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

Abstract

Excesses in di-photon, , and WW spectra indicate the existence of a new Higgs boson with mass GeV. However, no excess is observed in the ZZ channel. This pattern aligns with a Real Higgs Triplet model with hypercharge (). 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: (observed) vs (expected) in the VVZ (where or Z) channel and vs in WWZ, suggesting the possibility that these signals may be the manifestations of an extended Higgs sector. We investigate whether the 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 (), the 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.