Measurement of the CP properties of Higgs boson interactions with τ -leptons with the ATLAS detector
Abstrakt
A study of the charge conjugation and parity
(CP) properties of the interaction between the Higgs boson and τ -leptons is presented. The study is based on a measurement of CP-sensitive angular observables defined by the visible decay products of τ -leptons produced in Higgs boson decays. The analysis uses 139 fb-1 of proton-proton collision data recorded at a centre-of-mass energy of
SQUARE ROOT s = 13 TeV with the ATLAS detector at the Large Hadron Collider.
Contributions from CP-violating interactions between the Higgs boson and τ -leptons are described by a singlemixing angle parameter φτ in the generalised Yukawa interaction.
Without constraining the H RIGHTWARDS ARROW ττ signal strength to its expected value under the Standard Model hypothesis, the mixing angle φτ is measured to be 9°+-16°, with an expected value of 0° +-28° at the 68% confidence level. The pure CPodd hypothesis is disfavoured at a level of 3.4 standard deviations.
The results are compatible with the predictions for the Higgs boson in the Standard Model.