Search for the Z' boson decaying to a right-handed neutrino pair in leptophobic U(1) models

The U(1) extensions of the Standard Model contain a heavy neutral gauge boson Z'. If leptophobic, the boson can evade the stringent bounds from the dilepton resonance searches. We consider two theoretically well-motivated examples of leptophobic U(1) extensions in which the Z' decays to right-handed neutrinos (RHNs) with substantial branchings. The coexistence of a leptophobic Z' and the RHNs opens up a new possibility of searching for these particles simultaneously through the production of a Z' at the LHC and its decay to a RHN pair. For this decay to occur, the RHNs need to be lighter than the Z'. Hence, we study this process in an inverse seesaw setup where the RHNs can be in the TeV range. However, in this case, they have a pseudo-Dirac nature, i.e., a RHN pair would produce only opposite-sign lepton pairs, as opposed to the Majorana-type neutrinos, which can produce both same- and opposite-sign lepton pairs. Hence, the final state we study has a same-flavor opposite-sign lepton pair plus hadronically decaying boosted W bosons. Our analysis shows that the high luminosity LHC can discover a TeV-scale leptophobic Z' decaying via a RHN pair in a wide range of available parameters. Interestingly, large parameter regions beyond the reach of future dijet-resonance searches can be probed exclusively through our channel.

Automated summary

Explored the process of the Z' gauge boson decaying into pairs of right-handed neutrinos in leptophobic U(1) extensions. Analyzed the final state with same-flavor opposite-sign lepton pairs and hadronically decaying boosted W bosons, and found that the high luminosity LHC can discover TeV-scale leptophobic Z' in a wide range of parameter space.