Hidden Pion Varieties in Composite Models for Diphoton Resonances
  The diphoton excesses at 750 GeV seen in the LHC data may be the first hint for new physics at the TeV scale. We discuss variations of the model considered earlier, in which one or more diphoton excesses arise from composite pseudo Nambu-Goldstone bosons (hidden pions) associated with new strong dynamics at the TeV scale. We study the case in which the 750 GeV excess arises from a unique hidden pion leading to a diphoton final state as well as the case in which it arises from one of the hidden pions decaying into diphotons. We consider SU(N), SO(N), and Sp(N) gauge groups for the strong dynamics and find that SO(N) and Sp(N) models give extra hidden pions beyond those in the SU(N) models, which can be used to discriminate among models. 
Keisuke Harigaya, Yasunori Nomura
hep-ph hep-ex