arXiv:2608.18506·v1·High Energy Physics — Phenomenology

Axion-like particle at the 10 GeV scale: Higgs decays to wide jets and photons

Abstract

If axion-like particles (ALPs) exist, they may have renormalizable couplings only to the Higgs boson ( $h^{0}$ ) or to fields beyond the Standard Model. An ALP $A_{h}$ lighter than about 60 GeV would allow the $h^{0} \to A_{h} A_{h}$ decay, with a branching fraction determined by the explicit global symmetry breaking responsible for the main contributions to the $A_{h}$ mass ( $M_{A}$ ). New heavy fields that carry color and electric charge, such as squarks, can mediate $A_{h}$ decays at one loop mostly into gluons, but also into photons. Exploring LHC sensitivity to $A_{h}$ , we show that the $h^{0} \to A_{h} A_{h} \to (g g) (γ γ)$ channel leads to a diphoton resonance at $M_{A}$ whose production rate is consistent with a $3.5 σ$ excess reported by a CMS search at $M_{A} \approx 13.6$ GeV. For $M_{A}$ of order 10 GeV, the $h^{0} \to A_{h} A_{h} \to 4 g$ cascade decay leads to two wide jets (each with 2-prong substructure) that form a resonance at 125 GeV.

Comments: 25 pages, 6 figures