Critical net-baryon fluctuations in an expanding system

Abstract

In this work we study the consequences of a longitudinal Bjorken expansion and a Hubble-like temperature cooling scenario on a 1+1D non-linear model of the diffusive dynamics of fluctuations in the net-baryon density. The equilibrium behavior of the fluctuations is fully encoded in the temperature dependence of the susceptibilities on the crossover side both in the vicinity of the assumed location of the critical point and at vanishing baryo-chemical potential in-line with lattice QCD calculations. We demonstrate the great sensitivity of the fluctuation observables on the dynamics, in particular on the diffusion length and the freeze-out conditions. While the critical signals are visible and the critical region is broadened by the expansion, a too small diffusion length can strongly reduce the amplitude of the signals. We propose to search for significant anti-correlations of baryons at intermediate rapidity experimentally and to map out the rapidity dependence of the fourth-order cumulant, which in the presence of a critical point (and only in its presence) has a pronounced minimum at intermediate rapidities.

References in corpus (6)

• The QCD Equation of State to $\mathcal{O}({\mu }_B^6)$ from Lattice QCD
• A kinetic regime of hydrodynamic fluctuations and long time tails for a Bjorken expansion
• Second order cumulants of conserved charge fluctuations revisited I. Vanishing chemical potentials
• Freezing Out Fluctuations in Hydro+ Near the QCD Critical Point
• Stochastic hydrodynamics and hydro-kinetics: Similarities and differences
• Behavior of universal critical parameters in the QCD phase diagram

Cited by in corpus (6)

• Simulations of stochastic fluid dynamics near a critical point in the phase diagram
• Dynamical critical fluctuations near the QCD critical point with hydrodynamic cooling rate
• N-particle irreducible actions for stochastic fluids
• Covariant formulation of spinodal decomposition in rapidly expanding quark gluon plasma
• Dynamics of the conserved net-baryon density near QCD critical point within inhomogeneous quark-gluon plasma profile
• Dynamical and finite-size effects on the criterion of first-order phase transition