  Generalized quark number susceptibilities are expected to be good probes for
the phase transitions in QCD and the search of a possible critical point.
However, their computation in lattice QCD is plagued by the complex action
problem which appears at finite chemical potential mu. In this work we explore
the possibilities of an expansion in the fugacity parameter exp(mu beta) which
has features that make, in particular quark number related bulk observables
easily accessible. We present results at finite chemical potential for
generalized susceptibilities up to the 4th order as well as their ratios and
compare them to model calculations.
