Nucleon decay and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>n</mml:mi><mml:mo>−</mml:mo><mml:mover accent="true"><mml:mi>n</mml:mi><mml:mo stretchy="false">¯</mml:mo></mml:mover></mml:math> oscillations in a left-right symmetric model with large extra dimensions
Sudhakantha Girmohanta, Robert Shrock
Abstract
We study baryon-number-violating processes, including proton and bound neutron decays and $n\ensuremath{-}\overline{n}$ oscillations, in a left-right-symmetric (LRS) model in which quarks and leptons have localized wave functions 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 $n\ensuremath{-}\overline{n}$ 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 ${M}_{n\overline{n}}$ characterizing the physics responsible for $n\ensuremath{-}\overline{n}$ 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 $n\ensuremath{-}\overline{n}$ oscillations.