Two characteristic volumes in thermal nuclear multifragmentation

TL;DR

This study investigates the space-time characteristics of target multifragmentation in high-energy proton-gold collisions, revealing two characteristic volumes associated with the expansion and freeze-out stages, consistent with spinodal disintegration.

Contribution

It provides experimental determination of the expansion and freeze-out volumes in nuclear multifragmentation, supporting the spinodal disintegration scenario.

Findings

Expansion volume Vt = (2.9 +- 0.2) Vo

Freeze-out volume Vf = (11 +- 3) Vo

Results support spinodal disintegration model

Abstract

The paper is devoted to the experimental determination of the space-time characteristics for the target multifragmentation in p(8.1GeV) + Au collisions. The experimental data on the fragment charge distribution and kinetic energy spectra are analyzed within the framework of the statistical multifragmentation model. It is found that the partition of hot nuclei is specified after expansion of the target spectator to a volume equal to Vt = (2.9 +- 0.2) Vo, with Vo as the volume at normal density. However, the freeze-out volume is found to be Vf = (11 +- 3) Vo. At freeze-out, all the fragments are well separated and only the Coulomb force should be taken into account. The results are in accordance with a scenario of spinodal disintegration of hot nuclei.