Non-decoupling physics at future colliders

by Dave Sutherland

Thursday 21 Nov 2024, 14:00 → 15:00 Europe/London

BSM models where there are sizeable sources of electroweak symmetry breaking beyond the SM Higgs doublet, or where new particles get a sizeable fraction of their mass from coupling to the Higgs, are non-decoupling. They necessarily predict new states at the TeV scale or below, and are therefore a finite target for experiments. They are also an interesting target: they can significantly alter the electroweak phase transition, and they have a pattern of low energy effects that are distinct from those predicted by SMEFT.

Using their minimal gauge and Higgs couplings, I will argue that a future precision lepton collider (such as FCC-ee, CEPC, ILC, or CLIC) can probe virtually all the non-decoupling parameter space of scalar electroweak multiplets. Find them or not, this would provide fundamental information on the mechanism of electroweak symmetry breaking.