ordered phases.

  14. Dynamics of hard sphere colloidal dispersions

    NASA Technical Reports Server (NTRS)

    Zhu, J. X.; Chaikin, Paul M.; Phan, S.-E.; Russel, W. B.

    1994-01-01

    Our objective is to perform on homogeneous, fully equilibrated dispersions the full set of experiments characterizing the transition from fluid to solid and the properties of the crystalline and glassy solid. These include measurements quantifying the nucleation and growth of crystallites, the structure of the initial fluid and the fully crystalline solid, and Brownian motion of particles within the crystal, and the elasticity of the crystal and the glass. Experiments are being built and tested for ideal microgravity environment. Here we describe the ground based effort, which exploits a fluidized bed to create a homogeneous, steady dispersion for the studies. The differences between the microgravity environment and the fluidized bed is gauged by the Peclet number Pe, which measures the rate of convection/sedimentation relative to Brownian motion. We have designed our experiment to accomplish three types of measurements on hard sphere suspensions in a fluidized bed: the static scattering intensity as a function of angle to determine the structure factor, the temporal autocorrelation function at all scattering angles to probe the dynamics, and the amplitude of the response to an oscillatory forcing to deduce the low frequency viscoelasticity. Thus the scattering instrument and the colloidal dispersion were chosen such as that the important features of each physical property lie within the detectable range for each measurement.

  15. Unraveling Quantum Annealers using Classical Hardness.

    PubMed

    Martin-Mayor, Victor; Hen, Itay

    2015-01-01

    Recent advances in quantum technology have led to the development and manufacturing of experimental programmable quantum annealing optimizers that contain hundreds of quantum bits. These optimizers, commonly referred to as 'D-Wave' chips, promise to solve practical optimization problems potentially faster than conventional 'classical' computers. Attempts to quantify the quantum nature of these chips have been met with both excitement and skepticism but have also brought up numerous fundamental questions pertaining to the distinguishability of experimental quantum annealers from their classical thermal counterparts. Inspired by recent results in spin-glass theory that recognize 'temperature chaos' as the underlying mechanism responsible for the computational intractability of hard optimization problems, we devise a general method to quantify the performance of quantum annealers on optimization problems suffering from varying degrees of temperature chaos: A superior performance of quantum annealers over classical algorithms on these may allude to the role that quantum effects play in providing speedup. We utilize our method to experimentally study the D-Wave Two chip on different temperature-chaotic problems and find, surprisingly, that its performance scales unfavorably as compared to several analogous classical algorithms. We detect, quantify and discuss several purely classical effects that possibly mask the quantum behavior of the chip. PMID:26483257

  16. Computational Modeling Develops Ultra-Hard Steel

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Glenn Research Center's Mechanical Components Branch developed a spiral bevel or face gear test rig for testing thermal behavior, surface fatigue, strain, vibration, and noise; a full-scale, 500-horsepower helicopter main-rotor transmission testing stand; a gear rig that allows fundamental studies of the dynamic behavior of gear systems and gear noise; and a high-speed helical gear test for analyzing thermal behavior for rotorcraft. The test rig provides accelerated fatigue life testing for standard spur gears at speeds of up to 10,000 rotations per minute. The test rig enables engineers to investigate the effects of materials, heat treat, shot peen, lubricants, and other factors on the gear's performance. QuesTek Innovations LLC, based in Evanston, Illinois, recently developed a carburized, martensitic gear steel with an ultra-hard case using its computational design methodology, but needed to verify surface fatigue, lifecycle performance, and overall reliability. The Battelle Memorial Institute introduced the company to researchers at Glenn's Mechanical Components Branch and facilitated a partnership allowing researchers at the NASA Center to conduct spur gear fatigue testing for the company. Testing revealed that QuesTek's gear steel outperforms the current state-of-the-art alloys used for aviation gears in contact fatigue by almost 300 percent. With the confidence and credibility provided by the NASA testing, QuesTek is commercializing two new steel alloys. Uses for this new class of steel are limitless in areas that demand exceptional strength for high throughput applications.

  17. The smallest hard X-ray flare?

    NASA Astrophysics Data System (ADS)

    Glesener, Lindsay; Krucker, Sam; Hannah, Iain; Smith, David M.; Grefenstette, Brian; Marsh, Andrew; Hudson, Hugh S.; White, Stephen M.; Chen, Bin

    2016-05-01

    We report a NuSTAR observation of a small solar flare on 2015 September 1, estimated to be on the order of a GOES class A.05 flare in brightness. This flare is fainter than any hard X-ray (HXR) flares in the existing literature, and with a peak rate of only ˜5 counts s-1 detector-1 observed by RHESSI, is effectively the smallest that can just barely be detected by the current standard (indirectly imaging) solar HXR instrumentation, though we expect that smaller flares will continue to be discovered as instrumental and observational techniques progress. The flare occurred during a solar observation by the highly sensitive NuSTAR astrophysical HXR spacecraft, which used its direct focusing optics to produce detailed flare spectra and images. The flare exhibits properties commonly observed in larger flares, including a fast rise and more gradual decay, and similar spatial dimensions to the RHESSI microflares. We will discuss the presence of non-thermal (flare-accelerated) electrons during the impulsive phase. The flare is small in emission measure, temperature, and energy, though not in physical dimensions. Its presence is an indication that flares do indeed scale down to smaller energies and retain what we customarily think of as “flarelike” properties.

  18. Hard cosmic X-ray sources.

    NASA Technical Reports Server (NTRS)

    Peterson, L. E.

    1973-01-01

    A review of the observational status of X-ray sources detected in the 20 to 500 keV range is presented. Of the approximately 115 sources listed in the March 1972 edition of the UHURU 2-6 keV sky survey catalog, about 15 sources have been studied in hard X rays. Most of the data have been obtained from balloons, although the OSO-3, and more recently the OSO-7, have contributed. With the exception of CEN A, the SMC, and possibly M-87, all the sources detected at higher energies are galactic and heavily concentrated in the galactic plane. The Crab Nebula has been measured to about 500 keV in continuous emission and a component at the 33-msec pulsar period comprising about 20% of the total emission has been detected to 10 MeV. Objects such as SCO-1 and CYG-2 are characterized by an exponential spectrum, which varies over a 10-min time scale about a factor of two, and a flatter spectrum extending to above 40 keV which exhibits independent variability.

  19. Unraveling Quantum Annealers using Classical Hardness.

    PubMed

    Martin-Mayor, Victor; Hen, Itay

    2015-10-20

    Recent advances in quantum technology have led to the development and manufacturing of experimental programmable quantum annealing optimizers that contain hundreds of quantum bits. These optimizers, commonly referred to as 'D-Wave' chips, promise to solve practical optimization problems potentially faster than conventional 'classical' computers. Attempts to quantify the quantum nature of these chips have been met with both excitement and skepticism but have also brought up numerous fundamental questions pertaining to the distinguishability of experimental quantum annealers from their classical thermal counterparts. Inspired by recent results in spin-glass theory that recognize 'temperature chaos' as the underlying mechanism responsible for the computational intractability of hard optimization problems, we devise a general method to quantify the performance of quantum annealers on optimization problems suffering from varying degrees of temperature chaos: A superior performance of quantum annealers over classical algorithms on these may allude to the role that quantum effects play in providing speedup. We utilize our method to experimentally study the D-Wave Two chip on different temperature-chaotic problems and find, surprisingly, that its performance scales unfavorably as compared to several analogous classical algorithms. We detect, quantify and discuss several purely classical effects that possibly mask the quantum behavior of the chip.

  20. Revisiting the phase diagram of hard ellipsoids.

    PubMed

    Odriozola, Gerardo

    2012-04-01

    In this work, the well-known Frenkel-Mulder phase diagram of hard ellipsoids of revolution [D. Frenkel and B. M. Mulder, Mol. Phys. 55, 1171 (1985)] is revisited by means of replica exchange Monte Carlo simulations. The method provides good sampling of dense systems and so, solid phases can be accessed without the need of imposing a given structure. At high densities, we found plastic solids and fcc-like crystals for semi-spherical ellipsoids (prolates and oblates), and SM2 structures [P. Pfleiderer and T. Schilling, Phys. Rev. E 75, 020402 (2007)] for x : 1-prolates and 1 : x-oblates with x ≥ 3. The revised fluid-crystal and isotropic-nematic transitions reasonably agree with those presented in the Frenkel-Mulder diagram. An interesting result is that, for small system sizes (100 particles), we obtained 2:1- and 1.5:1-prolate equations of state without transitions, while some order is developed at large densities. Furthermore, the symmetric oblate cases are also reluctant to form ordered phases.

  1. Implementing QML for radiation hardness assurance

    NASA Astrophysics Data System (ADS)

    Winokur, P. S.; Sexton, F. W.; Fleetwood, D. M.; Terry, M. D.; Shaneyfelt, M. R.

    1990-12-01

    The US government has proposed a qualified manufacturers list (QML) methodology to qualify integrated circuits for high reliability and radiation hardness. An approach to implementing QML for single-event upset (SEU) immunity on 16k SRAMs that involves relating values of feedback resistance to system error rates is demonstrated. It is seen that the process capability indices, Cp and Cpk, for the manufacture of 400-k-ohm feedback resistors required to provide SEU tolerance do not conform to 6 sigma quality standards. For total-dose, interface trap charge, Delta Vit, shifts measured on transistors are correlated with circuit response in the space environment. Statistical process control (SPC) is illustrated for Delta Vit, and violations of SPC rules are interpreted in terms of continuous improvement. Design validation for SEU and quality conformance inspections for total-dose are identified as major obstacles to cost-effective QML implementation. Techniques and tools that will help QML provide real cost savings are identified as physical models, 3-D device-plus-circuit codes, and improved design simulators.

  2. Escape dynamics of many hard disks.

    PubMed

    Taniguchi, Tooru; Murata, Hiroki; Sawada, Shin-Ichi

    2014-11-01

    Many-particle effects in escapes of hard disks from a square box via a hole are discussed in a viewpoint of dynamical systems. Starting from N disks in the box at the initial time, we calculate the probability P_{n}(t) for at least n disks to remain inside the box at time t for n=1,2,...,N. At early times, the probabilities P_{n}(t),n=2,3,...,N-1, are described by superpositions of exponential decay functions. On the other hand, after a long time the probability P_{n}(t) shows a power-law decay ∼t^{-2n} for n≠1, in contrast to the fact that it decays with a different power law ∼t^{-n} for cases without any disk-disk collision. Chaotic or nonchaotic properties of the escape systems are discussed by the dynamics of a finite-time largest Lyapunov exponent, whose decay properties are related with those of the probability P_{n}(t). PMID:25493874

  3. Identifying Driver Genomic Alterations in Cancers by Searching Minimum-Weight, Mutually Exclusive Sets

    PubMed Central

    Lu, Songjian; Lu, Kevin N.; Cheng, Shi-Yuan; Hu, Bo; Ma, Xiaojun; Nystrom, Nicholas; Lu, Xinghua

    2015-01-01

    An important goal of cancer genomic research is to identify the driving pathways underlying disease mechanisms and the heterogeneity of cancers. It is well known that somatic genome alterations (SGAs) affecting the genes that encode the proteins within a common signaling pathway exhibit mutual exclusivity, in which these SGAs usually do not co-occur in a tumor. With some success, this characteristic has been utilized as an objective function to guide the search for driver mutations within a pathway. However, mutual exclusivity alone is not sufficient to indicate that genes affected by such SGAs are in common pathways. Here, we propose a novel, signal-oriented framework for identifying driver SGAs. First, we identify the perturbed cellular signals by mining the gene expression data. Next, we search for a set of SGA events that carries strong information with respect to such perturbed signals while exhibiting mutual exclusivity. Finally, we design and implement an efficient exact algorithm to solve an NP-hard problem encountered in our approach. We apply this framework to the ovarian and glioblastoma tumor data available at the TCGA database, and perform systematic evaluations. Our results indicate that the signal-oriented approach enhances the ability to find informative sets of driver SGAs that likely constitute signaling pathways. PMID:26317392

  4. Respiratory effects of hard-metal dust exposure

    SciTech Connect

    Balmes, J.R.

    1987-04-01

    Workers exposed to hard-metal dust are at risk of developing interstitial pulmonary fibrosis. Focusing on the lung parenchymal disorders that result, the author thoroughly reviews the background of the problem, animal studies and recent environmental data related to hard-metal disease, the clinical presentation, and finally its etiology.

  5. Effective volumes of hard homonuclear nonlinear triatomic molecules

    NASA Astrophysics Data System (ADS)

    Maeso, M. J.; Solana, J. R.

    Expressions to determine effective molecular volumes for nonlinear hard homonuclear triatomic molecules are derived. They are used, in combination with an equation of state previously proposed for hard-body molecular fluids, to reproduce accurately the existing simulation data for this kind of fluid, covering a wide range of bond angles.

  6. Equations of state for fused-hard-sphere fluids

    NASA Astrophysics Data System (ADS)

    Maeso, M. J.; Solana, J. R.

    1993-09-01

    Analytical equations of state for fused-hard-sphere fluids are developed from a generalization of the Carnahan-Starling method for obtaining the equation of state of the hard-sphere fluid. The results are in good agreement with existing simulation data.

  7. Correlation between magnetic properties and the hardness of powder steels

    SciTech Connect

    Ul`yanov, A.I.; Merzlyakov, E.F.; Faizullin, R.G.

    1994-07-01

    Density and carbon content are studied for their effect on strength (hardness) and magnetic (coercive force, saturation magnetization) properties of powder steels ZhGr1 and ZhGr1D3. It is shown that the hardness of articles made of these steels may be determined indirectly by measuring two magnetic characteristics.

  8. Wheat Quality Council, Hard Spring Wheat Technical Committee, 2014 Crop

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eleven experimental lines of hard spring wheat were grown at up to five locations in 2014 and evaluated for kernel, milling, and bread baking quality against the check variety Glenn. Wheat samples were submitted through the Wheat Quality Council and processed and milled at the USDA-ARS Hard Red Spr...

  9. Educating Hard of Hearing Children. Special Education in Transition 2.

    ERIC Educational Resources Information Center

    Ross, Mark, Ed.; Nober, Linda W., Ed.

    Viewpoints of an audiologist, speech-language pathologist, special educator, classroom teacher, and parent are presented in the book on the implications of P.L. 94-142, the Education for All Handicapped Children Act, for hard of hearing students. In the introduction, M. Ross considers the status of many hard of hearing students, noting the…

  10. Critical Configurations of Hard Disks on the Torus

    2013-04-16

    CCHDT constructs and classifies various arrangements of hard disks of a single radius places on the unit square with periodic boundary conditions. Specifially, a given configuration is evolved to the nearest critical point on a smoothed hard disk energy fuction, and is classified by the adjacency matrix of the canonically labelled contact graph.

  11. [A woman with a pigmentation of the hard palate].

    PubMed

    van der Meij, Erik H; Nieken, Judith; de Visscher, Jan G A M

    2013-01-01

    A bluish flat pigmented lesion of the hard palate of a 51-year-old woman was excised to exclude malignancy, in particular oral malignant melanoma. On histopathological examination, depositions of black pigment were seen accompanied by several foreign body giant cells. Probably due to a childhood trauma, a pencil point had penetrated the hard palate. PMID:24330792

  12. Hardness Analysis. Training Module 5.215.2.77.

    ERIC Educational Resources Information Center

    Bonte, John L.; Davidson, Arnold C.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with hardness analysis using the EDTA method and the calculation of hardness given metal ion concentrations and a factor table. Included are objectives, an instructor guide, student handouts, and transparency masters. A video tape is also…

  13. Decreased interoceptive accuracy following social exclusion.

    PubMed

    Durlik, Caroline; Tsakiris, Manos

    2015-04-01

    The need for social affiliation is one of the most important and fundamental human needs. Unsurprisingly, humans display strong negative reactions to social exclusion. In the present study, we investigated the effect of social exclusion on interoceptive accuracy - accuracy in detecting signals arising inside the body - measured with a heartbeat perception task. We manipulated exclusion using Cyberball, a widely used paradigm of a virtual ball-tossing game, with half of the participants being included during the game and the other half of participants being ostracized during the game. Our results indicated that heartbeat perception accuracy decreased in the excluded, but not in the included, participants. We discuss these results in the context of social and physical pain overlap, as well as in relation to internally versus externally oriented attention. PMID:25701592

  14. Ion exclusion chromatography of aromatic acids.

    PubMed

    Mansour, Fotouh R; Kirkpatrick, Christine L; Danielson, Neil D

    2013-08-01

    The determination of aromatic acids by ion exclusion chromatography is challenging due to peak tailing and the long retention time of hydrophobic solutes. This review discusses the retention mechanisms and the factors affecting retention, eluents and detection methods used in ion exclusion chromatography of aromatic acids such as mono-, di-, tri- and tetra-carboxylic acids, amino acids, sulfonates and phenol. In addition, the different approaches used to improve the chromatographic separation of these compounds are also discussed. These approaches include introducing an internal gradient of the ionic strength, using vacancy ion exclusion chromatography, employing a hydrophilic cation exchange resin or adding a modifier such as heptanol to the dilute sulfuric acid mobile phase. The applications of these methods in the analysis of aromatic acids are provided with a table summarizing the stationary phases, the mobile phases and the detection methods.

  15. Properties of vaccum arc deposited amorphous hard carbon films

    SciTech Connect

    Anders, S.; Anders, A.; Raoux, S.

    1995-12-31

    Amorphous hard carbon films formed by vacuum arc deposition are, hydrogen-free, dense, and very hard. The properties of amorphous hard carbon films depend strongly on the energy of the incident ions. A technique which is called Plasma Immersion Ion Implantation can be applied to vacuum arc deposition of amorphous hard carbon films to influence the ion energy. We have studied the influence of the ion energy on the elastic modulus determined by an ultrasonic method, and have measured the optical gap for films with the highest sp{sup 3} content we have obtained so far with this deposition technique. The results show an elastic modulus close to that of diamond, and an optical gap of 2.1 eV which is much greater than for amorphous hard carbon films deposited by other techniques.

  16. Boron suboxide: As hard as cubic boron nitride

    NASA Astrophysics Data System (ADS)

    He, Duanwei; Zhao, Yusheng; Daemen, L.; Qian, J.; Shen, T. D.; Zerda, T. W.

    2002-07-01

    The Vickers hardness of boron suboxide single crystals was measured using a diamond indentation method. Under a loading force of 0.98 N, our test gave an average Vickers hardness of 45 GPa. The average fracture toughness was measured as 4.5 MPa m1/2. We also measured the hardness of the cubic boron nitride and sapphire single crystals for comparison. The average measured hardness for boron suboxide was found to be very close to that of cubic boron nitride under the same loading force. Our results suggest that the boron suboxide could be a new superhard material for industrial applications, surpassed in hardness only by diamond and cubic boron nitride.

  17. Properties of vacuum arc deposited amorphous hard carbon films

    SciTech Connect

    Anders, S.; Anders, A.; Raoux, S.

    1995-04-01

    Amorphous hard carbon films formed by vacuum arc deposition are hydrogen-free, dense, and very hard. The properties of amorphous hard carbon films depend strongly on the energy of the incident ions. A technique which is called Plasma Immersion Ion Implantation can be applied to vacuum arc deposition of amorphous hard carbon films to influence the ion energy. The authors have studied the influence of the ion energy on the elastic modulus determined by an ultrasonic method, and have measured the optical gap for films with the highest sp{sup 3} content they have obtained so far with this deposition technique. The results show an elastic modulus close to that of diamond, and an optical gap of 2.1 eV which is much greater than for amorphous hard carbon films deposited by other techniques.

  18. Next-to-leading-order corrections to exclusive processes in kT factorization

    NASA Astrophysics Data System (ADS)

    Nandi, Soumitra; Li, Hsiang-Nan

    2007-08-01

    We calculate next-to-leading-order corrections to exclusive processes in the kT factorization theorem, taking πγ*→γ as an example. Partons off shell by kT2 are considered in both the quark diagrams from full QCD and the effective diagrams for the pion wave function. The gauge dependences in the above two sets of diagrams cancel, when deriving the kT-dependent hard kernel as their difference. The gauge invariance of the hard kernel is then proven to all orders by induction. The light-cone singularities in the kT-dependent pion wave function are regularized by rotating the Wilson lines away from the light cone. This regularization introduces a factorization-scheme dependence into the hard kernel, which can be minimized in the standard way. Both the large double logarithms ln⁡2kT and ln⁡2x, x being a parton momentum fraction, arise from the loop correction to the virtual photon vertex, the former being absorbed into the pion wave function and organized by the kT resummation and the latter absorbed into a jet function and organized by the threshold resummation. The next-to-leading-order corrections are found to be only a few percent for πγ*→γ, if setting the factorization scale to the momentum transfer from the virtual photon.

  19. Exclusive hadronic and nuclear processes in QCD

    SciTech Connect

    Brodsky, S.J.

    1985-12-01

    Hadronic and nuclear processes are covered, in which all final particles are measured at large invariant masses compared with each other, i.e., large momentum transfer exclusive reactions. Hadronic wave functions in QCD and QCD sum rule constraints on hadron wave functions are discussed. The question of the range of applicability of the factorization formula and perturbation theory for exclusive processes is considered. Some consequences of quark and gluon degrees of freedom in nuclei are discussed which are outside the usual domain of traditional nuclear physics. 44 refs., 7 figs. (LEW)

  20. Converting hard copy documents for electronic dissemination

    SciTech Connect

    Hoffman, F.

    1994-12-31

    Since the advent of computer systems, the goal of a paperless office, and even a paperless society, has been pursued. While the normal paper flow in an organization is far from totally automated, particularly for items requiring signatures or authorizations, electronic information dissemination is becoming an almost simple task. The reasons for providing on-line documents are many and include faster and easier access for everyone, elimination of printing costs, reduction of wasted shelf and desk space, and the security of having a centrally-located, always up-to-date document. New computer software even provides the user with the ability to annotate documents and to have bookmarks so that the old scribbled-in and dog-eared manual can be replaced without loosing this `customizability`. Moreover, new hypermedia capabilities mean that documents can be read in a non-linear fashion and can include color figures and photographs, audio, and even animation sequences, capabilities which exceed those of paper. The proliferation of network-based information servers, coupled with the growth of the Internet, has enticed academic, governmental, and even commercial organizations to provide increasing numbers of documents and data bases in electronic form via the network, not just to internal staff, but to the public as well. Much of this information, which includes everything from mundane company procedures to spiffy marketing brochures, was previously published only in hard copy. Converting existing documents to electronic form and producing only electronic versions of new documents poses some interesting challenges to the maintainer or author.