PT Journal AU De Romeri, V Kim, JS Martin Lozano, V Rolbiecki, K Ruiz de Austri, R TI Confronting dark matter with the diphoton excess from a parent resonance decay SO European Physical Journal C JI Eur. Phys. J. C PY 2016 BP 262 - 13pp VL 76 IS 5 DI 10.1140/epjc/s10052-016-4116-7 LA English AB A diphoton excess with an invariant mass of about 750 GeV has been recently reported by both ATLAS and CMS experiments at LHC. While the simplest interpretation requires the resonant production of a 750 GeV (pseudo) scalar, here we consider an alternative setup, with an additional heavy parent particle which decays into a pair of 750 GeV resonances. This configuration improves the agreement between the 8 and 13 TeV data. Moreover, we include a dark matter candidate in the form of a Majorana fermion which interacts through the 750 GeV portal. The invisible decays of the light resonance help to suppress additional decay channels into Standard Model particles in association with the diphoton signal. We realise our hierarchical framework in the context of an effective theory, and we analyse the diphoton signal as well as the consistency with other LHC searches. We finally address the interplay of the LHC results with the dark matter phenomenology, namely the compatibility with the relic density abundance and the indirect detection bounds. ER