Higgs boson coupling measurements and direct searches as complementary probes of the phenomenological MSSM

Abstract

The parameter space of the minimal supersymmetric standard model (MSSM) can be probed via many avenues, such as by precision measurements of the couplings of the $\ensuremath{\sim}126\text{ }\mathrm{GeV}$ Higgs boson, as well as the direct searches for supersymmetry (SUSY) partners. We examine the connection between these two collider observables at the LHC and International Linear Collider (ILC) in the $19/20$-parameter phenomenological MSSM (pMSSM). Within this scenario, we address two questions: (i) How will potentially null direct searches for SUSY at the LHC influence the predicted properties of the lightest SUSY Higgs boson? (ii) What can be learned about the properties of the superpartners from precision measurements of the Higgs boson couplings? In this paper, we examine these questions by employing three different large sets of pMSSM models with either the neutralino or gravitino being the lightest supersymmetric particle. We make use of the ATLAS direct SUSY searches at the $7/8\text{ }\text{ }\mathrm{TeV}$ LHC as well as expected results from 14 TeV operations, and the anticipated precision measurements of the Higgs boson couplings at the 14 TeV LHC and at the ILC. We demonstrate that the future Higgs coupling determinations can deeply probe the pMSSM parameter space and, in particular, can observe the effects of models that are projected to evade the direct searches at the 14 TeV LHC with $3\text{ }\text{ }{\mathrm{ab}}^{\ensuremath{-}1}$ of integrated luminosity. In addition, we compare the reach of the Higgs coupling determinations to the direct heavy Higgs searches in the ${M}_{A}\ensuremath{-}\mathrm{tan}\ensuremath{\beta}$ plane and show that they cover orthogonal regions. This analysis demonstrates the complementarity of the direct and indirect approaches in searching for supersymmetry, and the importance of precision studies of the properties of the Higgs boson.