Search for a light pseudoscalar Higgs boson in the dimuon decay channel in pp collisions at √s = 7 TeV

Abstract

The dimuon invariant mass spectrum is searched in the range between 5.5 and 14 GeV for a light pseudoscalar Higgs boson a, predicted in a number of new physics models, including the next-to-minimal supersymmetric standard model. The data sample used in the search corresponds to an integrated luminosity of 1.3 fb⁻¹ collected in pp collisions at √s = 7 TeV with the CMS detector at the LHC. No excess is observed above the background predictions and upper limits are set on the cross section times branching fraction σ × ℬ(pp → a → μ⁺μ⁻) in the range of 1.5–7.5 pb. These results improve on existing bounds on the abb̅ coupling for mₐ < mᵧ₍₁ₛ₎ and are the first significant limits for mₐ > mᵧ₍₃ₛ₎. Constraints on the supersymmetric parameter space are presented in the context of the next-to-minimal model.