A hidden, heavier resonance of the Higgs field

Abstract

In Veltman's original view, the Standard Model with a large Higgs particle mass of about 1 TeV was the natural completion of non-renormalizable Glashow model. This mass was thus a second threshold for weak interactions, as the W mass was for the non-renormalizable 4-fermion V-A theory. Today, after the observation of the narrow scalar resonance at 125 GeV, Veltman's large-mass idea seems to be ruled out. Yet, this is not necessarily true. Depending on the description of SSB in $\Phi^4$ theory, and by combining analytic calculations and lattice simulations, besides the known particle at 125 GeV, a new resonance of the Higgs field may also show up around 700 GeV. The peculiarity, though, is that this heavier state would couple to longitudinal vector bosons with the same typical strength of the low-mass state and thus represent a relatively narrow resonance. In this way, such hypothetical new resonance would naturally fit with some excess of 4-lepton events observed by ATLAS around 680 GeV. Analogous data from CMS are needed to confirm or disprove this interpretation. Implications of a two-mass structure for radiative corrections are also discussed.