  Any particle that is charged under $SU(3)_C$ and $U(1)_{EM}$ can mediate the
$gg \rightarrow {\gamma}{\gamma}$ process through loops. Near the threshold for
the new particle pair production, gauge boson exchanges necessitate the
resummation of ladder diagrams. We discuss the leading log order matching of
the one-loop result with non-relativistic effective theory resummed result. We
show how the diphoton invariant mass spectrum varies depending on decay width,
color representation and electric charge of the new particle. The exclusion
limits on the product of $SU(3)_C$ and $U(1)_{EM}$ charges of the new scalar or
fermion particle are obtained from current LHC data.
