Signature of same-sign top pair production mediated by a nonuniversal $Z^\prime$ with QCD next-to-leading accuracy at the LHC

TL;DR

This paper provides a detailed QCD NLO analysis of same-sign top pair production mediated by a non-universal Z' at the LHC, highlighting the impact on constraints, cross section dependence, and discovery potential.

Contribution

It offers the first comprehensive QCD NLO calculation for this process, including production, decay, and background analysis, improving the accuracy of predictions and discovery strategies.

Findings

QCD NLO corrections relax model constraints

Cross section dependence on factorization scale is reduced

Same-sign dilepton signals could be more easily discovered

Abstract

We present a detailed study of the same-sign top pair production mediated by a non-universal $Z^\prime$ including production and decay at the Large Hadron Collider (LHC) at the QCD next-to-leading order (NLO) level, using the narrow width approximation and helicity amplitudes method. We find that the QCD NLO corrections can loose the constraint on the model parameters and reduce the dependence of the total cross sections on the factorization scale significantly. We also study the signature and backgrounds of the process at the NLO level. In order to suppress the backgrounds, we further investigate the difference between the production rates of the positively and negatively charged dilepton at the LHC, and find that the same-sign dilepton signal of the new physics could be discovered more easily.