Same-sign Tops: A Powerful Diagnostic Test for Models of New Physics

TL;DR

This paper investigates the relationship between same-sign top quark production and the top forward-backward asymmetry, showing that many new physics models explaining the asymmetry are incompatible with LHC constraints on same-sign tops.

Contribution

It provides a model-independent analysis demonstrating that flavor-changing operators cannot simultaneously explain the asymmetry and satisfy LHC constraints.

Findings

Many models explaining $A^t_{FB}$ predict excessive same-sign top production.

Tree-level flavor-changing operators cannot reconcile $A^t_{FB}$ with LHC data.

Most proposed new physics models are constrained or ruled out by LHC same-sign top measurements.

Abstract

We study the connection between the same sign top (SST) and the top quark forward-backward asymmetry $A^t_{FB}$. We find that a large class of new physics models that have been proposed to account for the $A^t_{FB}$ lead to SST quark production rate much larger than the observed rate at the LHC and consequently are severely constrained or ruled out. Our model independent, general, operator analysis shows that none of the tree-level flavor-changing operators are able to explain $A^t_{FB}$ and simultaneously remain consistent with the same-sign top-quark production constraints from the LHC data.