New signatures of phase transition from Statistical Models of Nuclear multifragmentation

TL;DR

This paper introduces new experimental signatures for identifying liquid-gas phase transitions in nuclear matter, based on derivatives of accessible observables, which are easier to measure than traditional thermodynamic signatures.

Contribution

It proposes derivatives of order parameters as new, accessible indicators of phase transition, supported by statistical models and experimental data, enhancing detection methods in nuclear physics.

Findings

Derivative signals align with specific heat peaks

Proposed signatures are experimentally feasible

Confirmed by theoretical models and experiments

Abstract

The study of liquid-gas phase transition in heavy ion collisions has generated a lot of interest amongst the nuclear physicists in the recent years. In heavy ion collisions, there is no direct way of measuring the state variables like entropy, pressure, energy and hence unambiguous characterization of phase transition becomes difficult. This work proposes new signatures of phase transition that can be extracted from the observables which are easily accessible in experiments. It is observed that the temperature dependence of the first order derivative of the order parameters in nuclear liquid gas phase transition exhibit similar behavior as that of the variation of specific heat at constant volume Cv which is an established signature of first order phase transition. This motivates us to propose these derivatives as confirmatory signals of liquid-gas phase transition. The measurement of these signals in easily feasible in most experiments as compared to the other signatures like specific heat, caloric curve or bimodality. Total multiplicity, size of largest cluster are some of the order parameters which have been studied. Statistical Models based on canonical ensemble and lattice gas model has been used for the study. This temperature where the peak appears is designated to be the transition temperature and the effect of certain parameters on this has also been examined. The multiplicity derivative signature proposed in this work has been further confirmed by other theoretical models as well as in experimental study.