# Signature of clustering in quantum many body systems probed by the giant dipole resonance

## TL;DR

This study demonstrates that giant dipole resonance (GDR) measurements reveal large nuclear deformations and clustering phenomena in $^{32}$S at high angular momentum, providing insights into nuclear structure under extreme conditions.

## Contribution

It shows that GDR lineshape fragmentation at high spin indicates cluster formation and super-deformation in nuclei, offering a new probe for nuclear clustering phenomena.

## Key findings

- GDR lineshape splits into two peaks at high angular momentum.
- No clustering signature observed at low angular momentum.
- GDR lineshape differs from Jacobi shape transition, indicating cluster structures.

## Abstract

The present experimental study illustrates how large deformations attained by nuclei due to cluster formation are perceived through the giant dipole resonance (GDR) strength function. The high energy GDR $\gamma$-rays have been measured from $^{32}$S at different angular momenta ($J$) but similar temperatures in the reactions $^{4}$He(E$_{lab}$=45MeV) + $^{28}$Si and $^{20}$Ne(E$_{lab}$=145MeV) + $^{12}$C. The experimental data at lower J ($\sim$ 10$\hbar$) suggests a normal deformation, similar to the ground state value, showing no potential signature of clustering. However, it is found that the GDR lineshape is fragmented into two prominent peaks at high J ($\sim$ 20$\hbar$) providing a direct measurement of the large deformation developed in the nucleus. The observed lineshape is also completely different from the ones seen for Jacobi shape transition at high $J$ pointing towards the formation of cluster structure in super-deformed states of $^{32}$S at such high spin. Thus, the GDR can be regarded as a unique tool to study cluster formation at high excitation energies and angular momenta.