Additional evidence of a new 690 GeV scalar resonance

TL;DR

This paper presents evidence for a new 690 GeV scalar resonance, suggesting a second Higgs-like particle that stabilizes the Standard Model potential, supported by enhanced LHC data analysis.

Contribution

It introduces the possibility of a second Higgs resonance at 690 GeV, supported by combined LHC data analysis and theoretical considerations of scalar sector mass scales.

Findings

Evidence for a second resonance at 690 GeV

Correlations between different channels support the resonance

Statistical significance suggests the deviation is not a fluctuation

Abstract

An alternative to the idea of a metastable electroweak vacuum would be an initial restriction to the pure scalar sector of the Standard Model, but describing spontaneous symmetry breaking consistently with studies indicating that there are two different mass scales in the problem: a mass scale $M_H$ associated with the zero-point energy and a mass scale $m_h$ defined by the quadratic shape of the potential at its minimum. Therefore, differently from perturbation theory where these two mass scales coincide, the Higgs field could exhibit a second resonance with mass $(M_H)^{\rm Theor} = 690\,(30)$ GeV. This stabilises the potential, but the heavy Higgs $H$ would couple to longitudinal $W$s with the same typical strength as the low-mass state with $m_h=125$ GeV and so would still remain a relatively narrow resonance. While interesting signals from LHC experiments were previously pointed out, we have now enlarged our data sample, sharpened the analysis of some final states, and noted correlations between different channels that point directly to such a second resonance. The combined statistical evidence, even if roughly estimated, is thus so large that the observed deviations from the background cannot represent statistical fluctuations.