中国物理学会高能物理分会第十一届全国会员代表大会暨学术年会

At RHIC, a fireball forms in the Au-Au collision and rapidly cools during expansion, inside which the QCD matter undergoes a phase transition from quark-gluon-plasma to the hadronic phase. The phase transition signals are expected to be observed via the measurement of fluctuations of conserved charges such as baryon numbers [1]. Indeed, both the dynamical evolution and the spatially-nonuniform-temperature (and chemical potential) distribution of the fireball affect the fluctuations of QCD phase transition. However, the current studies of the QCD phase transition mainly focus on the dynamical effects [2], and the nonuniform-temperature effects are overlooked. In this talk, we will present the spatially-nonuniform-temperature effects on the QCD phase transition temperature, the fluctuations, and the correlation length via a simplified Ising-like model [3]. Different from the dynamical effects, which delay the phase transition, we reveal that the nonuniform-temperature effects lead to higher phase transition temperature. Besides, the suppression of the critical fluctuation can be as stronger as the dynamical slowing down effects, and the nonzero-momentum modes of fluctuations play a crucial role. Our study presents a different perspective to understand the recent STAR data and lattice results [4], and can be further generalized to other temperature-nonuniform systems like the compact stars. [1] J. Adamet al. (STAR Collaboration), Phys. Rev. Lett.126,092301 (2021). [2] M. Stephanov and Y. Yin, Phys. Rev. D98, 036006 (2018). [3] Jun-Hui Zheng and Lijia Jiang, Phys. Rev. D 104, 016031 (2021). [4] A. Bazavovet al.(HotQCD Collaboration), Phys. Lett. B795,15 (2019).