The LHC upper bounds for pp to diboson, tbar t cross section on fermionic dark matter

The ATLAS report in August 2016 provided an upper limit for the $pp\to$ diboson and $t\bar t$ cross sections. We consider a pseudoscalar-mediated fermionic dark matter together with gluon and photon effective operators interacting with the pseudoscalar. Choosing the resonance mass being $m_\rho=200, 750$ GeV and $2$ TeV, beside the relic density and the invisible Higgs decay constraints we constrain more the space of parameters with the diboson and $t\bar t$ cross section upper bounds. We finally provide some benchmarks consistent with all the constraints. Having exploited a pseudoscalar mediator, the DM-nucleon cross section is velocity suppressed so that the model evades easily the bounds put by the future direct detection experiments such as XENON1T.