Beyond the standard seesaw: neutrino masses from Kahler operators and broken supersymmetry

TL;DR

This paper explores how neutrino masses can originate from Kahler potential operators in supersymmetry, especially when heavy triplet mediators also serve as SUSY-breaking messengers, linking neutrino physics with collider and rare decay experiments.

Contribution

It introduces a novel mechanism for neutrino mass generation via Kahler operators and proposes a unified framework where seesaw mediators also mediate SUSY breaking, leading to testable predictions.

Findings

Neutrino masses can be generated by Kahler operators with SUSY-breaking effects.

Heavy SU(2)_W triplets can act as both seesaw mediators and SUSY-breaking messengers.

Correlations between neutrino parameters, sparticle masses, and lepton flavor violation are predicted.

Abstract

We investigate supersymmetric scenarios in which neutrino masses are generated by effective d=6 operators in the Kahler potential, rather than by the standard d=5 superpotential operator. First, we discuss some general features of such effective operators, also including SUSY-breaking insertions, and compute the relevant renormalization group equations. Contributions to neutrino masses arise at low energy both at the tree level and through finite threshold corrections. In the second part we present simple explicit realizations in which those Kahler operators arise by integrating out heavy SU(2)_W triplets, as in the type II seesaw. Distinct scenarios emerge, depending on the mechanism and the scale of SUSY-breaking mediation. In particular, we propose an appealing and economical picture in which the heavy seesaw mediators are also messengers of SUSY breaking. In this case, strong correlations exist among neutrino parameters, sparticle and Higgs masses, as well as lepton flavour violating processes. Hence, this scenario can be tested at high-energy colliders, such as the LHC, and at lower energy experiments that measure neutrino parameters or search for rare lepton decays.