2025/02/25 by Azumi Sakai, Koichi Murase, Sakai, Azumi +5 · 1 citation
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #High-Energy Particle Collisions Research #Nuclear Theory (nucl-th) #Quantum, superfluid, helium dynamics #Theoretical and Computational Physics
paper · pdf · doi:10.48550/arxiv.2502.17791
openalex publication_date 2025/02/25 · openalex created_date 2025/10/15 · openalex updated_date 2026/07/28
We develop a dynamical model to describe critical fluctuations in heavy-ion collisions, incorporating the baryon diffusion current and chiral condensate as dynamical degrees of freedom, to address their nontrivial scale separation. The model couples fluctuations of the chiral condensate σ with baryon density fluctuations n and the diffusion current ν based on a second-order diffusion equation with a finite relaxation time of the baryon diffusion τR. We analyze the spacetime evolution and these correlation functions of the fluctuations in one-dimensionally expanding background. We confirm that an appropriate relaxation time τR ensures causality. We show that propagating waves with finite τR split into two modes at the critical temperature due to a rapid change of kinetic coefficients. In the correlation functions, we find that dynamical σ blurs the structure and peak around the critical temperature. With finite τR, the effect of the critical fluctuations persists longer into the later stages of the evolution. These findings suggest importance of dynamical effects of the chiral condensate and baryon diffusion current in identifying critical-point signals in heavy-ion collisions, where the scale separation is nontrivial.