arXiv:1509.05786·v2·High Energy Physics — Lattice
The curvature of the freeze-out line in heavy ion collisions
A. Bazavov🇺🇸 · H.-T. Ding🇨🇳 · P. Hegde🇨🇳 · O. Kaczmarek🇩🇪 · F. Karsch🇩🇪 · E. Laermann🇩🇪 · Swagato Mukherjee🇺🇸 · H. Ohno🇺🇸 · P. Petreczky🇺🇸 · C.Schmidt🇩🇪 · S. Sharma🇺🇸 · W. Soeldner🇩🇪 · M. Wagner🇺🇸
Abstract
We calculate the mean and variance of net-baryon number and net-electric charge distributions from Quantum Chromodynamics (QCD) using a next-to-leading order Taylor expansion in terms of temperature and chemical potentials. We compare these expansions with experimental data from STAR and PHENIX, determine the freeze-out temperature in the limit of vanishing baryon chemical potential, and, for the first time, constrain the curvature of the freeze-out line through a direct comparison between experimental data on net-charge fluctuations and a QCD calculation. We obtain a bound on the curvature coefficient, kappa_2^f < 0.011, that is compatible with lattice QCD results on the curvature of the QCD transition line.
Comments: 5 pages, 2 figures