Precision calculations of Higgs properties to probe New Physics

by Johannes Braathen (DESY)

Monday 31 May 2021, 14:00 → 15:00 Europe/Berlin

The Higgs boson offers a unique opportunity to probe indirect signs of BSM Physics, via the precise investigation of its properties -- in particular its mass and trilinear coupling. In this talk I will discuss two related directions of research.

First, I will present recent progress in the calculation of two-loop corrections to the Higgs trilinear coupling in a range of theories: extensions of the Standard Model such as the Two-Higgs-Doublet Model and the Inert Doublet Model, as well as BSM theories with classical scale invariance.

In the second part of this talk, I will turn to neutral scalar mass calculations in general BSM theories, and in particular the treatment of tadpoles in this context. I will show that the usual procedure to treat tadpoles, as implemented for instance in automated public tools, can encounter numerical instabilities in BSM scenarios containing heavy scalars with small vacuum expectation values. I will present an alternative Fleischer-Jegerlehner-like approach that alleviates these instabilities, with illustrations for a toy model and NMSSM scenarios.