Measurement of Excitation Spectra in the ^{12}C(p,d) Reaction near the η^{'} Emission Threshold

Search for η^{'} Bound Nuclei in the ^{12}C(γ,p) Reaction with Simultaneous Detection of Decay Products

We measured missing mass spectrum of the ^{12}C(γ,p) reaction for the first time in coincidence with potential decay products from η^{'} bound nuclei. We tagged an (η+p) pair associated with the η^{'}N→ηN process in a nucleus. After applying kinematical selections to reduce backgrounds, no signal events were observed in the bound-state region. An upper limit of the signal cross section in the opening angle cosθ_{lab}^{ηp}<-0.9 was obtained to be 2.2  nb/sr at the 90% confidence level. It is compared with theoretical cross sections, whose normalization ambiguity is suppressed by measuring a quasifree η^{'} production rate. Our results indicate a small branching fraction of the η^{'}N→ηN process and/or a shallow η^{'}-nucleus potential.

Luminosity determination for the proton-deutron reactions using quasi-free reactions with WASA-at-COSY facility

The scientific aim of our research is experimental confirmation of the existence of mesic-nucleus: a new exotic kind of nuclear matter consisting of nucleons and mesons. In this report we present the method of luminosity determination for experiment performed atWASA-at-COSY detector dedicated to search for 3He-η bound state. This method is based on analysis of quasi-free $pd \to ppn_{{\rm{spec}}} $ reaction.

Search for the η-mesic bound states with the WASA-at-COSY detector

The experiments dedicated to the search for η-mesic Helium were performed with high statistics using WASA detection setups installed at the COSY accelerator in the Research Center Juelich. The search for the η-mesic bound states is conducted via the measurement of the excitation function for selected decay channels of the He-η systems using unique ramped beam technique. This report presents recent status of the data analysis.

Luminosity determination for the proton-deuteron reaction using pd → 3Heη channel with WASA-at-COSY detector

In this report one of the methods used for the luminosity determination for the experiment performed by WASA Collaboration to search for 3He-η mesic nuclei is presented. The method is based on the analysis of pd → 3Heη process.