Ground-state proton decay of {sup 69}Br and implications for the {sup 68}Se astrophysical rapid proton-capture process waiting point.

Journal Article · Fri Jun 24 00:00:00 EDT 2011 · Phys. Rev. Lett.

DOI:https://doi.org/10.1103/PhysRevLett.106.252503· OSTI ID:1019240

Rogers, A M; Famiano, M A; Lynch, W G; Wallace, M S; Amorini, F; Bazin, D; Charity, R J; Delaunay, F; de Souza, R T; Elson, J; Gade, A; Galaviz, D; van Goethem, M -J; Hudan, S; Lee, J; Lobastov, S; Lukyanov, S; Matos, M; Mocko, M; Schatz, H ; Shapira, D; Sobotka, L G; Tsang, M B; Verde, G ^[1]

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1. Physics

We report on the first direct measurement of the proton separation energy for the proton-unbound nucleus {sup 69}Br. Bypassing the {sup 68}Se waiting point in the rp process is directly related to the 2p-capture rate through {sup 69}Br, which depends exponentially on the proton separation energy. We find a proton separation energy for {sup 69}Br of S{sub p}({sup 69}Br) = -785{sub -40}{sup +34} keV; this is less bound compared to previous predictions which have relied on uncertain theoretical calculations. The influence of the extracted proton separation energy on the rp process occurring in type I x-ray bursts is examined within the context of a one-zone burst model.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC); National Science Foundation (NSF); Michigan State Univ.
• DOE Contract Number: DE-AC02-06CH11357
• OSTI ID: 1019240
• Report Number(s): ANL/PHY/JA-68882; TRN: US1103583
• Journal Information: Phys. Rev. Lett., Vol. 106, Issue 25 ; Jun. 24, 2011
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BINDING ENERGY
DECAY
PROTONS
GROUND STATES
BROMINE 69
SELENIUM 68