A charged Z' to conciliate the apparent disagreement between top-antitop Tevatron forward-backward asymmetry and LHC charge asymmetry

TL;DR

This paper introduces a charged Z' model that explains the discrepancy between Tevatron and LHC top quark asymmetry measurements by providing positive contributions at Tevatron and cancellations at LHC, consistent with current constraints.

Contribution

The paper proposes a novel charged Z' model that reconciles Tevatron and LHC top asymmetry results, with detailed analysis of parameter space and experimental constraints.

Findings

Model explains Tevatron asymmetry excess

Model predicts null or negative charge asymmetry at LHC

Proposed Z' width increase to evade constraints

Abstract

We propose a charged, electrically neutral, and flavour changing Z' model to conciliate the apparent disagreement between the important excess found in the top-antitop Tevatron forward-backward asymmetry and the null -compatible with negative- results found in the LHC charge asymmetry. We show that this model contributes positively to the forward-backward asymmetry, whereas naturally a new cancellation is turned on at the LHC, yielding a null, or even negative, charge asymmetry. We found the region in parameter space that is simultaneously allowed by the stringent Tevatron and LHC observables. We show that the model is safe to atomic parity violation constraints and to tj resonance searches, and propose a possible increase in the Z' width to avoid ttj constraints. We evaluate the constraints to the model, as well as distinctive features in the fore-coming experimental results.