Single top quark polarization at O(alpha_s) in t t-bar production at a polarized linear e^+ e^- collider

TL;DR

This paper investigates the next-to-leading order polarization of top quarks produced in electron-positron collisions with polarized beams, showing how beam polarization tuning can optimize top quark polarization for experimental analysis.

Contribution

It provides a detailed NLO analysis of top quark polarization in e+e- collisions, highlighting how beam polarization can be tuned to maximize or minimize polarization effects.

Findings

Maximal top polarization achievable with beam polarization tuning

Polarization can be nearly zero in the forward hemisphere

Results applicable over a wide energy range

Abstract

We present a detailed investigation of the NLO polarization of the top quark in t t-bar production at a polarized linear e^+ e^- collider with longitudinally polarized beams. By appropiately tuning the polarization of the beams one can achieve close to maximal values for the top quark polarization over most of the forward hemisphere for a large range of energies. This is quite welcome since the rate is largest in the forward hemisphere. One can also tune the beam polarization to obtain close to zero polarization over most of the forward hemisphere.