Discovery prospects of a light Higgs boson at the LHC in type-I 2HDM

Abstract: We present a comprehensive analysis of observing a light Higgs boson in the mass range $70$ -- $110$ GeV at the 13/14 TeV LHC, in the context of the type-I two-Higgs-doublet model. The decay of the light Higgs to a pair of bottom quarks is dominant in most parts of the parameter space, except in the fermiophobic limit. Here its decay to bosons, (mainly a pair of photons), becomes important. We perform an extensive collider analysis for the $b\bar{b}$ and $\gamma \gamma$ final states. The light scalar is tagged in the highly boosted regimes for the $b \bar{b}$ mode to reduce the enormous QCD background. This decay can be observed with a few thousand fb$^{-1}$ of integrated luminosity at the LHC. Near the fermiophobic limit, the decay of the light Higgs to a pair of photons can even be probed with a few hundred fb$^{-1}$ of integrated luminosity at the LHC.