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Sample records for light meson physics

  1. The light meson spectroscopy program

    SciTech Connect

    Smith, Elton S.

    2014-06-01

    Recent discoveries of a number of unexpected new charmomium-like meson states at the BaBar and Belle B-factories have demonstrated how little is still known about meson spectroscopy. In this talk we will review recent highlights of the light quark spectroscopy from collider and fixed target experiments.

  2. D meson decay channels that involve light scalar mesons

    NASA Astrophysics Data System (ADS)

    Fariborz, Amir

    2013-04-01

    A generalized linear sigma model of low-energy QCD is used to study several decay channels of D mesons that involve light scalar meson as a decay product. Such studies require reliable models for scalar mesons that take into account underlying mixing among quark-antiquarks, tetra quarks and glueballs. In this talk, the generalized linear sigma model of low-energy QCD for understanding the properties of scalar mosons will be briefly presented, and he application of this model to studies of heavier meson decays [such as the semileptonic decay Ds(1968)->f0(980) e^+ ν] will be presented, and a few directions for further extensions of the model will be outlined. Refs. A.H. Fariborz, R. Jora, J. Schechter and M.N. Shahid, ``Semi-leptonic Ds^+(1968) Decays as a Scalar Meson Probe,'' Physical Review D 84, 094024 (2011). A.H. Fariborz, R. Jora, J. Schechter and M.N. Shahid, ``Chiral Nonet Mixing in pi-pi Scattering,'' Physical Review D 84, 113004 (2011).

  3. Physics opportunities with meson beams

    SciTech Connect

    Briscoe, William J.; Doring, Michael; Haberzettl, Helmut; Manley, D. Mark; Naruki, Megumi; Strakovsky, Igor I.; Swanson, Eric S.

    2015-10-20

    Over the past two decades, meson photo- and electro-production data of unprecedented quality and quantity have been measured at electromagnetic facilities worldwide. By contrast, the meson-beam data for the same hadronic final states are mostly outdated and largely of poor quality, or even nonexistent, and thus provide inadequate input to help interpret, analyze, and exploit the full potential of the new electromagnetic data. To reap the full benefit of the high-precision electromagnetic data, new high-statistics data from measurements with meson beams, with good angle and energy coverage for a wide range of reactions, are critically needed to advance our knowledge in baryon and meson spectroscopy and other related areas of hadron physics. To address this situation, a state of-the-art meson-beam facility needs to be constructed. Furthermore, the present paper summarizes unresolved issues in hadron physics and outlines the vast opportunities and advances that only become possible with such a facility.

  4. Light O++ Mesons: Scalargators in Florida

    NASA Astrophysics Data System (ADS)

    Pennington, M. R.

    2010-08-01

    Light scalar mesons abound in hadron processes, like the alligators in the Florida Everglades. Moreover, scalars are intimately tied to the vacuum structure of QCD. They are the product of many decays. Consequently, a rich source of recent information about them has come from experiments producing heavy flavour mesons. Indeed, scalars will continue to dominate many of the processes to be studied at forthcoming facilities like BESIII in Beijing, FAIR at GSI Darmstadt and the GlueX experiment at JLab, making an understanding (or at least an excellent and theoretically consistent description) essential for the physics missions of these facilities.

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

    SciTech Connect

    Lindenbaum, S.J.

    1980-10-01

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

  6. Physics opportunities with meson beams

    DOE PAGESBeta

    Briscoe, William J.; Doring, Michael; Haberzettl, Helmut; Manley, D. Mark; Naruki, Megumi; Strakovsky, Igor I.; Swanson, Eric S.

    2015-10-20

    Over the past two decades, meson photo- and electro-production data of unprecedented quality and quantity have been measured at electromagnetic facilities worldwide. By contrast, the meson-beam data for the same hadronic final states are mostly outdated and largely of poor quality, or even nonexistent, and thus provide inadequate input to help interpret, analyze, and exploit the full potential of the new electromagnetic data. To reap the full benefit of the high-precision electromagnetic data, new high-statistics data from measurements with meson beams, with good angle and energy coverage for a wide range of reactions, are critically needed to advance our knowledgemore » in baryon and meson spectroscopy and other related areas of hadron physics. To address this situation, a state of-the-art meson-beam facility needs to be constructed. Furthermore, the present paper summarizes unresolved issues in hadron physics and outlines the vast opportunities and advances that only become possible with such a facility.« less

  7. Meson Spectroscopy in the Light Quark Sector

    SciTech Connect

    de Vita, Raffaella

    2014-04-01

    Understanding the hadron spectrum is one of the fundamental issues in modern particle physics. We know that existing hadron configurations include baryons, made of three quarks, and mesons, made of quark-antiquark pairs. However most of the mass of the hadrons is not due to the mass of these elementary constituents but to their binding force. Studying the hadron spectrum is therefore a tool to understand one of the fundamental forces in nature, the strong force, and Quantum Chromo Dynamics (QCD), the theory that describes it. This investigation can provide an answer to fundamental questions as what is the origin of the mass of hadrons, what is the origin of quark confinement, what are the relevant degrees of freedom to describe these complex systems and how the transition between the elementary constituents, quarks and gluons, and baryons and mesons occurs. In this field a key tool is given by meson spectroscopy. Mesons, being made by a quark and an anti-quark, are the simplest quark bound system and therefore the ideal benchmark to study the interaction between quarks and understand what the role of gluons is. In this investigation, it is fundamental to precisely determine the spectrum and properties of mesons but also to search for possible unconventional states beyond the configuration q{anti q} as tetraquarks (qq{anti qq}), hybrids (q{anti q}g) and glueballs. These states can be distinguished unambiguously from regular mesons when they have exotic quantum numbers, i.e. combinations of total angular momentum, spin and parity that are not allowed for q{anti q} states. These are called exotic quantum numbers and the corresponding states are referred to as exotics. The study of the meson spectrum and the search for exotics is among the goals of several experiments in the world that exploit different reaction processes, as e{sup +}e{sup −} annihilation, p{anti p} annihilation, pion scattering, proton-proton scattering and photo-production, to produce meson states

  8. B Decays Involving Light Mesons

    SciTech Connect

    Eschrich, Ivo Gough; /UC, Irvine

    2007-01-09

    Recent BABAR results for decays of B-mesons to combinations of non-charm mesons are presented. This includes B decays to two vector mesons, B {yields} {eta}{prime}({pi}, K, {rho}) modes, and a comprehensive Dalitz Plot analysis of B {yields} KKK decays.

  9. Rare meson decays into very light neutralinos

    SciTech Connect

    O'Leary, Ben

    2010-02-10

    Results are presented for the two-body decays of mesons into light neutralinos and from the first complete calculation of the loop-induced decays of kaons to pions plus light neutralinos and of B mesons to kaons plus light neutralinos. The branching ratios are shown to be strongly suppressed within the MSSM with minimal flavor violation, and no bounds on the neutralino mass can be inferred from experimental data, i.e. a massless neutralino is allowed.

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

    SciTech Connect

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

    2014-10-30

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

  11. Light Meson Decays from Photon-Induced Reactions with CLAS

    NASA Astrophysics Data System (ADS)

    Kunkel, Michael; CLAS Collaboration; Light Meson Decay (LMD) Team

    2015-04-01

    Photo-production experiments with the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Laboratory produce data sets with unprecedented statistics of light mesons. With these data sets, measurements of transition form factors for η, ω, and η ' via conversion decays can be performed using a line shape analysis on the invariant mass of the final state dileptons. Tests of fundamental symmetries and information on the light quark mass difference can be performed using a Dalitz plot analysis of the meson decay. In addition, the data allows for a search for dark matter, such as the heavy photon via conversion decays of light mesons and physics beyond the Standard Model can be searched for via invisible decays of η mesons. An overview of the first results and future prospects will be given.

  12. Light Vector Mesons in the Nuclear Medium

    SciTech Connect

    Wood, Michael; Nasseripour, Rakhsha; Weygand, Dennis; Djalali, Chaden; Tur, Clarisse; Mosel, Ulrich; Muehlich, Pascal; Adams, Gary; Amaryan, Moscov; Amaryan, Moskov; Ambrozewicz, Pawel; Anghinolfi, Marco; Asryan, Gegham; Avagyan, Harutyun; Baghdasaryan, Hovhannes; Baillie, Nathan; Ball, James; Baltzell, Nathan; Barrow, Steve; Battaglieri, Marco; Bedlinskiy, Ivan; Bektasoglu, Mehmet; Bellis, Matthew; Benmouna, Nawal; Berman, Barry; Biselli, Angela; Blaszczyk, Lukasz; Bouchigny, Sylvain; Boyarinov, Sergey; Bradford, Robert; Branford, Derek; Briscoe, William; Brooks, William; Burkert, Volker; Butuceanu, Cornel; Calarco, John; Careccia, Sharon; Carman, Daniel; Carnahan, Bryan; Casey, Liam; Chen, Shifeng; Cheng, Lu; Cole, Philip; Collins, Patrick; Coltharp, Philip; Crabb, Donald; Crannell, Hall; Crede, Volker; Cummings, John; Dashyan, Natalya; De Vita, Raffaella; De Sanctis, Enzo; Degtiarenko, Pavel; Denizli, Haluk; Dennis, Lawrence; Deur, Alexandre; Dharmawardane, Kahanawita; Dickson, Richard; Dodge, Gail; Doughty, David; Dugger, Michael; Dytman, Steven; Dzyubak, Oleksandr; Egiyan, Hovanes; Egiyan, Kim; Elfassi, Lamiaa; Elouadrhiri, Latifa; Eugenio, Paul; Fedotov, Gleb; Feldman, Gerald; Feuerbach, Robert; Fradi, Ahmed; Funsten, Herbert; Garcon, Michel; Gavalian, Gagik; Gilfoyle, Gerard; Giovanetti, Kevin; Girod, Francois-Xavier; Goetz, John; Gordon, Christopher; Gothe, Ralf; Griffioen, Keith; Guidal, Michel; Guler, Nevzat; Guo, Lei; Gyurjyan, Vardan; Hadjidakis, Cynthia; Hafidi, Kawtar; Hakobyan, Hayk; Hakobyan, Rafael; Hanretty, Charles; Hardie, John; Hassall, Neil; 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; Kellie, James; Khandaker, Mahbubul; Khetarpal, Puneet; 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; 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; Moriya, Kei; Morrow, Steven; Moteabbed, Maryam; Mueller, James; Munevar Espitia, Edwin; Mutchler, Gordon; Nadel-Turonski, Pawel; Niccolai, Silvia; Niculescu, Gabriel; Niculescu, Maria-Ioana; Niczyporuk, Bogdan; Niroula, Megh; Niyazov, Rustam; Nozar, Mina; Osipenko, Mikhail; Ostrovidov, Alexander; Park, Kijun; Pasyuk, Evgueni; Paterson, Craig; Pereira, Sergio; Pierce, Joshua; Pivnyuk, Nikolay; Pocanic, Dinko; Pogorelko, Oleg; Pozdnyakov, Sergey; Preedom, Barry; Price, John; Prok, Yelena; Protopopescu, Dan; Raue, Brian; Riccardi, Gregory; Ricco, Giovanni; Ripani, Marco; Ritchie, Barry; Ronchetti, Federico; Rosner, Guenther; Rossi, Patrizia; Sabatie, Franck; Salamanca, Julian; Salgado, Carlos; Santoro, Joseph; Sapunenko, Vladimir; Schumacher, Reinhard; Serov, Vladimir; Sharabian, Youri; Sharov, Dmitri; Shvedunov, Nikolay; Smith, Elton; Smith, Lee; Sober, Daniel; Sokhan, Daria; Stavinsky, Aleksey; Stepanyan, Stepan; Stepanyan, Samuel; Stokes, Burnham; Stoler, Paul; Strakovski, Igor; Strauch, Steffen; Taiuti, Mauro; Tedeschi, David; Tkabladze, Avtandil; Tkachenko, Svyatoslav; Todor, Luminita; Ungaro, Maurizio; Vineyard, Michael; Vlassov, Alexander; Watts, Daniel; Weinstein, Lawrence; Williams, Michael; Wolin, Elliott; Yegneswaran, Amrit; Zana, Lorenzo; Zhang, Bin; Zhang, Jixie; Zhao, Bo; Zhao, Zhiwen

    2008-07-01

    The light vector mesons ($\\rho$, $\\omega$, and $\\phi$) were produced in deuterium, carbon, titanium, and iron targets in a search for possible in-medium modifications to the properties of the $\\rho$ meson at normal nuclear densities and zero temperature. The vector mesons were detected with the CEBAF Large Acceptance Spectrometer (CLAS) via their decays to $e^{+}e^{-}$. The rare leptonic decay was chosen to reduce final-state interactions. A combinatorial background was subtracted from the invariant mass spectra using a well-established event-mixing technique. The $\\rho$ meson mass spectrum was extracted after the $\\omega$ and $\\phi$ signals were removed in a nearly model-independent way. Comparisons were made between the $\\rho$ mass spectra from the heavy targets ($A > 2$) with the mass spectrum extracted from the deuterium target. With respect to the $\\rho$-meson mass, we obtain a small shift compatible with zero. Also, we measure widths consistent with standard nuclear many-body eff

  13. Excited light meson spectroscopy from lattice QCD

    SciTech Connect

    Christopher Thomas, Hadron Spectrum Collaboration

    2012-04-01

    I report on recent progress in calculating excited meson spectra using lattice QCD, emphasizing results and phenomenology. With novel techniques we can now extract extensive spectra of excited mesons with high statistical precision, including spin-four states and those with exotic quantum numbers. As well as isovector meson spectra, I will present new calculations of the spectrum of excited light isoscalar mesons, something that has up to now been a challenge for lattice QCD. I show determinations of the flavor content of these mesons, including the eta-eta' mixing angle, providing a window on annihilation dynamics in QCD. I will also discuss recent work on using lattice QCD to map out the energy-dependent phase shift in pi-pi scattering and future applications of the methodology to the study of resonances and decays.

  14. Recent progress on light scalar mesons

    SciTech Connect

    Peláez, J. R.

    2014-07-23

    This is a brief account of the recent developments on the determination of the mass and widths of the much debated scalar mesons, paying particular attention to the causes of major revision of the σ or f{sub 0}(500) meson in the last edition of the Review of Particle Physics, which has finally acknowledged that the situation concerning the mass and width of this controversial state has been settled, although this was already well-known to scalar meson practitioners for about a decade. I will briefly comment on the dispersive approach, followed by several groups, which seems to have been the most decisive in support of the existence and precise determinations of scalar meson properties.

  15. Excited light isoscalar mesons from lattice QCD

    SciTech Connect

    Christopher Thomas

    2011-07-01

    I report a recent lattice QCD calculation of an excited spectrum of light isoscalar mesons, something that has up to now proved challenging for lattice QCD. With novel techniques we extract an extensive spectrum with high statistical precision, including spin-four states and, for the first time, light isoscalars with exotic quantum numbers. In addition, the hidden flavour content of these mesons is determined, providing a window on annihilation dynamics in QCD. I comment on future prospects including applications to the study of resonances.

  16. Light O{sup ++} Mesons: Scalargators in Florida

    SciTech Connect

    Pennington, M. R.

    2010-08-05

    Light scalar mesons abound in hadron processes, like the alligators in the Florida Everglades. Moreover, scalars are intimately tied to the vacuum structure of QCD. They are the product of many decays. Consequently, a rich source of recent information about them has come from experiments producing heavy flavour mesons. Indeed, scalars will continue to dominate many of the processes to be studied at forthcoming facilities like BESIII in Beijing, FAIR at GSI Darmstadt and the GlueX experiment at JLab, making an understanding (or at least an excellent and theoretically consistent description) essential for the physics missions of these facilities.

  17. Photoproduction and Decay of Light Mesons in CLAS

    SciTech Connect

    Amaryan, Moskov Jamalovich

    2013-08-01

    We present preliminary experimental results on photoproduction and decay of light mesons measured with CLAS setup at JLAB . This include Dalitz decay of pseudoscalar and vector mesons, radiative decay of pseudoscalar mesons as well hadronic decays of pseudoscalar and vector mesons. The collected high statistics in some of decay channels exceeds the world data by an order of magnitude and some other decay modes are observed for the first time. It is shown how the CLAS data will improve the world data on transition form factors of light mesons, Dalitz plot analyses, branching ratios of rare decay modes and other fundamental properties potentially accessible through the light meson decays.

  18. Hadronic D decays involving even-parity light mesons

    SciTech Connect

    Cheng, H.-Y.; Chiang, C.-W.

    2010-04-01

    We study the hadronic D meson decays into a pseudoscalar meson P and an even-parity meson M, where M represents a scalar meson S, an axial-vector meson A, or a tensor meson T. These decays are first analyzed in the flavor-diagram approach. Fits to the SP modes with S being a nonstrange scalar meson show that neither the simple qq picture nor the q{sup 2}q{sup 2} scheme is favored by data. Current measurements on the AP decays are insufficient for a meaningful analysis. Some TP data are inconsistent with the others. In certain cases, the W-annihilation diagrams indicated by the data are unexpectedly large. As a comparison, we also compute their decay rates in the factorization approach using form factors extracted from the covariant light-front model. We find that factorization works well for Cabibbo-allowed D{sup +{yields}}SP, AP decays free of the weak annihilation contributions (W-exchange or W-annihilation). For the other SP and AP modes, it is necessary to include weak annihilation contributions to account for the data. However, factorization fails for D{yields}TP decays for some unknown reason; the predicted rates are in general too small by at least 2 orders of magnitude compared to experiment. We also examine the finite-width effects of resonances. Some decay modes which are kinematically forbidden become physically allowed due to the finite width of the resonance. We show that the branching fraction of D{sup +{yields}{sigma}{pi}+} extracted from three-body decays is enhanced by a factor of 2, whereas B(D{sup 0{yields}}f{sub 2}(1270)K{sup 0}) is reduced by a factor of 4 by finite-width effects.

  19. Theoretical aspects of light meson spectroscopy

    SciTech Connect

    Barnes, T. |

    1995-12-31

    In this pedagogical review the authors discuss the theoretical understanding of light hadron spectroscopy in terms of QCD and the quark model. They begin with a summary of the known and surmised properties of QCD and confinement. Following this they review the nonrelativistic quark potential model for q{anti q} mesons and discuss the quarkonium spectrum and methods for identifying q{anti q} states. Finally, they review theoretical expectations for non-q{anti q} states (glueballs, hybrids and multiquark systems) and the status of experimental candidates for these states.

  20. Decay constants of p and d wave heavy light mesons

    SciTech Connect

    Veseli, Sinisa; Dunietz, Isard

    1996-07-01

    We investigate decay constants of P- and D-wave heavy-light mesons within the mock-meson approach. Numerical estimates are obtained using the relativistic quark model. We also comment on recent calculations of heavy-light pseudo-scalar and vector decay constants.

  1. Non-perturbative QCD Modeling and Meson Physics

    SciTech Connect

    Nguyen, T.; Souchlas, N. A.; Tandy, P. C.

    2009-04-20

    Using a ladder-rainbow kernel previously established for light quark hadron physics, we explore the extension to masses and electroweak decay constants of ground state pseudoscalar and vector quarkonia and heavy-light mesons in the c- and b-quark regions. We make a systematic study of the effectiveness of a constituent mass concept as a replacement for a heavy quark dressed propagator for such states. The difference between vector and axial vector current correlators is explored within the same model to provide an estimate of the four quark chiral condensate and the leading distance scale for the onset of non-perturbative phenomena in QCD.

  2. Non-perturbative QCD Modeling and Meson Physics

    NASA Astrophysics Data System (ADS)

    Nguyen, T.; Souchlas, N. A.; Tandy, P. C.

    2009-04-01

    Using a ladder-rainbow kernel previously established for light quark hadron physics, we explore the extension to masses and electroweak decay constants of ground state pseudoscalar and vector quarkonia and heavy-light mesons in the c- and b-quark regions. We make a systematic study of the effectiveness of a constituent mass concept as a replacement for a heavy quark dressed propagator for such states. The difference between vector and axial vector current correlators is explored within the same model to provide an estimate of the four quark chiral condensate and the leading distance scale for the onset of non-perturbative phenomena in QCD.

  3. Light meson decays from photon-induced reactions with CLAS

    NASA Astrophysics Data System (ADS)

    Kunkel, Michael C.

    2016-05-01

    Photo-production experiments with the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Laboratory produce data sets with unprecedented statistics for light mesons. With these data sets, measurements of transition form factors for η, ω, and η' mesons via conversion decays can be performed using the invariant mass distribution of the final state dileptons. Tests of fundamental symmetries and information on the light quark mass difference can be performed using a Dalitz plot analysis of the meson decay. An overview of the first results, from existing CLAS data, and future prospects within the newly upgraded CLAS12 apparatus are given.

  4. Light and heavy mesons in a soft-wall holographic approach

    SciTech Connect

    Branz, Tanja; Gutsche, Thomas; Lyubovitskij, Valery E.; Schmidt, Ivan; Vega, Alfredo

    2010-10-01

    We study the mass spectrum and decay constants of light and heavy mesons in a soft-wall holographic approach, using the correspondence of string theory in Anti-de Sitter space and conformal field theory in physical space-time.

  5. Heavy-light charm mesons spectroscopy and decay widths

    NASA Astrophysics Data System (ADS)

    Upadhyay, Alka; Batra, Meenakshi; Gupta, Pallavi

    2016-05-01

    We present the mass formula for heavy-light charm meson at one loop, using heavy quark effective theory. Formulating an effective Lagrangian, the masses of the ground state heavy mesons have been studied in the heavy quark limit, including leading corrections from finite heavy quark masses and nonzero light quark masses, using a constrained fit for the eight equations with 11 parameters including three coupling constants g, h, and g^' }. Masses determined using this approach are fitted to the experimentally known decay widths to estimate the strong coupling constants, showing a better match with available theoretical and experimental data.

  6. Lattice results for low moments of light meson distribution amplitudes

    SciTech Connect

    Arthur, R.; Boyle, P. A.; Broemmel, D.; Flynn, J. M.; Rae, T. D.; Sachrajda, C. T. C.; Donnellan, M. A.

    2011-04-01

    As part of the UKQCD and RBC collaborations'N{sub f}=2+1 domain-wall fermion phenomenology programme, we calculate the first two moments of the light-cone distribution amplitudes of the pseudoscalar mesons {pi} and K and the (longitudinally polarized) vector mesons {rho}, K{sup *}, and {phi}. We obtain the desired quantities with good precision and are able to discern the expected quark-mass dependence of SU(3)-flavor breaking effects. An important ingredient of the calculation is the nonperturbative renormalization of lattice operators using a regularization-independent momentum scheme.

  7. Heavy-light mesons in a relativistic model

    NASA Astrophysics Data System (ADS)

    Liu, Jing-Bin; Yang, Mao-Zhi

    2016-07-01

    We study the heavy-light mesons in a relativistic model, which is derived from the Bethe-Salpeter equation by applying the Foldy-Wouthuysen transformation to the heavy quark. The kernel we choose is based on scalar confinement and vector Coulomb potentials. The transverse interaction of the gluon exchange is also taken into account in this model. The spectra and wave functions of D, Ds, B, Bs meson states are obtained. The spectra are calculated up to the order of 1/m Q, and wave functions are treated to leading order. Supported by National Natural Science Foundation of China (11375088, 10975077, 10735080, 11125525)

  8. Probing the Gluon Self-Interaction in Light Mesons

    SciTech Connect

    Fischer, Christian S.; Williams, Richard

    2009-09-18

    We investigate masses and decay constants of light mesons from a coupled system of Dyson-Schwinger and Bethe-Salpeter equations. We explicitly take into account dominant non-Abelian contributions to the dressed quark-gluon vertex stemming from the gluon self-interaction. We construct the corresponding Bethe-Salpeter kernel that satisfies the axial-vector Ward-Takahashi identity. Our numerical treatment fully includes all momentum dependencies with all equations solved completely in the complex plane. This approach goes well beyond the rainbow-ladder approximation and permits us to investigate the influence of the gluon self-interaction on the properties of mesons. As a first result we find indications of a nonperturbative cancellation of the gluon self-interaction contributions and pion cloud effects in the mass of the rho meson.

  9. Light-Front Holography and Gauge/Gravity Duality: The Light Meson and Baryon Spectra

    SciTech Connect

    de Teramond, Guy F.; Brodsky, Stanley J.; /SLAC

    2009-12-09

    Starting from the bound state Hamiltonian equation of motion in QCD, we derive relativistic light-front wave equations in terms of an invariant impact variable {zeta} which measures the separation of the quark and gluonic constituents within the hadron at equal light-front time. These equations of motion in physical space-time are equivalent to the equations of motion which describe the propagation of spin-J modes in anti-de Sitter (AdS) space. Its eigenvalues give the hadronic spectrum, and its eigenmodes represent the probability amplitudes of the hadronic constituents at a given scale. An effective classical gravity description in a positive-sign dilaton background exp(+{kappa}{sup 2}z{sup 2}) is given for the phenomenologically successful soft-wall model which naturally encodes the internal structure of hadrons and their orbital angular momentum. Applications to the light meson and baryon spectrum are presented.

  10. Neutral B meson mixings and B meson decay constants with static heavy and domain-wall light quarks

    NASA Astrophysics Data System (ADS)

    Aoki, Yasumichi; Ishikawa, Tomomi; Izubuchi, Taku; Lehner, Christoph; Soni, Amarjit

    2015-06-01

    Neutral B meson mixing matrix elements and B meson decay constants are calculated. The static approximation is used for the b quark and the domain-wall fermion formalism is employed for light quarks. The calculations are carried out on 2 +1 -flavor dynamical ensembles generated by the RBC and UKQCD collaborations with lattice spacings of 0.086 fm (a-1˜2.3 GeV ) and 0.11 fm (1.7 GeV), and a fixed physical spatial volume of about (2.7 fm )3 . In the static quark action, link smearings are used to improve the signal-to-noise ratio. We employ two kinds of link smearings, HYP1 and HYP2, and their results are combined when taking the continuum limit. For the matching between the lattice and the continuum theory, one-loop perturbative O (a ) improvements are made to reduce discretization errors. As the most important quantity of this work, we obtain the SU(3) breaking ratio ξ =1.208 (60 ), where the error includes both the statistical and systematic errors. (The uncertainty from an infinite b -quark mass is not included.) We also find other neutral B meson mixing quantities, fB√{B^ B }=240 (22 ) MeV , fBs√{B^Bs}=290 (22 ) MeV , B^B=1.17 (22 ), B^Bs=1.22(13 ), and BB s/BB=1.028 (74 ), and the B meson decay constants fB=219 (17 ) MeV , fBs=264(19 ) MeV , and fB s/fB=1.193 (41 ) in the static limit of the b quark, which do not include an infinite b -quark mass uncertainty.

  11. Light-front description for the theta dependence of meson masses in the massive Schwinger model

    SciTech Connect

    Burkardt, M.; Harada, K.

    1998-05-01

    We present a continuum formulation for {theta} vacua in the massive Schwinger model on the light front, where {theta} enters as a background electric field. The effective coupling of the external field is partially screened due to vacuum polarization processes. For small fermion masses and small {theta}, we calculate the mass of the meson and find agreement with results from bosonization. {copyright} {ital 1998} {ital The American Physical Society}

  12. Light scalar mesons in central production at COMPASS

    NASA Astrophysics Data System (ADS)

    Austregesilo, Alexander

    2016-05-01

    COMPASS is a fixed-target experiment at the CERN SPS that studies the spectrum of light-quark hadrons. In 2009, it collected a large dataset using a 190 GeV/c positive hadron beam impinging on a liquid-hydrogen target in order to measure the central exclusive production of light scalar mesons. One of the goals is the search for so-called glueballs, which are hypothetical meson-like objects without valence-quark content. We study the decay of neutral resonances by selecting centrally produced pion pairs from the COMPASS dataset. The angular distributions of the two pseudoscalar mesons are decomposed in terms of partial waves, where particular attention is paid to the inherent mathematical ambiguities. The large dataset allows us to perform a detailed analysis in bins of the two squared four-momentum transfers carried by the exchange particles in the reaction. Possible parameterisations of the mass dependence of the partial-wave amplitudes in terms of resonances are also discussed.

  13. Study of Heavy-Light Mesons Properties Via the Variational Method for Cornell Interaction

    NASA Astrophysics Data System (ADS)

    Hassanabadi, H.; Ghafourian, M.; Rahmani, S.

    2016-04-01

    Using the variational method we calculate mesonic wave function. We report masses and decay constants for heavy-light mesons. Leptonic decay widths of charmed and beauty mesons are also calculated. The obtained results are compared with the available experimental and theoretical data.

  14. Charmless hadronic B decays involving scalar mesons: Implications on the nature of light scalar mesons

    SciTech Connect

    Cheng Haiyang; Chua Chunkhiang; Yang Kweichou

    2006-01-01

    The hadronic charmless B decays into a scalar meson and a pseudoscalar meson are studied within the framework of QCD factorization. Based on the QCD sum rule method, we have derived the leading-twist light-cone distribution amplitudes of scalar mesons and their decay constants. Although the light scalar mesons f{sub 0}(980) and a{sub 0}(980) are widely perceived as primarily the four-quark bound states, in practice it is difficult to make quantitative predictions based on the four-quark picture for light scalars. Hence, predictions are made in the 2-quark model for the scalar mesons. The short-distance approach suffices to explain the observed large rates of f{sub 0}(980)K{sup -} and f{sub 0}(980)K{sup 0} that receive major penguin contributions from the b{yields}sss process. When f{sub 0}(980) is assigned as a four-quark bound state, there exist extra diagrams contributing to B{yields}f{sub 0}(980)K. Therefore, a priori the f{sub 0}(980)K rate is not necessarily suppressed for a four-quark state f{sub 0}(980). The predicted B{sup 0}{yields}a{sub 0}{sup {+-}}(980){pi}{sup {+-}} and a{sub 0}{sup +}(980)K{sup -} rates exceed the current experimental limits, favoring a four-quark nature for a{sub 0}(980). The penguin-dominated modes a{sub 0}(980)K and a{sub 0}(1450)K receive predominant weak annihilation contributions. There exists a twofold experimental ambiguity in extracting the branching ratio of B{sup -}{yields}K{sub 0}*{sup 0}(1430){pi}{sup -}, which can be resolved by measuring other K{sub 0}*(1430){pi} modes in conjunction with the isospin symmetry consideration. Large weak annihilation contributions are needed to explain the K{sub 0}*(1430){pi} data. The decay B{sup 0}{yields}{kappa}{sup +}K{sup -} provides a nice ground for testing the 4-quark and 2-quark nature of the {kappa} meson. It can proceed through W-exchange and hence is quite suppressed if {kappa} is made of two quarks, while it receives a tree contribution if {kappa} is predominately a four

  15. Meson Transition Form Factors in Light-Front Holographic QCD

    SciTech Connect

    Brodsky, Stanley J.; Cao, Fu-Guang; de Teramond, Guy F.; /Costa Rica U.

    2011-06-22

    We study the photon-to-meson transition form factors (TFFs) F{sub M{gamma}}(Q{sup 2}) for {gamma}{gamma}* {yields} M using light-front holographic methods. The Chern-Simons action, which is a natural form in 5-dimensional anti-de Sitter (AdS) space, leads directly to an expression for the photon-to-pion TFF for a class of confining models. Remarkably, the predicted pion TFF is identical to the leading order QCD result where the distribution amplitude has asymptotic form. The Chern-Simons form is local in AdS space and is thus somewhat limited in its predictability. It only retains the q{bar q} component of the pion wavefunction, and further, it projects out only the asymptotic form of the meson distribution amplitude. It is found that in order to describe simultaneously the decay process {pi}{sup 0} {yields} {gamma}{gamma} and the pion TFF at the asymptotic limit, a probability for the q{bar q} component of the pion wavefunction P{sub q{bar q}} = 0.5 is required; thus giving indication that the contributions from higher Fock states in the pion light-front wavefunction need to be included in the analysis. The probability for the Fock state containing four quarks (anti-quarks) which follows from analyzing the hadron matrix elements, P{sub q{bar q}q{bar q}} {approx} 10%, agrees with the analysis of the pion elastic form factor using light-front holography including higher Fock components in the pion wavefunction. The results for the TFFs for the {eta} and {eta}{prime} mesons are also presented. The rapid growth of the pion TFF exhibited by the BABAR data at high Q{sup 2} is not compatible with the models discussed in this article, whereas the theoretical calculations are in agreement with the experimental data for the {eta} and {eta}{prime} TFFs.

  16. Meson transition form factors in light-front holographic QCD

    SciTech Connect

    Brodsky, Stanley J.; Cao Fuguang; de Teramond, Guy F.

    2011-10-01

    We study the photon-to-meson transition form factors (TFFs) F{sub M}{gamma}(Q{sup 2}) for {gamma}{gamma}{sup *}{yields}M using light-front holographic methods. The Chern-Simons action, which is a natural form in five-dimensional anti-de Sitter (AdS) space, is required to describe the anomalous coupling of mesons to photons using holographic methods and leads directly to an expression for the photon-to-pion TFF for a class of confining models. Remarkably, the predicted pion TFF is identical to the leading order QCD result where the distribution amplitude has asymptotic form. The Chern-Simons form is local in AdS space and is thus somewhat limited in its predictability. It only retains the qq component of the pion wave function, and further, it projects out only the asymptotic form of the meson distribution amplitude. It is found that in order to describe simultaneously the decay process {pi}{sup 0}{yields}{gamma}{gamma} and the pion TFF at the asymptotic limit, a probability for the qq component of the pion wave function P{sub qq}=0.5 is required, thus giving indication that the contributions from higher Fock states in the pion light-front wave function need to be included in the analysis. The probability for the Fock state containing four quarks P{sub qqqq}{approx}10%, which follows from analyzing the hadron matrix elements for a dressed current model, agrees with the analysis of the pion elastic form factor using light-front holography including higher Fock components in the pion wave function. The results for the TFFs for the {eta} and {eta}{sup '} mesons are also presented. The rapid growth of the pion TFF exhibited by the BABAR data at high Q{sup 2} is not compatible with the models discussed in this article, whereas the theoretical calculations are in agreement with the experimental data for the {eta} and {eta}{sup '} TFFs.

  17. B meson decays in leptons: powerful probes of new physics

    NASA Astrophysics Data System (ADS)

    Rotondo, Marcello

    2014-11-01

    We review some recent measurements of B meson decays that involve leptons in the final states and that are sensitive to physics beyond the Standard Model, such as the electroweak penguin decays B → Xsℓ+ℓ-, the Lepton Number Violating process B → Xℓ±ℓ'± and the tree-level dominated decay with τ leptons: B → τντ and B → D(∗)τντ.

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

    NASA Astrophysics Data System (ADS)

    Nefediev, A. V.

    2002-06-01

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

  19. Architectural Physics: Lighting.

    ERIC Educational Resources Information Center

    Hopkinson, R. G.

    The author coordinates the many diverse branches of knowledge which have dealt with the field of lighting--physiology, psychology, engineering, physics, and architectural design. Part I, "The Elements of Architectural Physics", discusses the physiological aspects of lighting, visual performance, lighting design, calculations and measurements of…

  20. The ground state of the Pomeron and its decays to light mesons and photons

    NASA Astrophysics Data System (ADS)

    Godizov, A. A.

    2016-07-01

    The problem of the timelike Pomeron coupling to light mesons and photons is considered in light of available data on high-energy meson-proton scattering. A possible correspondence of the f_2(1950) resonance to the ground state of the Pomeron is argued.

  1. Spectroscopy of mesons containing light quarks (u, d, s) or gluons

    NASA Astrophysics Data System (ADS)

    Diekmann, Bernd

    1988-02-01

    This paper gives an overview of the increase of experimental knowledge of mesons which are built by light quarks. This naturally includes also those mesonic states containing gluons and those with an exotic internal quark structure such as qq¯-qq¯. The resulting mesonic “zoo” will be compared with predictions from actual phenomenological ansatzes: e.g. potential models, the bag model, and QCD sum rules, and also more general approaches such as QCD lattice gauge theories.

  2. Light detectors for beauty physics

    NASA Astrophysics Data System (ADS)

    DeSalvo, R.

    1996-12-01

    Cherenkov light is used to identify beauty mesons in high energy interactions in an increasing number of experiments. Speed and pixel dimension requirements are generating a revival of the vacuum light detectors as the active component of Cherenkov light detectors in the new high luminosity and high background experiments. The insensitivity to magnetic fields of the most modern vacuum light detectors also helps making these devices more competitive.

  3. Search for medium effects on light vector mesons

    SciTech Connect

    Djalali, C; Nasseripour, R; Weygand, D P; Wood, M H

    2007-02-01

    The photoproduction of vector mesons on various nuclei has been studied using the Cebaf Large Acceptance Spectrometer (CLAS) at Jefferson Laboratory. The rho, omega, and phi mesons are observed via their decay to e+e. The rho spectral function is extracted from the data on carbon, iron, and titanium. We observe no effects on the mass of the rho meson, some widening in titanium and iron is observed consistent with standard collisional broadening.

  4. Strong decay constants of heavy tensor mesons in light cone QCD sum rules

    NASA Astrophysics Data System (ADS)

    Alhendi, H. A.; Aliev, T. M.; Savcı, M.

    2016-04-01

    Strong decay constants of the heavy tensor to heavy pseudoscalar (vector) and light pseudoscalar mesons are estimated within the light cone QCD sum rules. It is observed that the values of these coupling constants show a significant dependence on the choice of the Lorentz structure. Additionally, the decay widths of these mesons are calculated and discussed within the light of experimental data. A comparison of our results on these coupling constants with the predictions from the 3-point sum rules is performed.

  5. In-medium properties of light vector mesons

    SciTech Connect

    C. Djalali; R. Nasseripour; D. P. Weygand; M. H. Wood

    2007-08-01

    The photoproduction of vector mesons on various nuclei has been studied using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Laboratory. All three vector mesons ρ, ω and phi are observed via their decay to e+e-. The possible in-medium effects on the properties of the ρ meson are of particular interest. The ρ spectral function is extracted from the data on carbon, iron and titanium, and compared to the spectrum from liquid deuterium, which is relatively free of nuclear effects. We observe no effects on the mass of the ρ meson, some widening in titanium and iron is observed consistent with the collisional broadening.

  6. Search for gluonic excitations in light unconventional mesons

    SciTech Connect

    Paul Eugenio

    2007-07-01

    Studies of meson spectra via strong decays provide insight regarding QCD at the confinement scale. These studies have led to phenomenologicalmodels for QCD such as the constituent quark model. However, QCD allows for a much richer spectrum of meson states which include extra states such as exotics, hybrids, multi-quarks, and glueballs. First discussion of the status of exotic meson searches is given followed by a discussion of plans at Jefferson Lab to double the energy of the machine to 12 GeV, which will allow us to access photoproduction of mesons in search for gluonic excited states.

  7. Issues in light meson spectroscopy: The case for meson spectroscopy at CEBAF

    SciTech Connect

    Godfrey, S.

    1994-04-01

    The author reviews some outstanding issues in meson spectroscopy. The most important qualitative issue is whether hadrons with explicit gluonic degrees of freedom exist. To answer this question requires a much better understanding of conventional q{bar q} mesons. The author therefore begins by examining the status of conventional meson spectroscopy and how the situation can be improved. The expected properties of gluonic excitations are discussed with particular emphasis on hybrids to give guidance to experimental searches. Multiquark systems are commented upon as they are likely to be important in the mass region under study and will have to be understood better. In the final section the author discusses the opportunities that CEBAF can offer for the study of meson spectroscopy.

  8. 1{sup -+} exotic meson at light quark masses

    SciTech Connect

    Hedditch, J.N.; Kamleh, W.; Lasscock, B.G.; Leinweber, D.B.; Williams, A.G.; Zanotti, J.M.

    2005-12-01

    The mass of the 1{sup -+} exotic meson, created with hybrid interpolating fields, is explored in numerical simulations of quenched QCD on large (20{sup 3}x40) lattices to obtain good control of statistical and finite volume errors. Using the Fat-Link Irrelevant Clover (FLIC) fermion action, the properties of the 1{sup -+} are investigated at light quark masses approaching 25 MeV (m{sub {pi}}/m{sub {rho}}{approx_equal}1/3). Under the standard assumption that the coupling to the quenched a{sub 1}{eta}{sup '} channel comes with a negative metric, our results indicate that the 1{sup -+} exotic exhibits significant curvature close to the chiral limit, suggesting previous linear extrapolations have overestimated the mass of the 1{sup -+}. We find for the first time in lattice studies a 1{sup -+} mass consistent with the {pi}{sub 1}(1600) candidate. We also find a strangeness {+-}1 J{sup P}=1{sup -} state with a mass close to 2 GeV.

  9. Mass spectra of heavy-light mesons in heavy hadron chiral perturbation theory

    NASA Astrophysics Data System (ADS)

    Alhakami, Mohammad H.

    2016-05-01

    We study the masses of the low-lying charm and bottom mesons within the framework of heavy hadron chiral perturbation theory (HHChPT). We work to third order in the chiral expansion, where meson loops contribute. In contrast to previous approaches, we use physical meson masses in evaluating these loops. This ensures that their imaginary parts are consistent with the observed widths of the D mesons. The lowest odd- and even-parity, strange and nonstrange charm mesons provide enough constraints to determine only certain linear combinations of the low-energy constants in the effective Lagrangian. We comment on how lattice QCD could provide further information to disentangle these constants. Then, we use the results from the charm sector to predict the spectrum of odd and even parity of the bottom mesons. The predicted masses from our theory are in good agreement with experimentally measured masses for the case of the odd-parity sector. For the even-parity sector, the B -meson states have not yet been observed; thus, our results provide useful information for experimentalists investigating such states. The near degeneracy of nonstrange and strange scalar B mesons is confirmed in our predictions using HHChPT. We show why previous approaches of using HHChPT in studying the mass degeneracy in the scalar states of charm and bottom meson sectors gave unsatisfactory results.

  10. Medium Modification of the Light Vector Mesons in Nuclei

    SciTech Connect

    Nasseripour, R.; Djalali, C.; Wood, M.; Weygand, D.

    2008-10-13

    Theoretical calculations predict the modification of properties of vector mesons, such as a shift in their masses and/or broadening of their widths in dense nuclear matter. These effects can be related to partial restoration of chiral symmetry at high density or temperature. Photoproduction of vector mesons off nuclei were performed at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). The data were taken with a beam of tagged photons with energies up to 4 GeV on various nuclear targets. The properties of the {rho} vector mesons were investigated via their rare leptonic decay to e+e{sup -}. This decay channel is preferred over hadronic modes in order to eliminate final state interactions in the nuclear matter. The combinatorial background in the mass spectrum was removed by a self-normalizing mixed-event technique. The {rho} meson mass distributions were extracted for each of the targets. Statistically significant results regarding medium modification of the rho meson in the nuclear medium rule out large medium effects. Transparency studies of the {omega} and {phi} vector mesons allows a determination of their widths in the medium.

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  12. Medium Modification of the Light Vector Mesons in Nuclei

    SciTech Connect

    Nasseripour, Rakhsha; Djalali, Chaden; Wood, Michael; Weygand, Dennis

    2008-11-01

    Theoretical calculations predict the modification of properties of vector mesons, such as a shift in their masses and/or broadening of their widths in dense nuclear matter. These effects can be related to partial restoration of chiral symmetry at high density or temperature. Photoproduction of vector mesons off nuclei were performed at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). The data were taken with a beam of tagged photons with energies up to 4 GeV on various nuclear targets. The properties of the rho vector mesons were investigated via their rare leptonic decay to e+e?. This decay channel is preferred over hadronic modes in order to eliminate final state interactions in the nuclear matter. The combinatorial background in the mass spectrum was removed by a self-normalizing mixed-event technique. The rho meson mass distributions were extracted for each of the targets. Statistically significant results regarding medium modification of the rho meson in the nuc

  13. Seismic vulnerability study Los Alamos Meson Physics Facility (LAMPF)

    SciTech Connect

    Salmon, M.; Goen, L.K.

    1995-12-01

    The Los Alamos Meson Physics Facility (LAMPF), located at TA-53 of Los Alamos National Laboratory (LANL), features an 800 MeV proton accelerator used for nuclear physics and materials science research. As part of the implementation of DOE Order 5480.25 and in preparation for DOE Order 5480.28, a seismic vulnerability study of the structures, systems, and components (SSCs) supporting the beam line from the accelerator building through to the ends of die various beam stops at LAMPF has been performed. The study was accomplished using the SQUG GIP methodology to assess the capability of the various SSCs to resist an evaluation basis earthquake. The evaluation basis earthquake was selected from site specific seismic hazard studies. The goals for the study were as follows: (1) identify SSCs which are vulnerable to seismic loads; and (2) ensure that those SSCs screened during die evaluation met the performance goals required for DOE Order 5480.28. The first goal was obtained by applying the SQUG GIP methodology to those SSCS represented in the experience data base. For those SSCs not represented in the data base, information was gathered and a significant amount of engineering judgment applied to determine whether to screen the SSC or to classify it as an outlier. To assure the performance goals required by DOE Order 5480.28 are met, modifications to the SQUG GIP methodology proposed by Salmon and Kennedy were used. The results of this study ire presented in this paper.

  14. New Heavy-Light Mesons Q bar{q}

    NASA Astrophysics Data System (ADS)

    Matsuki, T.; Morii, T.; Sudoh, K.

    2007-06-01

    We succeed in reproducing the ℓ = 1 B mesons B1(5720), B2*(5745), and Bs2*(5839) that were recently reported by D0 and CDF, using our semi-relativistic quark potential model, which also succeeds in predicting the mass spectra of the narrow DsJ, as well as broad D0*(0+) and D1'(1+) particles observed a couple of years ago. par The mass of higher excited states (ell = 1, 2) of B and Bs mesons, which have not yet been observed, is also predicted to first order in p/mb with the internal quark momentum p and the b quark mass mb. We find that the corresponding BsJ are below the BK/B*K threshold and should have narrow decay widths, contrary to most other predictions. Also, already established states (ℓ = 0 and ell = 1) of D, Ds, B, and Bs heavy mesons are simultaneously reproduced in good agreement with experimental data, within one percent accuracy. To calculate these D/Ds and B/Bs heavy mesons, we use different values of the strong coupling, αsc and αsc, respectively.

  15. Approximate degeneracy of heavy-light mesons with the same L

    NASA Astrophysics Data System (ADS)

    Matsuki, Takayuki; Lü, Qi-Fang; Dong, Yubing; Morii, Toshiyuki

    2016-07-01

    Careful observation of the experimental spectra of heavy-light mesons tells us that heavy-light mesons with the same angular momentum L are almost degenerate. The estimate is given how much this degeneracy is broken in our relativistic potential model, and it is analytically shown that expectation values of a commutator between the lowest order Hamiltonian and L→2 are of the order of 1 /mQ with a heavy quark mass mQ. It turns out that nonrelativistic approximation of heavy quark system has a rotational symmetry and hence degeneracy among states with the same L. This feature can be tested by measuring higher orbitally and radially excited heavy-light meson spectra for D /Ds / B /Bs in LHCb and forthcoming BelleII.

  16. Superconformal Baryon-Meson Symmetry and Light-Front Holographic QCD

    SciTech Connect

    Dosch, Hans Guenter; de Teramond, Guy F.; Brodsky, Stanley J.

    2015-04-10

    We construct an effective QCD light-front Hamiltonian for both mesons and baryons in the chiral limit based on the generalized supercharges of a superconformal graded algebra. The superconformal construction is shown to be equivalent to a semi-classical approximation to light-front QCD and its embedding in AdS space. The specific breaking of conformal invariance inside the graded algebra uniquely determines the effective confinement potential. The generalized supercharges connect the baryon and meson spectra to each other in a remarkable manner. In particular, the π/b1 Regge trajectory is identified as the superpartner of the nucleon trajectory. However, the lowest-lying state on this trajectory, the π-meson is massless in the chiral limit and has no supersymmetric partner.

  17. Superconformal Baryon-Meson Symmetry and Light-Front Holographic QCD

    DOE PAGESBeta

    Dosch, Hans Guenter; de Teramond, Guy F.; Brodsky, Stanley J.

    2015-04-10

    We construct an effective QCD light-front Hamiltonian for both mesons and baryons in the chiral limit based on the generalized supercharges of a superconformal graded algebra. The superconformal construction is shown to be equivalent to a semi-classical approximation to light-front QCD and its embedding in AdS space. The specific breaking of conformal invariance inside the graded algebra uniquely determines the effective confinement potential. The generalized supercharges connect the baryon and meson spectra to each other in a remarkable manner. In particular, the π/b1 Regge trajectory is identified as the superpartner of the nucleon trajectory. However, the lowest-lying state on thismore » trajectory, the π-meson is massless in the chiral limit and has no supersymmetric partner.« less

  18. Physics of light

    SciTech Connect

    Doria, R.

    2012-09-24

    Physics of Light is derived. Based on such interpretation relating fields with same Lorentz nature, the electromagnetism is enlarged. The electromagnetic phenomena is not more restricted to Maxwell and electric charge. It englobes Maxwell and produces new types of electromagnetic fields and sectors. It centers the photon at its origin, new aspects as photonic charges and selfinteracting photons are obtained. As a case of this new electromagnetic spectrum one can take the set {l_brace}{gamma}Z{sup 0},W{sup {+-}}{r_brace}. It provides an electromagnetism involving photonic, massive, neutral, electric charged sectors which may antecede the electroweak unification.

  19. Light pseudoscalar mesons in a nonlocal three flavor chiral quark model

    SciTech Connect

    Gomez Dumm, D.; Scarpettini, A.; Scoccola, N.N.

    2004-12-02

    We study the properties of light pseudoscalar mesons in a three flavor chiral quark model with nonlocal separable interactions. We consider the case of a Gaussian regulator, evaluating meson masses and decay constants. Our results are found to be in good agreement with empirical values, in particular, in the case of the ratio f{kappa}/f{pi} and the decay {pi}0 {yields} {gamma}{gamma}. The model leads also to a reasonable description of the observed phenomenology in the {eta} - {eta}' sector, where two significantly different mixing angles are required. Detailed description of the work sketched here can be found elsewhere.

  20. Strong coupling constants of heavy baryons with light mesons in QCD

    SciTech Connect

    Aliev, T. M.; Azizi, K.; Savci, M.

    2012-10-23

    The strong coupling constants of the heavy spin-1/2 and spin-3/2 baryons with light pseudoscalar and vector mesons are calculated in the framework of the light cone QCD sum rules. Using the symmetry arguments, some structure independent relations among different correlation functions are obtained. It is shown that all possible transitions are described by only one invariant function, whose explicit expression is structure dependent.

  1. Neutral B-meson mixing from unquenched lattice QCD with domain-wall light quarks and static b quarks

    SciTech Connect

    Albertus, C.; Flynn, J. M.; Sachrajda, C. T.; Aoki, Y.; Ishikawa, T.; Boyle, P. A.; Wennekers, J.; Christ, N. H.; Dumitrescu, T. T.; Loktik, O.; Izubuchi, T.; Soni, A.; Van de Water, R. S.; Witzel, O.

    2010-07-01

    We demonstrate a method for calculating the neutral B-meson decay constants and mixing matrix elements in unquenched lattice QCD with domain-wall light quarks and static b-quarks. Our computation is performed on the '2+1' flavor gauge configurations generated by the RBC and UKQCD Collaborations with a lattice spacing of a{approx_equal}0.11 fm (a{sup -1}=1.729 GeV) and a lattice spatial volume of approximately (1.8 fm){sup 3}. We simulate at three different light sea quark masses with pion masses down to approximately 430 MeV, and extrapolate to the physical quark masses using a phenomenologically-motivated fit function based on next-to-leading order heavy-light meson SU(2) chiral perturbation theory. For the b-quarks, we use an improved formulation of the Eichten-Hill action with static link-smearing to increase the signal-to-noise ratio. We also improve the heavy-light axial current used to compute the B-meson decay constant to O({alpha}{sub s}pa) using one-loop lattice perturbation theory. We present initial results for the SU(3)-breaking ratios f{sub B{sub s}}/f{sub B{sub d}} and {xi}=f{sub B{sub s{radical}}}(B{sub B{sub s}})/f{sub B{sub d{radical}}}(B{sub B{sub d}}), thereby demonstrating the viability of the method. For the ratio of decay constants, we find f{sub B{sub s}}/f{sub B{sub d}}=1.15(12) and for the ratio of mixing matrix elements, we find {xi}=1.13(12), where in both cases the errors reflect the combined statistical and systematic uncertainties, including an estimate of the size of neglected O(1/m{sub b}) effects.

  2. Chiral symmetry of heavy-light scalar mesons with UA(1) symmetry breaking

    NASA Astrophysics Data System (ADS)

    Dmitrašinović, V.

    2012-07-01

    In a previous paper, based on a calculation in the nonrelativistic quark model, we advanced the hypothesis that the Ds(2317), D0(2308) mesons are predominantly four-quark states lowered in mass by the flavor-dependent Kobayashi-Kubo-Maskawa ’t Hooft UA(1) symmetry breaking effective interaction. Here we show similar results and conclusions in a relativistic effective chiral model calculation, based on three-light-quark (i.e., two q plus one q¯) local interpolators. To this end we classify the four-quark (three light plus one heavy quark) local interpolators according to their chiral transformation properties and then construct chiral invariant interactions. We evaluate the diagonal matrix elements of the Kobayashi-Kubo-Maskawa ’t Hooft interaction between different interpolating fields and show that the lowest-lying one is always the (antisymmetric) SU(3)F antitriplet belonging to the chiral (3, 3) multiplet. We predict bottom-strange Bs0 and the bottom-nonstrange B0 scalar mesons with equal masses at 5720 MeV, the strange meson being some 100 MeV lower than in most of the quark potential models. We also predict the JP=1+ bottom-nonstrange B1 and the bottom-strange Bs1 meson masses as 5732 MeV and 5765 MeV, respectively, using the Bardeen-Hill-Nowak-Rho-Zahed scalar-vector mass relation.

  3. Some heavy vector and tensor meson decay constants in light-front quark model

    NASA Astrophysics Data System (ADS)

    Geng, Chao-Qiang; Lih, Chong-Chung; Xia, Chuanhui

    2016-06-01

    We study the decay constants (f_M) of the heavy vector (D^{*}, D^{*}s, B^{*}, B^{*}s, B^{*}c) and tensor (D2^{*}, D_{s2}^{*}, B^{*}2, B^{*}_{s2}) mesons in the light-front quark model. With the known pseudoscalar meson decay constants of f_D, f_{D_s}, f_B, f_{B_s}, and f_{B_c} as the input parameters to determine the light-front meson wave functions, we obtain f_{D^{*}, D^{*}s, B^{*},B^{*}_s,B^{*}_c} = (252.0^{+13.8}_{-11.6}, 318.3^{+15.3}_{-12.6}, 201.9^{+43.2}_{-41.4}, 244.2± 7.0, 473.4± 18.2) and (264.9^{+10.2}_{-9.5}, 330.9^{+9.9}_{-9.0}, 220.2^{+49.1}_{-46.2}, 265.7± 8.0, 487.6± 19.2) MeV with Gaussian and power-law wave functions, respectively, while we have f_{D2^{*},D_{s2}^{*},B^{*}2,B^{*}_{s2}}= (143.6^{+24.9}_{-21.8}, 209.5^{+29.1}_{-24.2}, 80.9^{+33.8}_{-27.7}, 109.7^{+15.7}_{-15.0}) MeV with only Gaussian wave functions.

  4. Observation of chicJ radiative decays to light vector mesons.

    PubMed

    Bennett, J V; Mitchell, R E; Shepherd, M R; Besson, D; Pedlar, T K; Cronin-Hennessy, D; Gao, K Y; Hietala, J; Kubota, Y; Klein, T; Lang, B W; Poling, R; Scott, A W; Zweber, P; Dobbs, S; Metreveli, Z; Seth, K K; Tan, B J Y; Tomaradze, A; Libby, J; Martin, L; Powell, A; Wilkinson, G; Ecklund, K M; Love, W; Savinov, V; Mendez, H; Ge, J Y; Miller, D H; Shipsey, I P J; Xin, B; Adams, G S; Hu, D; Moziak, B; Napolitano, J; He, Q; Insler, J; Muramatsu, H; Park, C S; Thorndike, E H; Yang, F; Artuso, M; Blusk, S; Khalil, S; Li, J; Mountain, R; Nisar, S; Randrianarivony, K; Sultana, N; Skwarnicki, T; Stone, S; Wang, J C; Zhang, L M; Bonvicini, G; Cinabro, D; Dubrovin, M; Lincoln, A; Naik, P; Rademacker, J; Asner, D M; Edwards, K W; Reed, J; Briere, R A; Tatishvili, G; Vogel, H; Rosner, J L; Alexander, J P; Cassel, D G; Duboscq, J E; Ehrlich, R; Fields, L; Galik, R S; Gibbons, L; Gray, R; Gray, S W; Hartill, D L; Heltsley, B K; Hertz, D; Hunt, J M; Kandaswamy, J; Kreinick, D L; Kuznetsov, V E; Ledoux, J; Mahlke-Krüger, H; Mohapatra, D; Onyisi, P U E; Patterson, J R; Peterson, D; Riley, D; Ryd, A; Sadoff, A J; Shi, X; Stroiney, S; Sun, W M; Wilksen, T; Athar, S B; Patel, R; Yelton, J; Rubin, P; Eisenstein, B I; Karliner, I; Mehrabyan, S; Lowrey, N; Selen, M; White, E J; Wiss, J

    2008-10-10

    Using a total of 2.74 x 10(7) decays of the psi(2S) collected with the CLEO-c detector, we present a study of chi(cJ)-->gammaV, where V=rho(0), omega, phi. The transitions chi(c1)-->gammarho(0 and chi(c1)-->gammaomega are observed with B(chi(c1)-->gammarho(0))=(2.43+/-0.19+/-0.22) x 10(-4) and B(chi(c1)-->gammaomega)=(8.3+/-1.5+/-1.2) x 10(-5). In the chi(c1)-->gammarho(0) transition, the final state meson is dominantly longitudinally polarized. Upper limits on the branching fractions of other chi(cJ) states to light vector mesons are presented. PMID:18999588

  5. Hyperfine splitting and the Zeeman effect in holographic heavy-light mesons

    NASA Astrophysics Data System (ADS)

    Herzog, Christopher P.; Stricker, Stefan A.; Vuorinen, Aleksi

    2010-08-01

    We inspect the mass spectrum of heavy-light mesons in deformed N=2 super Yang-Mills theory using the AdS/CFT correspondence. We demonstrate how some of the degeneracies of the supersymmetric meson spectrum can be removed upon breaking the supersymmetry, thus leading to the emergence of a hyperfine structure. The explicit SUSY breaking scenarios we consider involve on the one hand, tilting one of the two fundamental D7-branes inside the internal R6 space, and on the other hand, applying an external magnetic field on the (untilted) branes. The latter scenario leads to the well-known Zeeman effect, which we inspect for both weak and strong magnetic fields.

  6. Hyperfine splitting and the Zeeman effect in holographic heavy-light mesons

    SciTech Connect

    Herzog, Christopher P.; Stricker, Stefan A.; Vuorinen, Aleksi

    2010-08-15

    We inspect the mass spectrum of heavy-light mesons in deformed N=2 super Yang-Mills theory using the AdS/CFT correspondence. We demonstrate how some of the degeneracies of the supersymmetric meson spectrum can be removed upon breaking the supersymmetry, thus leading to the emergence of a hyperfine structure. The explicit SUSY breaking scenarios we consider involve on the one hand, tilting one of the two fundamental D7-branes inside the internal R{sup 6} space, and on the other hand, applying an external magnetic field on the (untilted) branes. The latter scenario leads to the well-known Zeeman effect, which we inspect for both weak and strong magnetic fields.

  7. Symmetry-preserving contact interaction model for heavy-light mesons

    NASA Astrophysics Data System (ADS)

    Serna, F. E.; Brito, M. A.; Krein, G.

    2016-01-01

    We use a symmetry-preserving regularization method of ultraviolet divergences in a vector-vector contact interaction model for low-energy QCD. The contact interaction is a representation of nonperturbative kernels used Dyson-Schwinger and Bethe-Salpeter equations. The regularization method is based on a subtraction scheme that avoids standard steps in the evaluation of divergent integrals that invariably lead to symmetry violation. Aiming at the study of heavy-light mesons, we have implemented the method to the pseudoscalar π and K mesons. We have solved the Dyson-Schwinger equation for the u, d and s quark propagators, and obtained the bound-state Bethe-Salpeter amplitudes in a way that the Ward-Green-Takahashi identities reflecting global symmetries of the model are satisfied for arbitrary routing of the momenta running in loop integrals.

  8. Finite nuclei in relativistic models with a light chiral scalar meson

    SciTech Connect

    Furnstahl, R.J. ); Serot, B.D. )

    1993-05-01

    Relativistic chiral models with a light scalar meson appear to provide an economical marriage of successful relativistic mean-field theories and chiral symmetry. The scalar meson serves as both the chiral partner of the pion and the mediator of the intermediate-range nucleon-nucleon ([ital NN]) attraction. However, while some of these models can reproduce the empirical nuclear matter saturation point, they fail to reproduce observed properties of finite nuclei, such as spin-orbit splittings, shell structure, charge densities, and surface energetics. These deficiencies imply that this realization of chiral symmetry is incorrect. An alternative scenario, which features a heavy chiral scalar and dynamical generation of the [ital NN] attraction, is discussed.

  9. Finite nuclei in relativistic models with a light chiral scalar meson

    SciTech Connect

    Serot, B.D.; Furnstahl, R.J.

    1993-10-01

    Relativistic chiral models with a light scalar, meson appear to provide an economical marriage of successful relativistic mean-field theories and chiral symmetry. In these models, the scalar meson serves as both the chiral partner of the pion and the mediator of the intermediate-range nucleon-nucleon (NN) attraction. However, while some of these models can reproduce the empirical nuclear matter saturation point, they fail to reproduce observed properties of finite nuclei, such as spin-orbit splittings, shell structure, charge densities, and surface energetics. There deficiencies imply that this realization of chiral symmetry is incorrect. An alternative scenario for chiral hadronic models, which features a heavy chiral scalar and dynamical generation of the NN attraction, is discussed.

  10. Noninterceptive beam energy measurements in line D of the Los Alamos Meson Physics Facility

    SciTech Connect

    Gilpatrick, J.D.; Carter, H.; Plum, M.; Power, J.F.; Rose, C.R.; Shurter, R.B.

    1995-05-05

    Several members of the Accelerator and Operations Technology (AOT) division beam-diagnostics team performed time-of-flight (TOF) beam-energy measurements in line D of the Los Alamos Meson Physics Facility (LAMPF) using developmental beam time. These measurements provided information for a final design of an on-line beam energy measurement. The following paper discusses these measurements and how they apply to the final beam energy measurement design. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  11. Illuminating Physics with Light Bulbs.

    ERIC Educational Resources Information Center

    Leff, Harvey S.

    1990-01-01

    Presents ideas on how common household light bulbs can be used to develop interest in learning physics. Focuses on supermarket data taking and analyses, filament temperatures, detective work with three-way bulbs, and lifetime statistics. (YP)

  12. Meson/baryon/tetraquark supersymmetry from superconformal algebra and light-front holography

    NASA Astrophysics Data System (ADS)

    Brodsky, Stanley J.; de Téramond, Guy F.; Dosch, Hans Günter; Lorcé, Cédric

    2016-07-01

    Superconformal algebra leads to remarkable connections between the masses of mesons and baryons of the same parity — supersymmetric relations between the bosonic and fermionic bound states of QCD. Supercharges connect the mesonic eigenstates to their baryonic superpartners, where the mesons have internal angular momentum one unit higher than the baryons: LM = LB + 1. The dynamics of the superpartner hadrons also match; for example, the power-law fall-off of the form factors are the same for the mesonic and baryonic superpartners, in agreement with twist counting rules. An effective supersymmetric light-front Hamiltonian for hadrons composed of light quarks can be constructed by embedding superconformal quantum mechanics into AdS space. This procedure also generates a spin-spin interaction between the hadronic constituents. A specific breaking of conformal symmetry inside the graded algebra determines a unique quark-confining light-front potential for light hadrons in agreement with the soft-wall AdS/QCD approach and light-front holography. Only one mass parameter λ appears; it sets the confinement mass scale, a universal value for the slope of all Regge trajectories, the nonzero mass of the proton and other hadrons in the chiral limit, as well as the length scale which underlies their structure. The mass for the pion eigenstate vanishes in the chiral limit. When one includes the constituent quark masses using the Feynman-Hellman theorem, the predictions are consistent with the empirical features of the light-quark hadronic spectra. Our analysis can be consistently applied to the excitation spectra of the π, ρ, K, K∗ and ϕ meson families as well as to the N, Δ, Λ, Σ, Σ∗, Ξ and Ξ∗ baryons. We also predict the existence of tetraquarks which are degenerate in mass with baryons with the same angular momentum. The mass-squared of the light hadrons can be expressed in a universal and frame-independent decomposition of contributions from the constituent

  13. Medium modifications of light vector mesons in photoproduction reactions at Jlab

    SciTech Connect

    Djalali, Chaden; Wood, Michael; Nasseripour, Rakhsha; Weygand, Dennis

    2008-10-01

    DOI: http://dx.doi.org/10.1088/0954-3899/35/10/104035
    Theoretical calculations predict the modification of properties of vector mesons, such as a shift in their masses and/or broadening of their widths in dense nuclear matter. These effects can be related to partial restoration of chiral symmetry at high density or temperature. The light vector mesons (rho, omega, and phi) were photo-produced on H-2, C, Ti, Fe, and Pb targets at the Thomas Jefferson National Laboratory using the CEBAF Large Acceptance Spectrometer (CLAS). The data were taken with a beam of tagged photons with energies up to 4 GeV . The properties of the rho vector meson at normal nuclear densities and zero temperature,were investigated via their rare leptonic decay to e+e?. This decay channel is preferred over hadronic modes in order to eliminate final state interactions in the nuclear matter. A combinatorial background was subtracted from the invariant mass spectra using a well-established event-mixing techn

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

    SciTech Connect

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

    1994-09-01

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

  15. Noninterceptive beam energy measurements in line D of the Los Alamos Meson Physics Facility

    SciTech Connect

    Gilpatrick, J.D.; Carter, H.; Plum, M.; Power, J.F.; Rose, C.R.; Shurter, R.B.

    1995-12-31

    Several members of the Accelerator and Operations Technology (AOT) division beam-diagnostics team performed time-of-flight (TOF) beam-energy measurements in line D of the Los Alamos Meson Physics Facility (LAMPF) using developmental beam time. These measurements provided information for a final design of an on-line beam energy measurement. The following paper discusses these measurements and how they apply to the final beam energy measurement design.

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  17. Light water reactor health physics.

    PubMed

    Prince, Robert J; Bradley, Scott E

    2004-11-01

    In this article an overview of the historical development of light water reactor health physics programs is presented. Operational health physics programs have developed and matured as experience in operating and maintaining light water reactors has been gained. Initial programs grew quickly in both size and complexity with the number and size of nuclear units under construction and in operation. Operational health physics programs evolved to face various challenges confronted by the nuclear industry, increasing the effectiveness of radiological safety measures. Industry improvements in radiological safety performance have resulted in significant decreases in annual collective exposures from a high value of 790 person-rem in 1980 to 117 person-rem per reactor in 2002. Though significant gains have been made, the continued viability of the nuclear power industry is confronted with an aging workforce, as well as the challenges posed by deregulation and the need to maintain operational excellence. PMID:15551785

  18. Light water reactor health physics.

    PubMed

    Prince, Robert J; Bradley, Scott E

    2005-06-01

    In this article an overview of the historical development of light water reactor health physics programs is presented. Operational health physics programs have developed and matured as experience in operating and maintaining light water reactors has been gained. Initial programs grew quickly in both size and complexity with the number and size of nuclear units under construction and in operation. Operational health physics programs evolved to face various challenges confronted by the nuclear industry, increasing the effectiveness of radiological safety measures. Industry improvements in radiological safety performance have resulted in significant decreases in annual collective exposures from a high value of 790 person-rem in 1980 to 117 person-rem per reactor in 2002. Though significant gains have been made, the continued viability of the nuclear power industry is confronted with an aging workforce, as well as the challenges posed by deregulation and the need to maintain operational excellence. PMID:15891460

  19. Mesons in (2+1)-dimensional light front QCD: Investigation of a Bloch effective Hamiltonian

    NASA Astrophysics Data System (ADS)

    Chakrabarti, Dipankar; Harindranath, A.

    2001-11-01

    We study the meson sector of (2+1)-dimensional light front QCD using a Bloch effective Hamiltonian in the first nontrivial order. The resulting two-dimensional integral equation is converted into a matrix equation and solved numerically. We investigate the efficiency of Gaussian quadrature in achieving the cancellation of linear and logarithmic light front infrared divergences. The vanishing energy denominator problem, which leads to severe infrared divergences in 2+1 dimensions, is investigated in detail. Our study indicates that in the context of Fock space based effective Hamiltonian methods to tackle gauge theories in 2+1 dimensions, approaches such as the similarity renormalization method may be mandatory due to uncanceled infrared divergences caused by the vanishing energy denominator problem. We define and numerically study a reduced model which is relativistic, free from infrared divergences, and exhibits logarithmic confinement. The manifestation and violation of rotational symmetry as a function of the coupling are studied quantitatively.

  20. Applications of AdS/QCD and Light-Front Holography to Baryon Physics

    SciTech Connect

    Brodsky, Stanley J.; Teramond, Guy F. de

    2011-10-21

    The correspondence between theories in anti--de Sitter space and field theories in physical space-time leads to an analytic, semiclassical model for strongly-coupled QCD which has scale invariance at short distances and color confinement at large distances. These equations, for both mesons and baryons, give a very good representation of the observed hadronic spectrum, including a zero mass pion. Light-front holography allows hadronic amplitudes in the AdS fifth dimension to be mapped to frame-independent light-front wavefunctions of hadrons in physical space-time, thus providing a relativistic description of hadrons at the amplitude level. The meson and baryon wave-functions derived from light-front holography and AdS/QCD also have remarkable phenomenological features, including predictions for the electromagnetic form factors and decay constants. The approach can be systematically improved using light-front Hamiltonian methods. Some novel features of QCD for baryon physics are also discussed.

  1. Applications of AdS/QCD and Light-Front Holography to Baryon Physics

    SciTech Connect

    Brodsky, Stanley J.; de Teramond, Guy F.; /Costa Rica U.

    2011-08-22

    The correspondence between theories in anti-de Sitter space and field theories in physical space-time leads to an analytic, semiclassical model for strongly-coupled QCD which has scale invariance at short distances and color confinement at large distances. These equations, for both mesons and baryons, give a very good representation of the observed hadronic spectrum, including a zero mass pion. Light-front holography allows hadronic amplitudes in the AdS fifth dimension to be mapped to frame-independent light-front wavefunctions of hadrons in physical space-time, thus providing a relativistic description of hadrons at the amplitude level. The meson and baryon wavefunctions derived from light-front holography and AdS/QCD also have remarkable phenomenological features, including predictions for the electromagnetic form factors and decay constants. The approach can be systematically improved using light-front Hamiltonian methods. Some novel features of QCD for baryon physics are also discussed.

  2. Bc exclusive decays to charmonium and a light meson at next-to-leading order accuracy

    NASA Astrophysics Data System (ADS)

    Qiao, Cong-Feng; Sun, Peng; Yang, Deshan; Zhu, Rui-Lin

    2014-02-01

    In this paper, we study the Bc-meson exclusive decays to S-wave charmonia and light pseudoscalar or vector mesons, i.e., π, K, ρ, and K* at the next-to-leading order (NLO) in the QCD coupling. The nonfactorizable contribution is included, which is absent in traditional naive factorization. Numerical results show that NLO QCD corrections markedly enhance the branching ratio with a K factor of 1.75 for Bc±→ηcπ ± and 1.31 for Bc±→J/ψπ± using certain input parameters. And the theoretical uncertainties for their branching ratios are reduced compared with that of direct tree-level calculation. In order to investigate the asymptotic behavior, the analytic form is obtained in the heavy quark limit, i.e., mb→∞. We note that annihilation topologies contribute trivia in this limit, and the corrections at leading order in z=mc/mb expansion come from form factors and hard spectator interactions. At last, some related phenomenologies are also discussed.

  3. First Look at Heavy-Light Mesons with a Dressed Quark-Gluon Vertex

    NASA Astrophysics Data System (ADS)

    Gómez-Rocha, María; Hilger, Thomas; Krassnigg, Andreas

    2015-09-01

    Following up on earlier work, we investigate possible effects of a dressed quark-gluon vertex in heavy-light mesons. In particular, we study corrections to the popular rainbow-ladder truncation of the Dyson-Schwinger-Bethe-Salpeter equation system. We adopt a simple interaction kernel which reduces the resulting set of coupled integral equations to a set of coupled algebraic equations, which are solved numerically. In this way, we extend previous studies to quark-antiquark systems with unequal current-quark masses, at first for the pseudoscalar case, and investigate the resulting set of problems and solutions. We attempt to find patterns in—as well as to quantify corrections to—the rainbow-ladder truncation. In addition, we open this approach to phenomenological predictions of the heavy quark symmetry.

  4. Distributed data access in the LAMPF (Los Alamos Meson Physics Facility) control system

    SciTech Connect

    Schaller, S.C.; Bjorklund, E.A.

    1987-01-01

    We have extended the Los Alamos Meson Physics Facility (LAMPF) control system software to allow uniform access to data and controls throughout the control system network. Two aspects of this work are discussed here. Of primary interest is the use of standard interfaces and standard messages to allow uniform and easily expandable inter-node communication. A locally designed remote procedure call protocol will be described. Of further interest is the use of distributed databases to allow maximal hardware independence in the controls software. Application programs use local partial copies of the global device description database to resolve symbolic device names.

  5. Limited-scope probabilistic safety analysis for the Los Alamos Meson Physics Facility (LAMPF)

    SciTech Connect

    Sharirli, M.; Rand, J.L.; Sasser, M.K.; Gallegos, F.R.

    1992-01-01

    The reliability of instrumentation and safety systems is a major issue in the operation of accelerator facilities. A probabilistic safety analysis was performed or the key safety and instrumentation systems at the Los Alamos Meson Physics Facility (LAMPF). in Phase I of this unique study, the Personnel Safety System (PSS) and the Current Limiters (XLs) were analyzed through the use of the fault tree analyses, failure modes and effects analysis, and criticality analysis. Phase II of the program was done to update and reevaluate the safety systems after the Phase I recommendations were implemented. This paper provides a brief review of the studies involved in Phases I and II of the program.

  6. Ion-chamber-based loss monitor system for the Los Alamos Meson Physics Facility

    SciTech Connect

    Plum, M.A.; Brown, D.; Browman, A.; Macek, R.J.

    1995-05-01

    A new loss monitor system has been designed and installed at the Los Alamos Meson Physics Facility (LAMPF). The detectors are ion chambers filled with N{sub 2} gas. The electronics modules have a threshold range of 1:100, and they can resolve changes in beam loss of about 2% of the threshold settings. They can generate a trip signal in 2 {mu}s if the beam loss is large enough; if the response time of the Fast Protect System is included the beam will be shut off in about 37 {mu}s.

  7. Interactions of Charmed Mesons with Light Pseudoscalar Mesons from Lattice QCD and Implications on the Nature of the D*s0(2317)

    SciTech Connect

    Liuming, Liu; Orginos, Kostas; Guo, Feng-Kun; Hanhart, Christoph; Meissner, Ulf-G

    2014-11-01

    We study the scattering of light pseudoscalar mesons ( p , K ) off charmed mesons ( D , D s ) in full lattice QCD. The S -wave scattering lengths are calculated using Luscher’s finite volume technique. We use a relativistic formulation for the charm quark. For the light quark, we use domain- wall fermions in the valence sector and improved Kogut-Susskind sea quarks. We calculate the scattering lengths of isospin-3/2 Dπ , D sπ , D s K , isospin-0 DK and isospin-1 DK channels on the lattice. For the chiral extrapolation, we use a chiral unitary approach to next-to-leading order, which at the same time allows us to give predictions for other channels. It turns out that our results support the interpretation of the D*s0( 2317 ) as a DK molecule. At the same time, we also update a prediction for the isospin breaking hadronic decay width G ( D*s0( 2317 )→ D sπ ) to ( 133± 22 ) keV.

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

    SciTech Connect

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

    2015-03-10

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

  9. Investigating strangeness in the proton by studying the effects of Light Cone parton distributions in the Meson Cloud Model

    NASA Astrophysics Data System (ADS)

    Tuppan, Sam; Budnik, Garrett; Fox, Jordan

    2014-09-01

    The Meson Cloud Model (MCM) has proven to be a natural explanation for strangeness in the proton because of meson-baryon splitting into kaon-hyperon pairs. Total strangeness is predicted by integrated splitting functions, which represent the probability that the proton will fluctuate into a given meson-baryon pair. However, the momentum distributions s (x) and s (x) in the proton are determined from convolution integrals that depend on the parton distribution functions (PDFs) used for the mesons and baryons in the MCM. Theoretical calculations of these momentum distributions use many different forms for these PDFs. In our investigation, we calculate PDFs for K, K*, Λ, and Σ from two-body wave functions in a Light Cone Model (LCM) of the hadrons. We use these PDFs in conjunction with the MCM to create a hybrid model and compare our results to other theoretical calculations, experimental data from NuTeV, HERMES, ATLAS, and global parton distribution analyses. The Meson Cloud Model (MCM) has proven to be a natural explanation for strangeness in the proton because of meson-baryon splitting into kaon-hyperon pairs. Total strangeness is predicted by integrated splitting functions, which represent the probability that the proton will fluctuate into a given meson-baryon pair. However, the momentum distributions s (x) and s (x) in the proton are determined from convolution integrals that depend on the parton distribution functions (PDFs) used for the mesons and baryons in the MCM. Theoretical calculations of these momentum distributions use many different forms for these PDFs. In our investigation, we calculate PDFs for K, K*, Λ, and Σ from two-body wave functions in a Light Cone Model (LCM) of the hadrons. We use these PDFs in conjunction with the MCM to create a hybrid model and compare our results to other theoretical calculations, experimental data from NuTeV, HERMES, ATLAS, and global parton distribution analyses. This research has been supported in part by the

  10. Photoproduction opportunities at CEBAF: Meson spectroscopy and the physics of flying {phi}`s

    SciTech Connect

    Dzierba, A.R.

    1994-04-01

    The availability of high-intensity photon beams with an efficient duty-factor and with energies in the range 10 to 12 GeV makes possible studies in meson spectroscopy, rare decays and possibly symmetry tests such as CP and CPT. Indeed, with a 6 GeV tagged photon beam, realizable in the near future at CEBAF, measurements of rare radiative decays of the {phi}`s will be made. At higher energies, a photon beam could be used to answer a number of questions in meson spectroscopy. An even more exciting possibility is the use of photon beams to produce an intense source of {phi}`s. The physics contemplated at e{sup +}e{sup {minus}} {phi} factories, such as CP and CPT tests, might be also studied at CEBAF with completely different and complementary systematics; e.g. having the {phi}`s decay in flight may offer distinct advantages over {phi}`s produced at rest.

  11. The In-medium Mass and Widths of Light Vector Mesons

    SciTech Connect

    Djalali, C.; Paolone, M.; Weygand, D.; Wood, M. H.; Nasseripour, R.

    2011-05-23

    Partial restoration of chiral symmetry in ordinary nuclear matter suggests the modification of properties of vector mesons, such as a shift in mass and/or a change of width. Photoproduction of vector mesons off nuclei were performed at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). The properties of the {rho}, {omega} and {phi} mesons were investigated via their rare leptonic decay to e+e-. This decay channel has an advantage over hadronic modes as it eliminates final state interactions in the nuclear matter. After subtracting the combinatorial background, the meson mass distributions were extracted for each of the nuclear targets. No significant mass shift is observed, however substantial increase in the widths of the mesons is reported.

  12. The In-medium Mass and Widths of Light Vector Mesons

    SciTech Connect

    C. Djalali, M. Paolone, D. Weygand, M. H. Wood, R. Nasseripour

    2011-05-01

    Partial restoration of chiral symmetry in ordinary nuclear matter suggests the modification of properties of vector mesons, such as a shift in mass and/or a change of width. Photoproduction of vector mesons off nuclei were performed at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). The properties of the rho, omega and [cursive phi] mesons were investigated via their rare leptonic decay to e+e-. This decay channel has an advantage over hadronic modes as it eliminates final state interactions in the nuclear matter. After subtracting the combinatorial background, the meson mass distributions were extracted for each of the nuclear targets. No significant mass shift is observed, however substantial increase in the widths of the mesons is reported.

  13. High-energy neutron dosimetry at the Clinton P. Anderson Meson Physics Facility

    SciTech Connect

    Mallett, M.W.; Vasilik, D.G.; Littlejohn, G.J.; Cortez, J.R.

    1990-01-01

    Neutron energy spectrum measurements performed at the Clinton P. Anderson Meson Physics Facility indicated potential areas for high energy neutron exposure to personnel. The low sensitivity of the Los Alamos thermoluminescent dosimeter (TLD) to high energy neutrons warranted issuing a NTA dosimeter in addition to the TLD badge to employees entering these areas. The dosimeter consists of a plastic holder surrounding NTA film that has been desiccated and sealed in a dry nitrogen environment. A study of the fading of latent images in NTA film demonstrated the success of this packaging method to control the phenomenon. The Los Alamos NTA dosimeter is characterized and the fading study discussed. 10 refs., 4 figs., 2 tabs.

  14. Self-consistent covariant description of vector meson decay constants and chirality-even quark-antiquark distribution amplitudes up to twist 3 in the light-front quark model

    NASA Astrophysics Data System (ADS)

    Choi, Ho-Meoyng; Ji, Chueng-Ryong

    2014-02-01

    Although the meson decay amplitude described by a two-point function may be regarded as one of the simplest possible physical observables, it is interesting that this apparently simple amplitude bears abundant fundamental information on QCD vacuum dynamics and chiral symmetry. The light-front zero-mode issue of the vector meson decay constant fV is in this respect highly nontrivial and deserves careful analysis. We discuss the zero-mode issue in the light-front quark model (LFQM) prediction of fV from the perspective of the vacuum fluctuation consistent with the chiral symmetry of QCD. We extend the exactly solvable, manifestly covariant Bethe-Salpeter model calculation to the more phenomenologically accessible, realistic light-front quark model and present a self-consistent covariant description of fV, analyzing the twist-2 and twist-3 quark-antiquark distribution amplitudes with even chirality.

  15. Hadron Physics from Superconformal Quantum Mechanics and Its Light-Front Holographic Embedding

    NASA Astrophysics Data System (ADS)

    de Téramond, Guy F.

    2016-06-01

    The complex nonperturbative color-confining dynamics of QCD is well captured in a semiclassical effective theory based on superconformal quantum mechanics and its extension to the light-front. I describe here how this new approach to hadron physics incorporates confinement, the appearance of nearly massless pseudoscalar particles, and Regge spectroscopy consistent with experiment. It also gives remarkable connections between the meson and baryon spectrum across the light and heavy-light hadron spectrum. I also briefly discuss how higher spin states are consistently described in this framework by the holographic embedding of the superconformal theory in a higher dimensional semiclassical gravity theory.

  16. Project Physics Reader 4, Light and Electromagnetism.

    ERIC Educational Resources Information Center

    Harvard Univ., Cambridge, MA. Harvard Project Physics.

    As a supplement to Project Physics Unit 4, a collection of articles is presented in this reader for student browsing. The 21 articles are included under the following headings: Letter from Thomas Jefferson; On the Method of Theoretical Physics; Systems, Feedback, Cybernetics; Velocity of Light; Popular Applications of Polarized Light; Eye and…

  17. Thermal behaviors of light unflavored tensor mesons in the framework of QCD sum rule

    NASA Astrophysics Data System (ADS)

    Azizi, K.; Türkan, A.; Sundu, H.; Veli Veliev, E.; Yazıcı, E.

    2014-12-01

    In this paper, we investigated the sensitivity of the masses and decay constants of f2(1270) and a2(1320) tensor mesons to the temperature using OCD sum rule approach. In our calculations, we take into account new additional operators appearing in operator product expansion (OPE). At the end of numerical analyses we show that at deconfinement temperature the decay constants and masses decreased by 6% and 96% of their vacuum values, respectively. Our results on the masses and decay constants at zero temperature of the tensor mesons are consistent with the experimental data as well as the vacuum sum rules predictions.

  18. Light Vector Meson Photoproduction off of H at Jefferson Lab and rho-omega Interference in the Leptonic Decay Channel

    SciTech Connect

    Chaden Djalali

    2011-12-01

    Recent studies of light vector meson production in heavy nuclear targets has generated interest in {rho}-{omega} interference in the leptonic e{sup +}e{sup -} decay channel. An experimental study of the elementary process provides valuable input for theoretical models and calculations. In experiment E04-005 (g12), high statistics photoproduction data has been taken in Jefferson Lab's Hall B with the Cebaf Large Acceptance Spectrometer (CLAS). The invariant mass spectrum is fitted with two interfering relativistic Breit-Wigner functions to determine the interference phase. Preliminary analysis indicate a measurable {rho}-{omega} interference.

  19. Analysis of three-body B decays to heavy vector and light pseudoscalar mesons

    NASA Astrophysics Data System (ADS)

    Mohammadi, Behnam; Mehraban, Hossein

    2014-09-01

    In this research, we analysis the three-body decays of the B0 meson to J/\\psi {{K}^{+}}{{\\pi }^{-}} and \\psi (2S){{K}^{+}}{{\\pi }^{-}} final-state mesons. By taking the factorization approach, for these decay modes, color-suppressed internal W-emission and penguin Feynman diagrams can be plotted. The transition matrix elements of {{B}^{0}}\\to J/\\psi (\\psi (2S)){{K}^{+}}{{\\pi }^{-}} are factorized into a {{B}^{0}}\\to {{K}^{+}}{{\\pi }^{-}} form factor multiplied by the J/\\psi (\\psi (2S)) decay constant. We investigate these decays by using the Dalitz plot analysis with an important assumption. We assume that, in the {{B}^{0}}\\to J/\\psi (\\psi (2S)){{K}^{+}}{{\\pi }^{-}} decays, because the mass of the J/\\psi (\\psi (2S)) is too heavy against the K and π mesons, therefore it carries a small momentum. In particular, the backlash of the J/\\psi (\\psi (2S)) can be neglected. With this assumption we get that the J/\\psi (\\psi (2S)) meson remains stationary, and the K and π mesons move back to back. We calculate the nonresonant contribution of {{B}^{0}}\\to J/\\psi {{K}^{+}}{{\\pi }^{-}} and {{B}^{0}}\\to \\psi (2S){{K}^{+}}{{\\pi }^{-}} decays and the branching ratios become 1.15_{-0.64}^{+0.89}\\times {{10}^{-3}} and 0.69_{-0.04}^{+0.05}\\times {{10}^{-3}}, respectively, and the experimental results for them are (1.20+/- 0.60)\\times {{10}^{-3}} and (0.57+/- 0.04)\\times {{10}^{-3}}, respectively. Note that the resonant contributions are very small, so we ignore them in our calculations.

  20. Project Physics Tests 4, Light and Electromagnetism.

    ERIC Educational Resources Information Center

    Harvard Univ., Cambridge, MA. Harvard Project Physics.

    Test items relating to Project Physics Unit 4 are presented in this booklet. Included are 70 multiple-choice and 22 problem-and-essay questions. Concepts of light and electromagnetism are examined on charges, reflection, electrostatic forces, electric potential, speed of light, electromagnetic waves and radiations, Oersted's and Faraday's work,…

  1. Determination of light quark masses from the electromagnetic splitting of pseudoscalar meson masses computed with two flavors of domain wall fermions

    SciTech Connect

    Blum, Thomas; Doi, Takumi; Hayakawa, Masashi; Izubuchi, Taku; Yamada, Norikazu

    2007-12-01

    We determine the light quark masses from lattice QCD simulations incorporating the electromagnetic interaction of valence quarks, using the splittings of charged and neutral pseudoscalar meson masses as inputs. The meson masses are calculated on lattice QCD configurations generated by the RBC Collaboration for two flavors of dynamical domain-wall fermions, which are combined with QED configurations generated via quenched noncompact lattice QED. The electromagnetic part of the pion mass splitting is found to be m{sub {pi}{sup +}}-m{sub {pi}{sup 0}}=4.12(21) MeV, where only the statistical error is quoted, and similarly for the kaon, 1.443(55) MeV. Our results for the light quark masses are m{sub u}{sup MS}(2 GeV)=3.02(27)(19) MeV, m{sub d}{sup MS}(2 GeV)=5.49(20)(34) MeV, and m{sub s}{sup MS}(2 GeV)=119.5(56)(74) MeV, where the first error is statistical and the second reflects the uncertainty in our nonperturbative renormalization procedure. By averaging over {+-}e to cancel O(e) noise exactly on each combined gauge field configuration, we are able to work at physical {alpha}=1/137 and obtain very small statistical errors. In our calculation, several sources of systematic error remain, including finite volume, nonzero lattice spacing, chiral extrapolation, quenched QED, and quenched strange quark, which may be more significant than the errors quoted above. We discuss these systematic errors and how to reduce or eliminate them.

  2. Search for bound states of the eta-meson in light nuclei

    NASA Technical Reports Server (NTRS)

    Chrien, R. E.; Bart, S.; Pile, P.; Sutter, R.; Tsoupas, N.; Funsten, H. O.; Finn, J. M.; Lyndon, C.; Punjabi, V.; Perdrisat, C. F.

    1988-01-01

    A search for nuclear-bound states of the eta meson was carried out. Targets of lithium, carbon, oxygen, and aluminum were placed in a pion(+) beam at 800 MeV/c. A predicted eta bound state in O-15* (E sub x approx. = 540 MeV) with a width of approx. 9 MeV was not observed. A bound state of a size 1/3 of the predicted cross section would have been seen in this experiment at a confidence level of 3sigma (P is greater than 0.9987).

  3. Omega Meson Cloud and the Proton's Light Anti-Quark Distributions

    NASA Astrophysics Data System (ADS)

    Alberg, Mary; Henley, Ernest; Miller, Gerald

    2001-04-01

    Drell-Yan experiments(E866 Collaboration, E.A. Hawker et al., Phys. Rev. Lett. 80) (1998) 3715; J.C. Peng et al., Phys. Rev D58 (1999) 092004. have determined the momentum fraction (x) dependence of flavor asymmetry in the proton sea. The experimental cross sections are directly related to the ratio bard(x)/baru(x) , from which bar d(x) - baru(x) can be extracted using parton distribution functions determined from global analyses of high energy scattering data. Meson cloud models have provided a good description of the isovector asymmetry bard(x) - baru(x), but not for the ratio of bard(x)/baru(x), which also depends on the isoscalar components of the proton sea. We use the meson cloud model of the nucleon to calculate distribution functions for bard(x) and baru(x) in the proton. We find(M. Alberg, E. M. Henley and G.A. Miller, Phys.Lett. B471) (2000) 396. that the inclusion of the ω in the Fock state expansion of the cloud, with a coupling constant g_ω^2/4π≈ 8, allows a reasonably good description of the data for both bard(x) - baru(x) and bard(x)/baru(x) . We thank the USDOE and the USNSF for partial support of this work.

  4. Light mesons in QCD and unquenching effects from the 3PI effective action

    NASA Astrophysics Data System (ADS)

    Williams, Richard; Fischer, Christian S.; Heupel, Walter

    2016-02-01

    We investigate the impact of unquenching effects on QCD Green's functions, in the form of quark-loop contributions to both the gluon propagator and three-gluon vertex, in a three-loop inspired truncation of the three-particle irreducible (3PI) effective action. The fully coupled system of Dyson-Schwinger equations for the quark-gluon, ghost-gluon and three-gluon vertices, together with the quark propagator, are solved self-consistently; our only input are the ghost and gluon propagators themselves that are constrained by calculations within lattice QCD. We find that the two different unquenching effects have roughly equal, but opposite, impact on the quark-gluon vertex and quark propagator, with an overall negative impact on the latter. By taking further derivatives of the 3PI effective action, we construct the corresponding quark-antiquark kernel of the Bethe-Salpeter equation for mesons. The leading component is gluon exchange between two fully dressed quark-gluon vertices, thus introducing for the first time an obvious scalar-scalar component to the binding. We gain access to time-like properties of bound states by analytically continuing the coupled system of Dyson-Schwinger equations to the complex plane. We observe that the vector axial-vector splitting is in accord with experiment and that the lightest quark-antiquark scalar meson is above 1 GeV in mass.

  5. The leading twist light-cone distribution amplitudes for the S-wave and P-wave Bc mesons

    NASA Astrophysics Data System (ADS)

    Xu, Ji; Yang, Deshan

    2016-07-01

    The light-cone distribution amplitudes (LCDAs) serve as important nonperturbative inputs for the study of hard exclusive processes. In this paper, we calculate ten LCDAs at twist-2 for the S-wave and P-wave B c mesons up to the next-to-leading order (NLO) of the strong coupling α s and leading order of the velocity expansion. Each one of these ten LCDAs is expressed as a product of a perturbatively calculable distribution and a universal NRQCD matrix-element. By use of the spin symmetry, only two NRQCD matrix-elements will be involved. The reduction of the number of non-perturbative inputs will improve the predictive power of collinear factorization.

  6. Shape of mesons in holographic QCD

    SciTech Connect

    Torabian, Mahdi; Yee, Ho-Ung

    2009-10-15

    Based on the expectation that the constituent quark model may capture the right physics in the large N limit, we point out that the orbital angular momentum of the quark-antiquark pair inside light mesons of low spins in the constituent quark model may provide a clue for the holographic dual string model of large N QCD. Our discussion, relying on a few suggestive assumptions, leads to a necessity of world-sheet fermions in the bulk of dual strings that can incorporate intrinsic spins of fundamental QCD degrees of freedom. We also comment on the interesting issue of the size of mesons in holographic QCD.

  7. Light-Emitting Diodes: Learning New Physics

    ERIC Educational Resources Information Center

    Planinšic, Gorazd; Etkina, Eugenia

    2015-01-01

    This is the third paper in our Light-Emitting Diodes series. The series aims to create a systematic library of LED-based materials and to provide the readers with the description of experiments and pedagogical treatment that would help their students construct, test, and apply physics concepts and mathematical relations. The first paper, published…

  8. Physics of {pi}-meson condensation and high temperature cuprate superconductors

    SciTech Connect

    Sushkov, O. P.

    2009-08-15

    The idea of condensation of the Goldstone {pi}-meson field in nuclear matter had been put forward a long time ago. However, it was established that the normal nuclear density is too low, it is not sufficient to condensate {pi} mesons. This is why the {pi} condensation has never been observed. Recent experimental and theoretical studies of high-temperature cuprate superconductors have revealed condensation of Goldstone magnons, the effect fully analogous to the {pi} condensation. The magnon condensation has been observed. It is clear now that quantum fluctuations play a crucial role in the condensation, in particular they drive a quantum phase transition that destroys the condensate at some density of fermions.

  9. Unitary coupled-channels model for three-mesons decays of heavy mesons

    SciTech Connect

    Hiroyuki Kamano; Nakamura, Satoshi X.; Lee, Tsung-Shung H.; Sato, Toru

    2011-12-16

    In this study, a unitary coupled-channels model is presented for investigating the decays of heavy mesons and excited meson states into three light pseudoscalar mesons. The model accounts for the three-mesons final state interactions in the decay processes, as required by both the three-body and two-body unitarity conditions. In the absence of the Z-diagram mechanisms that are necessary consequences of the three-body unitarity, our decay amplitudes are reduced to a form similar to those used in the so-called isobar-model analysis. We apply our coupled-channels model to the three-pions decays of α1(1260), π2(1670), π2(2100), and D0 mesons, and show that the Z-diagram mechanisms can contribute to the calculated Dalitz plot distributions by as much as 30% in magnitudes in the regions where f0(600), ρ(770), and f2(1270) dominate the distributions. Also, by fitting to the same Dalitz plot distributions, we demonstrate that the decay amplitudes obtained with the unitary model and the isobar model can be rather different, particularly in the phase that plays a crucial role in extracting the CKM CP-violating phase from the data of B meson decays. Our results indicate that the commonly used isobar model analysis must be extended to account for the final state interactions required by the three-body unitarity to reanalyze the three-mesons decays of heavy mesons, thereby exploring hybrid or exotic mesons, and signatures of physics beyond the standard model.

  10. Unitary coupled-channels model for three-mesons decays of heavy mesons

    DOE PAGESBeta

    Hiroyuki Kamano; Nakamura, Satoshi X.; Lee, Tsung-Shung H.; Sato, Toru

    2011-12-16

    In this study, a unitary coupled-channels model is presented for investigating the decays of heavy mesons and excited meson states into three light pseudoscalar mesons. The model accounts for the three-mesons final state interactions in the decay processes, as required by both the three-body and two-body unitarity conditions. In the absence of the Z-diagram mechanisms that are necessary consequences of the three-body unitarity, our decay amplitudes are reduced to a form similar to those used in the so-called isobar-model analysis. We apply our coupled-channels model to the three-pions decays of α1(1260), π2(1670), π2(2100), and D0 mesons, and show that themore » Z-diagram mechanisms can contribute to the calculated Dalitz plot distributions by as much as 30% in magnitudes in the regions where f0(600), ρ(770), and f2(1270) dominate the distributions. Also, by fitting to the same Dalitz plot distributions, we demonstrate that the decay amplitudes obtained with the unitary model and the isobar model can be rather different, particularly in the phase that plays a crucial role in extracting the CKM CP-violating phase from the data of B meson decays. Our results indicate that the commonly used isobar model analysis must be extended to account for the final state interactions required by the three-body unitarity to reanalyze the three-mesons decays of heavy mesons, thereby exploring hybrid or exotic mesons, and signatures of physics beyond the standard model.« less

  11. MESON2000 Conference Summary

    SciTech Connect

    Barnes, T.

    2001-04-26

    This short contribution is a lite MESON2000 conference summary. As appropriate for the 600th anniversary of the Jagellonian University, it begins with a brief summary of the last 600 years of European history and its place in hadron physics. Next a ''physicist chirality'' order parameter PC is introduced. When applied to MESON2000 plenary speakers this order parameter illustrates the separation of hadron physicists into disjoint communities. The individual plenary talks in MESON2000 are next sorted according to the subconference associated with each of the 36 plenary speakers. Finally, I conclude with a previously unreported Feynman story regarding the use of models in hadron physics.

  12. CP violation in D meson decays: Would it be a sign of new physics?

    NASA Astrophysics Data System (ADS)

    Buccella, Franco; Lusignoli, Maurizio; Pugliese, Alessandra; Santorelli, Pietro

    2013-10-01

    Ascribing the large SU(3) violations in the singly Cabibbo suppressed decays of neutral D mesons to the final state interactions, one gets large strong phase differences, necessary for substantial direct CP violation. While the absolute value of the CP violating asymmetries depend on the uncertain strength of the penguin contribution, we predict an asymmetry for the decays into charged pions more than twice as large and having opposite sign with respect to that for charged kaons.

  13. Nonleptonic two-body decays of the B{sub c} meson in the light-front quark model and the QCD factorization approach

    SciTech Connect

    Choi, Ho-Meoyng; Ji, Chueng-Ryong

    2009-12-01

    We study exclusive nonleptonic two-body B{sub c}{yields}(D{sub (s)},{eta}{sub c},B{sub (s)})+F decays with F (pseudoscalar or vector mesons) factored out in the QCD factorization approach. The nonleptonic decay amplitudes are related to the product of meson decay constants and the form factors for semileptonic B{sub c} decays. As inputs in obtaining the branching ratios for a large set of nonleptonic B{sub c} decays, we use the weak form factors for the semileptonic B{sub c}{yields}(D{sub (s)},{eta}{sub c},B{sub (s)}) decays in the whole kinematical region and the unmeasured meson decay constants obtained from our previous light-front quark model. We compare our results for the branching ratios with those of other theoretical studies.

  14. Physics Challenges for ERL Light Sources

    SciTech Connect

    Lia Merminga

    2004-07-01

    We present an overview of the physics challenges encountered in the design and operation of Energy Recovering Linac (ERL) based light sources. These challenges include the generation and preservation of low emittance, high-average current beams, manipulating and preserving the transverse and longitudinal phase space, control of the multipass beam breakup instability, efficient extraction of higher order mode power and RF control and stability of the superconducting cavities. These key R&D issues drive the design and technology choices for proposed ERL light sources. Simulations and calculations of these processes will be presented and compared with experimental data obtained at the Jefferson Lab FEL Upgrade, a 10 mA ERL light source presently in commissioning, and during a 1 GeV demonstration of energy recovery at CEBAF.

  15. Light-Emitting Diodes: Learning New Physics

    NASA Astrophysics Data System (ADS)

    Planinšič, Gorazd; Etkina, Eugenia

    2015-04-01

    This is the third paper in our Light-Emitting Diodes series. The series aims to create a systematic library of LED-based materials and to provide the readers with the description of experiments and pedagogical treatment that would help their students construct, test, and apply physics concepts and mathematical relations. The first paper, published in the February 2014 issue of TPT,1 provided an overview of possible uses of LEDs in a physics course. The second paper2 discussed how one could help students learn the foundational aspects of LED physics through a scaffolded inquiry approach, specifically the ISLE cycle. The goals of this paper are to show how the activities described in our second paper help to deepen student understanding of physics and to broaden student knowledge by exploring new phenomena such as fluorescence. Activities described in this paper are suitable for advanced high school courses, introductory courses for physics and engineering majors, courses for prospective physics teachers, and professional development programs.

  16. Probabilistic risk assessment for the Los Alamos Meson Physics Facility worst-case design-basis accident

    SciTech Connect

    Sharirli, M.; Butner, J.M.; Rand, J.L.; Macek, R.J.; McKinney, S.J.; Roush, M.L.

    1992-12-01

    This paper presents results from a Los Alamos National Laboratory Engineering and Safety Analysis Group assessment of the worse-case design-basis accident associated with the Clinton P. Anderson Meson Physics Facility (LAMPF)/Weapons Neutron Research (WNR) Facility. The primary goal of the analysis was to quantify the accident sequences that result in personnel radiation exposure in the WNR Experimental Hall following the worst-case design-basis accident, a complete spill of the LAMPF accelerator 1L beam. This study also provides information regarding the roles of hardware systems and operators in these sequences, and insights regarding the areas where improvements can increase facility-operation safety. Results also include confidence ranges to incorporate combined effects of uncertainties in probability estimates and importance measures to determine how variations in individual events affect the frequencies in accident sequences.

  17. Probabilistic risk assessment for the Los Alamos Meson Physics Facility worst-case design-basis accident

    SciTech Connect

    Sharirli, M.; Butner, J.M.; Rand, J.L.; Macek, R.J. ); McKinney, S.J. ); Roush, M.L. . Center for Reliability Engineering)

    1992-01-01

    This paper presents results from a Los Alamos National Laboratory Engineering and Safety Analysis Group assessment of the worse-case design-basis accident associated with the Clinton P. Anderson Meson Physics Facility (LAMPF)/Weapons Neutron Research (WNR) Facility. The primary goal of the analysis was to quantify the accident sequences that result in personnel radiation exposure in the WNR Experimental Hall following the worst-case design-basis accident, a complete spill of the LAMPF accelerator 1L beam. This study also provides information regarding the roles of hardware systems and operators in these sequences, and insights regarding the areas where improvements can increase facility-operation safety. Results also include confidence ranges to incorporate combined effects of uncertainties in probability estimates and importance measures to determine how variations in individual events affect the frequencies in accident sequences.

  18. Physical Origin of Density Dependent Force of the Skyrme Type within the Quark Meson Coupling Model

    SciTech Connect

    Pierre Guichon; Hrayr Matevosyan; N. Sandulescu; Anthony Thomas

    2006-03-17

    A density dependent, effective nucleon-nucleon force of the Skyrme type is derived from the quark-meson coupling model--a self-consistent, relativistic quark level description of nuclear matter. This new formulation requires no assumption that the mean scalar field is small and hence constitutes a significant advance over earlier work. The similarity of the effective interaction to the widely used SkM* force encourages us to apply it to a wide range of nuclear problems, beginning with the binding energies and charge distributions of doubly magic nuclei. Finding impressive results in this conventional arena, we apply the same effective interaction, within the Hartree-Fock-Bogoliubov approach, to the properties of nuclei far from stability. The resulting two neutron drip lines and shell quenching are quite satisfactory. Finally, we apply the relativistic formulation to the properties of dense nuclear matter in anticipation of future application to the properties of neutron stars.

  19. Light-Front Quark Model Analysis of Meson-Photon Transition Form Factor

    NASA Astrophysics Data System (ADS)

    Choi, Ho-Meoyng; Ji, Chueng-Ryong

    2016-07-01

    We discuss {(π0, η, η') to γ^{*}γ} transition form factors using the light-front quark model. Our discussion includes the analysis of the mixing angles for {η-η'}. Our results for {Q2 F_{(π^0,η,η')toγ^*γ}(Q^2)} show scaling behavior for high Q 2 consistent with pQCD predictions.

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  1. The physics of attosecond light pulses

    NASA Astrophysics Data System (ADS)

    Agostini, Pierre; Di Mauro, Louis F.

    2004-06-01

    The word 'attosecond' (1 as = 10-18 s) officially entered the vocabulary of physics when sub-femtosecond pulses of UV/XUV light produced either by nonlinear frequency conversion of a ultra-short infrared pump pulse or Fourier synthesis of broad bandwidth radiation were established. The physics of these pulses is based on nonlinear, nonperturbative laser-atom interaction: stimulated Raman scattering or high harmonic generation (HHG) is used to generate the necessary bandwidth, which naturally encompasses the visible and UV/XUV spectral range. However, the crucial element for attosecond pulse generation is the control of the spectral phase. New methods of temporal characterization at frequencies lying in the UV/XUV had to be elaborated. These methods rely on the energy/momentum analysis of photoelectrons produced by XUV attosecond flashes in the presence of an intense infrared field whose optical cycle itself becomes the basic clock. Single 650 as pulses have been produced and applied to trace the dynamics of electrons inside atoms following the creation of an inner-shell hole. Periodic combs of 250 as pulses have been synthesized by superposing just four harmonics and applying to the attosecond timing of the electron motion in HHG. Although it is easy to increase the bandwidth by coupling more harmonics, a fundamental limit to the duration of the light bursts produced has been discovered. It is imposed by the lack of synchronization of the different harmonic orders. The current limit is estimated to be 130 as. The latest advances include a direct autocorrelation of an attosecond pulse train and the production of a single 250 as soft x-ray pulse. This paper offers a snapshot of the state-of-the-art in the production and characterization of attosecond light pulses, with a glimpse at the first steps in attophysics.

  2. Evidence for light scalar resonances in charm meson decays from Fermilab E791

    SciTech Connect

    Alan J. Schwartz

    2003-01-24

    From Dalitz-plot analyses of D{sup +} {yields} {pi}{sup -}{pi}{sup +}{pi}{sup +} and D{sup +} {yields} K{sup -}{pi}{sup +}{pi}{sup +} decays, we find evidence for light and broad scalar resonances {sigma}(500) and {kappa}(800). From a Dalitz-plot analysis of D{sub s}{sup +} {yields} {pi}{sup -}{pi}{sup +}{pi}{sup +} decays, they measure the masses and decay widths of the scalar resonances f{sub 0}(980) and f{sub 0}(1370).

  3. Analysis of heavy spin-3/2 baryon-heavy spin-1/2 baryon-light vector meson vertices in QCD

    SciTech Connect

    Aliev, T. M.; Savci, M.; Azizi, K; Zamiralov, V. S.

    2011-05-01

    The heavy spin-3/2 baryon-heavy spin-1/2 baryon vertices with light vector mesons are studied within the light cone QCD sum rules method. These vertices are parametrized in terms of three coupling constants. These couplings are calculated for all possible transitions. It is shown that correlation functions for these transitions are described by only one invariant function for every Lorenz structure. The obtained relations between the correlation functions of the different transitions are structure independent while explicit expressions of invariant functions depend on the Lorenz structure.

  4. Progress at LAMPF (Los Alamos Meson Physics Facility), January--December 1989

    SciTech Connect

    Poelakker, K.

    1990-12-01

    This report contains brief papers on research conducted at the lampf facility in the following areas: nuclear and particle physics; astrophysics; atomic and molecular physics; materials science; nuclear chemistry; radiation effects and radioisotope production.

  5. Light-Front Dynamics in Hadron Physics

    NASA Astrophysics Data System (ADS)

    Ji, Chueng-Ryong; Bakker, Bernard L. G.; Choi, Ho-Meoyng

    2013-03-01

    Light-front dynamics(LFD) plays an important role in the analyses of relativistic few-body systems. As evidenced from the recent studies of generalized parton distributions (GPDs) in hadron physics, a natural framework for a detailed study of hadron structures is LFD due to its direct application in Minkowski space as well as its distinct feature of accounting for the vacuum fluctuations in quantum field theories. In the last few years, however, it has been emphasized that treacherous points such as LF singularities and zero-modes should be taken into account for successful LFD applications to hadron phenomenology. In this paper, we discuss a typical example of the contemporary relativistic hadron physics in which the fundamental issues should be taken into account for the successful application of LFD. In particular, we focus on the kinematic issue of GPDs in deeply virtual Compton scattering (DVCS). Although this fundamental issue has been glossed over in the literature, it must be taken care of for the correct analysis of DVCS data.

  6. Review of meson spectroscopy: quark states and glueballs

    SciTech Connect

    Chanowitz, M.S.

    1981-11-01

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

  7. Light meson electromagnetic form factors from three-flavor lattice QCD with exact chiral symmetry

    NASA Astrophysics Data System (ADS)

    Aoki, S.; Cossu, G.; Feng, X.; Hashimoto, S.; Kaneko, T.; Noaki, J.; Onogi, T.

    2016-02-01

    We study the chiral behavior of the electromagnetic (EM) form factors of pions and kaons in three-flavor lattice QCD. In order to make a direct comparison of the lattice data with chiral perturbation theory (ChPT), we employ the overlap quark action that has exact chiral symmetry. Gauge ensembles are generated at a lattice spacing of 0.11 fm with four pion masses ranging between Mπ≃290 MeV and 540 MeV and with a strange quark mass ms close to its physical value. We utilize the all-to-all quark propagator technique to calculate the EM form factors with high precision. Their dependence on ms and on the momentum transfer is studied by using the reweighting technique and the twisted boundary conditions for the quark fields, respectively. A detailed comparison with SU(2) and SU(3) ChPT reveals that the next-to-next-to-leading order terms in the chiral expansion are important to describe the chiral behavior of the form factors in the pion mass range studied in this work. We estimate the relevant low-energy constants and the charge radii, and find reasonable agreement with phenomenological and experimental results.

  8. Progress at LAMPF (Los Alamos Meson Physics Facility): Progress report, January-December 1986

    SciTech Connect

    Allred, J.C.; Talley, B.

    1987-05-01

    Activities at LAMPF during the year of 1986 are summarized, including brief summaries of experiments in nuclear and particle physics, atomic and molecular physics, materials science, radiation-effects studies, biomedical research and instrumentation, nuclear chemistry, radioisotope production, and theory. The status of an advanced hadron facility currently under study is reported, as well as facility development and accelerator operations. (LEW)

  9. ρ meson decays of heavy hybrid mesons

    NASA Astrophysics Data System (ADS)

    Zhang, Liang; Huang, Peng-Zhi

    2016-07-01

    We calculate the ρ meson couplings between the heavy hybrid doublets Hh/Sh/Mh/Th and the ordinary qQ̅ doublets in the framework of the light-cone QCD sum rule. The sum rules obtained rely mildly on the Borel parameters in their working regions. The resulting coupling constants are rather small in most cases. Supported by National Natural Science Foundation of China (11105007)

  10. Formation of Slow Heavy Mesons in Nuclei

    NASA Astrophysics Data System (ADS)

    Hirenzaki, Satoru

    2009-10-01

    Meson - nucleus systems such as mesic atoms and mesic nuclei have been studied systematically for a long time. The binding energies and widths of these bound states provide us unique and valuable information on the meson-nucleus interactions. In addition, the measurements of light vector meson spectra in nucleus as the invariant mass of lepton pairs have also provided interesting information. So far, the properties of relatively light mesons have been studied well both theoretically and experimentally. In this contribution, to extend our studies to a domain of heavier mesons, we would like to report recent research activities on the formation of heavy mesons in nuclei with small momenta. We think it is very interesting to consider the in-medium properties of heavier mesons including heavy quark contents. As a first step to heavier mesons, we will report our studies on formation of slow phi meson in nuclei. In-medium properties of phi meson have been studied theoretically, which have close relation to K and K-bar meson properties in medium because of the strong coupling of phi to K and K-bar. The study of QCD sum rule and the data taken at KEK suggested 3 percent mass reduction of phi at the normal nuclear density, while the phi meson selfenergy calculated in some effective models indicated a significantly smaller attractive potential for phi. We will show the calculated spectra for some reactions.

  11. Introduction to light: the physics of light, vision and color

    SciTech Connect

    Waldman, G.

    1983-01-01

    This book designed as a text for a one-semester undergraduate course presents a nonmathematical treatment of optics. The material is divided into 11 chapters entitled: Early Ideas of Light, the Classical Theories, Modern Theories, Geometrical Optics, Polarization, Lasers, Holography, the Eye, Seeing, Light and Color in Nature, and Color Science. Additional mathematical details are included in the three appendixes. (BLM)

  12. Holographic Mesons:

    NASA Astrophysics Data System (ADS)

    Hovdebo, Jordan L.; Kruczenski, Martín; Mateos, David; Myers, Robert C.; Winters, David J.

    We study mesons in an {N} = 2 super Yang-Mills theory with fundamental matter from its dual string theory on AdS5 × S5 with a D7-brane probe. For quarks with a finite mass mq, the meson spectrum is discrete and exhibits a mass gap of order mq/√ {g2YM N}. The spectrum of mesons with large spin J is obtained from semiclassical rotating open strings attached to the D7-brane. It displays Regge behaviour for J << √ {g2YM N} whereas for J >> √ {g2YM N} it corresponds to that of two non-relativistic quarks bound by a Coulomb potential. We calculate around an isolated quark, to gain insight into the Regge behaviour of the spinning mesons.

  13. Meson Structure in a Relativistic Many-Body Approach

    SciTech Connect

    Llanes-Estrada, Felipe J.; Cotanch, Stephen R.

    2000-02-07

    Results from an extensive relativistic many-body analysis utilizing a realistic effective QCD Hamiltonian are presented for the meson spectrum. A comparative numerical study of the BCS, Tamm-Dancoff (TDA), and RPA treatments provides new, significant insight into the condensate structure of the vacuum, the chiral symmetry governance of the pion, and the meson spin, orbital, and flavor mass splitting contributions. In contrast to a previous glueball application, substantial quantitative differences are computed between TDA and RPA for the light quark sector with the pion emerging as a Goldstone boson only in the RPA. (c) 2000 The American Physical Society.

  14. Search for Light New Physics at B Factories

    DOE PAGESBeta

    Echenard, Bertrand

    2012-01-01

    Many extensions of the Standard Model include the possibility of light new particles, such as light Higgs bosons or dark matter candidates. These scenarios can be probed using the large datasets collected by B factories, complementing measurements performed at the LHC. This paper summarizes recent searches for light new physics conducted by the BABAR and Belle experiments.

  15. QCD on the Light-Front. A Systematic Approach to Hadron Physics

    NASA Astrophysics Data System (ADS)

    Brodsky, Stanley J.; de Téramond, Guy F.; Dosch, Hans Günter

    2014-06-01

    Light-front Hamiltonian theory, derived from the quantization of the QCD Lagrangian at fixed light-front time x + = x 0 + x 3, provides a rigorous frame-independent framework for solving nonperturbative QCD. The eigenvalues of the light-front QCD Hamiltonian H LF predict the hadronic mass spectrum, and the corresponding eigensolutions provide the light-front wavefunctions which describe hadron structure, providing a direct connection to the QCD Lagrangian. In the semiclassical approximation the valence Fock-state wavefunctions of the light-front QCD Hamiltonian satisfy a single-variable relativistic equation of motion, analogous to the nonrelativistic radial Schrödinger equation, with an effective confining potential U which systematically incorporates the effects of higher quark and gluon Fock states. Remarkably, the potential U has a unique form of a harmonic oscillator potential if one requires that the chiral QCD action remains conformally invariant. A mass gap and the color confinement scale also arises when one extends the formalism of de Alfaro, Fubini and Furlan to light-front Hamiltonian theory. In the case of mesons, the valence Fock-state wavefunctions of H LF for zero quark mass satisfy a single-variable relativistic equation of motion in the invariant variable , which is conjugate to the invariant mass squared . The result is a nonperturbative relativistic light-front quantum mechanical wave equation which incorporates color confinement and other essential spectroscopic and dynamical features of hadron physics, including a massless pion for zero quark mass and linear Regge trajectories with the same slope in the radial quantum number n and orbital angular momentum L. Only one mass parameter appears. The corresponding light-front Dirac equation provides a dynamical and spectroscopic model of nucleons. The same light-front equations arise from the holographic mapping of the soft-wall model modification of AdS5 space with a unique dilaton profile to QCD

  16. The global structure of the visual light field and its relation to the physical light field.

    PubMed

    Kartashova, Tatiana; Sekulovski, Dragan; de Ridder, Huib; Pas, Susan F Te; Pont, Sylvia C

    2016-08-01

    Human observers have been demonstrated to be sensitive to the local (physical) light field, or more precisely, to the primary direction, intensity, and diffuseness of the light at a point in a space. In the present study we focused on the question of whether it is possible to reconstruct the global visual light field, based on observers' inferences of the local light properties. Observers adjusted the illumination on a probe in order to visually fit it in three diversely lit scenes. For each scene they made 36 settings on a regular grid. The global structure of the first order properties of the light field could then indeed be reconstructed by interpolation of light vectors coefficients representing the local settings. We demonstrate that the resulting visual light fields (individual and averaged) can be visualized and we show how they can be compared to physical measurements in the same scenes. Our findings suggest that human observers have a robust impression of the light field that is simplified with respect to the physical light field. In particular, the subtle spatial variations of the physical light fields are largely neglected and the visual light fields were more similar to simple diverging fields than to the actual physical light fields. PMID:27548087

  17. The yields of light meson resonances in neutrino-nucleus interactions at Left-Pointing-Angle-Bracket E{sub {nu}} Right-Pointing-Angle-Bracket Almost-Equal-To 10 GeV

    SciTech Connect

    Agababyan, N. M.; Ammosov, V. V.; Grigoryan, N.; Gulkanyan, H.; Ivanilov, A. A.; Karamyan, Zh.; Korotkov, V. A.

    2011-02-15

    The total yields of the all well established light meson resonances (up to the {phi}(1020) meson) are estimated in neutrino-nucleus charged current interactions at Left-Pointing-Angle-Bracket E{sub {nu}} Right-Pointing-Angle-Bracket Almost-Equal-To 10 GeV, using the data obtained with SKAT bubble chamber. The yield of {phi} meson in neutrino production is obtained for the first time. For some resonances, the yields in the forward and backward hemispheres in the hadronic c.m.s. are also extracted. From the comparison of the obtained and available higher-energy data, an indication is obtained that the resonance yields rise almost linearly as a function of the mass W of the neutrino produced hadronic system. The fractions of pions originating from the light resonance decays are inferred.

  18. Project Physics Handbook 4, Light and Electromagnetism.

    ERIC Educational Resources Information Center

    Harvard Univ., Cambridge, MA. Harvard Project Physics.

    Seven experiments and 40 activities are presented in this handbook. The experiments are related to Young's experiment, electric forces, forces on currents, electron-beam tubes, and wave modulation and communication. The activities are primarily concerned with aspects of scattered and polarized light, colors, image formation, lenses, cameras,…

  19. Some recent results on meson spectroscopy

    SciTech Connect

    Chung, S.U.

    1987-06-01

    A comparative survey of established meson states with the predictions of a q anti q (quarkonium) model by Godfrey and Isgur shows that most meson states are well described, from pion to UPSILON(6S). However, a number of states in the light- quark isoscalar sector are not predicted at all in their model, pointing to a need for glueballs, hybrids and multi-quark states to fully account for recently reported meson states. 48 refs.

  20. Project Physics Text 4, Light and Electromagnetism.

    ERIC Educational Resources Information Center

    Harvard Univ., Cambridge, MA. Harvard Project Physics.

    Optical and electromagnetic fundamentals are presented in this fourth unit of the Project Physics text for use by senior high students. Development of the wave theory in the first half of the 19th Century is described to deal with optical problems at the early stage. Following explanations of electric charges and forces, field concepts are…

  1. Visible Light Communication Physical Layer Design for Jist Simulation

    NASA Astrophysics Data System (ADS)

    Tomaš, Boris

    2014-12-01

    Current advances in computer networking consider using visible light spectrum to encode and decode digital data. This approach is relatively non expensive. However, designing appropriate MAC or any other upper layer protocol for Visible Light Communication (VLC) requires appropriate hardware. This paper proposes and implements such hardware simulation (physical layer) that is compatible with existing network stack.

  2. Effects of School Lighting on Physical Development and School Performance.

    ERIC Educational Resources Information Center

    Hathaway, Warren E.

    1995-01-01

    This study collected data on the physical development, attendance, and school performance effects of four types of school lighting on elementary students over a two-year period. Results indicated that regular exposure to the lights had important nonvisual effects on students. Full-spectrum fluorescent lamps with ultraviolet supplements were found…

  3. B-meson decay constants from improved lattice nonrelativistic QCD with physical u, d, s, and c quarks.

    PubMed

    Dowdall, R J; Davies, C T H; Horgan, R R; Monahan, C J; Shigemitsu, J

    2013-05-31

    We present the first lattice QCD calculation of the decay constants f(B) and f(B(s)) with physical light quark masses. We use configurations generated by the MILC Collaboration including the effect of u, d, s, and c highly improved staggered quarks in the sea at three lattice spacings and with three u/d quark mass values going down to the physical value. We use improved nonrelativistic QCD (NRQCD) for the valence b quarks. Our results are f(B)=0.186(4) GeV, f(B(s))=0.224(4) GeV, f(B(s))/f(B)=1.205(7), and M(B(s))-M(B)=85(2) MeV, superseding earlier results with NRQCD b quarks. We discuss the implications of our results for the standard model rates for B((s))→μ(+)μ(-) and B→τν. PMID:23767714

  4. New results in atomic physics at the Advanced Light Source

    SciTech Connect

    Schlachter, A.S.

    1995-01-01

    The Advanced Light Source is the world's first low-energy third-generation synchrotron radiation source. It has been running reliably and exceeding design specifications since it began operation in October 1993. It is available to a wide community of researchers in many scientific fields, including atomic and molecular science and chemistry. Here, new results in atomic physics at the Advanced Light Source demonstrate the opportunities available in atomic and molecular physics at this synchrotron light source. The unprecedented brightness allows experiments with high flux, high spectral resolution, and nearly 100% linear polarization.

  5. Heavy meson observables and Dyson Schwinger equations.

    SciTech Connect

    Ivanov, M. A.

    1998-10-20

    Dyson-Schwinger equation (DSE) studies show that the b-quark mass-function is approximately constant, and that this is true to a lesser extent for the c-quark. This observation provides the basis for a study of the leptonic and semileptonic decays of heavy pseudoscalar mesons using a ''heavy-quark'' limit of the DSES, which, when exact, reduces the number of independent form factors. Semileptonic decays with light mesons in the final state are also accessible because the DSES provide a description of light-quark propagation characteristics and light-meson structure. A description of B-meson decays is straightforward, however, the study of decays involving the D-meson indicates that c-quark mass-corrections are quantitatively important.

  6. The physics of light distribution in hollow structures

    NASA Technical Reports Server (NTRS)

    Whitehead, Lorne A.

    1994-01-01

    The purpose of this paper is to serve as an introduction, for non-physicists, to the subject of light distribution in hollow structures. The motivation for light distribution is the importance of getting the maximum value from available light. We all recognize that photons cost money (one photon costs about $10(exp -25) to make) so we obviously want to try to make the maximum number of photons for a given cost. What is often overlooked, however, is that these photons have the highest value only if they are delivered to the right place in the correct quantity. This means that there is often substantial economic value in the high quality distribution of light. This problem is discussed from a very general perspective, in order to show the role of general optical films for manipulating light. The underlying physics at work in such films is described, and examples of common optical light distribution films are provided.

  7. The physics of light distribution in hollow structures

    NASA Astrophysics Data System (ADS)

    Whitehead, Lorne A.

    1994-03-01

    The purpose of this paper is to serve as an introduction, for non-physicists, to the subject of light distribution in hollow structures. The motivation for light distribution is the importance of getting the maximum value from available light. We all recognize that photons cost money (one photon costs about $10(exp -25) to make) so we obviously want to try to make the maximum number of photons for a given cost. What is often overlooked, however, is that these photons have the highest value only if they are delivered to the right place in the correct quantity. This means that there is often substantial economic value in the high quality distribution of light. This problem is discussed from a very general perspective, in order to show the role of general optical films for manipulating light. The underlying physics at work in such films is described, and examples of common optical light distribution films are provided.

  8. Light leptonic new physics at the precision frontier

    NASA Astrophysics Data System (ADS)

    Le Dall, Matthias

    2016-06-01

    Precision probes of new physics are often interpreted through their indirect sensitivity to short-distance scales. In this proceedings contribution, we focus on the question of which precision observables, at current sensitivity levels, allow for an interpretation via either short-distance new physics or consistent models of long-distance new physics, weakly coupled to the Standard Model. The electroweak scale is chosen to set the dividing line between these scenarios. In particular, we find that inverse see-saw models of neutrino mass allow for light new physics interpretations of most precision leptonic observables, such as lepton universality, lepton flavor violation, but not for the electron EDM.

  9. Physical behaviour of anthropogenic light propagation into the nocturnal environment

    PubMed Central

    Aubé, Martin

    2015-01-01

    Propagation of artificial light at night (ALAN) in the environment is now known to have non negligible consequences on fauna, flora and human health. These consequences depend on light levels and their spectral power distributions, which in turn rely on the efficiency of various physical processes involved in the radiative transfer of this light into the atmosphere and its interactions with the built and natural environment. ALAN can affect the living organisms by direct lighting and indirect lighting (scattered by the sky and clouds and/or reflected by local surfaces). This paper mainly focuses on the behaviour of the indirect light scattered under clear sky conditions. Various interaction processes between anthropogenic light sources and the natural environment are discussed. This work mostly relies on a sensitivity analysis conducted with the light pollution radiative transfer model, Illumina (Aubé et al. 2005 Light pollution modelling and detection in a heterogeneous environment: toward a night-time aerosol optical depth retrieval method. In Proc. SPIE 2005, vol. 5890, San Diego, California, USA). More specifically, the impact of (i) the molecular and aerosol scattering and absorption, (ii) the second order of scattering, (iii) the topography and obstacle blocking, (iv) the ground reflectance and (v) the spectrum of light devices and their angular emission functions are examined. This analysis considers different behaviour as a function of the distance from the city centre, along with different zenith viewing angles in the principal plane. PMID:25780231

  10. Charge transport and vector meson dissociation across the thermal phase transition in lattice QCD with two light quark flavors

    NASA Astrophysics Data System (ADS)

    Brandt, Bastian B.; Francis, Anthony; Jäger, Benjamin; Meyer, Harvey B.

    2016-03-01

    We compute and analyze correlation functions in the isovector vector channel at vanishing spatial momentum across the deconfinement phase transition in lattice QCD. The simulations are carried out at temperatures T /Tc=0.156 , 0.8, 1.0, 1.25 and 1.67 with Tc≃203 MeV for two flavors of Wilson-Clover fermions with a zero-temperature pion mass of ≃270 MeV . Exploiting exact sum rules and applying a phenomenologically motivated Ansatz allows us to determine the spectral function ρ (ω ,T ) via a fit to the lattice correlation function data. From these results we estimate the electrical conductivity across the deconfinement phase transition via a Kubo formula and find evidence for the dissociation of the ρ meson by resolving its spectral weight at the available temperatures. We also apply the Backus-Gilbert method as a model-independent approach to this problem. At any given frequency, it yields a local weighted average of the true spectral function. We use this method to compare kinetic theory predictions and previously published phenomenological spectral functions to our lattice study.

  11. Spin-Orbit and Tensor Forces in Heavy-quark Light-quark Mesons: Implications of the New Ds state at 2.32 GeV

    SciTech Connect

    Cahn, Robert N.; Jackson, J. David

    2003-05-01

    We consider the spectroscopy of heavy-quark light-quark mesons with a simple model based on the non-relativistic reduction of vector and scalar exchange between fermions. Four forces are induced: the spin-orbit forces on the light and heavy quark spins, the tensor force, and a spin-spin force. If the vector force is Coulombic, the spin-spin force is a contact interaction, and the tensor force and spin-orbit force on the heavy quark to order $1/m_1m_2$ are directly proportional. As a result, just two independent parameters characterize these perturbations. The measurement of the masses of three p-wave states suffices to predict the mass of the fourth. This technique is applied to the $D_s$ system, where the newly discovered state at 2.32 GeV provides the third measured level, and to the $D$ system. The mixing of the two $J^P=1^+$ p-wave states is reflected in their widths and provides additional constraints. The resulting picture is at odds with previous expectations and raises new puzzles.

  12. Chiral Extrapolation of Lattice Data for Heavy Meson Hyperfine Splittings

    SciTech Connect

    X.-H. Guo; P.C. Tandy; A.W. Thomas

    2006-03-01

    We investigate the chiral extrapolation of the lattice data for the light-heavy meson hyperfine splittings D*-D and B*-B to the physical region for the light quark mass. The chiral loop corrections providing non-analytic behavior in m{sub {pi}} are consistent with chiral perturbation theory for heavy mesons. Since chiral loop corrections tend to decrease the already too low splittings obtained from linear extrapolation, we investigate two models to guide the form of the analytic background behavior: the constituent quark potential model, and the covariant model of QCD based on the ladder-rainbow truncation of the Dyson-Schwinger equations. The extrapolated hyperfine splittings remain clearly below the experimental values even allowing for the model dependence in the description of the analytic background.

  13. Comparison of predicted ground-level airborne radionuclide concentrations to measured values resulting from operation of the Los Alamos Meson Physics Facility. Master's thesis

    SciTech Connect

    Hoak, W.V.

    1993-05-01

    A comparison study of measured and predicted downwind radionuclide concentrations from the Los Alamos Meson Physics Facility (LAMPF) was performed. The radionuclide emissions consist primarily of the radioisotopes 11C, 13N, and 150. The gases, vented to the outside environment by a stack located at the facility, potentially increase the radiation exposure at the facility boundary. Emission rate, meteorological, and radiation monitoring station data were collected between September 26, 1992 and October 3, 1992. The meteorological and emission data were input to the Clean Air Act Assessment Package-1988 (CAP88-PC) computer code. The downwind radionuclide air concentrations predicted by the code were compared to the air concentrations measured by the monitoring stations. The code was found to slightly over-predict downwind concentrations during unstable atmospheric conditions. For stable atmospheric conditions, the code was not useful for predicting downwind air concentrations. This is thought to be due to an underestimation of horizontal dispersion.

  14. Meson wave function from holographic approaches

    SciTech Connect

    Vega, Alfredo; Schmidt, Ivan; Branz, Tanja; Gutsche, Thomas; Lyubovitskij, Valery E.

    2010-08-04

    We discuss the light-front wave function for the valence quark state of mesons using the AdS/CFT correspondence. We consider two kinds of wave functions obtained in different holographic Soft-Wall approaches.

  15. Charmed meson physics accessible to an L = 10/sup 33/ cm/sup /minus/2/ sec/sup /minus/1/ e/sup +/e/sup /minus// collider operating near charm threshold

    SciTech Connect

    Schindler, R.H.

    1989-06-01

    In this report, the potential for dedicated charmed D/sup 0/, D/sup +/ and D/sub s/ meson physics in a high-luminosity e/sup +/e/sup /minus// collider operated near charm threshold is explored. The construction of such a high-luminosity collider or Tau-Charm Factory in conjunction with a new detector whose design draws heavily on the extensive operational experience of previous detectors at SPEAR, could achieve three orders-of-magnitude improvement in sensitivity in most areas of charmed meson studies. 27 refs., 10 figs., 9 tabs.

  16. Soft and Hard Scale QCD Dynamics in Mesons

    NASA Astrophysics Data System (ADS)

    Nguyen, T.; Souchlas, N. A.; Tandy, P. C.

    2011-09-01

    Using a ladder-rainbow kernel previously established for light quark hadron physics, we explore the extension to masses and electroweak decay constants of ground state pseudoscalar and vector quarkonia and heavy-light mesons in the c- and b-quark regions. We make a systematic study of the effectiveness of a constituent mass concept as a replacement for a heavy quark dressed propagator for such states. The difference between vector and axial vector current correlators is explored within the same model to provide an estimate of the four quark chiral condensate and the leading distance scale for the onset of non-perturbative phenomena in QCD.

  17. Theoretical overview: The New mesons

    SciTech Connect

    Quigg, Chris; /Fermilab

    2004-11-01

    After commenting on the state of contemporary hadronic physics and spectroscopy, I highlight four areas where the action is: searching for the relevant degrees of freedom, mesons with beauty and charm, chiral symmetry and the D{sub sJ} levels, and X(3872) and the lost tribes of charmonium.

  18. New light field camera based on physical based rendering tracing

    NASA Astrophysics Data System (ADS)

    Chung, Ming-Han; Chang, Shan-Ching; Lee, Chih-Kung

    2014-03-01

    Even though light field technology was first invented more than 50 years ago, it did not gain popularity due to the limitation imposed by the computation technology. With the rapid advancement of computer technology over the last decade, the limitation has been uplifted and the light field technology quickly returns to the spotlight of the research stage. In this paper, PBRT (Physical Based Rendering Tracing) was introduced to overcome the limitation of using traditional optical simulation approach to study the light field camera technology. More specifically, traditional optical simulation approach can only present light energy distribution but typically lack the capability to present the pictures in realistic scenes. By using PBRT, which was developed to create virtual scenes, 4D light field information was obtained to conduct initial data analysis and calculation. This PBRT approach was also used to explore the light field data calculation potential in creating realistic photos. Furthermore, we integrated the optical experimental measurement results with PBRT in order to place the real measurement results into the virtually created scenes. In other words, our approach provided us with a way to establish a link of virtual scene with the real measurement results. Several images developed based on the above-mentioned approaches were analyzed and discussed to verify the pros and cons of the newly developed PBRT based light field camera technology. It will be shown that this newly developed light field camera approach can circumvent the loss of spatial resolution associated with adopting a micro-lens array in front of the image sensors. Detailed operational constraint, performance metrics, computation resources needed, etc. associated with this newly developed light field camera technique were presented in detail.

  19. B physics: measurement of partial widths and search for direct cp violation in d0 meson decays

    SciTech Connect

    Acosta, D.; The CDF Collaboration

    2005-04-04

    We present a measurement of relative partial widths and decay rate CP asymmetries in K{sup -}K{sup +} and {pi}{sup -}{pi}{sup +} decays of D{sup 0} mesons produced in p{bar p} collisions at {radical}s = 1.96TeV. We use a sample of 2 x 10{sup 5} D*{sup +} {yields} D{sup 0}{pi}{sup +} (and charge conjugate) decays with the D{sup 0} decaying to K{sup -}{pi}{sup +}, K{sup -}K{sup +}, and {pi}{sup -}{pi}{sup +}, corresponding to 123 pb{sup -1} of data collected by the Collider Detector at Fermilab II experiment at the Fermilab Tevatron collider. No significant direct CP violation is observed. We measure {Lambda}(D{sup 0} {yields} K{sup -}K{sup +})/{Lambda}(D{sup 0} {yields} K{sup -}{pi}{sup +}) = 0.0992 {+-} 0.0011 {+-} 0.0012, {Lambda}(D{sup 0} {yields} {pi}{sup -}{pi}{sup +})/{Lambda}(D{sup 0} {yields} K{sup -}{pi}{sup +}) = 0.03594 {+-} 0.00054 {+-} 0.00040, A{sub CP} (K{sup -}K{sup +}) = (2.0 {+-} 1.2 {+-} 0.6)%, and A{sub CP} ({pi}{sup -}{pi}{sup +}) = (1.0 {+-} 1.3 {+-} 0.6) %, where, in all cases, the first uncertainty is statistical and the second is systematic.

  20. Meson Spectroscopy at Clas

    NASA Astrophysics Data System (ADS)

    Battaglieri, Marco

    The CLAS Collaboration is operating the CLAS detector at theThomas Jefferson National Laboratory (JLab) in USA. The unique combination of the detector large acceptance and high intensity of the continuous electron beam of CEBAF has opened the way to a comprehensive study of the hadrons structure in a kinematic domain between nuclear and particle physics. Meson spectroscopy plays a central role in the physics program of the Collaboration. Many exclusive channels have been studied with virtual and real photon beams in a wide kinematic domain providing key information about the hadron structure as well as the reactions dynamic. In this contribution, the rich physics program covered by present and future experiments will be reviewed.

  1. B meson dileptonic decays in the next-to-minimal supersymmetric model with a light CP-odd Higgs boson

    SciTech Connect

    Heng Zhaoxia; Oakes, Robert J.; Wang Wenyu; Yang Jinmin; Xiong Zhaohua

    2008-05-01

    In the next-to-minimal supersymmetric model (NMSSM) a light CP-odd Higgs boson is so far allowed by current experiments, which, together with a large tan{beta}, may greatly enhance the rare dileptonic decays B{yields}X{sub s}l{sup +}l{sup -} and B{sub s}{yields}l{sup +}l{sup -}{gamma}. We examine these decays paying special attention to the new operator allowed by the light CP-odd Higgs boson. We find that in the parameter space allowed by current experiments like CERN LEP II and b{yields}s{gamma}, the branching ratios of these rare decays can be greatly enhanced, and thus the existing experimental data on B{yields}X{sub s}{mu}{sup +}{mu}{sup -} can further stringently constrain the parameter space (especially the region with a superlight CP-odd Higgs boson and large tan{beta}). In the surviving parameter space we give the predictions for other dileptonic decay branching ratios and also show the results for the forward-backward asymmetry.

  2. Physical Layer Characteristics and Techniques for Visible Light Communications

    NASA Astrophysics Data System (ADS)

    Cui, Kaiyun

    With the rapid development of semiconductor lighting technologies, the light emitting diodes (LEDs) are promising to eventually replace traditional incandescent and fluorescent lamps for their high energy efficiency, environmental friendliness, and long lifetime. Visible light communication (VLC) utilizing lighting LEDs as transmitters has been an emerging research area since its first proposal. Ubiquitous communication coverage will become possible with wide deployment of lighting LEDs. This thesis studies physical layer characteristics of VLC systems based on either indoor LED lighting or outdoor LED traffic signaling infrastructure. Advanced communication techniques are proposed to cope with LED bandwidth limitations and grant multiple accesses. Their performance is comprehensively analyzed in typical lighting and signaling environments. Firstly, communication link issues are studied. A conversion method from photometric parameters for illumination to radiometric parameters for communication is developed. Two typical VLC links, the line-of-sight (LOS) link and non-line-of-sight (NLOS) diffuse link, are characterized both experimentally and numerically. Some optional reverse link provisions are evaluated for a full duplex system. Different noise sources and background interferences are analyzed, and dominant noises are identified under typical application scenarios. With identified signal propagation and noise characteristics, link performance is then evaluated. Secondly, transceiver design techniques to increase the data rate are proposed, including digital pre-equalization techniques and the optical orthogonal frequency division multiplexing (O-OFDM) whose peak to average power ratio (PAPR) issue is investigated. Thirdly, the capacity of the multiple-input multiple-output (MIMO) VLC system exploring inherent multiple LED transmitters and multiple photodetectors is evaluated. The effects of some system parameters involved in non-imaging and imaging transceivers

  3. Charge asymmetry in charmed-meson photoproduction

    SciTech Connect

    Berezhnoy, A. V. Likhoded, A. K.

    2006-01-15

    Within the perturbative-recombination model, the charge asymmetries in the D*{sup +}-D*{sup -}, D*{sup 0}-D*{sup 0}, and D{sup +}{sub s}-D{sup -}{sub s} yields are estimated under the kinematical conditions of the COMPASS experiment. Corrections that arise owing to the mass of a light quark in a charmed meson are taken into account. The yield of D{sup +}{sub s} mesons is predicted to be large in relation to the yield of D{sup -}{sub s} mesons.

  4. Meson Spectroscopy at JLab@12 GeV

    SciTech Connect

    Celentano, Andrea

    2013-03-01

    Meson, being the simplest hadronic bound system, is the ideal "laboratory" to study the interaction between quarks, to understand the role of the gluons inside hadrons and to investigate the origin of color confinement. To perform such studies it is important to measure the meson spectrum, with precise determination of resonance masses and properties, looking for rare qbar q states and for unconventional mesons with exotic quantum numbers (i.e. mesons with quantum numbers that are not compatible with a qbar q structure). With the imminent advent of the 12 GeV upgrade of Jefferson Lab a new generation of meson spectroscopy experiments will start: "Meson-Ex" in Hall B and "GLUEX" in Hall D. Both will use photo-production to explore the spectrum of mesons in the light-quark sector, in the energy range of few GeVs.

  5. Experimental Status of Exotic Mesons and the GlueX Experiment

    SciTech Connect

    Daniel Carman

    2006-10-22

    One of the unanswered and most fundamental questions in physics regards the nature of the confinement mechanism of quarks and gluons in QCD. Exotic hybrid mesons manifest gluonic degrees of freedom and their spectroscopy will provide the data necessary to test assumptions in lattice QCD and the specific phenomenology leading to confinement. Within the past two decades a number of experiments have put forth tantalizing evidence for the existence of exotic hybrid mesons in the mass range below 2 GeV. This talk represents an overview of the available data and what has been learned. In looking toward the future, the GlueX experiment at Jefferson Laboratory represents a new initiative that will perform detailed spectroscopy of the light-quark meson spectrum. This experiment and its capabilities will be reviewed.

  6. [Medium energy meson research

    SciTech Connect

    Crowe, K.M.

    1992-01-01

    The activities of this group are primarily concerned with experiments using the Crystal Barrel Detector. This detector is installed and operating at the Low Energy Antiproton Ring (LEAR) at CERN. QCD, the modem theory of the strong interaction, is reasonably well understood at high energies, but unfortunately, low-energy QCD is still not well understood, and is far from being adequately tested. The Crystal Barrel experiments are designed to provide some of the tests. The basic line of research involves meson spectroscopy, analyses bearing on the quark and/or gluon content of nuclear states, and the exploration of mechanisms and rules which govern p[bar p] annihilation dynamics. The Crystal Barrel Detector detects and identifies charged and neutral particles with a geometric acceptance close to 100%. The principal component of the detector is an array of 1,380 CsI(TI) crystals. These crystals surround a Jet Drift Chamber (JDC), located in a 1.5 Tesla magnetic field, which measures the momentum and dE/dx of charged particles. One of the very interesting physics goals of the detector is a search for exotic mesonic states -- glueballs and hybrids. Annihilation at rest will be studied with both liquid and gaseous hydrogen targets. The gaseous target offers the possibility of triggering on atomic L-shell X rays so that specific initial angular momentum states can be studied.These topics as well as other related topics are discussed in this report.

  7. [Medium energy meson research

    SciTech Connect

    Crowe, K.M.

    1992-12-01

    The activities of this group are primarily concerned with experiments using the Crystal Barrel Detector. This detector is installed and operating at the Low Energy Antiproton Ring (LEAR) at CERN. QCD, the modem theory of the strong interaction, is reasonably well understood at high energies, but unfortunately, low-energy QCD is still not well understood, and is far from being adequately tested. The Crystal Barrel experiments are designed to provide some of the tests. The basic line of research involves meson spectroscopy, analyses bearing on the quark and/or gluon content of nuclear states, and the exploration of mechanisms and rules which govern p{bar p} annihilation dynamics. The Crystal Barrel Detector detects and identifies charged and neutral particles with a geometric acceptance close to 100%. The principal component of the detector is an array of 1,380 CsI(TI) crystals. These crystals surround a Jet Drift Chamber (JDC), located in a 1.5 Tesla magnetic field, which measures the momentum and dE/dx of charged particles. One of the very interesting physics goals of the detector is a search for exotic mesonic states -- glueballs and hybrids. Annihilation at rest will be studied with both liquid and gaseous hydrogen targets. The gaseous target offers the possibility of triggering on atomic L-shell X rays so that specific initial angular momentum states can be studied.These topics as well as other related topics are discussed in this report.

  8. The comparative uptake and interaction of several radionuclides in the trophic levels surrounding the Los Alamos Meson Physics Facility (LAMPF) waste water ponds

    SciTech Connect

    Brooks, G.H. Jr.

    1989-08-01

    A study was undertaken to examine the uptake, distribution, and interaction of five activation products (Co-57, Be-7, Cs-134, Rb-83, and Mn-54) within the biotic and abiotic components surrounding the waste treatment lagoons of the Los Alamos Meson Physics Facility (LAMPF). The study attempted to ascertain where, and what specific interactions were taking place among the isotopes and the biotic/abiotic components. A statistical approach, utilizing Multivariate Analysis of Variance (MANOVA), was conducted testing the radioisotopic concentrations by (1) the trophic levels (TROPLVL) in each position sampled on the grid, (2) where sampled on the grid (TRAN), (3) where sampled with-in each grid line (PLOT), and (4) the side with which sampled (SIDE). This provided both the dependent and independent variables that would be tested. The Null Hypothesis (Ho) tested the difference in the mean values of the isotopes within/between each of the four independent variables. The Rb-83 statistic indicated an accumulation within the TRAN and PLOT variables within the sampled area. The Co-57 test statistic provided a value which indicated that accumulation of this isotope within TROPLVL was taking place. Mn-54 test values indicated that accumulation was also taking place at the higher trophic levels within the PLOT, TRAN, and SIDE positions. Cs-134 was found to accumulate to third level in this trophic level structure (TROPLVL-(vegetation)), and then decrease from there. The Be-7 component provided no variance from known compartmental transfers. 210 refs., 17 figs., 4 tabs.

  9. GlueX: Meson Spectroscopy in Photoproduction

    SciTech Connect

    Salgado, Carlos; Smith, Elton S.

    2014-03-01

    The goal of the GlueX experiment \\cite{gluex} is to provide crucial data to help understand the soft gluonic fields responsible for binding quarks in hadrons. Hybrid mesons, and in particular exotic hybrid mesons, provide the ideal laboratory for testing QCD in the confinement regime since these mesons explicitly manifest the gluonic degrees of freedom. Photoproduction is expected to be effective in producing exotic hybrids but there is little data on the photoproduction of light mesons. GlueX will use the new 12-GeV electron beam at Jefferson Lab to produce a 9-GeV beam of linearly polarized photons using the technique of coherent bremsstrahlung. A solenoid-based hermetic detector is under construction, which will be used to collect data on meson production and decays. These data will also be used to study the spectrum of conventional mesons, including the poorly understood excited vector mesons. This talk will give an update on the experiment as well as describe theoretical developments \\cite{Dudek:2011bn} to help understand how these data can provide insights into the fundamental theory of strong interactions.

  10. Decay constants of pseudoscalar mesons in a relativistic quark model

    SciTech Connect

    Micu, L.

    1997-04-01

    The decay constants of pseudoscalar mesons are calculated in a relativistic quark model which assumes that mesons are made of a valence quark-antiquark pair and of an effective vacuumlike component. The results are given as functions of quark masses and of some free parameters entering the expression of the internal wave functions of the mesons. Using F{sub {pi}{sup +}}=130.7 MeV, F{sub K{sup +}}=159.8 MeV to fix the parameters of the model, we predict 60MeV{le}F{sub D{sup +}}{le}185 MeV, 95MeV{le}F{sub D{sub s}}{le}230 MeV, 80MeV{le}F{sub B{sup +}}{le}205 MeV, 90MeV{le}F{sub B{sub s}}{le}235 MeV for the light quark masses m{sub u}=5.1 MeV, m{sub d}=9.3 MeV, m{sub s}=175 MeV and the heavy quark masses in the range 1GeV{le}m{sub c}{le}1.6 GeV, 4.1GeV{le}m{sub b}{le}4.5 GeV. In the case of light neutral mesons one obtains with the same set of parameters F{sub {pi}{sup 0}}{approx}138 MeV, F{sub {eta}}{approx}130 MeV, F{sub {eta}{sup {prime}}}{approx}78 MeV. The values are in agreement with the experimental data and other theoretical results. {copyright} {ital 1997} {ital The American Physical Society}

  11. Rare B Meson Decays With Omega Mesons

    SciTech Connect

    Zhang, Lei; /Colorado U.

    2006-04-24

    Rare charmless hadronic B decays are particularly interesting because of their importance in understanding the CP violation, which is essential to explain the matter-antimatter asymmetry in our universe, and of their roles in testing the ''effective'' theory of B physics. The study has been done with the BABAR experiment, which is mainly designed for the study of CP violation in the decays of neutral B mesons, and secondarily for rare processes that become accessible with the high luminosity of the PEP-II B Factory. In a sample of 89 million produced B{bar B} pairs on the BABAR experiment, we observed the decays B{sup 0} {yields} {omega}K{sup 0} and B{sup +} {yields} {omega}{rho}{sup +} for the first time, made more precise measurements for B{sup +} {yields} {omega}h{sup +} and reported tighter upper limits for B {yields} {omega}K* and B{sup 0} {yields} {omega}{rho}{sup 0}.

  12. B- and D-meson decay constants from three-flavor lattice QCD

    SciTech Connect

    Bazavov, A.; et al.

    2012-06-01

    We calculate the leptonic decay constants of B_{(s)} and D_{(s)} mesons in lattice QCD using staggered light quarks and Fermilab bottom and charm quarks. We compute the heavy-light meson correlation functions on the MILC asqtad-improved staggered gauge configurations which include the effects of three light dynamical sea quarks. We simulate with several values of the light valence- and sea-quark masses (down to ~m_s/10) and at three lattice spacings (a ~ 0.15, 0.12, and 0.09 fm) and extrapolate to the physical up and down quark masses and the continuum using expressions derived in heavy-light meson staggered chiral perturbation theory. We renormalize the heavy-light axial current using a mostly nonperturbative method such that only a small correction to unity must be computed in lattice perturbation theory and higher-order terms are expected to be small. We obtain f_{B^+} = 196.9(8.9) MeV, f_{B_s} = 242.0(9.5) MeV, f_{D^+} = 218.9(11.3) MeV, f_{D_s} = 260.1(10.8) MeV, and the SU(3) flavor-breaking ratios f_{B_s}/f_{B} = 1.229(26) and f_{D_s}/f_{D} = 1.188(25), where the numbers in parentheses are the total statistical and systematic uncertainties added in quadrature.

  13. Meson-meson interactions and Regge propagators

    SciTech Connect

    Beveren, Eef van Rupp, George

    2009-08-15

    By a reformulation of the loop expansion in the Resonance-Spectrum Expansion amplitude for meson-meson scattering, in terms of s-channel exchange of families of propagator modes, we obtain a formalism which allows for a wider range of applications. The connection with the unitarized amplitudes employed in some chiral theories is discussed. We also define an alternative for the Regge spectra and indicate how this may be observed in experiment.

  14. Meson Photoproduction Experiments with CLAS

    SciTech Connect

    Eugene Pasyuk

    2012-12-01

    A large part of the experimental program in Hall B of the Jefferson Lab is dedicated to light baryon spectroscopy. Meson photoprodcution experiments are essential part of this program. CEBAF Large Acceptance Spectrometer (CLAS) and availability of circularly and linearly polarized tagged photon beams and frozen spin polarized targets provide unique conditions for this type of experiments. This combination of experimental tools gives a remarkable opportunity to measure double polarization observables for different pseudo-scalar meson photoproduction processes. For the first time, a complete or nearly complete measurement became possible and will facilitate model independent extraction of the reaction amplitude. An overview of the experimental program and its current status together with recent results on double polarization measurements in π{sup +} photoproduction are presented.

  15. Beauty vector meson decay constants from QCD sum rules

    NASA Astrophysics Data System (ADS)

    Lucha, Wolfgang; Melikhov, Dmitri; Simula, Silvano

    2016-01-01

    We present the outcomes of a very recent investigation of the decay constants of nonstrange and strange heavy-light beauty vector mesons, with special emphasis on the ratio of any such decay constant to the decay constant of the corresponding pseudoscalar meson, by means of Borel-transformed QCD sum rules. Our results suggest that both these ratios are below unity.

  16. Towards a Theoretical Understanding of the XYZ Mesons from QCD

    NASA Astrophysics Data System (ADS)

    Braaten, Eric

    2016-03-01

    The XYZ mesons are mesons that contain a heavy quark and antiquark but have properties that seem to require additional constituents. Some of them are electrically charged, so they must be tetraquark mesons whose additional constituents are a light quark and antiquark. The list of XYZ mesons has grown to about two dozen over the last decade. A promising approach to understanding these mesons within QCD is the Born-Oppenheimer approximation, which reduces the problem to the solution of the Schrödinger equation in potentials that can be calculated using lattice QCD. The Born-Oppenheimer approximation has not yet revealed the pattern of the XYZ mesons, but it provides a compelling framework for understanding them from the fundamental theory.

  17. Scalar mesons in a linear sigma model with (axial-)vector mesons

    SciTech Connect

    Parganlija, D.; Kovacs, P.; Wolf, Gy.; Giacosa, F.; Rischke, D. H.

    2013-03-25

    The structure of the scalar mesons has been a subject of debate for many decades. In this work we look for qq states among the physical resonances using an extended Linear Sigma Model that contains scalar, pseudoscalar, vector, and axial-vector mesons both in the non-strange and strange sectors. We perform global fits of meson masses, decay widths and amplitudes in order to ascertain whether the scalar qq states are below or above 1 GeV. We find the scalar states above 1 GeV to be preferred as qq states.

  18. CP Violation in B Mesons

    SciTech Connect

    Lazzaro, Alfio; /Milan U. /INFN, Milan

    2007-05-11

    Symmetries and their conservation laws play a fundamental role in Physics. Among them, the discrete symmetries corresponding to charge (C), parity (P), and time (T) transformations are extensively used in the theory of the elementary particles and their interactions (so called Standard Model (SM)) to give the basis of the fundamental physical description of nature. Eventual discoveries of violations of these symmetries become a crucial test for our understanding of the nature. It was assumed that the three discrete symmetries were not violated until 1956 when it was found that P is violated in the weak interaction. Soon it was understood that also the C is violated in the weak interaction. At that time these two violated symmetries were replaced by their combination, CP, which was considered a new fundamental symmetry. In 1964 also the CP was found violated in the case of the neutral K meson system. Since that year there were many achievements in theories and experiments in order to explain this symmetry violation. In the last five years the main contribution comes from the discovery of the CP violation in B meson system. In this note we will describe briefly how the CP violation is described in the SM and the main experimental results obtained in the B mesons system.

  19. Casting light on BSM physics with SM standard candles

    NASA Astrophysics Data System (ADS)

    Curtin, David; Jaiswal, Prerit; Meade, Patrick; Tien, Pin-Ju

    2013-08-01

    The Standard Model (SM) has had resounding success in describing almost every measurement performed by the ATLAS and CMS experiments. In particular, these experiments have put many beyond the SM models of natural Electroweak Symmetry Breaking into tension with the data. It is therefore remarkable that it is still the LEP experiment, and not the LHC, which often sets the gold standard for understanding the possibility of new color-neutral states at the electroweak (EW) scale. Recently, ATLAS and CMS have started to push beyond LEP in bounding heavy new EW states, but a gap between the exclusions of LEP and the LHC typically remains. In this paper we show that measurements of SM Standard Candles can be repurposed to set entirely complementary constraints on new physics. To demonstrate this, we use W + W -cross section measurements to set bounds on a set of slepton-based simplified models which fill in the gaps left by LEP and dedicated LHC searches. Having demonstrated the sensitivity of the W + W -measurement to light sleptons, we also find regions where sleptons can improve the fit of the data compared to the NLO SM W + W -prediction alone. Remarkably, in those regions the sleptons also provide for the right relic-density of Bino-like Dark Matter and provide an explanation for the longstanding 3 σ discrepancy in the measurement of ( g - 2) μ.

  20. Extreme Light Infrastructure - Nuclear Physics Eli-Np Project

    NASA Astrophysics Data System (ADS)

    Gales, S.

    2015-06-01

    The development of high power lasers and the combination of such novel devices with accelerator technology has enlarged the science reach of many research fields, in particular High energy, Nuclear and Astrophysics as well as societal applications in Material Science, Nuclear Energy and Medicine. The European Strategic Forum for Research Infrastructures (ESFRI) has selected a proposal based on these new premises called "ELI" for Extreme Light Infrastructure. ELI will be built as a network of three complementary pillars at the frontier of laser technologies. The ELI-NP pillar (NP for Nuclear Physics) is under construction near Bucharest (Romania) and will develop a scientific program using two 10 PW class lasers and a Back Compton Scattering High Brilliance and Intense Low Energy Gamma Beam , a marriage of Laser and Accelerator technology at the frontier of knowledge. In the present paper, the technical description of the facility, the present status of the project as well as the science, applications and future perspectives will be discussed.

  1. Updated axial meson spectrum and scalar-glueball mixing in AdS/QCD

    NASA Astrophysics Data System (ADS)

    Bartz, Sean; Rollag, Joshua

    2016-03-01

    AdS/QCD is a proposed duality between strongly-coupled quantum chromodynamics and weakly-coupled 5D gravity that can offer new insight to hadronic physics. Previous work accurately models confinement and chiral symmetry breaking in the light hadron spectrum. We improve this model by incorporating new experimental data and making predictions for the scalar glueball sector. Recent COMPASS results indicate a new light axial-vector resonance between the ground state and the currently-accepted value for the first excited state. Incorporating this data lessens the model's dependence on unphysical short length scales. In addition, we analyze the mixing between scalar mesons and glueball by computing to first approximation the radial excitation spectra of these particles. We find good experimental agreement for the scalar mesons and show that predictions for the excited glueball spectrum differ from lattice results.

  2. Meson wave function from holographic models

    SciTech Connect

    Vega, Alfredo; Schmidt, Ivan; Branz, Tanja; Gutsche, Thomas; Lyubovitskij, Valery E.

    2009-09-01

    We consider the light-front wave function for the valence quark state of mesons using the AdS/CFT correspondence, as has been suggested by Brodsky and Teramond. Two kinds of wave functions, obtained in different holographic Soft-Wall models, are discussed.

  3. Neutrino Production of Mesons in the Generalized Parton Picture

    NASA Astrophysics Data System (ADS)

    McAskill, Tracy

    The handbag model and its usefulness in generating cross sections for light pseudoscalar mesons is investigated here. The soft part of the handbag model is first parametrized to fit well-known models of generalized parton distributions (GPD's), then cross sections are calculated directly from the GPD's. This is then directly extended to the calculation of neutrino cross sections for the production of the same type of light mesons.

  4. Towers of hybrid mesons

    SciTech Connect

    Semay, Claude; Buisseret, Fabien; Silvestre-Brac, Bernard

    2009-05-01

    A hybrid meson is a quark-antiquark pair in which, contrary to ordinary mesons, the gluon field is in an excited state. In the framework of constituent models, the interaction potential is assumed to be the energy of an excited string. An approximate, but accurate, analytical solution of the Schroedinger equation with such a potential is presented. When applied to hybrid charmonia and bottomonia, towers of states are predicted in which the masses are a linear function of a harmonic oscillator band number for the quark-antiquark pair. Such a formula could be a reliable guide for the experimental detection of heavy hybrid mesons.

  5. Tensor mesons produced in tau lepton decays

    SciTech Connect

    Lopez Castro, G.; Munoz, J. H.

    2011-05-01

    Light tensor mesons (T=a{sub 2}, f{sub 2} and K{sub 2}*) can be produced in decays of {tau} leptons. In this paper we compute the branching ratios of {tau}{yields}T{pi}{nu} decays by assuming the dominance of intermediate virtual states to model the form factors involved in the relevant hadronic matrix elements. The exclusive f{sub 2}(1270){pi}{sup -} decay mode turns out to have the largest branching ratio, of O(10{sup -4}). Our results indicate that the contribution of tensor meson intermediate states to the three-pseudoscalar channels of {tau} decays are rather small.

  6. B-meson decays

    SciTech Connect

    Schubert, K.R.

    1988-11-20

    The third generation of quarks, anticipated in 1973 by Kobayashi and Maskawa as one of the possibilities to explain CP violation of the K/sup o/-meson system within the framework of the Standard Model and in 1975 by the discovery of the third generation of leptons, was found at FNAL in 1977. It showed up in form of the UPSILON(1S) resonance, the lowest-energy 1/sup - -/ state of the b-quark- anti-b-antiquark system. Experiments at DESY in 1978 showed that the b-quark has charge 1/3. These and further experiments showed that the b- anti-b system follows the same spectroscopic and strong-interaction rules as the c- anti-c system. The physics of the b- anti-b system has been studied extensively at the DESY e/sup +/e/sup -/ storage ring DORIS using the detectors DASP-II, PLUTO, LENA, Crystal Ball, and ARGUS, and from 1980 on at the Cronell e/sup +/e/sup -/ ring CESR using CLEO and CUSB. Today we know twelve states of the b- anti-b system in contrast to seven of the c- anti-c system and only four in the e/sup +/e/sup -/ bound state system positronium. (AIP)

  7. Magnetic properties of ground-state mesons

    NASA Astrophysics Data System (ADS)

    Šimonis, V.

    2016-04-01

    Starting with the bag model a method for the study of the magnetic properties (magnetic moments, magnetic dipole transition widths) of ground-state mesons is developed. We calculate the M1 transition moments and use them subsequently to estimate the corresponding decay widths. These are compared with experimental data, where available, and with the results obtained in other approaches. Finally, we give the predictions for the static magnetic moments of all ground-state vector mesons including those containing heavy quarks. We have a good agreement with experimental data for the M1 decay rates of light as well as heavy mesons. Therefore, we expect our predictions for the static magnetic properties ( i.e., usual magnetic moments) to be of sufficiently high quality, too.

  8. Deflection of Light by Gravity: A Physical Approach.

    ERIC Educational Resources Information Center

    Diamond, Joshua B.

    1982-01-01

    Einstein's equivalence principle relates effects seen by an accelerating observer to those experienced by an observer in a gravitational field, providing an explanation of bending of a light beam by gravity. Because the calculations lead to results one-half the value found experimentally, obtaining the correct light deflection is discussed.…

  9. Light-Emitting Diodes: Exploration of Underlying Physics

    NASA Astrophysics Data System (ADS)

    Etkina, Eugenia; Planinšič, Gorazd

    2014-04-01

    This paper is the second in the series of LED-dedicated papers that have a goal to systematically investigate the use of LEDs in a general physics course. The first paper, published in the February 2014 issue, provided an overview of the course units where LEDs can be used and suggested three different ways of utilizing LEDs in an introductory physics course: (I) as "black boxes" that allow students to study certain properties of a system of interest, (II) as physical systems that allow students to learn a large amount of physics not usually encountered in a typical introductory course, and (III) as non-traditional devices that allow students to construct concepts that are traditionally a part of a general physics course. The present paper focuses on LED physics and how students can learn this physics through a guided inquiry approach (section II in the classification above). Specifically, we will: (1) introduce the Investigative Science Learning Environment (ISLE) approach,2 which we will use as a framework for student learning of the physics of the LEDs; (2) discuss the most important aspects of LED physics that students can learn in a general physics course; and (3) describe in detail classroom activities that follow the ISLE approach which will lead the students to the "discovery" of LED physics described in (2).

  10. Scalar meson spectroscopy with lattice staggered fermions

    SciTech Connect

    Bernard, Claude; DeTar, Carleton; Fu Ziwen; Prelovsek, Sasa

    2007-11-01

    With sufficiently light up and down quarks the isovector (a{sub 0}) and isosinglet (f{sub 0}) scalar meson propagators are dominated at large distance by two-meson states. In the staggered-fermion formulation of lattice quantum chromodynamics, taste-symmetry breaking causes a proliferation of two-meson states that further complicates the analysis of these channels. Many of them are unphysical artifacts of the lattice approximation. They are expected to disappear in the continuum limit. The staggered-fermion fourth-root procedure has its purported counterpart in rooted staggered chiral perturbation theory (rS{chi}PT). Fortunately, the rooted theory provides a strict framework that permits the analysis of scalar meson correlators in terms of only a small number of low-energy couplings. Thus the analysis of the point-to-point scalar meson correlators in this context gives a useful consistency check of the fourth-root procedure and its proposed chiral realization. Through numerical simulation we have measured correlators for both the a{sub 0} and f{sub 0} channels in the 'Asqtad' improved staggered-fermion formulation in a lattice ensemble with lattice spacing a=0.12 fm. We analyze those correlators in the context of rS{chi}PT and obtain values of the low-energy chiral couplings that are reasonably consistent with previous determinations.

  11. Extracting excited mesons from the finite volume

    SciTech Connect

    Doring, Michael

    2014-12-01

    As quark masses come closer to their physical values in lattice simulations, finite volume effects dominate the level spectrum. Methods to extract excited mesons from the finite volume are discussed, like moving frames in the presence of coupled channels. Effective field theory can be used to stabilize the determination of the resonance spectrum.

  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. Charmed-strange mesons revisited: Mass spectra and strong decays

    NASA Astrophysics Data System (ADS)

    Song, Qin-Tao; Chen, Dian-Yong; Liu, Xiang; Matsuki, Takayuki

    2015-03-01

    Inspired by the present experimental status of charmed-strange mesons, we perform a systematic study of the charmed-strange meson family in which we calculate the mass spectra of the charmed-strange meson family by taking a screening effect into account in the Godfrey-Isgur model and investigate the corresponding strong decays via the quark pair creation model. These phenomenological analyses of charmed-strange mesons not only shed light on the features of the observed charmed-strange states, but also provide important information on future experimental search for the missing higher radial and orbital excitations in the charmed-strange meson family, which will be a valuable task in LHCb, the forthcoming Belle II, and PANDA.

  14. Chemical physics: Quantum control of light-induced reactions

    NASA Astrophysics Data System (ADS)

    Chandler, David W.

    2016-07-01

    An investigation of how ultracold molecules are broken apart by light reveals surprising, previously unobserved quantum effects. The work opens up avenues of research in quantum optics. See Letter p.122

  15. Physics Prospects with GlueX

    SciTech Connect

    Alexander Somov

    2011-10-01

    The new experiment GlueX is being currently constructed at Jefferson Lab. The experiment was designed to search for hybrid mesons with exotic-quantum-numbers using a beam of linearly polarized photons incident on a liquid hydrogen target. We will discuss the discovery potential of the GlueX experiment and briefly overview its physics program. GlueX is a new experiment at Jefferson Lab. whose physics program is intended to improve our knowledge of strong interactions. The main goal of the experiment is to search for gluonic excitations in photoproduction. The experiment is expected to collect a data sample a few order of magnitudes larger than all existing photoproduction data. The physics topics of the experiment spans from light meson spectroscopy to Primakoff production of pseudoscalar mesons. The construction of the experiment has started in 2009 and the commissioning stage is expected to be finished in 2015.

  16. Lepton flavor violating decays of vector mesons

    SciTech Connect

    Gutsche, Thomas; Lyubovitskij, Valery E.; Helo, Juan C.; Kovalenko, Sergey

    2010-02-01

    We estimate the rates of lepton flavor violating decays of the vector mesons {rho}, {omega}, and {phi}{yields}e{mu}. The theoretical tools are based on an effective Lagrangian approach without referring to any specific realization of the physics beyond the standard model responsible for lepton flavor violation (Le{sub f}). The effective lepton-vector meson couplings are extracted from the existing experimental bounds on the nuclear {mu}{sup -}-e{sup -} conversion. In particular, we derive an upper limit for the Le{sub f} branching ratio Br({phi}{yields}e{mu}){<=}1.3x10{sup -21} which is much more stringent than the recent experimental result Br({phi}{yields}e{mu})<2x10{sup -6} presented by the SND Collaboration. Very tiny limits on Le{sub f} decays of vector mesons derived in this paper make direct experimental observation of these processes unrealistic.

  17. The Light Meter: A Powerful Tool in Physical Science.

    ERIC Educational Resources Information Center

    Espinoza, Fernando

    2000-01-01

    Discusses physics, earth science, and physical science concepts that are challenging for students and teachers because they are difficult to understand and demonstrate. Identifies ratio and inverse-square as a unifying-concept approach according to the National Education Standards. Supports teaching based on student-centered activities, long-term…

  18. Meson mass at real and imaginary chemical potentials

    SciTech Connect

    Kashiwa, Kouji; Sakai, Yuji; Yahiro, Masanobu; Matsuzaki, Masayuki; Kouno, Hiroaki

    2009-04-01

    Chemical-potential dependence of pi and sigma meson masses is analyzed at both real and imaginary chemical potentials, {mu}{sub R} and {mu}{sub I}, by using the Polyakov-loop extended Nambu-Jona-Lasinio (PNJL) model that possesses both the extended Z{sub 3} symmetry and chiral symmetry. In the {mu}{sub I} region, the meson masses have the Roberge-Weiss periodicity. The {mu}{sub I} dependence of the meson masses becomes stronger as temperature increases. We argue that meson masses and physical quantities in the {mu}{sub R} region will be determined from lattice QCD data on meson masses in the {mu}{sub I} region by using the PNJL model, if the data are measured in the future.

  19. Meson mass at real and imaginary chemical potentials

    NASA Astrophysics Data System (ADS)

    Kashiwa, Kouji; Matsuzaki, Masayuki; Kouno, Hiroaki; Sakai, Yuji; Yahiro, Masanobu

    2009-04-01

    Chemical-potential dependence of pi and sigma meson masses is analyzed at both real and imaginary chemical potentials, μR and μI, by using the Polyakov-loop extended Nambu-Jona-Lasinio (PNJL) model that possesses both the extended Z3 symmetry and chiral symmetry. In the μI region, the meson masses have the Roberge-Weiss periodicity. The μI dependence of the meson masses becomes stronger as temperature increases. We argue that meson masses and physical quantities in the μR region will be determined from lattice QCD data on meson masses in the μI region by using the PNJL model, if the data are measured in the future.

  20. Phenomenological Implications of the Nucleon's Meson Cloud

    NASA Astrophysics Data System (ADS)

    Hobbs, T. J.

    2015-09-01

    The long-distance structure of the interacting nucleon receives important contributions from its couplings to light hadronic degrees of freedom—a light meson cloud—while an analogous nonperturbative mechanism is expected to generate an intrinsic charm (IC) component to the proton wavefunction. We investigate both possibilities, keeping for the former a special eye to improving the theoretical understanding of the pion-nucleon vertex in light of proposed measurements. Regarding the latter possibility of IC, we highlight recent results obtained by a global QCD analysis of the light-front model proposed in Hobbs et al. (Phys Rev D 89:074008, 2014).

  1. Effective Hadron Dynamics: from the Proton Spin to Heavy Meson Systems

    NASA Astrophysics Data System (ADS)

    Subbaraman, Anand Hariharan

    In this thesis, chiral effective Lagrangians are used to study certain aspects of QCD in the low energy limit. A chiral Lagrangian including vector mesons as well as pseudoscalar mesons is developed. Careful attention is paid to SU(3) symmetry breaking effects, and the parameters are fitted to experiment. It is found that this Lagrangian explains certain SU(3) breaking effects in the meson sector much better than a model with pseudoscalars alone. The above Lagrangian is then used to study the "proton spin puzzle". The nucleon arises as a solitonic excitation of the mesonic fields in this model. It is shown that the explanation of the small value of the matrix element of the axial singlet current in the proton state is very satisfactory within this framework. A gauge invariant two-component decomposition of the above matrix element into "matter" and "glue" contributions is then displayed, and it is demonstrated that both these pieces are intrinsically small, though the "glue" part does tend to cancel out the "matter" part. The interactions of heavy mesons (mesons containing a single heavy quark) with light mesons is also studied. A formalism is developed to include light vector mesons as well as pseudoscalars into a chiral effective Lagrangian of heavy and light mesons. The parameters in the Lagrangian are fitted by the analysis of certain semi-leptonic heavy meson decays. The heavy-light Lagrangian is then used to study the picture of heavy baryons as bound states of the nucleon-as-soliton and heavy mesons. It is demonstrated that light vector mesons play a significant role in the binding of the soliton and the heavy meson. The heavy baryon mass splitting is estimated as a test of the model.

  2. Short-distance matrix elements for $D$-meson mixing for 2+1 lattice QCD

    SciTech Connect

    Chang, Chia Cheng

    2015-01-01

    We study the short-distance hadronic matrix elements for D-meson mixing with partially quenched Nf = 2+1 lattice QCD. We use a large set of the MIMD Lattice Computation Collaboration's gauge configurations with a2 tadpole-improved staggered sea quarks and tadpole-improved Lüscher-Weisz gluons. We use the a2 tadpole-improved action for valence light quarks and the Sheikoleslami-Wohlert action with the Fermilab interpretation for the valence charm quark. Our calculation covers the complete set of five operators needed to constrain new physics models for D-meson mixing. We match our matrix elements to the MS-NDR scheme evaluated at 3 GeV. We report values for the Beneke-Buchalla-Greub-Lenz-Nierste choice of evanescent operators.

  3. Regarding the scalar mesons

    SciTech Connect

    Liu Yunhu; Shao Jianxin; Wang Xiaogang; Zhang Ziying; Li Demin

    2008-02-01

    Based on the main assumption that the D{sub sJ}(2860) belongs to the 2{sup 3}P{sub 0} qq multiplet, the masses of the scalar meson nonet are estimated in the framework of the relativistic independent quark model, Regge phenomenology, and meson-meson mixing. We suggest that the a{sub 0}(1005), K{sub 0}*(1062), f{sub 0}(1103), and f{sub 0}(564) constitute the ground scalar meson nonet; it is supposed that these states would likely correspond to the observed states a{sub 0}(980), {kappa}(900), f{sub 0}(980), and f{sub 0}(600)/{sigma}, respectively. Also a{sub 0}(1516), K{sub 0}*(1669), f{sub 0}(1788), and f{sub 0}(1284) constitute the first radial scalar meson nonet, it is supposed that these states would likely correspond to the observed states a{sub 0}(1450), K{sub 0}*(1430), f{sub 0}(1710), and f{sub 0}(1370), respectively. The scalar state f{sub 0}(1500) may be a good candidate for the ground scalar glueball. The agreement between the present findings and those given by other different approaches is satisfactory.

  4. Toward the excited isoscalar meson spectrum from lattice QCD

    SciTech Connect

    Dudek, Jozef J.; Edwards, Robert G.; Guo, Peng; Thomas, Christopher E.

    2013-11-18

    We report on the extraction of an excited spectrum of isoscalar mesons using lattice QCD. Calculations on several lattice volumes are performed with a range of light quark masses corresponding to pion masses down to about ~400 MeV. The distillation method enables us to evaluate the required disconnected contributions with high statistical precision for a large number of meson interpolating fields. We find relatively little mixing between light and strange in most JPC channels; one notable exception is the pseudoscalar sector where the approximate SU(3)F octet, singlet structure of the η, η' is reproduced. We extract exotic JPC states, identified as hybrid mesons in which an excited gluonic field is coupled to a color-octet qqbar pair, along with non-exotic hybrid mesons embedded in a qq¯-like spectrum.

  5. Toward the excited isoscalar meson spectrum from lattice QCD

    DOE PAGESBeta

    Dudek, Jozef J.; Edwards, Robert G.; Guo, Peng; Thomas, Christopher E.

    2013-11-18

    We report on the extraction of an excited spectrum of isoscalar mesons using lattice QCD. Calculations on several lattice volumes are performed with a range of light quark masses corresponding to pion masses down to about ~400 MeV. The distillation method enables us to evaluate the required disconnected contributions with high statistical precision for a large number of meson interpolating fields. We find relatively little mixing between light and strange in most JPC channels; one notable exception is the pseudoscalar sector where the approximate SU(3)F octet, singlet structure of the η, η' is reproduced. We extract exotic JPC states, identifiedmore » as hybrid mesons in which an excited gluonic field is coupled to a color-octet qqbar pair, along with non-exotic hybrid mesons embedded in a qq¯-like spectrum.« less

  6. Selection rules for hadronic transitions of XYZ mesons.

    PubMed

    Braaten, Eric; Langmack, Christian; Smith, D Hudson

    2014-06-01

    Many of the XYZ mesons discovered in the last decade can be identified as bound states of a heavy quark and antiquark in Born-Oppenheimer (BO) potentials defined by the energy of gluon and light-quark fields in the presence of static color sources. The mesons include quarkonium hybrids, which are bound states in excited flavor-singlet BO potentials, and quarkonium tetraquarks, which are bound states in BO potentials with light-quark+antiquark flavor. The deepest hybrid potentials are known from lattice QCD calculations. The deepest tetraquark potentials can be inferred from lattice QCD calculations of static adjoint mesons. Selection rules for hadronic transitions are derived and used to identify XYZ mesons that are candidates for ground-state energy levels in the BO potentials for charmonium hybrids and tetraquarks. PMID:24949759

  7. CP Violation in B Mesons

    NASA Astrophysics Data System (ADS)

    Roe, Natalie A.

    2001-04-01

    Our world manifestly violates CP, the symmetry between matter and antimatter; there is no observational evidence for any significant amount of antimatter in the Universe. Andrei Sakharov was the first to point out that, in the context of Big Bang theory, a matter-dominated universe requires CP violation at the quantum level. Indeed, CP violation was subsequently observed as a tiny effect in K-meson decays, and it can be naturally accommodated in the Standard Model of fundamental particles with 3 generations of quarks. However, to produce the observed baryon asymmetry, baryogenesis calculations require more CP violation than the Standard Model affords. This is an intriguing puzzle whose solution will require input from both particle physics and cosmology, and it has inspired particle physicists to study CP violation with greater precision in a new generation of experiments. We are now entering this exciting new era in CP violation studies. Several new or upgraded experiments plan a program of detailed measurements of CP violating effects in B mesons. The predicted asymmetries are large, observable in a variety of decay channels, and the theoretical uncertainties are small for the best modes. Some interesting experimental results have recently been announced, and more precise measurements will soon follow. Future experiments are already planned to make even more definitive measurements. In this talk I will review the theoretical predictions and the connection to cosmology, survey the experimental scene, and describe how the study of CP violation in B mesons will allow us to make stringent tests of the Standard Model.

  8. Shedding light: laser physics and mechanism of action.

    PubMed

    De Felice, E

    2010-02-01

    Lasers have affected health care in many ways. Clinical applications have been found in a number of medical and surgical specialities. In particular, applications of laser technology in phlebology has made it essential for vein physicians to obtain a fundamental knowledge of laser physics, laser operation and also to be well versed in laser safety procedures. This article reviews recommended text books and current literature to detail the basics of laser physics and its application to venous disease. Laser safety and laser side effects are also discussed. PMID:20118342

  9. Boosting the Light: X-ray Physics in Confinement

    ScienceCinema

    Rhisberger, Ralf [HASYLAB/ DESY

    2010-01-08

    Remarkable effects are observed if light is confined to dimensions comparable to the wavelength of the light. The lifetime of atomic resonances excited by the radiation is strongly reduced in photonic traps, such as cavities or waveguides. Moreover, one observes an anomalous boost of the intensity scattered from the resonant atoms. These phenomena results from the strong enhancement of the photonic density of states in such geometries. Many of these effects are currently being explored in the regime of vsible light due to their relevance for optical information processing. It is thus appealing to study these phenomena also for much shorter wavelengths. This talk illuminates recent experiments where synchrotron x-rays were trapped in planar waveguides to resonantly excite atomos ([57]Fe nuclei_ embedded in them. In fact, one observes that the radiative decay of these excited atoms is strongly accelerated. The temporal acceleration of the decay goes along with a strong boost of the radiation coherently scattered from the confined atmos. This can be exploited to obtain a high signal-to-noise ratio from tiny quantities of material, leading to manifold applications in the investigation of nanostructured materials. One application is the use of ultrathin probe layers to image the internal structure of magnetic layer systems.

  10. Highly excited and exotic meson spectroscopy from lattice QCD

    SciTech Connect

    Christopher Thomas

    2011-05-01

    I will discuss recent progress in extracting highly excited and exotic meson spectra using lattice QCD. New results in the light meson sector will be presented, where a combination of techniques have enabled us to confidently identify the spin of extracted states. Highlights include many states with exotic quantum numbers and, for the first time in a lattice QCD calculation, spin-four states. I will conclude with comments on future prospects.

  11. Project Physics Teacher Guide 4, Light and Electromagnetism.

    ERIC Educational Resources Information Center

    Harvard Univ., Cambridge, MA. Harvard Project Physics.

    Teaching procedures of Project Physics Unit 4 are presented to help teachers make effective use of learning materials. Unit contents are discussed in connection with teaching aid lists, multi-media schedules, schedule blocks, and resources charts. Brief summaries are made for transparencies, 16mm films, and reader articles. Included is information…

  12. Light-Emitting Diodes: Exploration of Underlying Physics

    ERIC Educational Resources Information Center

    Etkina, Eugenia; Planinšic, Gorazd

    2014-01-01

    This paper is the second in the series of LED-dedicated papers that have a goal to systematically investigate the use of LEDs in a general physics course. The first paper, published in the February 2014 issue, provided an overview of the course units where LEDs can be used and suggested three different ways of utilizing LEDs in an introductory…

  13. Determination of U (1 )A restoration from pion and a0 -meson screening masses: Toward the chiral regime

    NASA Astrophysics Data System (ADS)

    Ishii, Masahiro; Yonemura, Koji; Takahashi, Junichi; Kouno, Hiroaki; Yahiro, Masanobu

    2016-01-01

    We incorporate the effective restoration of U (1 )A symmetry in the 2 +1 -flavor entanglement Polyakov-loop extended Nambu-Jona-Lasinio (EPNJL) model by introducing a temperature-dependent strength K (T ) to the Kobayashi-Maskawa-'t Hooft determinant interaction. T dependence of K (T ) is well determined from pion and a0-meson screening masses obtained by lattice QCD (LQCD) simulations with improved p4 staggered fermions. The strength is strongly suppressed in the vicinity of the pseudocritical temperature of chiral transition. The EPNJL model with the K (T ) well reproduces meson susceptibilities calculated by LQCD with domain-wall fermions. The model shows that the chiral transition is second order at the "light-quark chiral-limit" point where the light quark mass is zero and the strange quark mass is fixed at the physical value. This indicates that there exists a tricritical point. Hence, the location is estimated.

  14. Extreme light. An intense pursuit of fundamental high energy physics

    NASA Astrophysics Data System (ADS)

    Mourou, Gérard; Wheeler, Jonathan A.; Tajima, Toshiki

    2015-09-01

    By the compression of petawatt pulses to multi-exawatt, a new route for the generation of Schwinger intensities capable of producing highenergy radiation and particle beams with extremely short time structure down to the attosecond-zeptosecond regime is being presented. Far from the traditional laser investigation in the eV regime, this laser-based approach offers a new paradigm to investigate the structure of vacuum and applications to subatomic physics.

  15. B physics: evidence for the exclusive decay b^+/-_c -> j/psi pi^+ and measurement of the mass of the b^+/-_c meson

    SciTech Connect

    Acosta, D.; The CDF Collaboration

    2005-05-25

    We report the first evidence of a fully reconstructed decay mode of the B{sub c}{sup {+-}} meson in the channel B{sub c}{sup {+-}} {yields} J/{psi}{sup {+-}}, with J/{psi} {yields} {mu}{sup +}{mu}{sup -}. The analysis is based on an integrated luminosity of 360 pb{sup -1} in p{bar p} collisions collected by the Collider Detector at Fermilab. We observe 18.9 {+-} 5.7 signal events on a background of 10.0 {+-} 1.4 events and the fit to the J/{psi}{pi}{sup {+-}} mass spectrum yields a B{sub c}{sup {+-}} mass of 6287.0 {+-} 4.8(stat) {+-} 1.1(syst) MeV/c{sup 2}.

  16. Physical Dust Models in the Light of Planck

    NASA Astrophysics Data System (ADS)

    Draine, Bruce T.

    2015-08-01

    The Spitzer, Herschel, and Planck missions have provided observational data that challenge existing models of interstellar dust, and will guide us in the development of a new generation of dust models. The spectacular data from Planck now enable us to characterize the intensity of dust emission at wavelengths from 350um to 3mm, with invaluable measurements of polarized dust emission from 850um to 4mm. Models for interstellar dust are constrained by these new data, and also by many other observational constraints, such as infrared emission at shorter wavelengths, wavelength-dependent extinction and polarization of starlight, scattering of starlight, scattering and extinction of X-rays by dust, and ground-based studies of anomalous microwave emission.A physical dust model consists of dust grains with specified compositions, geometries, and sizes. The assumed physical properties of the dust should be consistent with the laws of physics, our understanding of candidate materials, and interstellar abundance constraints. I will review some contemporary dust models, and discuss how they fare when confronted with available data.

  17. Mesonic Form Factors

    SciTech Connect

    Frederic D. R. Bonnet; Robert G. Edwards; George T. Fleming; Randal Lewis; David Richards

    2003-07-22

    We have started a program to compute the electromagnetic form factors of mesons. We discuss the techniques used to compute the pion form factor and present preliminary results computed with domain wall valence fermions on MILC asqtad lattices, as well as Wilson fermions on quenched lattices. These methods can easily be extended to rho-to-gamma-pi transition form factors.

  18. Techniques in meson spectroscopy

    SciTech Connect

    Longacre, R.S.

    1991-12-31

    This report contains lectures on the following topics: the quark model and beyond using quantum chromodynamics; analysis of formation reactions; energy dependence of the partial wave amplitudes; where the data for the t-matrix analysis comes from; and coupled channel analysis of isoscalar mesons.

  19. Physical and Mechanical Properties of Composites and Light Alloys Reinforced with Detonation Nanodiamonds

    NASA Astrophysics Data System (ADS)

    Sakovich, G. V.; Vorozhtsov, S. A.; Vorozhtsov, A. B.; Potekaev, A. I.; Kulkov, S. N.

    2016-07-01

    The influence of introduction of particles of detonation-synthesized nanodiamonds into composites and aluminum-base light alloys on their physical and mechanical properties is analyzed. The data on microstructure and physical and mechanical properties of composites and cast aluminum alloys reinforced with diamond nanoparticles are presented. The introduction of nanoparticles is shown to result in a significant improvement of the material properties.

  20. CIPANP 2006 Low Energy Hadron Physics Summary

    SciTech Connect

    Schumacher, Reinhard A.

    2006-11-17

    Recent results in the areas of hypernuclear physics, exotic atoms, photo- and electro-production of light mesons and baryons, and medium modifications of meson properties were presented at this conference. Facility highlights presentations were given for five laboratories: the ELSA complex at Bonn, the LEPS facility at SPring-8, the CLAS facility at Jefferson Lab, the MAMI complex at Mainz, and the COSY complex at Juelich. These talks collectively showed remarkably active programs at all these laboratories, as well as at BNL, KEK, PSI, and Frascati. No 'brand new' results were reported at this conference.

  1. The physics of Cerenkov light production during proton therapy.

    PubMed

    Helo, Y; Kacperek, A; Rosenberg, I; Royle, G; Gibson, A P

    2014-12-01

    There is increasing interest in using Cerenkov emissions for quality assurance and in vivo dosimetry in photon and electron therapy. Here, we investigate the production of Cerenkov light during proton therapy and its potential applications in proton therapy. A primary proton beam does not have sufficient energy to generate Cerenkov emissions directly, but we have demonstrated two mechanisms by which such emissions may occur indirectly: (1) a fast component from fast electrons liberated by prompt gamma (99.13%) and neutron (0.87%) emission; and (2) a slow component from the decay of radioactive positron emitters. The fast component is linear with dose and doserate but carries little spatial information; the slow component is non-linear but may be localised. The properties of the two types of emission are explored using Monte Carlo modelling in GEANT4 with some experimental verification. We propose that Cerenkov emissions could contribute to the visual sensation reported by some patients undergoing proton therapy of the eye and we discuss the feasibility of some potential applications of Cerenkov imaging in proton therapy. PMID:25365447

  2. Gamma ray astrophysics, the extragalactic background light, and new physics

    SciTech Connect

    Serpico, Pasquale D.; /Fermilab

    2008-09-01

    Very high energy gamma-rays are expected to be absorbed by the extragalactic background light over cosmological distances via the process of electron-positron pair production. However, recent observations of cosmologically distant emitters by ground based gamma-ray telescopes might be indicative of a higher-than-expected degree of transparency of the universe. One mechanism to explain this observation is the oscillation between photons and axion-like-particles (ALPs). Here we explore this possibility, focusing on photon-ALP conversion in the magnetic fields in and round gamma-ray sources and in the magnetic field of the Milky Way, where some fraction of the ALP flux is converted back into photons. We show that this mechanism can be efficient in allowed regions of the ALP parameter space, as well as in typical configurations of the Galactic Magnetic Field. As case example, we consider the spectrum observed from a HESS source. We also discuss features of this scenario which could be used to distinguish it from standard or other exotic models.

  3. SOLAR NEUTRINO PHYSICS: SENSITIVITY TO LIGHT DARK MATTER PARTICLES

    SciTech Connect

    Lopes, Ilidio; Silk, Joseph E-mail: ilopes@uevora.pt

    2012-06-20

    Neutrinos are produced in several neutrino nuclear reactions of the proton-proton chain and carbon-nitrogen-oxygen cycle that take place at different radii of the Sun's core. Hence, measurements of solar neutrino fluxes provide a precise determination of the local temperature. The accumulation of non-annihilating light dark matter particles (with masses between 5 GeV and 16 GeV) in the Sun produces a change in the local solar structure, namely, a decrease in the central temperature of a few percent. This variation depends on the properties of the dark matter particles, such as the mass of the particle and its spin-independent scattering cross-section on baryon-nuclei, specifically, the scattering with helium, oxygen, and nitrogen among other heavy elements. This temperature effect can be measured in almost all solar neutrino fluxes. In particular, by comparing the neutrino fluxes generated by stellar models with current observations, namely {sup 8}B neutrino fluxes, we find that non-annihilating dark matter particles with a mass smaller than 10 GeV and a spin-independent scattering cross-section with heavy baryon-nuclei larger than 3 Multiplication-Sign 10{sup -37} cm{sup -2} produce a variation in the {sup 8}B neutrino fluxes that would be in conflict with current measurements.

  4. The physics of Cerenkov light production during proton therapy

    NASA Astrophysics Data System (ADS)

    Helo, Y.; Kacperek, A.; Rosenberg, I.; Royle, G.; Gibson, A. P.

    2014-12-01

    There is increasing interest in using Cerenkov emissions for quality assurance and in vivo dosimetry in photon and electron therapy. Here, we investigate the production of Cerenkov light during proton therapy and its potential applications in proton therapy. A primary proton beam does not have sufficient energy to generate Cerenkov emissions directly, but we have demonstrated two mechanisms by which such emissions may occur indirectly: (1) a fast component from fast electrons liberated by prompt gamma (99.13%) and neutron (0.87%) emission; and (2) a slow component from the decay of radioactive positron emitters. The fast component is linear with dose and doserate but carries little spatial information; the slow component is non-linear but may be localised. The properties of the two types of emission are explored using Monte Carlo modelling in GEANT4 with some experimental verification. We propose that Cerenkov emissions could contribute to the visual sensation reported by some patients undergoing proton therapy of the eye and we discuss the feasibility of some potential applications of Cerenkov imaging in proton therapy.

  5. Device physics of single layer organic light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Crone, B. K.; Campbell, I. H.; Davids, P. S.; Smith, D. L.; Neef, C. J.; Ferraris, J. P.

    1999-11-01

    We present experimental and device model results for electron only, hole only, and bipolar organic light-emitting diodes fabricated using a soluble poly (p-phenylene vinylene) based polymer. Current-voltage (I-V) characteristics were measured for a series of electron only devices in which the polymer thickness was varied. The I-V curves were described using a device model from which the electron mobility parameters were extracted. Similarly, the hole mobility parameters were extracted using a device model description of I-V characteristics for a series of hole only devices where the barrier to hole injection was varied by appropriate choices of hole injecting electrode. The electron and hole mobilities extracted from the single carrier devices are then used, without additional adjustable parameters, to describe the measured current-voltage characteristics of a series of bipolar devices where both the device thickness and contacts were varied. The model successfully describes the I-V characteristics of single carrier and bipolar devices as a function of polymer thickness and for structures that are contact limited, space charge limited, and for cases in between. We find qualitative agreement between the device model and measured external luminance for a thickness series of devices. We investigate the sensitivity of the device model calculations to the magnitude of the bimolecular recombination rate prefactor.

  6. Rare B Meson Decays at the Tevatron

    SciTech Connect

    Hopkins, Walter

    2012-01-01

    Rare B meson decays are an excellent probe for beyond the Standard Model physics. Two very sensitive processes are the b {yields} s{mu}{sup +}{mu}{sup -} and B{sub s,d}{sup 0} {yields} {mu}{sup +}{mu}{sup -} decays. We report recent results at a center of mass energy of {radical}s = 1.96 TeV from CDF II using 7 fb{sup -1} at the Fermilab Tevatron Collider.

  7. B meson decays into charmless pseudoscalar scalar mesons

    SciTech Connect

    Delepine, D.; Lucio M, J. L.; Ramirez, Carlos A.; Mendoza S, J. A.

    2007-06-19

    The nonleptonic weak decays of meson B into a scalar and pseudoscalar meson are studied. The scalar mesons under consideration are {sigma} (or f0(600)), f0(980), a0(980) and K{sub 0}{sup *}(1430). We calculate the Branching ratios in the Naive Factorization approximation. Scalars are assumed to be qq-bar bounded sates, but an estimation can be obtained in the case they are four bounded states.

  8. Spectroscopy of D Mesons

    SciTech Connect

    Bianco, Stefano

    2006-02-11

    The scenario of heavy quark meson spectroscopy underwent recently a major revolution, after the observation of BABAR and CLEO, confirmed by BELLE, of DsJ L=1 excited states, and by further evidences by SELEX. These experimental results have cast doubts on the incarnations of the ideas of Heavy Quark Effective Theory in heavy quark spectroscopy. I shall review the status of experimental data, discuss implications and sketch an outlook.

  9. Analysis tools for MesonEx at CLAS12

    NASA Astrophysics Data System (ADS)

    Glazier, D. I.

    2016-05-01

    The JLAB upgrade will soon be completed and the new CLAS12 detector system will collect large volumes of data allowing detailed investigations of many aspects of hadron physics. The focus of the MesonEx experiment is on the production of mesonic states by low Q2 virtual photons, or quasi-real photons. Studying such mesonic states is a particularly challenging data analysis problem, requiring well understood detector systems, clean signal and background separation, handling of large volumes of data and crucially a close collaboration between experimentalists and theorists to ensure the most sophisticated theoretical methods are used to interrogate the data. Here we briefly outline some of the analysis and methods that are being used to prepare for the MesonEx experiment.

  10. Let there be light--with gallium nitride: the 2014 Nobel Prize in Physics.

    PubMed

    Von Dollen, Paul; Pimputkar, Siddha; Speck, James S

    2014-12-15

    Significant gains in energy savings now underway can be traced to a single invention--the blue light-emitting diode. GaN-based blue LED technology not only resulted in efficient white light sources, but continues to enable a host of applications and scientific inquiries. The researchers primarily responsible for the development of the blue LED were awarded the 2014 Nobel Prize in Physics. PMID:25411140

  11. Production of polarized vector mesons off nuclei

    SciTech Connect

    Kopeliovich, B. Z.; Nemchik, J.; Schmidt, Ivan

    2007-08-15

    Using the light-cone QCD dipole formalism we investigate manifestations of color transparency (CT) and coherence length (CL) effects in electroproduction of longitudinally (L) and transversally (T) polarized vector mesons. Motivated by forthcoming data from the HERMES experiment we predict both the A and Q{sup 2} dependence of the L/T ratios for {rho}{sup 0} mesons produced coherently and incoherently off nuclei. For an incoherent reaction the CT and CL effects add up and result in a monotonic A dependence of the L/T ratio at different values of Q{sup 2}. In contrast, for a coherent process the contraction of the CL with Q{sup 2} causes an effect opposite to that of CT and we expect quite a nontrivial A dependence.

  12. 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.

  13. The charge form factor of pseudoscalar mesons in a relativistic constituent quark model

    SciTech Connect

    Cardarelli, F.; Pace, E.; Grach, I.L.

    1994-04-01

    The charge form factor of pseudoscalar mesons has been investigated in the light-cone formalism, up to Q{sup 2} relevant to CEBAF energies. The consequences of adopting the meson wave functions generated through the Godfrey-Isgur q{bar q} potential, which reproduces the mass spectra, are discussed.

  14. Semileptonic D{sub s}{sup +}(1968) decays as a scalar meson probe

    SciTech Connect

    Fariborz, Amir H.; Jora, Renata; Schechter, Joseph; Naeem Shahid, M.

    2011-11-01

    The unusual multiplet structures associated with the light spin zero mesons have recently attracted a good deal of theoretical attention. Here we discuss some aspects associated with the possibility of getting new experimental information on this topic from semileptonic decays of heavy charged mesons into an isosinglet scalar or pseudoscalar plus leptons.

  15. Quark condensate and deviations from string-like behaviour of meson spectra

    NASA Astrophysics Data System (ADS)

    Afonin, S. S.

    2003-12-01

    I analyze the hypothesis that deviations from the linear meson mass spectra appear due to the dynamical chiral symmetry breaking in QCD. It is shown that the linear mass spectrum for the light, non-strange vector and axial-vector mesons is then parametrized by the constant fπ, being successful phenomenologically. The toy model for deviations from linearity is proposed.

  16. Study of Scalar Mesons and Related Radiative Decays

    SciTech Connect

    Deirdre Black; Masayasu Harada; Joseph Schechter

    2002-06-01

    After a brief review of the puzzling light scalar meson sector of QCD, a brief summary will be given of a paper concerning radiative decays involving the light scalars. There, a simple vector meson dominance model is constructed in an initial attempt to relate a large number of the radiative decays involving a putative scalar nonet to each other. As an application it is illustrated why a{sub 0}(980)-f{sub 0}(980) mixing is not expected to greatly alter the f{sub 0}/a{sub 0} production ratio for radiative {phi} decays.

  17. Supersymmetry across the light and heavy-light hadronic spectrum

    SciTech Connect

    Dosch, Hans Gunter; de Teramond, Guy F.; Brodsky, Stanley J.

    2015-10-07

    Relativistic light-front bound-state equations for mesons and baryons can be constructed in the chiral limit from the supercharges of a superconformal algebra which connect baryon and meson spectra. Quark masses break the conformal invariance, but the basic underlying supersymmetric mechanism, which transforms meson and baryon wave functions into each other, still holds and gives remarkable connections across the entire spectrum of light and heavy-light hadrons. As a result, we also briefly examine the consequences of extending the supersymmetric relations to double-heavy mesons and baryons.

  18. Open bottom mesons in a hot asymmetric hadronic medium

    NASA Astrophysics Data System (ADS)

    Pathak, Divakar; Mishra, Amruta

    2015-04-01

    The in-medium masses and optical potentials of B and B ¯ mesons are studied in an isospin asymmetric, strange, hot, and dense hadronic environment using a chiral effective model. The chiral SU(3 ) model originally designed for the light-quark sector, is generalized to include the heavy-quark sector (c and b ) to derive the interactions of the B and B ¯ mesons with the light hadrons. Owing to the large mass of bottom quark, we use only the empirical form of these interactions for the desired purpose, while treating the bottom degrees of freedom to be frozen in the medium. Hence, all medium effects are attributable to the in-medium interaction of the light-quark content of these open bottom mesons. Both B and B ¯ mesons are found to experience net attractive interactions in the medium, leading to lowering of their masses in the medium. The mass degeneracy of particles and antiparticles, (B+, B-) as well as (B0, B¯ 0), is observed to be broken in the medium, owing to equal and opposite contributions from a vectorial Weinberg-Tomozawa interaction term. Addition of hyperons to the medium lowers further the in-medium mass for each of these four mesons, while a nonzero isospin asymmetry is observed to break the approximate mass degeneracy of each pair of isospin doublets. These medium effects are found to be strongly density dependent and bear a considerably weaker temperature dependence. The results obtained in the present investigation are compared to predictions from the quark-meson coupling model, heavy meson effective theory, and the QCD sum rule approach.

  19. Hyperfine meson splittings: chiral symmetry versus transverse gluon exchange

    SciTech Connect

    Felipe J. Llanes-Estrada; Stephen R. Cotanch; Adam P. Szczepaniak; Eric S. Swanson

    2004-02-01

    Meson spin splittings are examined within an effective Coulomb gauge QCD Hamiltonian incorporating chiral symmetry and a transverse hyperfine interaction necessary for heavy quarks. For light and heavy quarkonium systems the pseudoscalar-vector meson spectrum is generated by approximate BCS-RPA diagonalizations. This relativistic formulation includes both S and D waves for the vector mesons which generates a set of coupled integral equations. A smooth transition from the heavy to the light quark regime is found with chiral symmetry dominating the /pi-/rho mass difference. A good, consistent description of the observed meson spin splittings and chiral quantities, such as the quark condensate and the /pi mass, is obtained. Similar comparisons with TDA diagonalizations, which violate chiral symmetry, are deficient for light pseudoscalar mesons indicating the need to simultaneously include both chiral symmetry and a hyperfine interaction. The /eta{sub b} mass is predicted to be around 9400 MeV consistent with other theoretical expectations and above the unconfirmed 9300 MeV candidate. Finally, for comparison with lattice results, the J reliability parameter is also evaluated.

  20. The hybrid mesons quest: the MesonEx experiment at Jefferson Laboratory

    NASA Astrophysics Data System (ADS)

    Rizzo, A.; CLAS Collaboration

    2016-02-01

    The meson spectroscopy plays nowadays a central role in the investigation of hadron structure thanks to the possible existence of exotic hybrid mesons, quark-antiquark-gluon bound states. Their explicit gluonic degrees of freedom which should clearly emerge from a Partial Wave Analysis (PWA) of the corresponding Dalitz plot of the exotic particle decay, may result in final JPC configurations not allowed in the constituent quark model. Besides this clear signature, hybrid mesons are also expected to have a large particle multiplicity decays, requiring for their search an experimental apparatus with high performances in terms of rate capability, resolution and almost a full acceptance to apply PWA methods. New-generation experiments are planned at Thomas Jefferson National Laboratory (VA, USA) for which an unprecedented statistics of large multiplicity decay events with fully reconstructed kinematics will be available. In particular for the MesonEx (CLAS12) experiment in Hall B, a wide scientific program that will start in 2016 has been deployed to study the meson spectrum at energies up to 11 GeV. A key role in such program is played by the Forward Tagger apparatus of the experiment, which will allow to extend the study of meson electro-production to very low Q2 values, in a quasi-real photo production kinematical region, where the production of hybrid mesons is expected to be favorite. Currently a new analysis framework for the search of the hybrid mesons is being set up by the HASPECT network, an international structure which gather people involved into theoretical and experimental hadronic physics all over the world. The goals of the network is to develop new analysis models and statistical techniques to unfold the signal and background distributions in high-statistics datasets. In this work are briefly presented the first preliminary results from the application of a statistical technique, namely the sPlot, to the data already acquired by the CLAS experiment for

  1. The Hall D Physics Program at JLab

    SciTech Connect

    Leckey, John P.

    2012-09-01

    GlueX is one of the flagship experiments of the 12 GeV era at the Thomas Jefferson National Accelerator Facility (JLab). The energy of the electron accelerator at JLab is presently undergoing an upgrade from 6 GeV to 12 GeV and a 4th experimental hall (Hall D) is being added. The GlueX experimental apparatus consists of a tagged coherent bremsstrahlung photon beam incident on a liquid hydrogen target. The photoproduced mesons, which are created inside of a 2.2 T solenoid, will then pass through a pair of drift chambers and eventually deposit their energy into either of two calorimeters, depending on their respective angles. GlueX will attempt to map out the light meson spectrum and search for meson-gluon hybrids to better understand the confinement of quarks and gluons in quantum chromodynamics (QCD). There is little data on the photoproduction of light mesons and the GlueX experiment will exceed the current photoproduction data by several orders of magnitude in the first year alone. Photoproduction is specifically well suited to search for meson-gluon hybrids because in the flux tube model the production cross-sections are higher for meson-gluon hybrids from photons, with the spins of the virtual quark-antiquark pair aligned, than from other sources such as pions, with the spins of the quark-antiquark pair anti-aligned. There are also other Hall D experiments proposed to look for physics beyond the Standard Model by studying Eta rare or forbidden decay channels such as eta to two neutral pions. The 12 GeV upgrade of the JLab accelerator and the complete physics program of Hall D will be presented.

  2. The Spectrophotometer II: A Module on the Spectral Properties of Light. Tech Physics Series.

    ERIC Educational Resources Information Center

    Frank, Nathaniel; And Others

    This module is designed to give the learner an understanding of the nature of light and how its properties are used in the design of spectrophotometers. Problems promote the use of spectrophotometers in qualitative analysis, the optical elements used in a monochromator, and the physical properties of the prism and the diffraction grating. Other…

  3. Student Understanding of Light as an Electromagnetic Wave: Relating the Formalism to Physical Phenomena.

    ERIC Educational Resources Information Center

    Ambrose, Bradley S.; Heron, Paula R. L.; Vokos, Stamatis; McDermott, Lillian C.

    1999-01-01

    Some serious difficulties that students have in understanding physical optics may be due in part to a lack of understanding of light as an electromagnetic wave. Describes the development and use of tutorials designed to address students' conceptual difficulties. (Contains over 15 references.) (Author/WRM)

  4. Physical characterization and profiling of airway epithelial derived exosomes using light scattering.

    PubMed

    Kesimer, Mehmet; Gupta, Richa

    2015-10-01

    Exosomes and other extracellular vesicles have been gaining interest during the last decade due to their emerging role in biology and, disease pathogenesis and their biomarker potential. Almost all published research related to exosomes and other extracellular vesicles include some form of physical characterization. Therefore, these vesicles should be precisely profiled and characterized physically before studying their biological role as intercellular messengers, biomarkers or therapeutic tools. Using a combination of light scattering techniques, including dynamic light scattering (DLS) and multi-angle laser light scattering combined with size exclusion separation (SEC-MALLS), we physically characterized and compared distinct extracellular vesicles derived from the apical secretions of two different cultured airway epithelial cells. The results indicated that epithelial cells release vesicles with distinct physical properties and sizes. Human primary tracheobronchial cell culture (HTBE) derived vesicles have a hydrodynamic radius (Rh) of approximately 340 nm while their radius of gyration (Rg) is approximately 200 nm. Electron microscopy analysis, however, revealed that their spherical component is 40-100 nm in size, and they carry filamentous, entangled membrane mucins on their surface that increases their overall radius. The mucin decoration on the surface defines their size and charge as measured using light scattering techniques. Their surface properties mirror the properties of the cells from which they are derived. This may provide a unique tool for researchers to elucidate the unanswered questions in normal airway biology and innate and adaptive defense, including the remodeling of airways during inflammation, tumorigenesis and metastasis. PMID:25823850

  5. Using the Overhead Projector as a Light Source for Physics Demonstrations

    ERIC Educational Resources Information Center

    Mak, Se-Yuen

    2006-01-01

    This article illustrates how the overhead projector can be used as a light source in some peculiar ways for physics demonstrations. Five examples are included: (1) Study of chromatic aberration; (2) Making giant Newton's rings; (3) Comparison of the rate of heat absorption by different surfaces; (4) Demonstration of greenhouse effect; and (5)…

  6. Physical and biogeochemical controls on light attenuation in a eutrophic, back-barrier estuary

    NASA Astrophysics Data System (ADS)

    Ganju, N. K.; Miselis, J. L.; Aretxabaleta, A. L.

    2014-12-01

    Light attenuation is a critical parameter governing the ecological function of shallow estuaries. In these systems primary production is often dominated by benthic macroalgae and seagrass; thus light penetration to the bed is of primary importance. We quantified light attenuation in three seagrass meadows in Barnegat Bay, New Jersey, a shallow eutrophic back-barrier estuary; two of the sites were located within designated Ecologically Sensitive Areas (ESAs). We sequentially deployed instrumentation measuring photosynthetically active radiation, chlorophyll a (chl a) fluorescence, dissolved organic matter fluorescence (fDOM; a proxy for colored dissolved organic matter (CDOM) absorbance), turbidity, pressure, and water velocity at 10 min intervals over 3-week periods at each site. At the southernmost site, where sediment availability was highest, light attenuation was highest and dominated by turbidity and to a lesser extent chl a and CDOM. At the central site, chl a dominated followed by turbidity and CDOM, and at the northernmost site turbidity and CDOM contributed equally to light attenuation. At a given site, the temporal variability of light attenuation exceeded the difference in median light attenuation between the three sites. Vessel wakes, anecdotally implicated in increasing sediment resuspension, did not contribute to local resuspension within the seagrass beds, though frequent vessel wakes were observed in the channels. With regards to light attenuation and water clarity, physical and biogeochemical variables appear to outweigh any regulation of boat traffic within the ESAs.

  7. Physical and biogeochemical controls on light attenuation in a eutrophic, back-barrier estuary

    USGS Publications Warehouse

    Ganju, Neil K.; Miselis, Jennifer L.; Aretxabaleta, Alfredo L.

    2014-01-01

    Light attenuation is a critical parameter governing the ecological function of shallow estuaries. In these systems primary production is often dominated by benthic macroalgae and seagrass; thus light penetration to the bed is of primary importance. We quantified light attenuation in three seagrass meadows in Barnegat Bay, New Jersey, a shallow eutrophic back-barrier estuary; two of the sites were located within designated Ecologically Sensitive Areas (ESAs). We sequentially deployed instrumentation measuring photosynthetically active radiation, chlorophyll-a (chl-a) fluorescence, dissolved organic matter fluorescence (fDOM; a proxy for colored DOM absorbance), turbidity, pressure, and water velocity at 10 min intervals over three week periods at each site. At the southernmost site, where sediment availability was highest, light attenuation was highest and dominated by turbidity and to a lesser extent chl-a and CDOM. At the central site, chl-a dominated followed by turbidity and CDOM, and at the northernmost site turbidity and CDOM contributed equally to light attenuation. At a given site, the temporal variability of light attenuation exceeded the difference in median light attenuation at the three sites, indicating the need for continuous high-temporal resolution measurements. Vessel wakes, anecdotally implicated in increasing sediment resuspension, did not contribute to local resuspension within the seagrass beds, though frequent vessel wakes were observed in the channels. With regards to light attenuation and water clarity, physical and biogeochemical variables appear to outweigh any regulation of boat traffic within the ESAs.

  8. A framework for validating light fields created using physically based rendering techniques

    NASA Astrophysics Data System (ADS)

    Whittinghill, David M.

    This research study presents a framework for applying physically based global illumination techniques to the creation of software models of light fields that are then validated against actual light fields measured in physical experiments. A prior experiment was performed by horticulture scientists in which the light field of an empty plant growth chamber was measured using quantum sensors at fixed spatial intervals. The result was a light map consisting of a 9 x 45, fixed-width, two-dimensional graph of sensor readings that described the intensity of radiant energy present in the chamber at the chosen locations. A single observation of the growth chamber was made resulting in a single data set consisting of 45 different, location-sensitive irradiance observations. To test this framework a series of simulations were performed in which the physical attributes of the growth chamber were duplicated as closely as possible in a virtual growth chamber software model. Modeled attributes included physical dimensions, wall and light reflectivity, and full-spectrum light characterization. Light transport was modeled using a physically based, global illumination rendering technique called photon mapping. Virtual sensors that recorded the intensity of the light that transmitted through their surface were placed in the virtual chamber at the same position and interval as the ones that were used in the physical experiment. The output of the virtual chamber experiments were represented as a graph in the same configuration as the one in the physical experiment. The experiment was conducted using a modified version of pbrt, a physically based, extensible renderer developed by Matt Pharr and Greg Humphreys [1]. As photon mapping uses a stochastic algorithm, many repetitions of the virtual chamber experiment were performed and the mean and standard deviation were recorded as a global measure for each chamber as well as for each individual sensor location. The global means of the

  9. Photoproduction of Mesons on Quasi-Free Nucleons

    NASA Astrophysics Data System (ADS)

    Keshelashvili, I.

    2014-11-01

    The investigation of excited baryon states is important to understand the underling nature/symmetries of hadronic matter. Historically, the first nucleon excitation experiments have been done using charged pion and kaon secondary beams. Later the antiproton-proton scattering has also been involved. However, since the beginning of the 90's meson photoproduction reactions have been considered as a powerful tool in baryon spectroscopy. In this contribution, we overview our experimental programs conducted at the bremsstrahlung photon beams of the MAMI accelerator in Mainz and the ELSA accelerator in Bonn. The results are differential and total cross sections for photoproduction of light neutral mesons and of meson pairs off quasi-free nucleons bound in the deuteron (and sometimes other light nuclei). The scientific programs of this experiments also include single and double polarization measurements as well.

  10. Exotic meson spectroscopy with CLAS

    SciTech Connect

    Adams, G.; Napolitano, J.

    1994-04-01

    The identification and study of mesons with explicit gluonic degrees of freedom will provide major constraints on nonperturbative QCD and models thereof. CLAS will provide a unique opportunity for studying these resonances by measuring photoproduction of multi-meson final states.