Neutrinoless double beta decay in minimal left–right symmetric model with universal seesaw

Abstract

We present a detailed discussion on neutrinoless double beta decay [Formula: see text] within left–right symmetric models based on the gauge symmetry of type [Formula: see text] as well as [Formula: see text] where fermion masses including that of neutrinos are generated through a universal seesaw mechanism. We find that one or more of the right-handed neutrinos could be as light as a few keV if left–right symmetry breaking occurs in the range of a few TeV to 100 TeV. With such light right-handed neutrinos, we perform a detailed study of new physics contributions to [Formula: see text] and constrain the model parameters from the latest experimental bound on such a rare decay process. We find that the new physics contribution to [Formula: see text] in such a scenario, particularly the heavy–light neutrino mixing diagrams, can individually saturate the existing experimental bounds, but their contributions to total [Formula: see text] half-life cancel each other due to unitarity of the total [Formula: see text] mass matrix. The effective contribution to half-life therefore, arises from the purely left and purely right neutrino and gauge boson mediated diagrams. We find that the parameter space saturating the [Formula: see text] bounds remains allowed from the latest experimental bounds on charged lepton flavor violating decays like [Formula: see text]. We finally include the bounds from cosmology and supernova to constrain the parameter space of the model.