The Higgs Mass beyond the CMSSM

TL;DR

This paper explores extensions of the CMSSM to accommodate a 125 GeV Higgs mass, revealing viable dark matter and phenomenological regions when the universality scale is below the GUT scale, differing from traditional models.

Contribution

It investigates non-standard CMSSM variants with lower universality scales and independent Higgs masses, identifying new viable parameter spaces consistent with recent LHC results.

Findings

Large parameter regions with correct relic density emerge when M_in < M_GUT.

Coannihilation processes become significant in sub-GUT models.

Viable sub-GUT mSUGRA regions are identified, unlike in GUT-scale models.

Abstract

The apparent discovery of a Higgs boson with mass ~125 GeV has had a significant impact on the constrained minimal supersymmetric extension of the Standard Model in which the scalar masses, gaugino masses and tri-linear A-terms are assumed to be universal at the GUT scale (the CMSSM). Much of the low-mass parameter space in the CMSSM has been excluded by supersymmetric particle searches at the LHC as well as by the Higgs mass measurement and the emergent signal for B_s to mu^+ mu^-. Here, we consider the impact of these recent LHC results on several variants of the CMSSM with a primary focus on obtaining a Higgs mass of ~125 GeV. In particular, we consider the one- and two-parameter extensions of the CMSSM with one or both of the Higgs masses set independently of the common sfermion mass, m_0 (the NUHM1,2). We also consider the one-parameter extension of the CMSSM in which the input universality scale M_in is below the GUT scale (the sub-GUT CMSSM). We find that when M_in < M_GUT large regions of parameter space open up where the relic density of neutralinos can successfully account for dark matter with a Higgs boson mass ~125 GeV. In some of these regions essential roles are played by coannihilation processes that are usually less important in the CMSSM with M_in = M_GUT. Finally, we reconsider mSUGRA models with sub-GUT universality, which have the same number of parameters as the CMSSM. Here too, we find phenomenologically viable regions of parameter space, which are essentially non-existent in GUT-scale mSUGRA models. Interestingly, we find that the preferred range of the A-term straddles that predicted by the simplest Polonyi model.