Observation of the critical end point in the phase diagram for hot and dense nuclear matter

by Roy Lacey (Stony Brook University)

Thursday 15 Jan 2015, 15:00 → 16:00 US/Eastern

Small Seminar Room (Brookhaven National Laboratory, Physics Department, Bldg. 510)

2015 Seminar Schedule

Abstract: Excitation functions for the Gaussian emission source radii difference (R_out^2-R_side^2) obtained from two-pion interferometry measurements in Au+Au (sqrt{S_NN} = 7.7-200 GeV) and Pb+Pb (sqrt{S_NN}=2.76 TeV) collisions, are studied for a broad range of collision centralities. The observed non-monotonic excitation functions validate the finite-size scaling patterns expected for the deconfinement phase transition and the critical end point (CEP), in the temperature vs. baryon chemical potential (T, mu_B) plane of the nuclear matter phase diagram. A Finite-Size Scaling (FSS) analysis of these data indicate a second order phase transition with the estimates T^{CEP} ~ 165 MeV and mu^{CEP}_B ~ 95 MeV for the location of the critical end point. The critical exponents (Î ~ 0.66 and Î ~ 1.2) extracted via the same FSS analysis, places the CEP in the 3D Ising Model universality class.