Determination of the direct capture contribution for N-13(p,gamma)O-14 from the O-14 -> N-13+p asymptotic normalization coefficient
Academic Article
Overview
Research
Identity
Additional Document Info
Other
View All
Overview
abstract
13N(p, )14O is one of the key reactions which trigger the onset of the hot CNO cycle. This transition occurs when the proton capture rate on 13N is faster, due to increasing stellar temperature (=108 K), than the 13N -decay rate. The rate of this reaction is dominated by the resonant capture through the first excited state of 14O (Er=0.528 MeV). However, through constructive interference, direct capture below the resonance makes a non-negligible contribution to the reaction rate. We have determined this direct contribution by measuring the asymptotic normalization coefficient for 14O13N+p. In our experiment, an 11.8 MeV/nucleon 13N radio-active beam was used to study the 14N( 13N, 14O)13C peripheral transfer reaction, and the asymptotic normalization coefficient, (Cp1/214O)2=29. 04.3 fm-1, was extracted from the measured cross section. The radiative capture cross section was estimated using an R-matrix approach with the measured asymptotic normalization coefficient and the latest resonance parameters. We find the 5 factor for 13N(p, )14O to be larger than previous estimates. Consequently, the transition from the cold to hot CNO cycle for novae would be controlled by the slowest proton capture reaction 14N(p, )15O.
