Weak proton capture reactions on 1H and 3He and tritium beta decay.

Abstract

The cross sections for the weak proton capture reactions {ital p}+{ital p}{r arrow}{ital d}+{ital e}{sup +}+{nu}{sub {ital e}} and {ital p}+{sup 3}He{r arrow}{sup 4}He+{ital e}{sup +}+{nu}{sub {ital e}} have been calculated with realistic wave functions determined by using the Argonne {ital v}{sub 14} nucleon-nucleon interaction. To minimize the uncertainty in the axial exchange current operator, its matrix element has been adjusted so as to reproduce the measured Gamow-Teller matrix element for {beta} decay of tritium. The exchange current contribution enhances the calculated rate of the {ital pp} capture reaction by 1.5% and decreases that of the {ital p} {sup 3}He reaction by almost a factor of 5.