Explaining the 750 GeV diphoton excess with a colored scalar charged under a new confining gauge interaction

We consider a charged scalar particle \(\chi\) of mass around 375 GeV charged under both \(SU(3)_c\) and a new confining non-abelian gauge interaction. After pair production, these interactions confine the exotic scalar into non-relativistic bound states whose decays into photons can explain the 750 GeV diphoton excess observed at the LHC. Taking the new confining group to be \(\mathrm{SU}(2)\), we find \(\chi\) must carry an electric charge of \(Q \sim [\frac{1}{2}, 1]\) to fit the data. Interestingly, we find that pair production of the scalars and the subsequent formation of the bound state dominates over direct bound state resonance production. This explanation is quite weakly constrained by current searches and data from the forthcoming run at the LHC will be able to probe our scenario more fully. In particular dijet, mono-jet, di-Higgs and jet + photon searches may be the most promising discovery channels.