# The top-quark polarization beyond the Standard Model in electron-positron annihilation

## TL;DR

This paper investigates top-quark polarization in electron-positron collisions at future colliders, analyzing how anomalous couplings affect polarization observables across different energies and angles.

## Contribution

It provides a detailed calculation of top-quark polarization components considering effective field theory interactions beyond the Standard Model.

## Key findings

- Polarization components depend on anomalous couplings and scattering angle.
- Extrema of polarization observables vary with collider energy.
- Averaged polarization components reveal sensitivity to new physics.

## Abstract

Electron-positron annihilation into a pair of top quarks is considered at the energy of the future collider CLIC. Polarization components of the top quark are calculated with the $\gamma t \bar{t}$ and $Z t \bar{t}$ interactions which follow from the Lagrangian of the effective field theory of the Standard Model. The polarization vector as a function of the scattering angle is calculated and averaged components of polarization are analyzed as functions of anomalous coupling constants. Extrema of these observables (maxima, minima and saddle points) are studied as functions of the $e^+ e^-$ energy.