Leptoquarks with exactly stable protons

Abstract

We explore a novel mechanism to restrict TeV-scale leptoquark interactions and render the proton exactly stable to all orders in the effective field theory expansion. A scalar condensate breaks a lepton-flavoured U(1)X gauge symmetry in the ultraviolet and generates neutrino masses, leaving a discrete Z9 or Z18 gauge symmetry in the infrared, forbidding ΔB=1 processes. This provides an elegant framework to address the flavour anomalies and can be adapted to many other new-physics models. The U(1)X can emerge from a gauge–flavour unified SU(12)×SU(2)×SU(2) theory at even higher energies.