Abstract

We present a strategy to study the parameter space of the Type – II CP conserving Two Higgs Doublet Model with a softly broken Z2 symmetry by parametrizing the Higgs scalar potential in the physical basis. In this basis, the input parameters are the masses of the 4 scalar physical states, mH± , mA, mH , mh, the ratio of the Higgs vacuum expectation values, tanβ, two mixing angles, α and β, and the softly breaking parameter scale of the Z2 symmetry, M . Using the physical basis, we present numerical scans of the available 2HDM parameter region where we modify the Lilith program to study constraints from signal strength measurements of the 125GeV Higgs boson on the cos(β − α) and tanβ plane in the Type - II 2HDM.

We also impose certain theoretical constraints on the masses of H, A, and H± to eliminate all exotic decays, and to allow space for SM particle decays. From these results, we define three benchmark scenarios, namely the decoupling limit, near the decoupling limit, and the crescent limit. The crescent limit allows us to probe non-SM Higgs phenomenology that is of interest for future LHC Higgs searches. Our results suggest that in the crescent limit, when kinematically accessible H → hh, A → Zh and H± → W ±h should become high priorities in searching for additional Higgs bosons.

Keywords— 2HDM, Higgs Physics, Z2 Symmetry, Crescent limit, Lilith