Lifetime of the 6793-keV state in 15O.
The energy derived from the CN cycle at low stellar temperatures is regulated by the 14N(p,gamma)15O reaction. A previous direct measurement of this reaction has been interpreted as showing evidence for a subthreshold resonance which makes a major contribution to the reaction rate at low temperatures. This resonance, at E(c.m.) = -504 keV would correspond to the known Ex = 6793-keV state in 15O. We have measured a mean lifetime of 1.60(+0.75)(-0.72) fs (90% C.L.) for this state using the Doppler-shift attenuation method. This lifetime is a factor of 15 longer than that inferred from the (p,gamma) data and implies that the contribution of the subthreshold resonance is negligible.
Bertone
P F
PF
The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3255, USA.
Champagne
A E
AE
Powell
D C
DC
Iliadis
C
C
Hale
S E
SE
Hansper
V Y
VY