Generalized quark number susceptibilities from fugacity expansion at finite chemical potential for $N_f$ = 2 Wilson fermions

Abstract

Generalized susceptibilities of the net quark number have been proposed to be good probes for the transitions in the QCD phase diagram and for the search of a possible critical end point. In this article we explore a new strategy for computing quark number susceptibilities from lattice QCD via an expansion in the fugacity parameter $e^{μβ}$. All quark number related bulk observables are particularly easy to access in this approach and we present results for generalized quark number susceptibilities up to 4-th order. Ratios of these quantities are studied and compared with model calculations for the high- and low temperature regions up to a chemical potential of $μβ\approx1.0$.

References, comments and two plots added: Fig. 1 now contains a second plot with logarithmic scale and we added a new Fig. 7 showing our results for the QCD phase diagram. Final version to appear in Phys. Rev. D