Is gamma-Ray Emission from Novae Affected by Interference Effects in the F-18(p, alpha)O-15 Reaction?

A. M. Laird*, A. Parikh, A. St. J. Murphy, K. Wimmer, A. A. Chen, C. M. Deibel, T. Faestermann, S. P. Fox, B. R. Fulton, R. Hertenberger, D. Irvine, J. Jose, R. Longland, D. J. Mountford, B. Sambrook, D. Seiler, H. -F. Wirth, Alex Murphy

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The 18F(p, alpha)O-15 reaction rate is crucial for constraining model predictions of the gamma-ray observable radioisotope F-18 produced in novae. The determination of this rate is challenging due to particular features of the level scheme of the compound nucleus, Ne-19, which result in interference effects potentially playing a significant role. The dominant uncertainty in this rate arises from interference between J(pi) = 3/2(+) states near the proton threshold (S-p = 6.411 MeV) and a broad J(pi) = 3/2(+) state at 665 keVabove threshold. This unknown interference term results in up to a factor of 40 uncertainty in the astrophysical S-factor at nova temperatures. Here we report a new measurement of states in this energy region using the F-19(He-3, t)Ne-19 reaction. In stark contrast to previous assumptions we find at least 3 resonances between the proton threshold and E-cm = 50 keV, all with different angular distributions. None of these are consistent with J(pi) = 3/2(+) angular distributions. We find that the main uncertainty now arises from the unknown proton width of the 48 keV resonance, not from possible interference effects. Hydrodynamic nova model calculations performed indicate that this unknown width affects F-18 production by at least a factor of two in the model considered. DOI: 10.1103/PhysRevLett.110.032502

Original languageEnglish
Article number032502
Number of pages5
JournalPhysical Review Letters
Volume110
Issue number3
DOIs
Publication statusPublished - 15 Jan 2013

Keywords

  • SHELL NUCLEI
  • NUCLEOSYNTHESIS
  • STATES
  • NE-19

Fingerprint

Dive into the research topics of 'Is gamma-Ray Emission from Novae Affected by Interference Effects in the F-18(p, alpha)O-15 Reaction?'. Together they form a unique fingerprint.

Cite this