학술논문
$^{57}$Zn $\beta$-delayed proton emission establishes the $^{56}$Ni $rp$-process waiting point bypass
Document Type
Working Paper
Author
Saxena, M.; Ong, W. -J; Meisel, Z.; Hoff, D. E. M.; Smirnova, N.; Bender, P. C.; Burcher, S. P.; Carpenter, M. P.; Carroll, J. J.; Chester, A.; Chiara, C. J.; Conaway, R.; Copp, P. A.; Crider, B. P.; Derkin, J.; Estrade, A.; Hamad, G.; Harke, J. T.; Jain, R.; Jayatissa, H.; Liddick, S. N.; Longfellow, B.; Mogannam, M.; Montes, F.; Nepal, N.; Ogunbeku, T. H.; Richard, A. L.; Schatz, H.; Soltesz, D.; Subedi, S. K.; Sultana, I.; Tamashiro, A. S.; Tripathi, V.; Xiaog, Y.; Zink, R.
Source
Subject
Language
Abstract
We measured the $^{57}$Zn $\beta$-delayed proton ($\beta$p) and $\gamma$ emission at the National Superconducting Cyclotron Laboratory. We find a $^{57}$Zn half-life of 43.6 $\pm$ 0.2 ms, $\beta$p branching ratio of (84.7 $\pm$ 1.4)%, and identify four transitions corresponding to the exotic $\beta$-$\gamma$-$p$ decay mode, the second such identification in the $f p$-shell. The $p/\gamma$ ratio was used to correct for isospin mixing while determining the $^{57}$Zn mass via the isobaric multiplet mass equation. Previously, it was uncertain as to whether the rp-process flow could bypass the textbook waiting point $^{56}$Ni for astrophysical conditions relevant to Type-I X-ray bursts. Our results definitively establish the existence of the $^{56}$Ni bypass, with 14-17% of the $rp$-process flow taking this route.