Speaker
Description
Fluctuations of conserved quantities are proposed as sensitive observables to search for the QCD critical point in heavy-ion collisions. Recently, the STAR experiment has conducted precision measurement of net-proton fluctuations in Au+Au collisions at √sNN = 7.7 – 27 GeV, during the RHIC Beam Energy Scan II program [1] and reported the preliminary results of proton number fluctuation in fixed-target Au+Au collisions at √sNN = 3 – 3.9 GeV in the QM2025 conference. However, at lower collision energies, initial volume fluctuations (IVF) can significantly distort the observed event-by-event fluctuations, potentially obscures genuine energy dependence in the high order cumulant ratios. To address this issue, we have developed a novel centrality-independent analysis framework [2] that systematically suppresses the IVF background, thereby isolating the intrinsic, physics-driven fluctuations. In this talk, we present a new method that can effectively suppress the IVF effect and might provide essential insights into the possible existence of the QCD critical point and the nature of the QCD phase transition.
[1] B. E. Aboona et al. (STAR), Precision Measurement of Net-Proton-Number Fluctuations in Au+Au Collisions at RHIC, Phys. Rev. Lett. 135, 142301 (2025), arXiv:2504.00817 [nucl-ex].
[2] Z. Wang and X. Luo, A centrality-independent framework for revealing genuine higher-order cumulants in heavy-ion collisions, Physics Letters B 871, 139984 (2025), arXiv:2505.03666
