Two source emission behavior of projectile fragments alpha in 84^Kr interactions at around 1 GeV per nucleon

TL;DR

This study investigates the emission patterns of alpha particles from 84Kr projectile interactions at around 1 GeV per nucleon, revealing a two-source emission mechanism with distinct temperature regions.

Contribution

It introduces a two-source model for alpha emission in relativistic heavy-ion collisions, challenging the traditional Participant-Spectator model assumptions.

Findings

Alpha particles originate from two distinct sources with different temperatures.

Most alpha emissions come from a cold source, with a minor contribution from a hot contact layer.

The angular distribution cannot be explained by simple collision geometry.

Abstract

The emission of projectile fragments alpha has been studied in 84^Kr interactions with nuclei of the nuclear emulsion detector composition at relativistic energy below 2 GeV per nucleon. The angular distribution of projectile fragments alpha in terms of transverse momentum could not be explained by a straight and clean-cut collision geometry hypothesis of Participant - Spectator (PS) Model. Therefore, it is assumed that projectile fragments alpha were produced from two separate sources that belong to the projectile spectator region differing drastically in their temperatures. It has been clearly observed that the emission of projectile fragments alpha are from two different sources. The contribution of projectile fragments alpha from contact layer or hot source is a few percent of the total emission of projectile fragments alphas. Most of the projectile fragments alphas are emitted from the cold source.