Investigating the astrophysically important Ex = 2.646 MeV state in 20Na

M. A. Hofstee, The University of North Carolina at Chapel Hill
J. C. Blackmon, The University of North Carolina at Chapel Hill
A. E. Champagne, The University of North Carolina at Chapel Hill
N. P.T. Bateman, Yale University
P. D. Parker, Yale University
K. Yildiz, Yale University
B. M. Young, Yale University
R. B. Vogelaar, Princeton University
M. S. Smith, ORNL Physics Division
A. J. Howard, Trinity College Hartford


Observations of neon lines in the spectra of energetic novae have prompted a renewed look at explosive hydrogen burning. The 19Ne(p, γ)20Na reaction is expected to play a major role in the breakout of the hot CNO cycle to the rp-process, which can process CNO nuclei to heavier elements. The reaction rate is dominated by the lowest resonance in the 19Ne + p system, corresponding to the Ex = 2.646 MeV state in 20Na. A large variety of nuclear experimental techniques have been used to study this state; e.g. charge exchange reactions, β-delayed proton decay and radioactive beams. Their results have lead to a Jπ = 3+ assignment for this state [B. Brown et al., Phys. Rev. C 48 (1993) 1456], allowing an estimate of the proton width (Γp). This leaves the gamma width (Γγ) to be determined. We have performed 20Ne(3He, experiments to measure the branching ratio ( Γγ Γ) of the Ex = 2.646 MeV excited state in 20Na. © 1995.