Using Light Charged Particles to Probe the Asymmetry Dependence of the Nuclear Caloric Curve

TL;DR

This study investigates how the nuclear caloric curve depends on neutron-proton asymmetry by analyzing light charged particle probes in heavy ion collisions, revealing a linear relationship between temperature and asymmetry.

Contribution

It extends previous work by using multiple temperature probes to confirm the linear dependence of nuclear temperature on asymmetry, including kinetic and chemical thermometer methods.

Findings

All temperature measurements show a linear dependence on asymmetry.

The asymmetry dependence strength varies with probe species.

Emission-time ordering influences the asymmetry dependence.

Abstract

Recently, we observed a clear dependence of the nuclear caloric curve on neutron-proton asymmetry $\frac{N-Z}{A}$ through examination of fully reconstructed equilibrated quasi-projectile 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 which is consistent with an average emission-time ordering.