Abstract
The CMS experiment at the LHC has performed the first measurement of
the CP structure of the Yukawa coupling between the Higgs boson and tau
leptons. The measurement is based on data collected in proton-proton
collisions at \sqrt{s} = 13s=13
TeV during 2016-18, corresponding to an integrated luminosity of
137\text{ fb}^{-1}137 fb−1.
The analysis utilizes the angular correlation between the decay planes
of tau leptons produced in Higgs boson decays, where dedicated analysis
techniques are used to optimise the reconstruction of tau decay planes.
The measured value of the CP mixing angle is
4\pm17^{\circ}4±17∘,
at 68\%68%
confidence level. The pure CP-odd hypothesis is excluded by
3.23.2
standard deviations. The analysis strategies and the results of the
measurement are presented.