Neutrino Process Nucleosynthesis and the ${}^{11}$B/${}^{10}$B Ratio

Abstract

We consider the evolution of the light elements ($Li,Be$ and $B$) incorporating the effects of their production by both neutrino process and cosmic-ray nucleosynthesis. We test the viability of the neutrino process to resolve the long standing problem of the ${}^{11}$B/${}^{10}$B isotopic ratio which amounts to 4 at the time of the formation of the solar system. This hypothesis may be ultimately constrained by the $B/Be$ ratio observed in halo stars. Though we are able to obtain a solar isotopic ratio ${}^{11}B{/}^{10}B\simeq 4$, the current paucity of data at low metallicity prevents us from making a definitive conclusion regarding the resolution of this problem. We show however, that neutrino process nucleosynthesis leads to a relatively model independent prediction that the $B/Be$ elemental ratio is large ($>$ 50) at low metallicities ($[Fe/H]<-3.0$), if $Be$ is produced as a secondary element (as is the case in the conventional scenario of galactic cosmic-ray nucleosynthesis).

14 pages, LaTeX