Observable proton decay from Planck scale physics

Abstract

In the Standard Model, no dim-5 $\ensuremath{\Delta}B\ensuremath{\ne}0$ operators exist, so that Planck-scale-induced proton decay amplitudes are suppressed by at least $1/{M}_{P\ensuremath{\ell}}^{2}$. If the Standard Model is augmented by a light, color-nonsinglet boson, then $O(1/{M}_{P\ensuremath{\ell}})$ proton-decay amplitudes are possible. These always conserve $B+L$, so that the dominant decay modes are $p\ensuremath{\rightarrow}{\ensuremath{\Pi}}^{+}\ensuremath{\nu}$ and $p\ensuremath{\rightarrow}{\ensuremath{\Pi}}^{+}{\ensuremath{\Pi}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$, where ${\ensuremath{\Pi}}^{+}={\ensuremath{\pi}}^{+}$ or ${K}^{+}$.