New results on the pd --> 3He eta production near threshold

TL;DR

This paper reports new measurements of eta meson production in proton-deuteron collisions near threshold, revealing a transition in angular distributions and evidence of strong eta-3He final state interactions.

Contribution

It provides the first detailed differential cross sections at multiple energies, highlighting the transition in emission patterns and supporting strong final state interactions.

Findings

Transition from isotropic to anisotropic angular distributions

Evidence of strong eta-3He final state interaction

Total cross sections consistent with model predictions

Abstract

Measurements on the eta meson production in proton-deuteron collisions have been performed using the COSY-11 facility at COSY Juelich. Here we present preliminary results on total and differential cross sections for the pd --> 3He eta reaction at five excess energies between Q = 5.1 and Q = 40.6 MeV. The obtained angular distributions for the emitted eta mesons in the center of mass system expose a transition from an almost isotropic emission to a highly anisotropic distribution. The extracted total cross sections support a strong eta-3He final state interaction and will be compared with model predictions.