Hi, I am studying the Higgs discovery and i've got a doubt. One of the process used to discover Higgs is the decay H -> γγ in 2 photons. At LHC there are detectors of photons that can measure energy and momentum of them. So if you measure the energy and the momentum of both, you can calculate the mass of the particle from which they are produced. This is easy if you only receive 2 photons, but if you get many of them, how can you decide which of them come from the same process? For example, if 2 Higgs decay in 4 γ, how can i decide the couples?