Nucleon Decay and $n$-$\bar{n}$ Oscillations in a Left-Right Symmetric Model with Large Extra Dimensions

Abstract

We study baryon-number-violating processes, including proton and bound neutron decays and $n-\bar{n}$ oscillations, in a left-right-symmetric (LRS) model in which quarks and leptons have localized wavefunctions in extra dimensions. In this model we show that, while one can easily suppress baryon-number-violating nucleon decays well below experimental bounds, this does not suppress $n-\bar{n}$ transitions, which may occur at levels comparable to current limits. This is qualitatively similar to what was found in an extra-dimensional model with a Standard-Model low-energy effective field theory (SMEFT). We show that experimental data imply a lower limit on the mass scale $M_{n\bar{n}}$ characterizing the physics responsible for $n-\bar{n}$ oscillations in the LRS model that is significantly higher than in the extra-dimensional model using a SMEFT and explain the reason for this. Our results provide further motivation for new experiments to search for $n-\bar{n}$ oscillations.

Comments: 10 pages, latex. arXiv admin note: text overlap with arXiv:1911.05102