Constrained SUSY seesaws with a 125 GeV Higgs

TL;DR

This paper analyzes how three SUSY seesaw models can accommodate a 125 GeV Higgs within CMSSM constraints, comparing their phenomenology and potential for future experimental discrimination.

Contribution

It provides a comparative analysis of type I, II, and III SUSY seesaw models with CMSSM boundary conditions, highlighting differences in SUSY particle masses and experimental signatures.

Findings

Type II and III models have lighter SUSY particles than type I for the same parameters.

Large parameter values are required to achieve a 125 GeV Higgs in these models.

Future LHC data and muon decay limits can help distinguish between seesaw models.

Abstract

Motivated by the ATLAS and CMS discovery of a Higgs-like boson with a mass around 125 GeV, and by the need of explaining neutrino masses, we analyse the three canonical SUSY versions of the seesaw mechanism (type I, II and III) with CMSSM boundary conditions. In type II and III cases, SUSY particles are lighter than in the CMSSM (or the constrained type I seesaw), for the same set of input parameters at the universality scale. Thus, to explain $m_{h^0} \simeq 125 GeV$ at low energies, one is forced into regions of parameter space with very large values of $m_0$, $M_{1/2}$ or $A_0$. We compare the squark and gluino masses allowed by the ATLAS and CMS ranges for $m_{h^0}$ (extracted from the 2011-2012 data), and discuss the possibility of distinguishing seesaw models in view of future results on SUSY searches. In particular, we briefly comment on the discovery potential of LHC upgrades, for squark/gluino mass ranges required by present Higgs mass constraints. A discrimination between different seesaw models cannot rely on the Higgs mass data alone, therefore we also take into account the MEG upper limit on BR$(\mu \to e \gamma)$ and show that, in some cases, this may help to restrict the SUSY parameter space, as well as to set complementary limits on the seesaw scale.