文章基本信息

标题：A QCD chiral critical point at small chemical potential: is it there or not?
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作者：P. de Forcrand
期刊名称：PoS - Proceedings of Science
印刷版ISSN：1824-8039
出版年度：2007
出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：For a QCD chiral critical point to exist, the parameter region of small quark masses for which the finite temperature transition is first-order must expand when the chemical potential is turned on. This can be tested by a Taylor expansion of the critical surface (mu,d,ms)c(m). We present a new method to perform this Taylor expansion numerically, which we first test on an effective model of QCD with static, dense quarks. We then present the results for QCD with 3 degenerate flavors. For a lattice with Nt = 4 time-slices, the first-order region shrinks as the chemical potential is turned on. This implies that, for physical quark masses, the analytic crossover which occurs at m = 0 between the hadronic and the plasma regimes remains crossover in the m-region where a Taylor expansion is reliable, i.e. m . T. We present preliminary results from finer lattices indicating that this situation persists, as does the discrepancy between the curvature of Tc(mc(m = 0),m) and the experimentally observed freeze-out curve.