Variations on a Higgs theme

Understand

We show how the $Z$ boson can be generated in gluon-gluon fusion and yield two photons, via $gg\to Z\to \gamma\gamma$, through massive fermion loops only, thereby contributing events to a candidate Higgs sample in the di-photon channel.

• A sub-leading contribution also exists from $q\bar q\to Z\to\gamma\gamma$ events.
• Assuming the Standard Model, the corresponding event rates are negligible at the LHC stages of 7, 8 TeV, given the luminosities collected therein (about 5 and 20 fb$^{-1}$, respectively).
• Conversely, at 14 TeV, the first process become accessible for luminosities of order 300 fb$^{-1}$.