Search for light pseudoscalar Higgs bosons in 2HDM using 13 TeV LHC Data

A search for a light pseudoscalar higgs boson (a1) is performed within the framework of two higgs doublet model extensions of the standard model. Using the 2016 LHC data collected at sqrt{s} = 13 TeV by the CMS experiment, this search looks for gg -> H -> a1a1 -> µµττ , where H can be the 125 GeV state or a heavier state. Due to the large mass difference between the H and the a1, the two τ's will be highly boosted and collimated, failing the standard CMS tau reconstruction algorithm. Therefore, we devise a dedicated di-tau technique to increase reconstruction efficiencies, particularly at ΔR{ττ} < 0.5.