The singly-charged scalar singlet as the origin of neutrino masses

A bstract We consider the generation of neutrino masses via a singly-charged scalar singlet. Under general assumptions we identify two distinct structures for mass matrix. This yields constraint antisymmetric Yukawa coupling singlet to left-handed lepton doublets, irrespective how breaking lepton-number conservation is achieved. The disfavours large hierarchies among couplings. study implications phenomenology lepton-flavour universality, measurements W -boson mass, flavour violation in charged-lepton sector and decays also discuss parameter space that can address Cabibbo Angle Anomaly.