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

Abstract : 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)msand 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(69Br)allows for a reaction flow via 68Se(2p, γ)of at most 20%. Uncertainties are sufficiently reduced to conclude that 68Se(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.
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Physics Letters B, Elsevier, 2014, 738, pp.453-456. 〈10.1016/j.physletb.2014.10.023〉
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Contributeur : Michel Lion <>
Soumis le : vendredi 17 octobre 2014 - 18:54:58
Dernière modification le : jeudi 1 février 2018 - 01:26:38

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M. Del Santo, Z. Meisel, Dominique Bazin, A. Becerril, B.A. Brown, et al.. β-delayed proton emission of $^{69}$Kr and the $^{68}$Se rp-process waiting point. Physics Letters B, Elsevier, 2014, 738, pp.453-456. 〈10.1016/j.physletb.2014.10.023〉. 〈in2p3-01075517〉

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