Selection rules for helicity amplitudes in massive gauge theories

TL;DR

This paper explores how helicity amplitude vanishing theorems extend to high-energy spontaneously broken gauge theories, revealing patterns of suppression related to gauge boson masses and energies, with applications to the effective W approximation.

Contribution

It generalizes vanishing theorems for helicity amplitudes to broken gauge theories at high energy using elementary arguments.

Findings

Helicity amplitudes exhibit specific m/E suppression patterns in broken gauge theories.

Vanishing theorems from unbroken theories extend with modifications to broken cases.

Applications include insights into the polarized effective W approximation.

Abstract

After a rediscussion of the vanishing theorems for helicity amplitudes in unbroken gauge theories, we study the case of spontaneously broken gauge theories at high energy. The vanishing theorems generalize to a definite pattern of m/E-suppression of the amplitudes that vanish in the massless case, where E is the energy scale of the process and m is the mass of the gauge vectors. We use only elementary arguments, and as an application we show how these methods can be employed to understand some aspects of the effective W approximation in the polarized case.