Phenomenology of SUSY SU(5) with type I+III seesaw

TL;DR

This paper explores a supersymmetric SU(5) model with a combined type I+III seesaw mechanism, analyzing its phenomenology, flavor violation, and dark matter implications, revealing experimental prospects and constraints for the model.

Contribution

It introduces a unified SU(5) model with a mixed seesaw mechanism and studies its phenomenological implications, including flavor violation and dark matter relic density, under universal boundary conditions.

Findings

BR(μ→eγ) is within MEG experiment reach for high seesaw scale.

Current bounds on τ→μγ restrict its future observability.

Model allows for a specific neutralino relic density and an upper bound on dark matter mass.

Abstract

We consider a supersymmetric SU(5) model where two neutrino masses are obtained via a mixed type I+III seesaw mechanism induced by the component fields of a single SU(5) adjoint. We have analyzed the phenomenology of the model paying particular attention to flavour violating processes and dark matter relic density, assuming universal boundary conditions. We have found that, for a seesaw scale larger than $10^{12\div 13}$ GeV, BR$(\mu\to e \gamma)$ is in the reach of the MEG experiment in sizable regions of the parameter space. On the other side, current bounds on it force BR$(\tau \to \mu \gamma)$ to be well below the reach of forthcoming experiments, rendering thus the model disprovable if a positive signal is found. The same bounds still allow for a sizable positive contribution to $\epsilon_K$, while the CP violation in the $B_s$ mixing turns out to be too small to account for the di-muon anomaly reported by the D0 collaboration. Finally, the regions where the neutralino relic density is within the WMAP bounds can be strongly modified with respect to the constrained MSSM case. In particular, a peculiar coannihilation region, bounded from above, can be realized, which allows us to put an upper bound on the dark matter mass for certain set-ups of the parameters.