Investigating the cluster production mechanism with isospin triggering: Thermal models versus coalescence models

Abstract

Isospin triggering allows to distinguish coalescence from thermal production of light clusters in heavy ion collisions. Triggering on $Y(π^-) - Y(π^+)$ allows to select very neutron or proton rich final states. The deuteron (cluster) production with coalescence ($d \propto n \cdot p$) leads then to an inverse parabolic dependence of the deuteron yield on $ΔY_π$. In contrast, in a thermal model, cluster production is independent on $ΔY_π$. The observation of a maximum deuteron (cluster) yield as function of $ΔY_π$ provides confirmation of the coalescence mechanism.