Hadronic fluctuations and correlations at nonzero chemical potential

We present a lattice study of fluctuations and correlations among the conserved charges baryon number and strangeness in (2+1)-flavor QCD. The lattice calculations are based on a Taylor expansion of the pressure. Results are presented at zero and nonzero density on lattices with four and six time slices, corresponding to a lattice spacing of $a\approx 0.25$ fm and $a\approx 0.16$ fm, respectively. The quark masses are almost physical, i.e. the light quark mass has been chosen to one tenth of the physical strange quark mass while the strange quark mass has been set to its physical value. We find that all analyzed fluctuations and correlations develop a peak at nonzero density, when they are treated in an expansion up to sixth order. Especially below the critical temperature ($T_c$) fluctuations and correlations increase drastically, whereas above $T_c$ they are rather unaffected.