Abstract
The recent LHC Run-2 data have shown a possible excess in diphoton events, suggesting the existence of a new resonance with mass . If plays the role of a portal particle connecting the Standard Model and the invisible dark sector, the diphoton excess should be correlated with another photon excess, namely, the excess in the diffuse gamma rays towards the Galactic Center, which can be interpreted by the annihilation of dark matter (DM). We investigate the necessary conditions for a consistent explanation for the two photon excesses, especially the requirement on the width-to-mass ratio and decay channels, in a collection of DM models where the DM particle can be scalar, fermionic, and vector, and can be generated through -channel fusion or annihilation. We show that the minimally required is determined by a single parameter proportional to , where the integer depends on the nature of the DM particle. We find that for the scalar DM model with generated from annihilation, the minimally required can be as low as . For the scalar DM model with generated from fusion and fermionic DM model with from annihilation, the required are typically of . The vector DM models, however, require very large of order one. For the DM models which can consistently explain both the excesses, the predicted cross sections for gamma-ray line are typically of , which are close to the current limits from the Fermi-LAT experiment.
- Received 7 June 2016
DOI:https://doi.org/10.1103/PhysRevD.94.035019
© 2016 American Physical Society