  We report on a new lifetime measurement of the E_x=6792 keV state in 15O via
the Doppler-shift attenuation method at the E=259 keV resonance in the reaction
14N(p,g)15O. This subthreshold state is of particular importance for the
determination of the ground state astrophysical S factor of 14N(p,g)15O at
stellar energies. The measurement technique has been significantly improved
compared with previous work. The conclusion of a finite lifetime drawn there
cannot be confirmed with the present data. In addition, the lifetime of the two
states at E_x=5181 and 6172 keV have been measured with the same technique in
order to verify the experimental method. We observe an attenuation factor
F(tau)>0.98 for the E_x =6172 and 6792 keV states, respectively, corresponding
to tau<0.77 fs. The attenuation factor for the E_x=5181 keV state results in
F(tau)=0.78+/-0.02 corresponding to tau=8.4+/-1.0 fs in excellent agreement
with literature.

Nuclear Experiment