Decoupling theorem in top productions/decays revisited -- To what extent can we understand it visually?

TL;DR

This paper revisits the decoupling theorem in top-quark processes, aiming to provide an intuitive, visual understanding of why angular distributions are unaffected by nonstandard decay interactions under certain conditions.

Contribution

It offers a simplified, conceptual explanation of the decoupling theorem, moving beyond detailed calculations to enhance intuitive understanding.

Findings

The decoupling theorem holds under specific conditions in top-quark decays.

A visual and intuitive framework explains why angular distributions are insensitive to nonstandard interactions.

The approach facilitates better conceptual grasp of top-quark decay dynamics.

Abstract

I revisit here the decoupling theorem in top-quark productions/decays, which states that the angular distribution of any final-particle produced in those processes does not depend on any possible nonstandard top-quark decay interactions at their leading order when certain conditions are satisfied. Towards a simple, intuitive and visual understanding of this theorem, I will study to what extent we could explain why such a theorem holds without relying on any specific/detailed calculations.