Symmetries and composite dynamics for the 750 GeV diphoton excess

Understand

The ATLAS and CMS experiments at LHC observe small excesses of diphoton events with invariant mass around 750 GeV.

• Here we study the possibility of nearly parity degenerate and vector-scalar degenerate spectra as well as composite dynamics in 2 scenarios for explaining the excess: Production of a pseudo-scalar via gluon or photon fusion or via decay of a parent particle together with soft additional final states.
• We discuss possible underlying realizations of the scenarios motivated by dynamical models of electroweak symmetry breaking (without new coloured states) and fermion masses.