Kurtosis and compressibility near the chiral phase transition

Understand

The properties of net quark number fluctuations in the vicinity of the QCD chiral phase transition are discussed in terms of an effective chiral model in the mean-field approximation.

• We focus on the ratio of the fourth- to second- order cumulants (kurtosis) and the compressibility of the system and discuss their dependence on the pion mass.
• It is shown that near the chiral phase transition, both observables are sensitive to the value of $m_\pi$.
• For physical $m_\pi$, the kurtosis exhibits a peak whereas the inverse compressibility shows a dip at the pseudocritical temperature.