Optimizing Higgs boson CP measurement in H → τ τ decay with ML techniques

Abstract

Current measurements of the CP state of the Higgs boson have favoured a scalar Higgs boson but are not able to exclude a mixing of scalar and pseudoscalar Higgs boson states. A measurement of possible mixed CP states of the Higgs boson is best done through the H → τ τ decay mode. The decay products of τ leptons, produced in H → τ τ decays, encode the CP information of the Higgs. This presents a challenge as a large proportion of τ decays involve cascade decays to three pions. This results in increased complexity in defining a CP sensitive observable. Deep learning tools (through neural networks) have been employed to extract as much sensitivity as possible. This neural network approach has b..