Boosting the charged Higgs search prospects using jet substructure at the LHC

Charged Higgs bosons are predicted in variety of theoretically well-motivated new physics models with extended Higgs sectors. In this study, we focus on a type-II two Higgs doublet model (2HDM-II) and consider a heavy charged Higgs with its mass ranging from 500 GeV to 1 TeV as dictated by the $b\to s\gamma$ constraints which render $M_{H^\pm}>480$ GeV. We study the dominant production mode $H^\pm t$ associated production with $H^\pm \to W^\pm A$ being the dominant decay channel when the pseudoscalar $A$ is considerably lighter. For such a heavy charged Higgs, both the decay products $W^\pm$ and $A$ are relatively boosted. In such a scenario, we apply the jet substructure analysis of tagging the fat pseudoscalar and $W$ jets in order to eliminate the standard model background efficiently. We perform a detailed detector simulation for the signal and background processes at the 14 TeV LHC. We introduce various kinematical cuts to determine the signal significance for a number of benchmark points with charged Higgs boson mass from 500 GeV to 1 TeV in the $W^\pm A$ decay channel. Finally we perform a multivariate analysis utilizing a boosted decision tree algorithm to optimize these significances.