Dirac Neutrino Masses from Generalized Supersymmetry Breaking

TL;DR

This paper shows how Dirac neutrino masses in the sub-eV range can naturally arise in supersymmetric models with generalized supersymmetry breaking, involving novel mechanisms that suppress neutrino masses and dipole moments.

Contribution

It introduces a new mechanism for generating Dirac neutrino masses via hard and nonholomorphic supersymmetry breaking couplings in gauge-extended models.

Findings

Neutrino masses naturally in the sub-eV range.

Neutrino magnetic and electric dipole moments vanish at one-loop.

Effective Dirac mass terms can arise at tree level or one-loop.

Abstract

We demonstrate that Dirac neutrino masses in the experimentally preferred range are generated within supersymmetric gauge extensions of the Standard Model with a generalized supersymmetry breaking sector. If the usual superpotential Yukawa couplings are forbidden by the additional gauge symmetry (such as a U(1)'), effective Dirac mass terms involving the "wrong Higgs" field can arise either at tree level due to hard supersymmetry breaking fermion Yukawa couplings, or at one-loop due to nonanalytic or "nonholomorphic" soft supersymmetry breaking trilinear scalar couplings. As both of these operators are naturally suppressed in generic models of supersymmetry breaking, the resulting neutrino masses are naturally in the sub-eV range. The neutrino magnetic and electric dipole moments resulting from the radiative mechanism also vanish at one-loop order.