Experimental signals for a second resonance of the Higgs field

Abstract

In the region of invariant mass 620–740 GeV, we have analyzed the ATLAS sample of 4-lepton events that could indicate a new scalar resonance produced mainly via gluon–gluon fusion. These data suggest the existence of a new heavy state [Formula: see text] whose mass 660–680 GeV would fit well with the theoretical range [Formula: see text] for the hypothetical second resonance of the Higgs field that has been recently proposed and which would couple to longitudinal W’s with the same typical strength of the low-mass state at [Formula: see text] GeV. Since the total width [Formula: see text] is very poorly determined, to sharpen the analysis of the precious ATLAS data, we have considered a particular correlation between resonating peak cross-section [Formula: see text] and the ratio [Formula: see text]. This correlation should be nearly insensitive to the precise value of [Formula: see text] and mainly determined by the lower mass [Formula: see text] GeV. Equivalently, if this correlation holds true, one could also fit [Formula: see text] from the 4-lepton data in the high-mass range 620–740 GeV. The result [Formula: see text] GeV reproduces the direct measurement of the Higgs particle mass and thus supports the idea that [Formula: see text] and [Formula: see text] are the masses of two different excitations of the same field. Therefore, if we combine with the excess at 680 GeV in the ATLAS [Formula: see text] distribution, there are now two signals for a new resonance in the same mass region. Even though, quantitatively, the global statistical significance of each effect is modest, still the sharp correlation [Formula: see text] in the 4-lepton channel should induce to consider seriously these indications.