Baryon-number-violating nucleon and dinucleon decays in a model with large extra dimensions

It is known that limits on baryon-number-violating nucleon decays do not, in general, imply corresponding suppression of n-n transitions. Indeed, it has been shown, using a model with fermions propagating in higher dimensions, that even with nucleon decays suppressed far below observable levels, n-n oscillations can occur at a rate comparable to existing experimental limits, motivating new searches for such oscillations. In the context of this model we investigate a related question, namely the implications of limits on ΔL=-1 proton and bound neutron decays mediated by four-fermion operators for rates of nucleon decays mediated by k-fermion operators with k=6 and k=8. These include a variety of nucleon and dinucleon decays to dilepton and trilepton final states with ΔL=-3,-2,1, and 2. We carry out a low-energy effective field theory analysis of relevant operators for these decays and show that, in this extra-dimensional model, the rates for these decays are strongly suppressed and hence are in accord with experimental limits.