https://doi.org/10.1051/epjconf/20146609009
Search for the η-mesic 4He with WASA-at-COSY
1 M. Smoluchowski Institute of Physics, Jagiellonian University, 30-059 Cracow, POLAND
2 IKP, Forschungszentrum Jülich, D-52425 Jülich, GERMANY
a e-mail: wojciech.krzemien@if.uj.edu.pl
Published online: 20 March 2014
We conduct a search for the He − η bound state with the WASA-at-COSY facility measuring the excitation functions for the reaction channels: dd → 3Hepπ− and dd → 3Henπ0, where the outgoing N − π pairs originate from the conversion of the η meson on a nucleon inside the He nucleus. Two dedicated experiments were performed at the Cooler Synchrotron COSY-Jülich with the WASA detector. The analysis of the 2008 data shows no signal of the 4He − η bound state. An upper limit for the cross-section for the bound state formation and decay in the process dd → (4He − η)bound → 3Hepπ−, was determined at the 90 % confidence level. In November 2010 a new data set was collected.
© Owned by the authors, published by EDP Sciences, 2013
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.