Bulletin of the American Physical Society
2010 Fall Meeting of the APS Division of Nuclear Physics
Volume 55, Number 14
Tuesday–Saturday, November 2–6, 2010; Santa Fe, New Mexico
Session FH: Ultra-relativistic Heavy-Ions: Probing the QCD EoS |
Hide Abstracts |
Chair: Bryon Neufeld, Los Alamos National Laboratory Room: Lamy |
Thursday, November 4, 2010 4:00PM - 4:12PM |
FH.00001: QCD thermodynamics with HISQ action Peter Petreczky, Alexei Bazavov We present recent results on chiral and deconfinement aspects of the QCD transition using lattice calculations with the Highly Improved Staggered Quark (HISQ) action. We will discuss the role of taste symmetry violation, inherent in the staggered formulation, in several observables including the trace anomaly, fluctuation of conserved charges, chiral condensate and its susceptibility. We will compare the lattice results with the prediction of the Hadron Resonance Gas model and give an estimate of the chiral transition temperature. [Preview Abstract] |
Thursday, November 4, 2010 4:12PM - 4:24PM |
FH.00002: ABSTRACT WITHDRAWN |
Thursday, November 4, 2010 4:24PM - 4:36PM |
FH.00003: ABSTRACT WITHDRAWN |
Thursday, November 4, 2010 4:36PM - 4:48PM |
FH.00004: Particle identification for RHIC's Energy Scan Abhilash Nair In an effort to search for a possible critical point of the QCD phase transition between Quark-Gluon Plasma and hadronic matter, the Relativistic Heavy Ion Collider (RHIC) has conducted an energy scan, taking Au+Au data at multiple collision energies in 2010. In this talk we will discuss the experimental technique employed for identification of pions, kaons, and (anti)proton at low transverse momenta ($<$1 GeV/c) with STAR Time Projection Chamber (TPC) detector. To explore antiparticle to particle ratios, and their evolution with beam energy, various aspects of data analysis and quality assurance will be discussed with regard to this topic. [Preview Abstract] |
Thursday, November 4, 2010 4:48PM - 5:00PM |
FH.00005: Higher Moments of Proton and Net-proton Multiplicity Distributions at RHIC Xiaofeng Luo One of the main goals of RHIC Beam Energy Scan (BES) program is to search for the QCD critical point in order to further our understanding of the phase structure of the hot and dense QCD matter created in high-energy nuclear collisions at RHIC. The STAR detector with its large, uniform acceptance is particularly suitable for fluctuation measurements, which are among the most promising for the search. Due to the higher sensitivity to the critical point compared to the variance ($\sigma $2) and direct connection to Lattice calculations [1,2], higher moments of proton and net-proton multiplicity distributions will be used [3]. In this talk, we will present measurements for higher moments (variance ($\sigma $2), skewness (S) and kurtosis ($\kappa ))$ of proton and net-proton multiplicity distributions measured at RHIC. It is observed that both S and~$\kappa $ are positive at all collision centralities and energies. The results of the products of the moment $\kappa $*$\sigma $2 and S*$\sigma $, which have been related by Lattice QCD calculation and QCD-based models to the ratio of different orders of the baryon number susceptibility [1] and long range correlations [2] will also be presented. [1] M. Cheng et al., Phys. Rev. D 79, 074505(2009), R. V. Gavai and S. Gupta, arXiv:1001.3796 [2] M. A. Stephanov, Phys. Rev. Lett. 102, 032301(2009) [3] M.M. Aggarwal et al. (STAR Collaboration), arXiv:1004.4959 (http://arxiv.org/abs/1004.4959) [Preview Abstract] |
Thursday, November 4, 2010 5:00PM - 5:12PM |
FH.00006: Source anisotropy in non-central heavy ion collisions in the RHIC energy scan - model expectations Michael Lisa, Elliot Mount The beam energy scan program at RHIC aims to identify nontrivial structure (phase boundaries, critical points) in the phase diagram of strongly-interacting matter. There may be corresponding features in the QCD Equation of State (e.g. ``soft spots'') which affect the dynamic evolution of the system, generating observables that vary non-trivially with the collision energy. We focus on the freezeout spatial anisotropy of the source created in non-central heavy ion collisions; this anisotropy is estimated from the azimuthal dependence of HBT radii from two-pion correlations [1]. While measurements of this anisotropy have been made at only a few energies, an intriguing and unexplained non-monotonic behaviour has been noted [2]. Using several transport model calculations, we will discuss the effect of the Equation of State and timescales on the freezeout anisotropy. Important technical aspects of model-to-data comparisons will be discussed. This will provide important context on the data available thus far, as well as newly emerging results from the beam energy scan by STAR Collaboration. \\[4pt] [1] Retiere and Lisa, Phys. Rev. {\bf C70} 044907 (2004); nucl-th/0312024\\[0pt] [2] Lisa and Pratt, arXiv:0811.1352 [Preview Abstract] |
Thursday, November 4, 2010 5:12PM - 5:24PM |
FH.00007: Measurement of Charge Asymmetry Correlations in High Energy Heavy Ion Collisions Quan Wang A possible manifestation of local parity violation in relativistic heavy-ion collisions is the event-wise separation of positive and negative charge along the direction perpendicular to the reaction plane. A direct consequence of this separation is a reduction in the correlation between the multiplicity asymmetries of positive($A_{+,UD}$) and negative($A_{-,UD}$) particles in the up and down hemispheres(UD) separated by the reaction plane, and an enhancement in the variances of $A_{\pm,UD}$. The reduction and/or enhancement in the up and down direction is compared to the reference asymmetry correlations in the left and right hemispheres(LR) separated by the plane normal to the reaction plane ($A_{+,LR}$ and $A_{-,LR}$). This talk reports the above correlations in Au+Au and d+Au collisions at 200 GeV measured by the STAR experiment at RHIC. The correlations are found to be significant and can be negative, reflecting the presence of charge (anti-)correlations unrelated to the local parity violation. It is further found that the UD correlations are always larger than LR correlations. These differences between UD and LR have important implications on the proposed local parity violation in the strong interaction. [Preview Abstract] |
Thursday, November 4, 2010 5:24PM - 5:36PM |
FH.00008: Di-lepton production in p+p collisions at $\sqrt{s_{_{NN}}} = 200$ GeV Bingchu Huang, Lijuan Ruan, Yifei Zhang Ultra-relativistic heavy ion collisions provide a unique
environment to study properties of strongly interacting matter at
high temperature and high energy density. One of the crucial
probes of this strongly interacting matter are dilepton
measurements at low ($M_{ll}<1.1 GeV/c2$) and intermediate
($1.1 |
Thursday, November 4, 2010 5:36PM - 5:48PM |
FH.00009: Measurement of Low Transverse Momentum Direct Photons Via External Conversions in Au+Au Collisions at $\sqrt{s} = 200$ GeV with the PHENIX Detector at RHIC Richard Petti Photons are an important probe of the hot and dense partonic
medium created through the collision of heavy ions at RHIC. This
is because they escape the medium with little modification and
carry information about the earliest stages of the collision,
including thermal radiation. It is also predicted that most of
the direct photons with $1 |
Thursday, November 4, 2010 5:48PM - 6:00PM |
FH.00010: Using Higher Moments of Fluctuations and their Ratios in the Search for the QCD Critical Point Christiana Athanasiou, Krishna Rajagopal, Misha Stephanov The QCD critical point can be found in heavy ion collision experiments via the non-monotonic behavior of many fluctuation observables as a function of the collision energy. The event-by-event fluctuations of various particle multiplicities and momenta are enhanced in those collisions that freeze out near the critical point. Higher, non-Gaussian, moments of the event-by-event distributions of such observables are particularly sensitive to critical fluctuations, since their magnitude depends on the critical correlation length to a high power. We present quantitative estimates of the contribution of critical fluctuations to the third and fourth moments of the pion, proton and net proton multiplicities and mean transverse momenta, as well as estimates of various measures of pion-proton correlations, all as a function of the same five non-universal parameters, one of which is the correlation length that parametrizes proximity to the critical point. From these several dozen fluctuation observables, many dimensionless ratios can be constructed. We show how to use these ratios to discover the critical point and, if it is found, to overconstrain the values of the non-universal parameters. [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