Mounting evidence for a 95 GeV Higgs boson
Biekoetter, Thomas, S. Heinemeyer, G. Weiglein
Abstract
In 2018 CMS reported an excessin the light Higgs-boson searchin the diphoton decay mode atabout 95~GeVbased on Run~1 and first year Run~2 data.The combined local significance of theexcess was $2.8\,\sigma$.The excess is compatible with thelimits obtained in the ATLAS searchesfrom the diphoton search channel.Recently, CMS reported another localexcess with a significance of$3.1\,\sigma$ in the light Higgs-boson searchin the di-tau final state, which iscompatible with the interpretationof a Higgs boson with a mass ofabout 95~GeV.We show that the observed results can be interpreted as manifestations of a Higgs boson in the Two-Higgs DoubletModel with an additional realsinglet (N2HDM).We find that the lightest Higgs bosonof the N2HDM can fitboth excesses simultaneously,while the second-lightest state issuch that it satisfies the Higgs-boson measurements at125~GeV, and the full Higgs-bosonsector is compatible with all Higgs exclusionbounds from the searches atLEP, the Tevatron and the LHC aswell as with other theoretical andexperimental constraints.Finally, we demonstrate that itis furthermore possible toaccommodate the excesses observedby CMS in the two search channels togetherwith a local $2.3\,\sigma$ excessin the $b \bar b$ final stateobserved at LEP in the same mass range