The diphoton excess at 750 GeV

Jong Soo Kim

Instituto de Física Teórica, UAM/CSIC, Madrid

 

Motivated by the recent diphoton excesses reported by both ATLAS and CMS collaborations, we provide a model-independent combination of results obtained at 8 and 13 TeV center-of-mass energy at the LHC. We consider s-channel resonant production of spin-0 and spin-2 particles with a mass of 750 GeV that subsequently decay to two photons. The size of the excess reported by ATLAS appears to be in tension with other measurements, in particular under spin-2 particle hypothesis.
In order to alleviate the tension, we suggest that a new heavy spinless particle is produced in gluon fusion at the LHC and decays to a couple of lighter pseudoscalars which then decay to photons. The new resonances could arise from a new strongly interacting sector and couple to Standard Model gauge bosons only via the corresponding Wess-Zumino-Witten anomaly. We present a detailed recast of the newest 13 TeV data from ATLAS and CMS together with the 8 TeV data to scan the consistency of the parameter space for those resonances.