Aachen 2019 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

T: Fachverband Teilchenphysik

T 28: Higgs-Zerfälle in Fermionen I

T 28.8: Talk

Tuesday, March 26, 2019, 17:50–18:05, H04

Constraining Higgs CP properties using H→ττ decays — •Alina Manthei, Peter Wagner, Maike Hansen, Christian Grefe, Philip Bechtle, and Klaus Desch — Physikalisches Institut Universität Bonn

In 2012, the discovery of a resonance featuring properties consistent with those of the Higgs boson affirmed the theory of the Higgs mechanism, an essential component of the Standard Model of Particle Physics. The latter predicts the Higgs boson to be CP even. Although measurements revealed that the Higgs cannot be fully CP odd, the existence of a CP-mixed Higgs cannot be ruled out, which can be considered as an indication of physics beyond the Standard Model. Only in the case of the coupling to fermions, it is possible to define a model-independent observable that allows to distinguish between the different CP scenarios. Due to the large QCD background in the channel H→ bb, this analysis makes use of the decay to τ leptons, the next to heaviest fermionic decay products of the Higgs boson. Due to the short lifetime of the τ, it immediately decays further so that only its decay products can be detected. By examining the decay of the τ lepton to only one charged prong, an angle between the two decay planes of the τs can be defined, an observable that serves to determine the CP phase in the coupling of the Higgs to the two τs. Via the measurement of this angle, the transverse spin correlations can be studied and a mixing angle between the CP even and CP odd states can be extracted. The state of the measurement descibed above will be presented and an outlook towards further steps will be given.