Positivity bound on the imaginary part of the right-chiral tensor coupling $g_R$ in polarized top quark decay

TL;DR

This paper establishes a positivity bound on the imaginary part of the right-chiral tensor coupling in polarized top quark decay by analyzing angular distributions at NLO QCD, resulting in a specific numerical constraint.

Contribution

It introduces a novel positivity bound on Im g_R in polarized top decay using angular distribution analysis at NLO QCD.

Findings

Bound on Im g_R: -0.0420 to 0.0420

Method based on angular decay distribution analysis

First such bound at NLO QCD

Abstract

We derive a positivity bound on the right-chiral tensor coupling Im $g_R$ in polarized top quark decay by analyzing the angular decay distribution of the three-body polarized top quark decay $t(\uparrow)\to b+\ell^+ +\nu_\ell$ in NLO QCD. We obtain the bound $-0.0420 \le$ Im $g_R \le 0.0420$.