# Antiproton--proton annihilation into light neutral meson pairs within an effective meson theory

## TL;DR

This paper models antiproton-proton annihilation into light neutral meson pairs using an effective meson theory, successfully describing existing data and providing predictions for future experiments at PANDA, FAIR.

## Contribution

It applies an effective meson model with form factors and SU(3) symmetry to describe neutral meson production in antiproton-proton annihilation, extending previous work to include multiple meson channels.

## Key findings

- Fair agreement with existing angular distribution data.
- Model reproduces $ ext{π}^0 ext{π}^0$ production data.
- Predictions for $ ext{π}^0 ext{η}$ and $ ext{η} ext{η}$ channels.

## Abstract

Antiproton--proton annihilation into light neutral mesons in the few GeV energy domain is investigated in view of a global description of the existing data and predictions for future experiments at PANDA, FAIR. An effective meson model earlier developed, with mesonic and baryonic degrees of freedom in $s$, $t$, and $u$ channels, is applied here to $\pi^0\pi^0$ production. Form factors with logarithmic $s$ and $t(u)$ dependencies are applied. A fair agreement with the existing angular distributions is obtained. Applying SU(3) symmetry, it is straightforward to recover the angular distributions for $ \pi^0\eta$, and $\eta\eta$ production in the same energy range. A good agreement is generally obtained with all existing data.