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

TL;DR

This paper introduces a novel lattice QCD method using fugacity expansion to compute generalized quark number susceptibilities up to fourth order, aiding the study of QCD phase transitions and critical points.

Contribution

It presents a new approach for calculating quark number susceptibilities from lattice QCD via fugacity expansion, simplifying access to these observables.

Findings

Computed susceptibilities up to 4th order.

Compared susceptibility ratios with model predictions.

Analyzed high- and low-temperature regimes at finite chemical potential.

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 $e^{\mu\beta}$. 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 $\mu\beta\approx1.0$.