Multi-alpha Boson Gas state in Fusion Evaporation Reaction and Three-body Force

TL;DR

This paper presents experimental evidence for an alpha boson gas state in a fusion evaporation reaction, highlighting the role of three-body forces among alpha particles and supporting cluster formation models.

Contribution

It provides the first experimental evidence of alpha boson gas state with three-body force effects in fusion reactions, supported by model calculations.

Findings

Observation of alpha emission spectra with multiplicity 2 and 3

Spectral tails consistent with three-body force models

Support for alpha cluster formation with three-body interactions

Abstract

The experimental evidence for the $\alpha$ Boson gas state in the $^{11}$C+$^{12}$C$\rightarrow$$^{23}$Mg$^{\ast}$ fusion evaporation reaction is presented. By measuring the $\alpha$ emission spectrum with multiplicity 2 and 3, we provide insight into the existence of a three-body force among $\alpha$ particles. The observed spectrum exhibited distinct tails corresponding to $\alpha$ particles emitted in pairs and triplets consistent well with the model-calculations of AV18-UX and chiral effective field theory of NV2-3-la*, indicating the formation of $\alpha$ clusters with three-body force in the Boson gas state.