Natural Alignment in the Two Higgs Doublet Model

Who: Apostolos Pilaftsis (Manchester University)
When: Monday, October 10, 2016 at 14:15
Where: The CP³ meeting room

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 New 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 present a novel symmetry justification for ‘natural’ alignment without necessarily decoupling or fine-tuning. I will show that there exist only three different symmetry realizations of such a natural alignment to occur in the 2HDM. In the second part of my talk, I will analyze new collider signatures for the heavy Higgs sector in the natural alignment limit, which dominantly lead to third-generation quarks in the final state and can serve as a useful observational tool during the Run-II phase of the LHC.