Two-loop corrections to the Higgs trilinear coupling in models with extended scalar sectors
Abstract
The Higgs trilinear coupling λhhh is of great importance to understand the structure of the Higgs sector and allows searching for indirect signs of Beyond-the-Standard-Model (BSM) physics, even if new states are somehow hidden. In particular, in models with extended Higgs sectors, it is known that non-decouplings effects in BSM-scalar contributions at one loop can cause λhhh to deviate significantly from its SM prediction, raising the question of what happens at two loops. We review here our calculation of the leading two-loop corrections to λhhh in an aligned scenario of a Two-Higgs-Doublet Model. We find their typical size to be 10-20% of the one-loop corrections, meaning that they do not modify significantly the one-loop non-decoupling effects, but are not entirely negligible either.