Non-coherent contributions in charge-exchange reactions and $\eta$--$\eta'$ mixing

TL;DR

This paper investigates charge-exchange reactions involving eta and eta' mesons, proposing a new method to measure non-coherent contributions and estimating eta-eta' mixing based on experimental data.

Contribution

It introduces a novel approach to account for non-coherent contributions in Regge theory and provides an estimate of eta-eta' mixing from experimental reactions.

Findings

Disagreements with Regge theory explained by mode change from coherent to non-coherent summation.

Proposed experimental method to measure non-coherent contributions.

Estimated eta-eta' mixing angle from charge-exchange reaction data.

Abstract

We analyse $K^- p \to (\eta, \eta',\pi^0) \Lambda$ on the basis of the fit of data in a wide region of energies, and $\pi^- p \to (\eta, \eta') n$ at the energies of GAMS-4$\pi$. We show that disagreements between the data and the predictions of Regge theory may be explained by the mode change of summation of intermediate contributions at increasing energy, from coherent to non-coherent. A method of experimental measurement of the non-coherent contributions is proposed. On the basis of available data on the charge-exchange reactions the $\eta$--$\eta'$ mixing is estimated.