학술논문
First direct measurement of $^{59}$Cu(p,$\alpha$)$^{56}$Ni: A step towards constraining the Ni-Cu cycle in the Cosmos
Document Type
Working Paper
Author
Randhawa, J. S.; Kanungo, R.; Refsgaard, J.; Mohr, P.; Ahn, T.; Alcorta, M.; Andreoiu, C.; Bhattacharjee, S. S.; Davids, B.; Christian, G.; Chen, A. A.; Coleman, R.; Garrett, P.; Grinyer, G. F.; Fuakye, E. Gyabeng; Hackman, G.; Jain, R.; Kapoor, K.; Krücken, R.; Laffoley, A.; Lennarz, A.; Liang, J.; Meisel, Z.; Nikhil, N.; Psaltis, A.; Radich, A.; Rocchini, M.; Saei, N.; Saxena, M.; Singh, M.; Svensson, C.; Subramaniam, P.; Talebitaher, A.; Upadhyayula, S.; Waterfield, C.; Williams, J.; Williams, M.
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Subject
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Abstract
Reactions on the proton-rich nuclides drive the nucleosynthesis in Core-Collapse Supernovae (CCSNe) and in X-ray bursts (XRBs). CCSNe eject the nucleosynthesis products to the interstellar medium and hence are a potential inventory of p-nuclei, whereas in XRBs nucleosynthesis powers the light curves. In both astrophysical sites the Ni-Cu cycle, which features a competition between $^{59}$Cu(p,$\alpha$)$^{56}$Ni and $^{59}$Cu(p,$\gamma$)$^{60}$Zn, could potentially halt the production of heavier elements. Here, we report the first direct measurement of $^{59}$Cu(p,$\alpha$)$^{56}$Ni using a re-accelerated $^{59}$Cu beam and cryogenic solid hydrogen target. Our results show that the reaction proceeds predominantly to the ground state of $^{56}$Ni and the experimental rate has been found to be lower than Hauser-Feshbach-based statistical predictions. New results hint that the $\nu p$-process could operate at higher temperatures than previously inferred and therefore remains a viable site for synthesizing the heavier elements.