title: Lifetime of the 6793-keV state in 15O.
abstract: 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.
authors.affiliation: The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3255, USA.
authors.forename: P F
authors.initials: PF
authors.lastname: Bertone
authors.forename: A E
authors.initials: AE
authors.lastname: Champagne
authors.forename: D C
authors.initials: DC
authors.lastname: Powell
authors.forename: C
authors.initials: C
authors.lastname: Iliadis
authors.forename: S E
authors.initials: SE
authors.lastname: Hale
authors.forename: V Y
authors.initials: VY
authors.lastname: Hansper