Unstable mode of the net-baryon density near the spinodal decomposition region*

Abstract This paper investigates conserved net-baryon multiplicity fluctuations near the spinodal decomposition region based on the stochastic diffusion equation, model B. The convex anomaly in the spinodal region induces the unstable mode, and the correlation function dominates at the harder mode. The unstable mode results in oscillating behavior of second-order multiplicity fluctuations with increasing spatial interval. This oscillating behavior of multiplicity fluctuations with respect to acceptance may indicate the existence of the convex anomaly of spinodal decomposition.