β-delayed proton emission of 69Kr and the 68Se rp-process waiting point

Autor: M. Del Santo, Z. Meisel, D. Bazin, A. Becerril, B.A. Brown, H. Crawford, R. Cyburt, S. George, G.F. Grinyer, G. Lorusso, P.F. Mantica, F. Montes, J. Pereira, H. Schatz, K. Smith, M. Wiescher
Jazyk: angličtina
Rok vydání: 2014
Předmět:
Zdroj: Physics Letters B, Vol 738, Iss , Pp 453-456 (2014)
Druh dokumentu: article
ISSN: 0370-2693
03937895
DOI: 10.1016/j.physletb.2014.10.023
Popis: The slow β-decay of the 68Se waiting point in the astrophysical rp-process can in principle be bypassed by a sequential two proton capture. The rate of this reaction sequence depends exponentially on the 69Br proton separation energy. We studied β-delayed proton emission of 69Kr and extracted a proton separation energy of −641(42) keV. In addition, we determined a 69Kr β-decay half-life of T1/2=28(1) ms and an excitation energy of 3153(55) keV of the 69Kr isobaric analog state in 69Br. X-ray burst model calculations show that regardless of the values of other uncertain masses in the region, the new Sp(Br69) allows for a reaction flow via Se68(2p,γ) of at most 20%. Uncertainties are sufficiently reduced to conclude that Se68(2p,γ) has at best a very small effect on burst light curve and composition, and that 68Se is a strong rp-process waiting point. Our results also exclude the possibility of a suggested longer lived, so far unobserved, 69Br ground state. Keywords: Rp-process, Waiting point, X-ray burst
Databáze: Directory of Open Access Journals
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