Dirac or inverse seesaw neutrino masses from gauged B–L symmetry

Abstract

The gauged [Formula: see text] symmetry is one of the simplest and well-studied extension of Standard Model. In the conventional case, addition of three singlet right-handed neutrinos each transforming as [Formula: see text] under the [Formula: see text] symmetry renders it anomaly-free. It is usually assumed that the [Formula: see text] symmetry is spontaneously broken by a singlet scalar having two units of [Formula: see text] charge, resulting in a natural implementation of Majorana seesaw mechanism for neutrinos. However, as we discuss here, there is another simple anomaly-free solution which leads to Dirac or inverse seesaw masses for neutrinos. These new possibilities are explored along with an application to neutrino mixing with [Formula: see text] flavor symmetry.