Combined explanation of LHC multilepton, diphoton, and top-quark excesses

In this article, we propose the Δ 2 HDM S as a combined explanation of several excesses and anomalies observed at the LHC. Especially, t t ¯ differential distributions point towards the associated production of new electroweak scale Higgs bosons decaying into bottom quarks and W bosons ( > 5 σ ) with masses consistent with the diphoton excesses at ≈ 95     GeV and ≈ 151.5     GeV ( 3.8 σ and 4.9 σ , respectively). Furthermore, CMS found indications for resonant t t ¯ production at ≈ 400     GeV ( 3.5 σ ) and both ATLAS and CMS reported elevated four-top and t t ¯ W cross sections. The Δ 2 HDM S is obtained by supplementing the SM Higgs ( H 2 ) with a second scalar doublet ( H 1 ), real scalar singlet ( S ), and a Higgs triplet with zero hypercharge ( Δ ). We fix the masses of the neutral tripletlike and the singletlike scalars by the diphoton excesses, i.e., m Δ 0 = 151.5     GeV and m S = 95     GeV , respectively. H , the C P -even component of H 1 , is produced via gluon fusion from a top-loop and decays dominantly to S + Δ 0 whose subsequent decays to W + W − and b b ¯ explain the differential t t ¯ distributions for σ ( p p → H → S Δ 0 ) ≈ 5     pb . Choosing the top-Yukawa of H 1 accordingly, the C P -odd Higgs boson A turns out to have the right production cross section to account for the resonant t t ¯ excess at 400 GeV, while the top-associated production of H and A results in new physics pollution of Standard Model t t ¯ W and t t ¯ t t ¯ cross sections, as preferred by the data. Published by the American Physical Society 2024