Discovering heavy new physics in boosted Z channels: Z →l+l- vs Z →ν ν ¯ discovering heavy new physics in boosted Z ... backovic et al.

We propose a strategy for new physics searches in channels which contain a boosted Z boson and a boosted massive jet in the final state. Our proposal exploits the previously overlooked advantages of boosted Z→νν¯ topologies, where collimated neutrinos result in signals with large missing energy. We illustrate the advantage of this channel in a case study of singly produced TeV scale charge 2/3 fermionic top partners (T′) which decay to tZ final states. A comparison with the di-leptonic channel reveals that, despite the large tt¯ background, signals with missing energy combined with jet substructure techniques offer superior probes of new physics at TeV scales. The effect can be attributed to a factor of ∼3 enhancement in the signal cross section, coming from the branching ratio of Z→νν¯. We exploit the unique event topology of singly produced top partners to suppress the tt¯ background, as well as further improve on the existing proposals to detect T′ in the boosted di-lepton channel. Our conclusions on advantages of Z→νν¯ can be extended to most resonance searches which utilize a boosted Z boson in the final state.