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Title: Mass, quark-number, and {radical}(s{sub NN}) dependence of the second and fourth flow harmonics in ultrarelativistic nucleus-nucleus collisions

Abstract

We present STAR measurements of the azimuthal anisotropy parameter v{sub 2} for pions, kaons, protons, {lambda},{lambda},{xi}+{xi}, and {omega}+{omega}, along with v{sub 4} for pions, kaons, protons, and {lambda}+{lambda} at midrapidity for Au+Au collisions at {radical}(s{sub NN})=62.4 and 200 GeV. The v{sub 2}(p{sub T}) values for all hadron species at 62.4 GeV are similar to those observed in 130 and 200 GeV collisions. For observed kinematic ranges, v{sub 2} values at 62.4, 130, and 200 GeV are as little as 10-15% larger than those in Pb+Pb collisions at {radical}(s{sub NN})=17.3 GeV. At intermediate transverse momentum (p{sub T} from 1.5-5 GeV/c), the 62.4 GeV v{sub 2}(p{sub T}) and v{sub 4}(p{sub T}) values are consistent with the quark-number scaling first observed at 200 GeV. A four-particle cumulant analysis is used to assess the nonflow contributions to pions and protons and some indications are found for a smaller nonflow contribution to protons than pions. Baryon v{sub 2} is larger than antibaryon v{sub 2} at 62.4 and 200 GeV, perhaps indicating either that the initial spatial net-baryon distribution is anisotropic, that the mechanism leading to transport of baryon number from beam- to midrapidity enhances v{sub 2} or that antibaryon and baryon annihilation is larger inmore » the in-plane direction.« less

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;  [1]
  1. Yale University, New Haven, Connecticut 06520 (United States) (and others)
Publication Date:
OSTI Identifier:
20995310
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 75; Journal Issue: 5; Other Information: DOI: 10.1103/PhysRevC.75.054906; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ANNIHILATION; ANTIBARYONS; BARYON NUMBER; COLLISIONS; GEV RANGE; GOLD; HARMONICS; KAONS; LEAD; OMEGA BARYONS; PIONS; PROTONS; QUARKS; RELATIVISTIC RANGE; TRANSVERSE MOMENTUM

Citation Formats

Abelev, B. I., Baumgart, S., Bielcik, J., Bielcikova, J., Caines, H., Catu, O., Chikanian, A., Du, F., Finch, E., Harris, J. W., Heinz, M., Knospe, A. G., Lamont, M. A. C., Lin, G., Majka, R., Nattrass, C., Salur, S., Sandweiss, J., Smirnov, N., and Witt, R.. Mass, quark-number, and {radical}(s{sub NN}) dependence of the second and fourth flow harmonics in ultrarelativistic nucleus-nucleus collisions. United States: N. p., 2007. Web. doi:10.1103/PHYSREVC.75.054906.
Abelev, B. I., Baumgart, S., Bielcik, J., Bielcikova, J., Caines, H., Catu, O., Chikanian, A., Du, F., Finch, E., Harris, J. W., Heinz, M., Knospe, A. G., Lamont, M. A. C., Lin, G., Majka, R., Nattrass, C., Salur, S., Sandweiss, J., Smirnov, N., & Witt, R.. Mass, quark-number, and {radical}(s{sub NN}) dependence of the second and fourth flow harmonics in ultrarelativistic nucleus-nucleus collisions. United States. doi:10.1103/PHYSREVC.75.054906.
Abelev, B. I., Baumgart, S., Bielcik, J., Bielcikova, J., Caines, H., Catu, O., Chikanian, A., Du, F., Finch, E., Harris, J. W., Heinz, M., Knospe, A. G., Lamont, M. A. C., Lin, G., Majka, R., Nattrass, C., Salur, S., Sandweiss, J., Smirnov, N., and Witt, R.. Tue . "Mass, quark-number, and {radical}(s{sub NN}) dependence of the second and fourth flow harmonics in ultrarelativistic nucleus-nucleus collisions". United States. doi:10.1103/PHYSREVC.75.054906.
@article{osti_20995310,
title = {Mass, quark-number, and {radical}(s{sub NN}) dependence of the second and fourth flow harmonics in ultrarelativistic nucleus-nucleus collisions},
author = {Abelev, B. I. and Baumgart, S. and Bielcik, J. and Bielcikova, J. and Caines, H. and Catu, O. and Chikanian, A. and Du, F. and Finch, E. and Harris, J. W. and Heinz, M. and Knospe, A. G. and Lamont, M. A. C. and Lin, G. and Majka, R. and Nattrass, C. and Salur, S. and Sandweiss, J. and Smirnov, N. and Witt, R.},
abstractNote = {We present STAR measurements of the azimuthal anisotropy parameter v{sub 2} for pions, kaons, protons, {lambda},{lambda},{xi}+{xi}, and {omega}+{omega}, along with v{sub 4} for pions, kaons, protons, and {lambda}+{lambda} at midrapidity for Au+Au collisions at {radical}(s{sub NN})=62.4 and 200 GeV. The v{sub 2}(p{sub T}) values for all hadron species at 62.4 GeV are similar to those observed in 130 and 200 GeV collisions. For observed kinematic ranges, v{sub 2} values at 62.4, 130, and 200 GeV are as little as 10-15% larger than those in Pb+Pb collisions at {radical}(s{sub NN})=17.3 GeV. At intermediate transverse momentum (p{sub T} from 1.5-5 GeV/c), the 62.4 GeV v{sub 2}(p{sub T}) and v{sub 4}(p{sub T}) values are consistent with the quark-number scaling first observed at 200 GeV. A four-particle cumulant analysis is used to assess the nonflow contributions to pions and protons and some indications are found for a smaller nonflow contribution to protons than pions. Baryon v{sub 2} is larger than antibaryon v{sub 2} at 62.4 and 200 GeV, perhaps indicating either that the initial spatial net-baryon distribution is anisotropic, that the mechanism leading to transport of baryon number from beam- to midrapidity enhances v{sub 2} or that antibaryon and baryon annihilation is larger in the in-plane direction.},
doi = {10.1103/PHYSREVC.75.054906},
journal = {Physical Review. C, Nuclear Physics},
number = 5,
volume = 75,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}
  • We present STAR measurements of the azimuthal anisotropy parameter {nu}{sub 2} for pions, kaons, protons, {Lambda},{bar {Lambda}},{Xi}+{bar {Xi}}, and {Omega}+{bar {Omega}}, along with {nu}{sub 4} for pions, kaons, protons, and {Lambda}+{bar {Lambda}} at midrapidity for Au+Au collisions at {radical}s{sub NN}=62.4 and 200 GeV. The {nu}{sub 2}(p{sub T}) values for all hadron species at 62.4 GeV are similar to those observed in 130 and 200 GeV collisions. For observed kinematic ranges, {nu}{sub 2} values at 62.4, 130, and 200 GeV are as little as 10-15% larger than those in Pb+Pb collisions at {radical}s{sub NN}=17.3 GeV. At intermediate transverse momentum (p{sub T}more » from 1.5-5 GeV/c), the 62.4 GeV {nu}{sub 2}(p{sub T}) and {nu}{sub 4}(pT) values are consistent with the quark-number scaling first observed at 200 GeV. A four-particle cumulant analysis is used to assess the nonflow contributions to pions and protons and some indications are found for a smaller nonflow contribution to protons than pions. Baryon {nu}{sub 2} is larger than antibaryon {nu}{sub 2} at 62.4 and 200 GeV, perhaps indicating either that the initial spatial net-baryon distribution is anisotropic, that the mechanism leading to transport of baryon number from beam- to midrapidity enhances {nu}{sub 2} or that antibaryon and baryon annihilation is larger in the in-plane direction.« less
  • We present STAR measurements of the azimuthal anisotropyparameter v_2 for pions, kaons, protons, Lambda, bar Lambda, Xi+bar Xi,and \Omega + bar Omega, along with v_4 for pions, kaons, protons, andLambda + bar Lambda at mid-rapidity for Au+Au collisions at sqrt sNN=62.4and 200 GeV. The v_2(p_T) values for all hadron species at 62.4 GeV aresimilar to those observed in 130 and 200 GeV collisions. For observedkinematic ranges, v_2 values at 62.4, 130, and 200 GeV are as little as10 percent-15 percent larger than those in Pb+Pb collisions at sqrt s NN=17.3 GeV. At intermediate transverse momentum (p_T from 1.5-5 GeV/c),the 62.4more » GeV v_2(p_T) and v_4(p_T) values are consistent with thequark-number scaling first observed at 200 GeV. A four-particle cumulantanalysis is used to assess the non-flow contributions to pions andprotons and some indications are found for a smaller non-flowcontribution to protons than pions. Baryon v_2 is larger than anti-baryonv_2 at 62.4 and 200 GeV perhaps indicating either that the initialspatial net-baryon distribution is anisotropic, that the mechanismleading to transport of baryon number from beam- to mid-rapidity enhancesv_2, or that anti-baryon and baryon annihilation is larger in thein-plane direction.« less
  • Elliptic flows of charged particles produced in nucleus-nucleus collisions at high energy are studied in the framework of a multisource ideal-gas model. The participant nucleon number at a fixed impact parameter is calculated by a geometrical picture of the participant-spectator model. Then, the dependence of elliptic flow on participant nucleon number is obtained in the combined framework of the two models. Our calculated results are approximately in agreement with the experimental data of the PHENIX Collaboration.
  • We predict the elliptic flow parameter v{sub 2} in U+U collisions at {radical}(s{sub NN})=200 GeV and in Pb+Pb collisions at {radical}(s{sub NN})=2.76 TeV using a hybrid model in which the evolution of the quark gluon plasma is described by ideal hydrodynamics with a state-of-the-art lattice QCD equation of state and the subsequent hadronic stage is described by a hadron cascade model.
  • Taking into account entropy generation during evolution of a viscous fluid, we have estimated the inverse Knudsen number, the ideal hydrodynamic limit for elliptic flow, and the quark-gluon plasma viscosity to entropy ratio in {radical}(s{sub NN})=62 and 200 GeV Cu+Cu/Au+Au collisions. The viscosity to entropy ratio is estimated as {eta}/s=0.17{+-}0.10{+-}0.20, where the first error is statistical, the second one is systematic. In a central Au+Au collision, the inverse Knudsen number is {approx_equal}2.80{+-}1.63, which is presumably too small for complete equilibration. In peripheral collisions it is even less. The ideal hydrodynamic limit for elliptic flow is {approx}40% more than the experimentalmore » flow in a central collision.« less