Di-photon resonance and Dark Matter as heavy pions
  We analyse confining gauge theories where the 750 GeV di-photon resonance is a composite techni-pion that undergoes anomalous decays into SM vectors. These scenarios naturally contain accidentally stable techni-pions Dark Matter candidates. The di-photon resonance can acquire a larger width by decaying into Dark Matter through the CP-violating $\theta$-term of the new gauge theory reproducing the cosmological Dark Matter density as thermal relic. 
Michele Redi, Alessandro Strumia, Andrea Tesi, Elena Vigiani
hep-ph