New vector bosons and the diphoton excess

We consider the possibility that the recently observed diphoton excess at ∼750 GeV∼750 GeV can be explained by the decay of a scalar particle (φ  ) to photons. If the scalar is the remnant of a symmetry-breaking sector of some new gauge symmetry, its coupling to photons can be generated by loops of the charged massive vectors of the broken symmetry. If these new W′W′ vector bosons carry color, they can also generate an effective coupling to gluons. In this case the diphoton excess could be entirely explained in a simplified model containing just φ   and W′W′. On the other hand, if W′W′ does not carry color, we show that, provided additional colored particles exist to generate the required φ   to gluon coupling, the diphoton excess could be explained by the same W′W′ commonly invoked to explain the diboson excess at ∼2 TeV∼2 TeV. We also explore possible connections between the diphoton and diboson excesses with the anomalous tt¯ forward–backward asymmetry.