Year: 2019
Type: article
Abstract: In the framework of a baryon-number-violating effective Lagrangian, we calculate improved lower bounds on partial lifetimes for proton and bound neutron decays, including $p\ensuremath{\rightarrow}{\ensuremath{\ell}}^{+}{{\ensuremath{\ell}}^{\ensuremath{'}}}^{+}{{\ensuremath{\ell}}^{\ensuremath{'}}}^{\ensuremath{-}}$, $n\ensuremath{\rightarrow}\overline{\ensuremath{\nu}}{\ensuremath{\ell}}^{+}{{\ensuremath{\ell}}^{\ensuremath{'}}}^{\ensuremath{-}}$, $p\ensuremath{\rightarrow}{\ensuremath{\ell}}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}}$, and $n\ensuremath{\rightarrow}\overline{\ensuremath{\nu}}\overline{\ensuremath{\nu}}\ensuremath{\nu}$, where $\ensuremath{\ell}$ and ${\ensuremath{\ell}}^{\ensuremath{'}}$ denote $e$ or $\ensuremath{\mu}$, with both $\ensuremath{\ell}={\ensuremath{\ell}}^{\ensuremath{'}}$ and $\ensuremath{\ell}\ensuremath{\ne}{\ensuremath{\ell}}^{\ensuremath{'}}$ cases. Our lower bounds are substantially stronger than the corresponding lower bounds from direct experimental searches. We also present lower bounds on $(\ensuremath{\tau}/B{)}_{p\ensuremath{\rightarrow}{\ensuremath{\ell}}^{+}\ensuremath{\gamma}}$, $(\ensuremath{\tau}/B{)}_{n\ensuremath{\rightarrow}\overline{\ensuremath{\nu}}\ensuremath{\gamma}}$, $(\ensuremath{\tau}/B{)}_{p\ensuremath{\rightarrow}{\ensuremath{\ell}}^{+}\ensuremath{\gamma}\ensuremath{\gamma}}$, and $(\ensuremath{\tau}/B{)}_{n\ensuremath{\rightarrow}\overline{\ensuremath{\nu}}\ensuremath{\gamma}\ensuremath{\gamma}}$. Our method relies on relating the rates for these decay modes to the rates for decay modes of the form $p\ensuremath{\rightarrow}{\ensuremath{\ell}}^{+}M$ and $n\ensuremath{\rightarrow}\overline{\ensuremath{\nu}}M$, where $M$ is a pseudoscalar or vector meson, and then using the experimental lower bounds on the partial lifetimes for these latter decays.
Authors: Sudhakantha Girmohanta, Robert Shrock
Institution: Stony Brook University
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Funder: National Science Foundation
OpenAlex ID: W2981125656