Speaker
Description
The current LHC Higgs data suggest that the couplings of the observed
125 GeV Higgs boson must be remarkably close to the Standard Model
(SM) expectations. This implies that any Beyond-the-Standard-Model
physics due to an extended Higgs sector must lead to the so-called SM
alignment limit, where one of the Higgs bosons behaves exactly like
that of the SM. In the context of the Two Higgs Doublet Model (2HDM),
this alignment is often associated with either decoupling of the heavy
Higgs sector or fine-tuning the parameters of the 2HDM potential. In
the first part of my talk, I will review the Higgs symmetries required
for achieving natural alignment without decoupling or
fine-tuning. However, the exact imposition of these symmetries lead to
CP conservation in the Higgs potential. In the second part of my talk,
I will then show how CP violation could be maximised in this case by
spontaneous, soft and explicit breaking of these symmetries, while
maintaining agreement with LHC data and constraints on a non-zero
electron electric dipole moment. Finally, if time permits, I will
discuss the collider signatures for a 2HDM Higgs sector in the natural
alignment limit, which dominantly lead to third-generation quarks in
the final state, like 4 tops, and can serve as a useful observational
tool during the last upgraded phases of the LHC.
