Discriminating Different $Z^\prime$s via Asymmetries at the LHC

TL;DR

This paper investigates how to optimize asymmetries in various final states at the LHC to distinguish between different $Z^\prime$ models, including QCD corrections, enhancing model discrimination capabilities.

Contribution

It extends previous work by analyzing four types of asymmetries in multiple final states and optimizing cuts to improve $Z^\prime$ model discrimination at the LHC.

Findings

Optimal cuts improve discrimination between $Z^\prime$ models.

QCD corrections are included for $bar b$ and $tar t$ final states.

Different asymmetries have varying effectiveness depending on the final state.

Abstract

In practice the asymmetry, which is defined based on the angular distribution of the final states in scattering or decay processes, can be utilized to scrutinize underlying dynamics in and/or beyond the standard model (BSM). As one of the possible BSM physics which might be discovered early at the LHC, extra neutral gauge bosons $Z^\prime$s are theoretical well motivated. Once $Z^\prime$s are discovered at the LHC, it is crucial to discriminate different $Z^\prime$s in various BSM. In principle such task can be accomplished by measuring the angular distribution of the final states which are produced via $Z^\prime$-mediated processes. In the real data analysis, asymmetry is always adopted. In literature several asymmetries have been proposed at the LHC. Based on these works, we stepped further on to study how to optimize the asymmetries in the left-right model and the sequential standard model, as the examples of BSM. In this paper, we examined four kinds of asymmetries, namely rapidity-dependent forward-backward asymmetry, one-side forward-backward asymmetry, central charge asymmetry and edge charge asymmetry (see text for details), with $\ell^+\ell^-$ ($\ell=e,\mu$), $b\bar b$ and $t\bar t$ as the final states. In the calculations with $b\bar b$ and $t\bar t$ final states, the QCD-induced higher order contributions to the asymmetric cross section were also included. For each kind of final states, we estimated the four kinds of asymmetries and especially the optimal cut usually associated with the definition of the asymmetry. Our numerical results indicated that the capacity to discriminate $Z^\prime$ models can be improved by imposing the optimal cuts.