(^{57}\)Zn \(\beta\)-delayed proton emission establishes the \(^{56}\)Ni \(rp\)-process waiting point bypass

• Published in: arXiv.org 2022-04
• Main Authors: Saxena, M, W -J Ong, 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
• Format: Article
• Language: English
• Subjects: Cyclotrons; Emission; Protons
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2204.01621

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.