Using light charged particles to probe the asymmetry dependence of the nuclear caloric curve

Abstract

Recently, we observed a clear dependence of the nuclear caloric curve on neutron-proton asymmetry $\frac{N\ensuremath{-}Z}{A}$ through examination of fully reconstructed equilibrated quasiprojectile sources produced in heavy-ion collisions at $E/A=35$ MeV. In the present work, we extend our analysis using multiple light charged particle probes of the temperature. Temperatures are extracted with five distinct probes using a kinetic thermometer approach. Additionally, temperatures are extracted using two probes within a chemical thermometer approach (Albergo method). All seven measurements show a significant linear dependence of the source temperature on the source asymmetry. For the kinetic thermometer, the strength of the asymmetry dependence varies with the probe particle species in a way that is consistent with an average emission-time ordering.