The rate of the final step in the astrophysical αp process, the 34Ar(α, p)37K reaction, has been measured using the Jet Experiments in Nuclear Structure and Astrophysics (JENSA) gas-jet target and sORRUBA, at the ReA3 facility. Despite having a considerable impact on the observable light curves of x-ray bursts and the composition of the ashes of hydrogen and helium burning on accreting neutron stars, there were large uncertainties on this rate, due to a previous lack of experimental data.
In this first direct measurement constraining the 34Ar(α, p)37K reaction cross section, agreement was found between the data and statistical model predictions This indicates the applicability of the statistical model for predicting astrophysical (α, p) reaction rates in this part of the αp process, in contrast to earlier findings from indirect reaction studies indicating orders-of-magnitude discrepancies. This removes a significant uncertainty in models of hydrogen and helium burning on accreting neutron stars.
“First Direct Measurement Constraining the 34Ar(α,p)37K Reaction Cross Section for Mixed Hydrogen and Helium Burning in Accreting Neutron Stars”, J. Browne, K.A. Chipps, Konrad Schmidt, H. Schatz, S. Ahn, S. D. Pain, F. Montes, W. J. Ong, U. Greife, et al., Phys Rev. Lett. 130 212701 (2023)
