Solar Neutrinos from theHe3(p,e+ν)He4Reaction

The cross section for the ${\beta }^{+}$ decay of continuum states of ${}_{}{}^4{}_{}{}^{}\mathrm{Li}$ has been recalculated using and improved normalization for the $S$-wave proton inside the nucleus and the newly measured value of the thermal-neutron capture cross section of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$. In addition, the contributions of first-forbidden transitions have been added. The new value of the $S$ factor is found to be 8.1 × ${10}^{-20\mathrm{}}$ keV b, too small for this reaction to produce a measureable flux of solar neutrinos on Earth.