Centrality bin-width independent information entropy in Au + Au collisions at √s_NN = 4.7 - 200 GeV from AMPT model

摘要: Net-proton multiplicity distributions within finite centrality bins are subject to volume fluctuations, known as the Centrality Bin Width Effect (CBWE). The information entropy of net-proton multiplicity distributions normally serves as an effective observable to reflect the critical fluctuation phenomena, providing a valuable tool for studying the QCD phase transition and the potential existence of the critical point in heavy-ion collisions. However, CBWE may cause inaccuracies in the original information entropy. In this work, the Centrality Bin Width Correction (CBWC) method is applied to correct the original information entropy. A Multi-phase Transport (AMPT) model is used as the event generator to simulate Au+Au collisions across a range of center-of-mass energies √s_NN = 4.7 - 200 GeV with impact parameters ranging from 0 to 14 fm. Simulations are conducted with and without mid-rapidity cut (|y| < 0.5) and a transverse-momentum cut (0.4 < P_T < 0.8 GeV/c). By comparing the original and corrected information entropy values, significant differences are observed regardless of whether a mid-rapidity or transverse momentum cut is applied, demonstrating the necessity of applying the CBWC method. The corrected information entropy improves stability and centrality-independence and enhances its effectiveness in probing the QCD critical point.