Simplest Radiative Dirac Neutrino Mass Models

Understand

If neutrinos are Dirac particles, their right-handed partners must be present in the theory.

• Once introduced in the Standard Model (SM), the difference between the baryon number $B$ and the lepton number $L$ can be promoted to a local $U(1)_{B-L}$ symmetry since the corresponding gauge anomalies can be canceled by the right-handed neutrinos.
• Furthermore, the extremely small neutrino mass can be explained naturally if it is originated from the quantum correction.
• In this work, we propose simplest models of radiative Dirac neutrino mass using only $U(1)_{B-L}$ symmetry, and without introducing additional fermions and without imposing ad hoc symmetries.