  Among the questions that would be raised by the observation of a new
resonance at the LHC, particularly pressing are those concerning the production
mechanism: What is the initial state? Is the resonance produced independently
or in association with other particles? Here we present two weakly-coupled
renormalizable models for production of a diphoton resonance that differ in
both their initial and final states. In one model, a scalar particle produced
through gluon fusion decays into a diphoton particle and a light, long-lived
pseudoscalar. In another model, a $Z'$ boson produced from the annihilation of
a strange-antistrange quark pair undergoes a cascade decay that leads to a
diphoton particle and two sterile neutrinos. Various kinematic distributions
may differentiate these models from the canonical model where a diphoton
particle is directly produced in gluon fusion.

High Energy Physics - Phenomenology;High Energy Physics - Experiment