In-event background and signal reconstruction for two-photon invariant-mass analyses

A method is presented for the reconstruction of both the background and signal in invariant-mass analyses for two-photon decays. The procedure does not make use of event mixing techniques and as such is based exclusively on an event-by-event analysis. Consequently, topological correlations of the event (e.g. jet structures) are automatically taken into account. By means of the decay process $\pi^{0} \to \gamma \gamma$ it will be demonstrated how the procedure allows for determination of the $\pi^{0}$ yield from the observed decay photons.