Measurement of higher cumulants of net-charge multiplicity distributions in Au + Au collisions at
= 7.7-200 GeV
Adare, A.*; Imai, Kenichi; Nagamiya, Shoji; Sako, Hiroyuki
; Sato, Susumu
; Tanida, Kiyoshi
; PHENIX Collaboration*; 506 of others*
We report the measurement of cumulants (
,
) of the net-charge distributions measured within pseudorapidity (
) in Au + Au collisions at
= 7.7-200 GeV with the PHENIX experiment at the Relativistic Heavy Ion Collider. The ratios of cumulants (e.g.,
,
) of the net-charge distributions, which can be related to volume independent susceptibility ratios, are studied as a function of centrality and energy. These quantities are important to understand the quantum-chromodynamics phase diagram and possible existence of a critical end point. The measured values are very well described by expectation from negative binomial distributions. We do not observe any nonmonotonic behavior in the ratios of the cumulants as a function of collision energy. The measured values of
and
can be directly compared to lattice quantum-chromodynamics calculations and thus allow extraction of both the chemical freeze-out temperature and the baryon chemical potential at each center-of-mass energy. The extracted baryon chemical potentials are in excellent agreement with a thermal-statistical analysis model.