Reconstruction of Bremsstrahlung $\gamma$-rays Spectrum in Heavy Ion Reactions with Richardson-Lucy Algorithm

TL;DR

This paper demonstrates the use of the Richardson-Lucy algorithm to reconstruct the bremsstrahlung gamma-ray spectrum in heavy ion reactions, providing evidence for high momentum tails in nucleon distributions and validating the method's effectiveness for future experiments.

Contribution

The paper introduces the Richardson-Lucy algorithm for reconstructing bremsstrahlung gamma-ray spectra, enabling more accurate analysis of nucleon momentum distributions in heavy ion reactions.

Findings

Reconstructed gamma-ray spectrum matches simulation results.

Evidence supports the existence of high momentum tails in nucleons.

RL algorithm proves effective for spectral reconstruction in nuclear experiments.

Abstract

The high momentum tail (HMT) in the momentum distribution of nucleons above the Fermi surface has been regarded as an evidence of short-range correlations (SRCs) in atomic nuclei. It has been showcased recently that the $np$ Bremsstrahlung radiation in heavy ion reactions can be used to extract HMT information. The Richardson-Lucy (RL) algorithm is introduced to the reconstruction of the original Bremsstrahlung $\gamma$-ray energy spectrum from experimental measurements. By solving the inverse problem of the detector response to the $\gamma$-rays, the original energy spectrum of the Bremsstrahlung $\gamma$ in 25 MeV/u $^{86}$Kr + $^{124}$Sn has been reconstructed and compared to the isospin- and momentum-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) simulations. The analysis based on hypothesis test suggests the existence of the HMT of nucleons in nuclei, in accordance with the previous conclusions. With its effectiveness being demonstrated, it is feasible to apply the RL algorithm in future experiments of measuring the Bremsstrahlung $\gamma$-rays in heavy ion reactions.