Optimal estimation of Dimension-8 Neutral Triple Gauge Couplings at $e^+ e^-$ Colliders

TL;DR

This paper assesses the potential to measure dimension-8 neutral triple gauge couplings at future $e^+ e^-$ colliders using SMEFT and optimal observables, providing sensitivity estimates and comparing with current LHC limits.

Contribution

It introduces a novel application of optimal observable techniques to dimension-8 SMEFT operators for ZZV couplings at $e^+ e^-$ colliders, including polarization effects and correlation analysis.

Findings

Optimal observable method improves sensitivity to NP couplings.

Beam polarization enhances measurement precision.

Comparison shows advantages over cut-based analysis.

Abstract

We investigate the measurement of non-standard ZZV (V = {\gamma}, Z) couplings through Z-boson pair production at the $e^+ e^-$ colliders. We adopt Standard Model Effective Field Theory (SMEFT) approach to study these anomalous neutral triple gauge couplings. There are one CP-conserving and three CP-violating dim-8 SMEFT operators that contribute to ZZV couplings. Using optimal observable technique, the sensitivity of these NP couplings has been estimated and then we compare it with the latest experimental limits on dim-8 couplings at CERN LHC. Effect of beam polarization and correlations among CP-violating ZZV couplings are discussed. Comparison of statistical limits of new physics couplings between optimal observable technique and contemporary cut-based analysis has also been studied in detail.