First direct measurement of the Higgs-tau Yukawa coupling

• Mohammadhassan Hassanshahi (Imperial College London)

I will present the first direct measurement of the CP structure of the Higgs-tau Yukawa coupling (DOI: 10.1007/JHEP06(2022)012). The measurement was performed using proton-proton collision data recorded by the CMS experiment at CERN which corresponds to an integrated luminosity of 137 $fb^{-1}$ and $\sqrt s=13$ TeV center of mass-energy. The analysis uses the angular correlation between the decay planes of tau leptons produced in Higgs boson decays. Several techniques were employed to optimize the CP sensitivity. The effective mixing angle between CP-even and CP-odd τ Yukawa couplings is found to be −1 ± 19°, compared to an expected value of 0 ± 21° at the 68.3% confidence level. The data disfavour the pure CP-odd scenario at 3.0 standard deviations. The results are compatible with predictions for the standard model Higgs boson.