Search For a Light Pseudoscalar Higgs Boson with Boosted Topologies at CMS

A search is performed for a light pseudoscalar Higgs boson (a) motivated by the theoretical framework of two Higgs doublet plus singlet models (2HDM+S). This search uses 2016 LHC data collected at 13 TeV by the CMS experiment and analyzes the decay channel H->a a->mu mu tau tau, with H being either the 125 GeV state or a more massive Higgs boson. Final state taus have a boosted and collimated topology due to the large mass difference between the H and a. Thus, a novel algorithm for this special final state is designed to increase the identification efficiency. Expected limits are derived in the context of four types of 2HDM+S models for H(125), and are complementary to current CMS results with resolved final state particles. Model-independent expected limits for heavier H masses are also presented. This analysis will be updated with machine learning techniques for the Full Run 2 dataset.