Like-sign dilepton signals from a leptophobic Z' boson

TL;DR

This paper explores a light leptophobic Z' boson that could explain observed like-sign dilepton excesses at Tevatron and discusses its detection prospects at LHC, highlighting a new potential signal for physics beyond the Standard Model.

Contribution

It introduces a leptophobic Z' model from E6 that can produce observable like-sign dileptons via heavy neutrino decays, explaining experimental anomalies and guiding future collider searches.

Findings

Z' boson could be as light as 350 GeV and still evade detection.

The like-sign dilepton signal can explain Tevatron excess.

LHC can probe Z' masses up to 2.5 TeV with 30 fb-1.

Abstract

A new leptophobic neutral gauge boson Z' with small mixing to the Z can have a mass as light as M_Z' ~ 350 GeV, and still have escaped detection at LEP and Tevatron. Such a Z' boson can be derived from E6 and, if the new heavy neutrino singlets in the 27 representation are lighter than M_Z'/2, the process p p(pbar) -> Z' -> NN -> l+- l+- X is observable. Indeed, this new signal could explain the small excess of like-sign dileptons found at Tevatron. Implications for LHC are also discussed. In particular, the Tevatron excess could be confirmed with less than 1 fb-1, and leptophobic Z' masses up to 2.5 TeV can be probed with 30 fb-1.