Speaker
Description
We discuss a $\sim 3\,\sigma$
signal (local) in the light Higgs-boson search
in the diphoton decay mode at $\sim$ 96 GeV as reported by
CMS, together with a $\sim 2\,\sigma$ excess (local)
in the $b \bar b$ final state
at LEP in the same mass range.
We interpret this possible signal as a Higgs boson in the
2~Higgs Doublet Model type~II with an additional Higgs singlet, which can be either complex (2HDMS) or real (N2HDM), where the 2HDMS so far has never been analyzed as an explanation of these excesses. An emphasis of our work are the differences between and the possible distinction of the two models in this context.
We find that the lightest CP-even Higgs boson of the two models can
equally yield a perfect fit to both excesses simultaneously, while the second lightest
state is in full agreement with the Higgs-boson measurements at
125 GeV, and the full Higgs-boson
sector is in agreement with all Higgs exclusion
bounds from LEP, the Tevatron and the LHC as well as other theoretical and
experimental constraints.
We derive bounds on the 2HDMS and N2HDM Higgs sectors from a fit to both excesses and describe how this signal can be further analyzed at
future $e^+e^-$~colliders, such as the ILC. We analyze in
detail the anticipated precision of the coupling measurements of the
96 GeV Higgs boson at the ILC. We find that these Higgs-boson measurements at the LHC and the ILC cannot distinguish between the two Higgs-sector realizations.
