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Melting Sequence of Quarkonia

Description: In this talk I discuss what we can learn about quarkonium dissociation from lattice-potential based models, and summarize the current understanding of lattice data on quarkonium.
Date: April 5, 2008
Creator: Mocsy,A.
Partner: UNT Libraries Government Documents Department

Numerical Tests of the Improved Fermilab Action

Description: Recently, the Fermilab heavy-quark action was extended to include dimension-six and -seven operators in order to reduce the discretization errors. In this talk, we present results of the first numerical simulations with this action (the OK action), where we study the masses of the quarkonium and heavy-light systems. We calculate combinations of masses designed to test improvement and compare results obtained with the OK action to their counterparts obtained with the clover action. Our preliminary results show a clear improvement.
Date: November 1, 2010
Creator: Detar, C.; Kronfeld, A.S. & Oktay, M.B.
Partner: UNT Libraries Government Documents Department

Quarkonia as a multi-purpose tool

Description: Quarkonia can be a very useful tool for understanding the medium in which they are produced and pass through. However, their usefulness as a tool depends on how well certain aspects of their behavior in cold matter are understood.
Date: December 21, 2010
Creator: Vogt, R
Partner: UNT Libraries Government Documents Department


Description: Here I review the temperature-dependence of heavy quarkonia correlators in potential models with three different screened potentials, and compare these to the results from lattice QCD. None of the potentials investigated yield results consistent with the lattice data, indicating that screening is likely not the mechanism for heavy quarkonia suppression. I also discuss a simple toy model, not based on temperature-dependent screening, that can reproduce the lattice results.
Date: March 11, 2006
Creator: MOCSY, A.
Partner: UNT Libraries Government Documents Department

Quarkonium production in high energyproton-proton and proton-nucleus collisions

Description: We present a brief overview of the most relevant current issues related to quarkonium production in high energy proton-proton and proton-nucleus collisions along with some perspectives. After reviewing recent experimental and theoretical results on quarkonium production in pp and pA collisions, we discuss the emerging field of polarization studies. Afterwards, we report on issues related to heavy-quark production, both in pp and pA collisions, complemented by AA collisions. To put the work in broader perpectives, we emphasize the need for new observables to investigate the quarkonium production mechanisms and reiterate the qualities that make quarkonia a unique tool for many investigations in particle and nuclear physics.
Date: March 14, 2011
Creator: del Valle, Z C; Corcella, G; Fleuret, F; Ferreiro, E G; Kartvelishvili, V; Kopeliovich, B et al.
Partner: UNT Libraries Government Documents Department

Realizing the potential of quarkonium

Description: I recall the development of quarkonium quantum mechanics after the discovery of {Upsilon}. I emphasize the empirical approach to determining the force between quarks from the properties of c{anti c} and b{anti b} bound states. I review the application of scaling laws, semiclassical methods, theorems and near-theorems, and inverse- scattering techniques. I look forward to the next quarkonium spectroscopy in the B{sub c} system.
Date: July 1, 1997
Creator: Quigg, C.
Partner: UNT Libraries Government Documents Department


Description: The RIKEN-BNL Workshop on Quarkonium Production in Relativistic Nuclear Collisions was held September 28--October 2, 1998, at Brookhaven National Laboratory. The Workshop brought together about 50 invited participants from around the world and a number of Brookhaven physicists from both particle and nuclear physics communities.
Date: April 20, 1999
Creator: Kharzeev, D.
Partner: UNT Libraries Government Documents Department

Quarkonium: New Developments

Description: To illustrate the campaign to understand heavy quarkonium systems, the author focuses on a puzzling new state, X(3872) {yields} {pi}{sup +}{pi}{sup -} J/{psi}. Studying the influence of open-charm channels on charmonium properties leads us to propose a new charmonium spectroscopy: additional discrete charmonium levels that can be discovered as narrow resonances of charmed and anticharmed mesons. I recall some expectations for a new spectroscopy of mesons with beauty and charm, the B{sub c} (b{bar c}) system. Throughout, I call attention to open issues for theory and experiment.
Date: March 23, 2004
Creator: Quigg, Chris
Partner: UNT Libraries Government Documents Department


Description: We discuss the calculations of quarkonium spectral functions in potential models and their implications for the interpretation of the lattice data on quarkonium correlators. In particular, we find that melting of different quarkonium states does not lead to significant change in the Euclidean time correlators. The large change of the quarkonium correlators above deconfinement observed in the scalar and axial-vector channels appears to be due to the zero mode contribution.
Date: July 30, 2007
Partner: UNT Libraries Government Documents Department

Heavy Quarkonium Production in Single Transverse Polarized HighEnergy Scattering

Description: We formulate the single transverse spin asymmetry in heavyquarkoniumproduction in lepton-nucleon and nucleon-nucleon collisionsinthe non-relativistic limit. We findthat the asymmetry is very sensitiveto the production mechanism. The finalstate interactions with the heavyquark and antiquark cancel out among themselves whenthe pair are producedin a color-single configuration, or cancel out with the initialstateinteraction in pp scattering when they are in color-octet. As aconsequence, the asymmetry is nonzero in ep collisions only in thecolor-octet model, whereas in pp collisions only in the color-singletmodel.
Date: January 17, 2008
Creator: Yuan, Feng
Partner: UNT Libraries Government Documents Department

Quarkonium shadowing in pPb and Pb+Pb collisions

Description: The d+Au data from RHIC, including the pA results from the fixed-target CERN SPS pA data, suggest increased importance of initial-state shadowing and decreasing nuclear absorption with increasing energy. This is not surprising since smaller x is probed at higher energy while absorption due to multiple scattering is predicted to decrease with energy. The CERN SPS data suggest a J/{psi} absorption cross section of about 4 mb without shadowing, and a larger absorption cross section if it is included since the SPS x range is in the antishadowing region. The d+Au RHIC data support smaller absorption, {sigma}{sup J/{psi}}{sub abs} {approx} 0-2 mb. Thus our predictions for J/{psi} and {Upsilon} production in pPb and Pb+Pb interactions at the LHC are shown for initial-state shadowing alone with no absorption or dense matter effects. We note that including absorption would only move the calculated ratios down in proportion to the absorption survival probability since, at LHC energies, any rapidity dependence of absorption is at very large |y|, outside the detector acceptance.
Date: May 21, 2007
Creator: Vogt, R
Partner: UNT Libraries Government Documents Department

Quarkonium Spectroscopy at BaBar

Description: The Babar experiment at the high luminosity storage ring PEP-II offers excellent opportunities in quarkonium spectroscopy. Recent Babar results obtained in this field are reported.
Date: April 21, 2006
Creator: Negrini, M.
Partner: UNT Libraries Government Documents Department

Static hybrid quarkonium potential with improved staggered quarks

Description: The authors are studying the effects of light dynamical quarks on the excitation energies of a flux tube between a static quark and antiquark. They report preliminary results of an analysis of the ground state potential and the {Sigma}{prime}{sub g}{sup +} and II{sub u} potentials. They have measured these potentials on closely matched ensembles of gauge configurations, generated in the quenched approximation and with 2+1 flavors of Asqtad improved staggered quarks.
Date: January 6, 2004
Creator: al., C. Bernard et
Partner: UNT Libraries Government Documents Department

Radial and orbital q{anti q} excitations: ``Higher quarkonia``

Description: Identification of the spectrum of non-{ital q{anti q}} exotica such as glueballs, hybrids and molecules will require a detailed understanding of radially and orbitally excited quarkonia, since these states are a background to non-{ital q{anti q}} states. The data likely to become available experimentally on these higher-mass resonances are their total widths and strong branching fractions to dominant modes. We advocate the use of these branching fractions to distinguish quarkonia from exotica; in this contribution we summarize our recent detailed {sup 3}P{sub 0} decay model calculations of the 374 two-body open-flavor decay modes of the 32 lightest {ital n{anti n}} states above 1S and 1P, which should be useful for this program.
Date: December 31, 1996
Creator: Barnes, T.
Partner: UNT Libraries Government Documents Department

Light-cone quantization and QCD phenomenology

Description: In principle, quantum chromodynamics provides a fundamental description of hadronic and nuclear structure and dynamics in terms of their elementary quark and gluon degrees of freedom. In practice, the direct application of QCD to reactions involving the structure of hadrons is extremely complex because of the interplay of nonperturbative effects such as color confinement and multi-quark coherence. A crucial tool in analyzing such phenomena is the use of relativistic light-cone quantum mechanics and Fock state methods to provide tractable and consistent treatments of relativistic many-body systems. In this article we present an overview of this formalism applied to QCD, focusing in particular on applications to the final states in deep inelastic lepton scattering that will be relevant for the proposed European Laboratory for Electrons (ELFE), HERMES, HERA, SLAC, and CEBAF. We begin with a brief introduction to light-cone field theory, stressing how it many allow the derivation of a constituent picture, analogous to the constituent quark model, from QCD. We then discuss several applications of the light-cone Fock state formalism to QCD phenomenology. The Fock state representation includes all quantum fluctuations of the hadron wavefunction, including far off-shell configurations such as intrinsic charm and, in the case of nuclei, hidden color. In some applications, such as exclusive processes at large momentum transfer, one can make first-principle predictions using factorization theorems which separate the hard perturbative dynamics from the nonpertubative physics associated with hadron binding. The Fock state components of the hadron with small transverse size, which dominate hard exclusive reactions, have small color dipole moments and thus diminished hadronic interactions. Thus QCD predicts minimal absorptive corrections, i.e., color transparency for quasi-elastic exclusive reactions in nuclear targets at large momentum transfer.
Date: December 1995
Creator: Brodsky, S. J. & Robertson, D. G.
Partner: UNT Libraries Government Documents Department

Recent Results on J/{psi}, {psi}(2S) and {Upsilon}production at CDF

Description: CDF has obtained new results on quarkonium production in p{anti p} collisions at {radical}s = 1.8 TeV. The author reports on measurements of {Upsilon} meson production, {Upsilon}(1S) production from {chi}{sub b} feeddown, and the production polarization of {Upsilon}(1S), J/{psi} and {psi}(2S) mesons.
Date: January 25, 2000
Creator: Cropp, R.
Partner: UNT Libraries Government Documents Department

Quark-antiquark bound states in the relativistic spectator formalism

Description: The quark-antiquark bound states are discussed using the relativistic spectator (Gross) equations. A relativistic covariant framework for analyzing confined bound states is developed. The relativistic linear potential developed in an earlier work is proven to give vanishing meson {r_arrow} q + {anti q} decay amplitudes, as required by confinement. The regularization of the singularities in the linear potential that are associated with nonzero energy transfers (i.e. q{sup 2} = 0, q{sup {mu}} {ne} 0) is improved. Quark mass functions that build chiral symmetry into the theory and explain the connection between the current quark and constituent quark masses are introduced. The formalism is applied to the description of pions and kaons with reasonable results.
Date: November 1, 1999
Creator: Savkli, Cetin & Gross, Franz
Partner: UNT Libraries Government Documents Department

Explicit quark-hadron duality in 1+1 dimensions

Description: Explicit quark-hadron duality in the limit of heavy quark mass is studied using the 't Hooft model, where both partonic and hadronic amplitudes may be computed exactly. Results for weak decays of heavy mesons are presented for both standard spectator decays, where the duality limit is convincingly approached, and annihilation decays of the valence quark-antiquark pair, where the approach to asymptotic duality is much less precise.
Date: June 1, 1998
Creator: Lebed, Richard F.
Partner: UNT Libraries Government Documents Department

Quarkonia production and polarization studies with CDF

Description: In this paper the authors present results on production and polarization of the J/{psi}, {psi}(2S), {chi}e, {Upsilon} and {chi}b states at {radical}s = 1.8 TeV. These results were obtained from data taken with the CDF detector at Fermilab. They cover recently completed analyses of the 1992--96 collider run.
Date: April 16, 2001
Creator: Papadimitriou, Vaia
Partner: UNT Libraries Government Documents Department

Summary (Summary Talk at the Quarkonium Production in Nuclear Collisions Workshop).

Description: This summary is an attempt to overview the wealth of new results and ideas in quarkonium physics presented at the Seattle Workshop. The Workshop in Seattle has shown that the physics of heavy quarkonium continues to develop at a fast pace; moreover, we have every reason to believe that the next year, with RHIC turning on, will mark the beginning of the new exciting era in this field.
Date: May 11, 1998
Creator: Kharzeev, D.
Partner: UNT Libraries Government Documents Department

Charm and beauty production and polarization at CDF

Description: In this paper the authors present results on Charm and Beauty production as well as on production and polarization of Quarkonia at {radical}s = 1.8 TeV. These results were obtained from data taken with the CDF detector at Fermilab. They cover recently completed analyses of the 1992--96 collider run.
Date: October 10, 2000
Creator: Papadimitriou, Vaia
Partner: UNT Libraries Government Documents Department

Spin structure of the proton

Description: In these lectures the author argues that their response to the spin crisis should not be to abandon the naive quark model baby, but rather to allow it to mature. He begin by recalling what a beautiful baby the quark model is via an overview of its successes in spectroscopy, dynamics, and valence spin structure. He also introduces the conservative hypothesis that dynamical q{anti q} pairs are its key missing ingredient. He then discusses dressing the baby. He first shows that it can be clothed in glue without changing its spectroscopic successes. In the process, several dynamical mysteries associated with quark model spectroscopy are potentially explained. Next, he dresses the baby in q{anti q} pairs, first showing that this can be done without compromising the naive quark model's success with either spectroscopy or the OZI rule. Finally, he shows that despite their near invisibility elsewhere, pairs do play an important role in the proton's spin structure by creating an antipolarized q{anti q} sea. In the context of an explicit calculation he demonstrate that it is plausible that the entire ''spin crisis'' arises from this effect.
Date: August 1, 1995
Creator: Isgur, Nathan
Partner: UNT Libraries Government Documents Department