Some comments on $\bar n p$-annihilation branching ratios into $\pi \pi$-, $\bar K K$- and $\pi \eta$-channels

TL;DR

This paper analyzes low-momentum antineutron-proton annihilation branching ratios, comparing experimental flight data with atomic state data, revealing suppression in certain channels and clarifying the role of isospin amplitudes.

Contribution

It provides a comparative analysis of $ar n p$ and $p ar p$ annihilation branching ratios, highlighting suppression effects and addressing isospin amplitude contributions.

Findings

Suppression of $ar n p o ext{π}^+ ext{π}^0$ branching ratio compared to $p ar p$ data.

No evidence of dynamic I=0-amplitude suppression in $Nar N o Kar K$.

Comparison between flight measurements and atomic state data.

Abstract

We give some remarks on the $\bar n p$-partial branching ratios in flight at low momenta of antineutron, measured by OBELIX collaboration. The comparison is made to the known branching ratios from the $p \bar p$-atomic states. The branching ratio for the reaction $\bar n p \to \pi^+\pi^0$ is found to be suppressed in comparison to what follows from the $ p \bar p$-data. It is also shown, that there is no so called dynamic I=0-amplitude suppression for the process $N\bar N \to K\bar K$.