On the maximal diphoton width
Alberto Salvio (Theoretical Physics Department, CERN, Geneva, Switzerland); Florian Staub (Theoretical Physics Department, CERN, Geneva, Switzerland); Alessandro Strumia (Theoretical Physics Department, CERN, Geneva, Switzerland, Dipartimento di Fisica, Università di Pisa and INFN, largo Bruno Pontecorvo 3, Pisa, Italy); Alfredo Urbano (Theoretical Physics Department, CERN, Geneva, Switzerland)
Motivated by the 750 GeV diphoton excess found at LHC, we compute the maximal width into γγ that a neutral scalar can acquire through a loop of charged fermions or scalars as function of the maximal scale at which the theory holds, taking into account vacuum (meta)stability bounds. We show how an extra gauge symmetry can qualitatively weaken such bounds, and explore collider probes and connections with Dark Matter.
