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Abstract |
The low-lying energy levels of proton-rich Cu-56 have been extracted using in-beam gamma-ray spectroscopy with the state-of-the-art gamma-ray tracking array GRETINA in conjunction with the S800 spectrograph at the National Superconducting Cyclotron Laboratory at Michigan State University. Excited states in Cu-56 serve as resonances in the Ni-55(p,gamma)Cu-56 reaction, which is a part of the rp process in type-I x-ray bursts. To resolve existing ambiguities in the reaction Q value, a more localized isobaric multiplet mass equation (IMME) fit is used, resulting in Q = 639 +/- 82 keV. We derive the first experimentally constrained thermonuclear reaction rate for Ni-55(p,.) Cu-56. We find that, with this newrate, the rp processmay bypass the (56)Niwaiting point via the Ni-55(p,gamma) reaction for typical x-ray burst conditions with a branching of up to similar to 40%. We also identify additional nuclear physics uncertainties that need to be addressed before drawing final conclusions about the rp-process reaction flow in the Ni-56 region. |
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Address |
[Ong, W. -J.; Langer, C.; Montes, F.; Bazin, D.; Brown, B. A.; Browne, J.; Cyburt, R.; Deleeuw, E. B.; Gade, A.; Keek, L.; Kontos, A.; Lemasson, A.; Lunderberg, E.; Meisel, Z.; Noji, S.; Nunes, F. M.; Perdikakis, G.; Pereira, J.; Quinn, S. J.; Recchia, F.; Schatz, H.; Scott, M.; Simon, A.; Spyrou, A.; Stevens, J.; Stroberg, S. R.; Weisshaar, D.; Wheeler, J.; Wimmer, K.; Zegers, R. G. T.] Michigan State Univ, Natl Superconducting Cyclotron Lab, E Lansing, MI 48824 USA |
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