Constraining CP-violating Higgs sectors at the LHC using gluon fusion

Abstract

We investigate the constraints that the LHC can set on a 126 GeV Higgs boson that is an admixture of CP eigenstates. Traditional analyses rely on Higgs couplings to massive vector bosons, which are suppressed for CP-odd couplings, so that these analyses have limited sensitivity. Instead we focus on Higgs production in gluon fusion, which occurs at the same order in αS for both CP-even and -odd Higgs couplings to top quarks. We study the Higgs plus two jet final state followed by Higgs decay into a pair of tau leptons. We show that using the 8 TeV data set it is possible to rule out the pure CP-odd hypothesis in this channel alone at nearly 95% C.L, assuming that the Higgs is CP-even. We also..