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Title: Narrowing of the charge balance function and hadronization time in relativistic heavy-ion collisions

Abstract

The width of charge balance function in high energy hadron-hadron and relativistic heavy-ion collisions are studied using the Monte Carlo generators PYTHIA and AMPT, respectively. The narrowing of balance function as the increase of multiplicity is found in both cases. The mean parton-freeze-out time of a heavy-ion collision event is used as the characteristic hadronization time for the event. It turns out that for a fixed multiplicity interval the width of balance function is consistent with being independent of hadronization time.

Authors:
; ;  [1]
  1. Institute of Particle Physics, Huazhong Normal University, Wuhan 430079 (China)
Publication Date:
OSTI Identifier:
20990996
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 75; Journal Issue: 2; Other Information: DOI: 10.1103/PhysRevC.75.021903; (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; BALANCES; FREEZING OUT; FUNCTIONS; HADRONS; HEAVY ION REACTIONS; MONTE CARLO METHOD; RELATIVISTIC RANGE; WIDTH

Citation Formats

Du, Jiaxin, Li, Na, and Liu, Lianshou. Narrowing of the charge balance function and hadronization time in relativistic heavy-ion collisions. United States: N. p., 2007. Web. doi:10.1103/PHYSREVC.75.021903.
Du, Jiaxin, Li, Na, & Liu, Lianshou. Narrowing of the charge balance function and hadronization time in relativistic heavy-ion collisions. United States. doi:10.1103/PHYSREVC.75.021903.
Du, Jiaxin, Li, Na, and Liu, Lianshou. Thu . "Narrowing of the charge balance function and hadronization time in relativistic heavy-ion collisions". United States. doi:10.1103/PHYSREVC.75.021903.
@article{osti_20990996,
title = {Narrowing of the charge balance function and hadronization time in relativistic heavy-ion collisions},
author = {Du, Jiaxin and Li, Na and Liu, Lianshou},
abstractNote = {The width of charge balance function in high energy hadron-hadron and relativistic heavy-ion collisions are studied using the Monte Carlo generators PYTHIA and AMPT, respectively. The narrowing of balance function as the increase of multiplicity is found in both cases. The mean parton-freeze-out time of a heavy-ion collision event is used as the characteristic hadronization time for the event. It turns out that for a fixed multiplicity interval the width of balance function is consistent with being independent of hadronization time.},
doi = {10.1103/PHYSREVC.75.021903},
journal = {Physical Review. C, Nuclear Physics},
number = 2,
volume = 75,
place = {United States},
year = {Thu Feb 15 00:00:00 EST 2007},
month = {Thu Feb 15 00:00:00 EST 2007}
}
  • The two-particle azimuthal angle correlation (TPAC) and azimuthal charge balance function (ACBF) are used to study the anisotropic expansion in relativistic heavy ion collisions. It is demonstrated by the relativistic quantum molecular dynamics (RQMD) model and a multi-phase transport (AMPT) model that the small-angle correlation in TPAC indeed presents anisotropic expansion, and the large-angle (or back-to-back) correlation is mainly due to global momentum conservations. The AMPT model reproduces the observed TPAC, but the RQMD model fails to reproduce the strong correlations in both small and large azimuthal angles. The width of ACBF from RQMD and AMPT models decreases from peripheralmore » to central collisions, consistent with experimental data, but in contrast to the expectation from thermal model calculations. The ACBF is insensitive to anisotropic expansion. It is a probe for the mechanism of hadronization, similar to the charge balance function in rapidity.« less
  • Balance functions have been measured in terms of relative pseudorapidity ( Δη ) for charged particle pairs at the BNL Relativistic Heavy Ion Collider (RHIC) from Au + Au collisions atmore » $$\sqrt{s}$$$_{NN}$$ = 7.7 GeV to 200 GeV using the STAR detector. These results are compared with balance functions measured at the CERN Large Hadron Collider from Pb + Pb collisions at $$\sqrt{s}$$$_{NN}$$ = 2.76 TeV by the ALICE Collaboration. The width of the balance function decreases as the collisions become more central and as the beam energy is increased. In contrast, the widths of the balance functions calculated using shuffled events show little dependence on centrality or beam energy and are larger than the observed widths. Balance function widths calculated using events generated by UrQMD are wider than the measured widths in central collisions and show little centrality dependence. The measured widths of the balance functions in central collisions are consistent with the delayed hadronization of a deconfined quark gluon plasma (QGP). Finally, the narrowing of the balance function in central collisions at $$\sqrt{s}$$$_{NN}$$ = 7.7 GeV implies that a QGP is still being created at this relatively low energy.« less
  • Bmore » alance functions have been measured in terms of relative pseudorapidity (Δη) for charged particle pairs at the NL Relativistic Heavy Ion Collider from Au + Au collisions at s NN =7.7GeV to 200 GeV using the STAR detector. These results are compared with balance functions measured at the CERN Large Hadron Collider from Pb + Pb collisions at s NN =2.76TeV by the ALICE Collaboration. The width of the balance function decreases as the collisions become more central and as the beam energy is increased. In contrast, the widths of the balance functions calculated using shuffled events show little dependence on centrality or beam energy and are larger than the observed widths. alance function widths calculated using events generated by UrQMD are wider than the measured widths in central collisions and show little centrality dependence. The measured widths of the balance functions in central collisions are consistent with the delayed hadronization of a deconfined quark gluon plasma (QGP). The narrowing of the balance function in central collisions at s NN =7.7 GeV implies that a QGP is still being created at this relatively low energy.« less