Karlsruhe 2024 – scientific programme
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T: Fachverband Teilchenphysik
T 100: Higgs 4 (coupling to taus, CP, rare decays)
T 100.3: Talk
Thursday, March 7, 2024, 16:30–16:45, Geb. 30.41: HS 2
Test of CP invariance in Higgs boson production via vector boson fusion exploiting the H→τhadτhad decay mode — •Daniel Bahner, Ö. Oğul Öncel, and Markus Schumacher — Physikalisches Institut, Freiburg, Deutschland
Violation of CP invariance is one of the Sakharov conditions to explain the observed baryon asymmetry in our universe (BAU). While CP violation is already realized in the Standard Model via CKM matrix, it is not sufficient to explain the observed magnitude of BAU. The discovery of the Higgs boson has opened a new window to search for additional sources of CP violation. The vector-boson fusion (VBF) production of the Higgs boson is one of them. Here, it is possible to probe CP-violating contributions to the HVV vertex.
In this talk, the subsequent Higgs boson decay into two hadronically decaying tau leptons is considered. The dominant background process in this decay channel is the irreducible Z→ττ process. A data-driven Fake Factor method is used to estimate the sizeable contribution from events in which jets are misidentified as hadronically decaying tau leptons. A neural network is exploited to discriminate signal from background processes.
CP-odd observables are used in a profile-likelihood fit to perform a test of CP invariance and to constrain the strength of new CP-violating interactions. The talk will discuss the analysis strategy, CP-odd observables, and first results including systematic uncertainties based on √s=13 TeV proton-proton collision data collected by the ATLAS detector corresponding to Lint=140 fb−1.
Keywords: CP violation; Vector boson fusion; Higgs boson; Hadronic decays of tau leptons