Tracking Down the Top Quark Forward-Backward Asymmetry with Monotops

TL;DR

This paper explores a model where scalar top partners produce top quark asymmetry via t-channel exchange, fitting collider data and predicting detectable monotop signals at the LHC.

Contribution

It introduces a novel scalar top partner model linking top asymmetry to neutrino sector physics, consistent with collider constraints and predicting new monotop signatures.

Findings

Viable parameter space consistent with Tevatron and LHC data

Model remains unconstrained by atomic parity violation tests

Predicted monotop signals could be observed at the LHC

Abstract

We revisit the possibility that the top quark forward-backward asymmetry arises from the on-shell production and decay of scalar top partners to top-antitop pairs with missing transverse energy. Although the asymmetry is produced by t-channel exchange of a light mediator, the model remains unconstrained by low energy atomic parity violation tests. An interesting connection to the active neutrino sector through a Type-I seesaw operator helps to evade stringent monojet constraints and opens up a richer collider phenomenology. After performing a global fit to top data from both the Tevatron and the LHC, we obtain a viable region of parameter space consistent with all phenomenological and collider constraints. We also discuss the discovery potential of a predicted monotop signal and related lepton charge asymmetry at the LHC.