Bulletin of the American Physical Society
2005 2nd Joint Meeting of the Nuclear Physics Divisions of the APS and The Physical Society of Japan
Sunday–Thursday, September 18–22, 2005; Maui, Hawaii
Session KH: Relativistic Heavy Ions: Theory |
Hide Abstracts |
Sponsoring Units: DNP JPS Chair: Masayuki Asakawa, Osaka University Room: Ritz-Carlton Hotel Plantation 1 |
Thursday, September 22, 2005 2:00PM - 2:15PM |
KH.00001: From Hard Scattering to Classical Color Fields to Quark Gluon Plasma Joseph Kapusta, Rainer Fries, Yang Li We present a new approach to determine the energy-momentum tensor density between two colliding nuclei at very high energies shortly after the collision. Perturbative QCD is used to calculate the first hard scattering between partons in the colliding nuclei. The resulting fluctuation in the local color charge is used as a source for solving the classical equations of motion for the gluon field. This classical field decays into quark gluon plasma. Coherence arguments and energy- momentum conservation, including the decelerating nuclei, lead to constraints on the local energy density and pressure of the plasma phase. Our results can serve as initial conditions for a subsequent hydrodynamic evolution of the system. [Preview Abstract] |
Thursday, September 22, 2005 2:15PM - 2:30PM |
KH.00002: Quark production in high-energy pA collisions in the Color Glass Condensate framework Hirotsugu Fujii, Francois Gelis, Raju Venugopalan We present quantitative estimates of heavy flavor production in pA reactions at collider energies in the framework of the color glass condensate. We first quantify the breaking of kT-factorization as a function of the saturation scale, the quark mass and the transverse momentum. Next we evaluate the open charm/bottom cross sections numerically, and study their sensitivity to physical parameters. Our results are compared to the RHIC data for charm production and predictions are made charm and bottom production for the LHC. Finally, we apply our formalism (which includes re-scatterings of the produced quark pairs) to quarkonium production at RHIC and LHC. [Preview Abstract] |
Thursday, September 22, 2005 2:30PM - 2:45PM |
KH.00003: Proton-Nucleus Scattering in the Color Glass Condensate Kazunori Itakura We present an alternative description of the proton-nucleus collision within the framework of the Color Glass Condensate (CGC). This is based on the eikonal approximation for three valence quarks in a projectile proton which propagate in the strong gauge field created by the target nucleus treated as the CGC. The similar construction was recently done for the C-odd Odderon exchange. This description directly allows us to compute the evolution of the scattering amplitude between a 3-quark state and the CGC. We show the evolution equations in the weak and strong field regimes, and discuss the effects of gluon saturation. [Preview Abstract] |
Thursday, September 22, 2005 2:45PM - 3:00PM |
KH.00004: Confinement- Deconfinement Phase Transition at nonzero Chemical Potential Ariel Zhitnitsky We present arguments suggesting that large size overlapping instantons are the driving mechanism of the confinement-deconfinement phase transition at nonzero chemical potential $\mu$. The arguments are based on the picture that instantons at very large chemical potential in the weak coupling regime are localized configurations with finite size $\rho\sim\mu^{-1}$. At the same time, the same instantons at smaller chemical potential in the strong coupling regime are well represented by the so-called instanton-quarks with fractional topological charge $1/N_c$. We estimate the critical chemical potential $\mu_c(T)$ where this phase transition takes place as a function of temperature in the domain where our approach is justified. In this picture, the long standing problem of the ``accidental" coincidence of the chiral and deconfinement phase transitions at nonzero temperature (observed in lattice simulations) is naturally resolved. We also derive results at nonzero isospin chemical potential $\mu_I$ where direct lattice calculations are possible, and our predictions can be explicitly tested. [Preview Abstract] |
Thursday, September 22, 2005 3:00PM - 3:15PM |
KH.00005: Quarkonium Spectral Functions at zero and finite temperature Peter Petreczky I present calculations of quarkonium spectral functions at zero and finite temperature in lattice QCD. Calculations are performed in quenched approximation using both isotropic and anisotropic lattices. Lattice artifacts and systematic uncertainties are investigated in the zero temperature limit in detailed where many data points in the time direction are available. Then finite temperature spectral functions for charmonia and bottomonia spectral functions are presented. It has been found that 1S state charmonia ( $J/psi$, $\eta_c$ ) can survive in the plasma up to temperatures $1.5T_c$ with little in-medium modification, while 1S bottomonia states ( $\Upsilon$ and $\eta_b$ ) exist in the plasma up to temperatures $4.5T_c$. The 1P states ($\chi_c$, $\chi_b$), on the other hand, dissolve at tempearures of about $1.1T_c$. [Preview Abstract] |
Thursday, September 22, 2005 3:15PM - 3:30PM |
KH.00006: Diquark frangmentation model of baryon production in ultrarelativistic nucleus-nucleus collisions Kosuke Terasaki, Tetsuo Matsui Quark recombination model has been proposed to explain anomalous production of baryons with transverse momenta of a few GeV/c observed in Au+Au collisions at RHIC. The model explains the observed enhancement of baryon/meson ratio as well as the quark-number scaling of eliptic flow associated with baryons. The recent RHIC data shows, however, jet-like correlations of associated hadron production, the feature which may be more naturally explained by the quark fragmentation model. In this work, we study a new hybrid mechanism of baryon production which involves (color anti-triplet) di-quark formation by recombination of a pair of thermal quarks and its subsequent fragmentation into a baryon. This model, which we call ``diquark fragmentation model,'' incorporates two desirable features of the recombination model and the quark fragmentation model. Our results show, however, that there is a significant reduction of baryon momentum from that of its parent diquark at the time of the diquark fragmentation, and this leads to a suppression of baryon production at relevant momentum range. We found about 10 - 20\% of baryons are still produced at RHIC compared to usual recombination model at the transverse momentum of 2.5 - 4 GeV. [Preview Abstract] |
Thursday, September 22, 2005 3:30PM - 3:45PM |
KH.00007: Proposal for a High Energy Nuclear Database David Brown, Ramona Vogt We propose to develop a high-energy heavy-ion experimental database and make it accessible to the scientific community through an on-line interface. The database will be searchable and cross-indexed with relevant publications, including published detector descriptions. It should eventually contain all published data from the Bevalac, AGS, SPS and FNAL fixed-target programs to the RHIC and LHC colliders; proton-proton, proton-nucleus to nucleus-nucleus collisions as well as other relevant systems; and all measured observables. Such a database would have tremendous scientific payoff as it makes systematic studies easier and allows simpler benchmarking of theoretical models to a broad range of experiments. Furthermore, there is a growing need for compilations of high-energy nuclear data for applications including stockpile stewardship, technology development for inertial confinement fusion and target and source development for upcoming facilities such as the Next Linear Collider. To enhance the utility of the database, we propose periodic data evaluations and topical reviews. [Preview Abstract] |
Thursday, September 22, 2005 3:45PM - 4:00PM |
KH.00008: Form-factor dependence of B$_c$ absorption cross sections by nucleons M.A.K. Lodhi, Rian Marshall The cross sections for B$_c$ absorption by nucleons are examined using a gauged SU5 hadronic Lagrangianin a meson-baryonic exchange model. Only the charm exchange processes are examined with the assumption that lighter exchange processes dominate. Results are obtained without and with monopole form-factors to account for the hadron structure. Results with form-factors tend towards a range of about 1 to 7 mb near threshold energies. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700