Truly Minimal Left-Right Model of Quark and Lepton Masses

Abstract

We propose a left-right model of quarks and leptons based on the gauge group $SU(3{)}_C\times SU(2{)}_L\times SU(2{)}_R\times U(1{)}_{B-L}$, where the scalar sector consists of only two doublets: (1,2,1,1) and (1,1,2,1). As a result, any fermion mass, whether it be Majorana or Dirac, must come from dimension-five operators. This allows us to have a common view of quark and lepton masses, including the smallness of Majorana neutrino masses as the consequence of a double seesaw mechanism.

Comments: Version to appear in PRL, title changed by journal to "Left-right model of quark and lepton masses without a scalar bidoublet"