Measuring the Temperature of Hot Nuclear Fragments

TL;DR

This paper introduces a new temperature measurement method for hot nuclear fragments based on transverse momentum fluctuations, addressing contamination issues and exploring mass dependence to improve accuracy.

Contribution

The study presents a novel thermometer using transverse momentum fluctuations and investigates its dependence on fragment mass and properties.

Findings

Proton transverse momentum fluctuations effectively indicate temperature.

Transverse direction reduces contamination from collective motion.

Mass dependence observed may relate to nucleon Fermi momentum or fragment properties.

Abstract

A new thermometer based on fragment momentum fluctuations is presented. This thermometer exhibited residual contamination from the collective motion of the fragments along the beam axis. For this reason, the transverse direction has been explored. Additionally, a mass dependence was observed for this thermometer. This mass dependence may be the result of the Fermi momentum of nucleons or the different properties of the fragments (binding energy, spin etc..) which might be more sensitive to different densities and temperatures of the exploding fragments. We expect some of these aspects to be smaller for protons (and/or neutrons); consequently, the proton transverse momentum fluctuations were used to investigate the temperature dependence of the source.