Determination of the Neutron-Capture Rate of 17C for the R-process Nucleosynthesis

TL;DR

This study measures the neutron-capture rate of 17C relevant to the r-process nucleosynthesis, providing experimental data that refines theoretical models and impacts astrophysical element production scenarios.

Contribution

It presents the first experimental determination of the 17C neutron-capture rate, constraining theoretical calculations and revising previous estimates used in astrophysical models.

Findings

The measured capture rate is significantly lower than previous Hauser-Feshbach estimates.

Updated rates show minimal impact on the synthesis of heavy elements in astrophysical scenarios.

Experimental data constrains theoretical models of neutron capture on 17C.

Abstract

With the R$^{3}$B-LAND setup at GSI we have measured exclusive relative-energy spectra of the Coulomb dissociation of $^{18}$C at a projectile energy around 425~AMeV on a lead target, which are needed to determine the radiative neutron-capture cross sections of $^{17}$C into the ground state of $^{18}$C. Those data have been used to constrain theoretical calculations for transitions populating excited states in $^{18}$C. This allowed to derive the astrophysical cross section $\sigma^{*}_{\mathrm{n}\gamma}$ accounting for the thermal population of $^{17}$C target states in astrophysical scenarios. The experimentally verified capture rate is significantly lower than those of previously obtained Hauser-Feshbach estimations at temperatures $T_{9}\leq{}1$~GK. Network simulations with updated neutron-capture rates and hydrodynamics according to the neutrino-driven wind model as well as the neutron-star merger scenario reveal no pronounced influence of neutron capture of $^{17}$C on the production of second- and third-peak elements in contrast to earlier sensitivity studies.