Multi-lepton probes of the Drell-Yan production of triplet higgses

Excesses in di-photon, Zγ Z γ , and WW spectra indicate the existence of a new Higgs boson with mass 152± 1 152 ± 1 GeV. However, no excess is observed in the ZZ channel. This pattern aligns with a Real Higgs Triplet model with hypercharge $$Y = 0$$ Y = 0 ( SM Δ SM ). A prediction of this model is the Drell–Yan production of scalars at the LHC, which dominantly decay to electroweak bosons, thus enhancing the cross sections of triboson channels such as WWZ , WZZ , and WWW . Interestingly, both ATLAS and CMS have reported higher-than-expected significances for such processes: 6.4σ 6.4 σ (observed) vs 4.7σ 4.7 σ (expected) in the VVZ (where $$V = W$$ V = W or Z ) channel and 4.4σ 4.4 σ vs 3.6σ 3.6 σ in WWZ , suggesting the possibility that these signals may be the manifestations of an extended Higgs sector. We investigate whether the Δ SM can account for these triboson excesses through electroweak production and decay of triplet scalars. We find that while current data prefers a non-zero new physics signal ( 2.6σ 2.6 σ ), the Δ SM predicts more events than observed, such that it is consistent with data but not preferred over the SM. However, this tension could be clarified with Run 3 and HL-LHC data.