Minimal model of a diphoton resonance: Production without gluon couplings

We consider the phenomenology of a resonance that couples to photons but not gluons, and estimate its production rate at the LHC from photon-photon fusion in elastic $pp$ scattering using the equivalent photon and narrow width approximations. The rate is sensitive only to the mass, the spin, the total width of the resonance, and its branching fraction to photons. Production cross sections of 3–6 fb at 13 TeV can be easily accommodated for a 750 GeV resonance with partial photon width of 15 GeV. This provides the minimal explanation of the reported diphoton anomaly in the early LHC Run II data.

Figure 1

Resonance production via photon-photon fusion in elastic $pp$ scattering.

Figure 2

The two-photon production cross section as a function of beam energy with a partial width ${\mathrm{\Gamma }}_{\gamma \gamma }=15\mathrm{GeV}$, total width $\mathrm{\Gamma }=45\mathrm{GeV}$, and three values of $q_{*}$: 130 (dotted), 150 MeV (solid), and 170 MeV (dashed).

Figure 3

The ratio of the two-photon production cross section at 13 and 8 TeV as a function of $q_{*}$.