Search for eta-mesic nuclei with WASA-at-COSY

TL;DR

This study searches for eta-mesic helium nuclei using the WASA detector at COSY, analyzing specific nuclear reactions to find evidence of eta meson binding within helium.

Contribution

It introduces a novel experimental approach to detect eta-mesic nuclei through excitation functions of specific nuclear reactions at COSY.

Findings

No conclusive evidence of eta-mesic helium found yet.

Experimental method successfully measures relevant excitation functions.

Analysis is ongoing to interpret the data.

Abstract

We search for an evidence of eta-mesic He with the WASA detector. Two dedicated experiments were performed at the Cooler Synchrotron COSY-Juelich. The experimental method is based on the measurement of the excitation functions for the two reaction channels: dd->3Heppi- and dd->3Henpi0, where the outgoing N-pi pairs originate from the conversion of the eta meson on a nucleon inside the He nucleus.In this contribution, the experimental method is shortly described and the current status of the analysis is presented.