Limited validity of West and Yennie integral formula for elastic scattering of hadrons

TL;DR

This paper critically examines the West and Yennie integral formula for elastic hadron scattering, revealing its limited validity under specific conditions related to the ratio of real to imaginary parts of the amplitude.

Contribution

It identifies the conditions under which the West and Yennie formula is valid, highlighting its limitations in describing elastic hadron scattering.

Findings

The formula is only valid when the ratio of real to imaginary parts of the amplitude is constant.

The applicability of the formula is restricted to specific kinematic conditions.

The common use of the formula may lead to inaccuracies outside these conditions.

Abstract

The commonly used West and Yennie integral formula for the relative phase between the Coulomb and elastic hadronic amplitudes might be consistently applied to only if the hadronic amplitude had the constant ratio of the real to the imaginary parts al all kinematically allowed values of four momentum transfer squared.