Update on the LHC di-photon excess
Jernej Kamenik, Jozef Stefan Institute and University of Ljubljana
Germán Gómez-Vargas, PUC-Chile
Run 2 LHC data show hints of a new resonance in the diphoton distribution at an invariant mass of 750 GeV. I will discuss these intriguing results in terms of a new boson, extracting information on its properties and exploring theoretical interpretations. Scenarios covered include both a narrow or a wider resonance of either spin zero or two. If ATLAS indications of a sizable width persist, pertubativity, unitarity and vacuum stability considerations suggest that the new particle is likely to belong to a strongly-interacting sector. Possible connections of a sizable invisible width with cosmological dark matter will be briefly discussed. Finally, I will cover several key experimental tests of the excess and its interpretations. In particular, within the framework of effective field theory, the resonance production and decays through electroweak interactions are already highly constrained and will allow in the future to elucidate the electroweak quantum numbers as well as the main production channels of the new particle.