A3a: Extended Higgs sectors at the LHC

Project A3a targets specifically electroweak baryogenesis for the generation of the baryon-antibaryon asymmetry of the Universe by making a link between Higgs physics, cosmology and collider physics. In a global fit the still allowed amount of CP violation, which is necessary for baryogenesis, is determined; optimal observables for the measurement of CP violation at the LHC are derived. By taking into account all relevant experimental and theoretical constraints at highest possible precision we derive the implications of a strong first order phase transition for the LHC phenomenology of extended Higgs sectors. Furthermore, the spectrum of gravitational waves generated in the phase transition is investigated.

1. Precision studies of the electroweak vacuum: vacuum stability of the 2HDM and the NMSSM at next-to-leading order; symmetry structure of extended Higgs sectors with dark matter candidates; non-perturbative evolution of the Higgs potential ; machine learning methods in the numerical evolution.
2. Precision predictions for LHC phenomenology: corrections to Higgs decays, e.g. electroweak corrections in the CP-violating 2HDM, SUSY-NLO corrections for charged Higgs in the CP-violating NMSSM, NLO SUSY-QCD corrections to gluon fusion into the MSSM pseudoscalar; impact of higher-order corrections on model parameters.
3. Phenomenology and analysis: information geometry of new light scalar, matrix element method for complex phase space configurations, generative adversarial networks for phase space mapping, impact of precision predictions on global analysis.