Likelihood analysis of the sub-GUT MSSM in light of LHC 13-TeV data

Abstract

Abstract We describe a likelihood analysis using MasterCode of variants of the MSSM in which the soft supersymmetry-breaking parameters are assumed to have universal values at some scale $$M_\mathrm{in}$$ Min below the supersymmetric grand unification scale $$M_\mathrm{GUT}$$ MGUT , as can occur in mirage mediation and other models. In addition to $$M_\mathrm{in}$$ Min , such ‘sub-GUT’ models have the 4 parameters of the CMSSM, namely a common gaugino mass $$m_{1/2}$$ m1/2 , a common soft supersymmetry-breaking scalar mass $$m_0$$ m0 , a common trilinear mixing parameter A and the ratio of MSSM Higgs vevs $$\tan \beta $$ tanβ , assuming that the Higgs mixing parameter $$\mu > 0$$ μ>0 . We take into account constraints on strongly- and electroweakly-interacting sparticles from $$\sim 36$$ ∼36 /fb of LHC data at 13 TeV and the LUX and 2017 PICO, XENON1T and PandaX-II searches for dark matter scattering, in addition to the previous LHC and dark matter constraints as well as full sets of flavour and electroweak constraints. We find a preference for $$M_\mathrm{in}\sim 10^5$$ Min∼105 to $$10^9 \,\, \mathrm {GeV}$$ 109GeV , with $$M_\mathrm{in}\sim M_\mathrm{GUT}$$ Min∼MGUT disfavoured by $$\Delta \chi ^2 \sim 3$$ Δχ2∼3 due to the $$\mathrm{BR}(B_{s, d} \rightarrow \mu ^+\mu ^-)$$ BR(Bs,d→μ+μ-) constraint. The lower limits on strongly-interacting sparticles are largely determined by LHC searches, and similar to those in the CMSSM. We find a preference for the LSP to be a Bino or Higgsino with $$m_{\tilde{\chi }^0_{1}} \sim 1 \,\, \mathrm {TeV}$$ mχ~10∼1TeV , with annihilation via heavy Higgs bosons H / A and stop coannihilation, or chargino coannihilation, bringing the cold dark matter density into the cosmological range. We find that spin-independent dark matter scattering is likely to be within reach of the planned LUX-Zeplin and XENONnT experiments. We probe the impact of the $$(g-2)_\mu $$ (g-2)μ constraint, finding similar results whether or not it is included.