High-precision mass measurement of ${}^{24}$Si and a refined determination of the $rp$ process at the $A=22$ waiting point

Abstract

We report a high precision mass measurement of ${}^{24}\mathrm{Si}$, performed with the LEBIT facility at the National Superconducting Cyclotron Laboratory. The atomic mass excess, $10753.8$(37) keV, is a factor of 5 more precise than previous results. This substantially reduces the uncertainty of the ${}^{23}\mathrm{Al}(p,{\hat{I}}^3{)}^{24}\mathrm{Si}$ reaction rate, which is a key part of the rapid proton capture ($rp$) process powering Type I X-ray bursts. The updated rate constrains the onset temperature of the $(\hat{I}\pm ,p)$ process at the ${}^{22}\mathrm{Mg}$ waiting-point to a precision of 9%.

6 pages, 3 figures