Annihilation into Channels with Strangeness and the OZI Rule Violation

TL;DR

This paper investigates mechanisms behind nucleon-antinucleon annihilation into strange channels, highlighting two-meson rescattering effects that violate the OZI rule and explaining observed reaction ratios.

Contribution

It demonstrates that two-meson rescattering significantly enhances OZI-violating reactions and provides a detailed explanation for observed reaction ratios in nucleon-antinucleon annihilation.

Findings

Two-meson rescattering exceeds OZI tree level predictions by two orders of magnitude.

The model explains the observed ratio of $ ext{phi} ext{pi}/ ext{omega} ext{pi}$ in annihilation.

Interference effects account for suppression and enhancement in photon-involving channels.

Abstract

Two-step mechanisms in the $N\bar{N}$ annihilation and their role in the OZI rule violating reactions are discussed. In particular the two meson rescattering mechanism for $\pi\phi$ channel including all off-shell effects is typically two orders of magnitude bigger than the OZI tree level expectation and explains the observed ratio $\phi \pi/\omega \pi$ in the annihilation at rest. The rates for the final states including photons, $\gamma\omega$ and $\gamma\phi$, can be explained in the vector dominance model. The observed rate for $p\bar{p}\to\gamma\omega$ is suppressed due to destructive interference between the intermediate $\rho$ and $\omega$ states while the interference in $p\bar{p}\to\gamma\phi$ is required to be constructive leading to a large ratio $\gamma\phi/\gamma\omega$.