Erlangen 2026 – scientific programme

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T: Fachverband Teilchenphysik

T 64: Invited Topical Talks III

T 64.2: Invited Topical Talk

Thursday, March 19, 2026, 14:15–14:45, AudiMax

Probing CP invariance of Higgs boson production and decay and its interpretation in effective field theories with the ATLAS detector — •Lorenzo Rossini — University of Freiburg

The origin of the observed baryon asymmetry in the universe is one open question that can be explained if the three Sakharov conditions are fulfilled. One of these conditions includes the violation of the invariance under combined charge (C) and parity (P) conjugation. However, the magnitude of CP violating effects in the Standard Model (SM) is not enough to explain the observations. The Higgs boson is a promising candidate to search for additional CP-violating interactions.

The ATLAS experiment at the LHC has a vast program of measurements of the properties of the Higgs boson, and in particular its CP properties in interactions with gauge bosons or fermions. This talk will summarize tests of CP invariance of Higgs boson production and decay, and the interpretation of the results using Effective Field Theory, with focus on analyses in which the decay mode into a pair of tau-leptons is exploited

Moreover, comparison (and future combinations) with other ATLAS analyses will be discussed. This talk will present results from analyses based on proton-proton collision data collected by the ATLAS experiment at a center-of-mass energy of √s=13 TeV and √s=13.6 TeV during Run 2 and early Run 3.

Keywords: Higgs; CP violation; Effective Field Theory; tau-leptons; ATLAS