QCD Critical Point and Net-Proton Number Fluctuations at RHIC-STAR

In the search of QCD phase boundary and critical point, higher-order cumulants of conserved quantities are proposed as promising observables and have been studied extensively both experimentally and theoretically. In this paper we present cumulant ratios up to 6th-order of net-proton number distributions in Au+Au collisions at √SNN = 7.7 - 200 GeV$\sqrt {{{\rm{S}}_{{\rm{NN}}}}} = 7.7 - 200\,{\rm{GeV}}$SNN=7.7−200 GeV from STAR Beam Energy Scan program phase I and √S = 200 GeV p + p$\sqrt {\rm{s}} = 200\,{\rm{GeV}}\,p + p$s=200 GeV p+p collisions. The results are compared with various models and Lattice QCD calculations.