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Title: Charged and strange hadron elliptic flow in Cu + Cu collisions at √sNN = 62.4 and 200 GeV

Abstract

We present the results of an elliptic flow, v{sub 2}, analysis of Cu+Cu collisions recorded with the solenoidal tracker detector (STAR) at the BNL Relativistic Heavy Ion Collider at {radical}s{sub NN} = 62.4 and 200 GeV. Elliptic flow as a function of transverse momentum, v{sub 2}(p{sub T}), is reported for different collision centralities for charged hadrons h{sup {+-}} and strangeness-containing hadrons K{sub S}{sup 0}, {Lambda}, {Xi}, and {phi} in the midrapidity region |{eta}| < 1.0. Significant reduction in systematic uncertainty of the measurement due to nonflow effects has been achieved by correlating particles at midrapidity, |{eta}| < 1.0, with those at forward rapidity, 2.5 < |{eta}| < 4.0. We also present azimuthal correlations in p+p collisions at {radical}s = 200 GeV to help in estimating nonflow effects. To study the system-size dependence of elliptic flow, we present a detailed comparison with previously published results from Au+Au collisions at {radical}s{sub NN} = 200 GeV. We observe that v{sub 2}(p{sub T}) of strange hadrons has similar scaling properties as were first observed in Au+Au collisions, that is, (i) at low transverse momenta, p{sub T} < 2 GeV/c, v{sub 2} scales with transverse kinetic energy, m{sub T}-m, and (ii) at intermediate p{sub T},more » 2 < p{sub T} < 4 GeV/c, it scales with the number of constituent quarks, n{sub q}. We have found that ideal hydrodynamic calculations fail to reproduce the centrality dependence of v{sub 2}(p{sub T}) for K{sub s}{sup 0} and {Lambda}. Eccentricity scaled v{sub 2} values, v{sub 2}/{var_epsilon}, are larger in more central collisions, suggesting stronger collective flow develops in more central collisions. The comparison with Au+Au collisions, which go further in density, shows that v{sub 2}/{var_epsilon} depends on the system size, that is, the number of participants N{sub part}. This indicates that the ideal hydrodynamic limit is not reached in Cu+Cu collisions, presumably because the assumption of thermalization is not attained.« less

Authors:
;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) Relativistic Heavy Ion Collider
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
989156
Report Number(s):
BNL-93802-2010-JA
Journal ID: ISSN 0556-2813; R&D Project: PO-003; KB0202012; TRN: US1007042
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Journal Name:
Physical Review C
Additional Journal Information:
Journal Volume: 81; Journal Issue: 4; Journal ID: ISSN 0556-2813
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 74 ATOMIC AND MOLECULAR PHYSICS; BNL; HADRONS; HEAVY IONS; HYDRODYNAMICS; KINETIC ENERGY; PARTICLE RAPIDITY; QUARKS; THERMALIZATION; TRANSVERSE MOMENTUM; relativistic heavy ion collider

Citation Formats

Abelev, B I, Dunlop, J, and et al. STAR Collaboration. Charged and strange hadron elliptic flow in Cu + Cu collisions at √sNN = 62.4 and 200 GeV. United States: N. p., 2010. Web. doi:10.1103/PhysRevC.81.044902.
Abelev, B I, Dunlop, J, & et al. STAR Collaboration. Charged and strange hadron elliptic flow in Cu + Cu collisions at √sNN = 62.4 and 200 GeV. United States. https://doi.org/10.1103/PhysRevC.81.044902
Abelev, B I, Dunlop, J, and et al. STAR Collaboration. Fri . "Charged and strange hadron elliptic flow in Cu + Cu collisions at √sNN = 62.4 and 200 GeV". United States. https://doi.org/10.1103/PhysRevC.81.044902.
@article{osti_989156,
title = {Charged and strange hadron elliptic flow in Cu + Cu collisions at √sNN = 62.4 and 200 GeV},
author = {Abelev, B I and Dunlop, J and et al. STAR Collaboration},
abstractNote = {We present the results of an elliptic flow, v{sub 2}, analysis of Cu+Cu collisions recorded with the solenoidal tracker detector (STAR) at the BNL Relativistic Heavy Ion Collider at {radical}s{sub NN} = 62.4 and 200 GeV. Elliptic flow as a function of transverse momentum, v{sub 2}(p{sub T}), is reported for different collision centralities for charged hadrons h{sup {+-}} and strangeness-containing hadrons K{sub S}{sup 0}, {Lambda}, {Xi}, and {phi} in the midrapidity region |{eta}| < 1.0. Significant reduction in systematic uncertainty of the measurement due to nonflow effects has been achieved by correlating particles at midrapidity, |{eta}| < 1.0, with those at forward rapidity, 2.5 < |{eta}| < 4.0. We also present azimuthal correlations in p+p collisions at {radical}s = 200 GeV to help in estimating nonflow effects. To study the system-size dependence of elliptic flow, we present a detailed comparison with previously published results from Au+Au collisions at {radical}s{sub NN} = 200 GeV. We observe that v{sub 2}(p{sub T}) of strange hadrons has similar scaling properties as were first observed in Au+Au collisions, that is, (i) at low transverse momenta, p{sub T} < 2 GeV/c, v{sub 2} scales with transverse kinetic energy, m{sub T}-m, and (ii) at intermediate p{sub T}, 2 < p{sub T} < 4 GeV/c, it scales with the number of constituent quarks, n{sub q}. We have found that ideal hydrodynamic calculations fail to reproduce the centrality dependence of v{sub 2}(p{sub T}) for K{sub s}{sup 0} and {Lambda}. Eccentricity scaled v{sub 2} values, v{sub 2}/{var_epsilon}, are larger in more central collisions, suggesting stronger collective flow develops in more central collisions. The comparison with Au+Au collisions, which go further in density, shows that v{sub 2}/{var_epsilon} depends on the system size, that is, the number of participants N{sub part}. This indicates that the ideal hydrodynamic limit is not reached in Cu+Cu collisions, presumably because the assumption of thermalization is not attained.},
doi = {10.1103/PhysRevC.81.044902},
url = {https://www.osti.gov/biblio/989156}, journal = {Physical Review C},
issn = {0556-2813},
number = 4,
volume = 81,
place = {United States},
year = {2010},
month = {4}
}