H(650) -> W+W-/ZZ predicts H++ -> W+W+ and H+ -> ZW+, as indicated by LHC data

TL;DR

This paper discusses the potential existence of a 650 GeV scalar resonance at the LHC, its implications for new charged scalars, and how these findings fit within extended Higgs models like the Georgi-Machacek model.

Contribution

It predicts the existence of a doubly charged scalar H++ and other charged scalars based on LHC data, linking these to unitarity sum rules and extended Higgs models.

Findings

Indications of a 650 GeV scalar resonance at LHC with over 6 sigma significance.

Predicted large coupling of H++ to W+W+ and potential additional decay modes.

Model interpretation suggests a scalar content similar to the Georgi-Machacek model.

Abstract

Several indications for neutral scalars are observed at the LHC. One of them, a broad resonance peaked at about 650 GeV which we call H(650), was first observed by an outsider combining published histograms from ATLAS and CMS on ZZ -> 4 leptons searches, and this combination shows a local significance close to 4 s.d. Since then, CMS has reported two other indications at the same mass, with similar local significances: H->WW->2leptons+neutrinos and H(650)->bbh(125) where mbb~90 GeV and h(125)->gam gam. ATLAS has completed its analysis of ZZ->4 leptons from which we infer an indication for H(650) with 3.5 s.d. significance. Combining these three results, one gets a global statistical significance above 6 s.d. H(650) has a coupling to WW similar to h(125) and therefore we argue that a sum rule (SR) required by unitarity for W+W- scattering implies that there should be a compensating effect from a doubly charged scalar H++, with a large coupling to W+W+. We therefore predict that this mode should become visible through the vector boson fusion process W+W+->H++, naturally provided by LHC. A recent indication for H++(450)->W+W+ from ATLAS allows a model independent interpretation of this result through the SR constraint which gives BR(H++->W+W+)~10%, implying the occurrence of additional decay modes H+W+ and H+H+ from one or several light H+ with masses below mH++ - mW or MH++/2, that is mH+ < 370 GeV or 225 GeV. A similar analysis is performed for H+(375)->ZW, indicated by ATLAS and CMS. Both channels suggest a scalar field content similar to the Georgi Machacek model with triplets, at variance with the models usually considered. Implications on precision measurements are presented followed by a complete extraction of the GM parameters. An alternate interpretation of the 650 GeV resonance as a tensor is also briefly discussed. Implications for precision measurements are presented.