Measurement of Higher Moments of Multiplicity Distributions of Conserved Quantities in the STAR Experiment at RHIC.

The higher moments of multiplicity distributions of the net proton (proxy for net baryon), net kaon (proxy for net strangeness) and net charge are expected to show large fluctuations near the QCD critical point. The STAR experiment performed measurements of various higher order moments and moments products of net proton, net charge and net kaon distributions in Au+Au collisions as a function of collision energy (√s_NN = 7.7 - 200 GeV) in the Beam Energy Scan I (BES-I) program.

We will present results on collision energy and centrality dependence of higher moments of the net proton, net kaon and net charge multiplicity distribution over all BES-I energies from STAR. In the most central (0-5%) collisions, the κσ² of net proton distribution as a function of collision energy exhibit a non-monotonic behaviour and shows deviation in the lower energy region from corresponding predictions from a Poisson baseline, a transport model and a thermal model, none of which include any physics of criticality. We will also discuss results from measurements of the ratio of sixth to second order cumulant (C₆/C₂) of net charge and net proton distributions, motivated towards the search for possible signals of a crossover transition.