Axion-like Particle at 10 GeV Scale: Higgs Decays to Wide Jets and Photons

The concept of axion-like particles (ALPs) has garnered significant attention in the realm of high energy physics. ALPs are hypothetical particles that may interact with the Higgs boson or fields beyond the Standard Model. A recent study delves into the possibility of ALPs existing at the 10 GeV scale, examining the decay patterns of the Higgs boson.

## Introduction to Axion-like Particles ALPs are particles that may have renormalizable couplings to the Higgs boson or to fields beyond the Standard Model. If ALPs exist, they could have a significant impact on our understanding of the universe. The study focuses on an ALP, denoted as $A_h$, which is lighter than approximately 60 GeV. This mass range allows for the $h^0 o A_h A_h$ decay, with a branching fraction determined by the explicit global symmetry breaking responsible for the main contributions to the $A_h$ mass.

## Decay Patterns of Axion-like Particles The decay patterns of ALPs are a crucial aspect of the study. New heavy fields, such as squarks, can mediate $A_h$ decays at one loop, primarily into gluons, but also into photons. The researchers explore the LHC sensitivity to $A_h$, revealing that the $h^0 o A_h A_h o (gg)(\gamma\gamma)$ channel leads to a diphoton resonance at $M_A$. This production rate is consistent with a $3.5\sigma$ excess reported by a CMS search at $M_A \approx 13.6$ GeV.

## Experimental Implications For $M_A$ of order 10 GeV, the $h^0 o A_h A_h o 4g$ cascade decay leads to two wide jets, each with 2-prong substructure, forming a resonance at 125 GeV. The study highlights the potential for experimental detection of ALPs at the LHC. The researchers present their findings in the context of existing CMS searches, demonstrating the feasibility of detecting ALPs at the 10 GeV scale.

The search for axion-like particles continues to be an active area of research, with potential implications for our understanding of the universe. As experiments and observations continue to probe the existence of ALPs, our knowledge of these hypothetical particles will undoubtedly expand, shedding light on the mysteries of the universe.