PREPRINT
6F61481C-F479-41FB-8A3A-780B75E9BC43

# New ${}^{32}$Cl(p,$\gamma$)${}^{33}$Ar reaction rate for astrophysical rp-process calculations

H. Schatz, C. A. Bertulani, B. A. Brown, R. R. C. Clement, A. A. Sakharuk, B. M. Sherrill
arXiv:nucl-ex/0511040

Submitted on 22 November 2005

## Abstract

The ${}^{32}$Cl(p,$\gamma$)${}^{33}$Ar reaction rate is of potential importance in the rp-process powering type I X-ray bursts. Recently Clement et al. \cite{CBB04} presented new data on excitation energies for low lying proton unbound states in ${}^{33}$Ar obtained with a new method developed at the National Superconducting Cyclotron Laboratory. We use their data, together with a direct capture model and a USD shell model calculation to derive a new reaction rate for use in astrophysical model calculations. In particular, we take into account capture on the first excited state in ${}^{32}$Cl, and also present a realistic estimate of the remaining uncertainties. We find that the ${}^{32}$Cl(p,$\gamma$)${}^{33}$Ar reaction rate is dominated entirely by capture on the first excited state in ${}^{32}$Cl over the whole temperature range relevant in X-ray bursts. In the temperature range from 0.2 to 1 GK the rate is up to a factor of 70 larger than the previously recommended rate based on shell model calculations only. The uncertainty is now reduced from up to a factor of 1000 to a factor of 3 at 0.3-0.7 GK and a factor of 6 at 1.5 GK.

## Preprint

Comment: To be published in Phys. Rev. C

Subjects: Nuclear Experiment; Astrophysics; Nuclear Theory