Cross-section measurement of the $^{130}$Ba(p,$\gamma$)$^{131}$La reaction for $\gamma$-process nucleosynthesis

TL;DR

This study measures the total cross-sections of the $^{130}$Ba(p,$ ext{γ}$)$^{131}$La reaction at low energies to test statistical model predictions and improve understanding of proton capture in the A~130 mass region relevant to $ ext{γ}$-process nucleosynthesis.

Contribution

It provides the first experimental cross-section data for this reaction in the astrophysically relevant energy range, testing and refining optical model potentials used in statistical models.

Findings

The measured cross-sections align well with the SMARAGD code using the JLM potential at higher energies.

The energy dependence at low energies is better modeled by the TALYS code with the Bauge potential and a constant renormalization.

The data serve as a crucial benchmark for optical model potentials in this mass region.

Abstract

A measurement of total cross-section values of the $^{130}$Ba(p,$\gamma$)$^{131}$La reaction at low proton energies allows a stringent test of statistical model predictions with different proton+nucleus optical model potentials. Since no experimental data are available for proton-capture reactions in this mass region around A~$\approx$~130, this measurement can be an important input to test the global applicability of proton+nucleus optical model potentials. The total reaction cross-section values were measured by means of the activation method. After the irradiation with protons, the reaction yield was determined by use of $\gamma$-ray spectroscopy using two clover-type high-purity germanium detectors. In total, cross-section values for eight different proton energies could be determined in the energy range between 3.6 MeV $\leq E_p \leq$ 5.0 MeV, thus, inside the astrophysically relevant energy region. The measured cross-section values were compared to Hauser-Feshbach calculations using the statistical model codes TALYS and SMARAGD with different proton+nucleus optical model potentials. With the semi-microscopic JLM proton+nucleus optical model potential used in the SMARAGD code, the absolute cross-section values are reproduced well, but the energy dependence is too steep at the lowest energies. The best description is given by a TALYS calculation using the semi-microscopic Bauge proton+nucleus optical model potential using a constant renormalization factor.