Quark Fluctuations in a Chiral Model at finite chemical potential

During recent years the phenomenological importance of fluctuations in finite temperature/finite density QCD has been recognized [1]. The analysis of fluctuations is an essential method to characterize the thermodynamic properties of a system. Enhanced fluctuations signal the onset of a phase transition [2]. Thus, measuring modifications in the magnitude of fluctuations in heavy ion collisions on an event–by–event basis is considered as a phenomenological probe of deconfinement and chiral symmetry restoration [1]. Recently the quark susceptibilities have been computed in lattice QCD [3, 4]. Of particular interest are the results on isovector, quark number and the off-diagonal quark susceptibilites. The quark number susceptibilities χff ′ are defined by