Dipole moments of the Electron, Neutrino and Neutron in the MSSM without R-parity Symmetry

TL;DR

This paper investigates the effects of R-parity violation in the MSSM on electric dipole moments of particles, finding no 1-loop contributions for electrons and neutrons but non-zero neutrino dipole moments at 1-loop, with implications for experimental constraints.

Contribution

It demonstrates that R-parity violating couplings do not induce 1-loop EDMs for electrons and neutrons, but do generate neutrino dipole moments at 1-loop, providing new constraints on these couplings.

Findings

Electron and neutron EDMs arise at 2-loop level.

Neutrino dipole moments are non-zero at 1-loop.

Constraints on R-parity violating couplings from neutrino dipole moments.

Abstract

We show that in the MSSM without R-parity symmetry there are no new contributions to electron and neutron electric dipole moments (EDMs) at 1-loop induced by the R-parity violating Yukawa couplings. Non-zero EDMs for the electron and neutron first arise at the 2-loop level. As an example we estimate the contribution of a two-loop graph which induces electron EDMs. On the other hand, we show that the (Majorana) neutrino electric and magnetic transition moments are non-zero even at the 1-loop level. Constraints on the R-parity violating couplings are derived from the existing bounds on the neutrino dipole moments.