Speaker: Jiang Yun
Title: 125 GeV Higgs Bosons in the 2HDM
Host: Markus Luty
Room: 432,
Abstract: The current Higgs boson data at 125 GeV state appears to
exhibit a substantial excess in the di-photon final state, whereas a
more or less SM-like rate is observed in the ZZ decaying to four
lepton channel. Beyond the SM, the two-Higgs-doublet model (2HDM)
containing a second Higgs doublet is one of the simplest extensions.
We examine the maximum Higgs signal enhancements that can be achieved
in the 2HDM (when either a single Higgs or multiple Higgses have
mass(es) near 125 GeV). In general, the constraints of vacuum
stability, unitarity and perturbativity play the key role in
restricting possibilities for signal enhancement. The Type II model
allows for an enhancement in the di-photon rate (relative to the SM)
of the order of 2-3 but associated with an even larger ZZ signal, a
situation disfavored by the LHC observations. In contrast, the maximal
value for the di-photon signal in the Type I model can reach the order
of 1.3 for which the ZZ signal is of order 1, both being consistent
with the current data.
