München 2006 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 21: Postersitzung
HK 21.19: Poster
Dienstag, 21. März 2006, 15:30–17:00, P
Search for the η-bound states at COSY — •Daniil Kirillov and Hartmut Machner — Institut für Kernphysik, FZ-Jülich, 52425 Jülich
A large acceptance plastic scintillator detector ’ENSTAR’ has been designed and built for studies of a new form of nuclear matter - ’η-mesic’ nuclei (ηA). These nuclei, which are solely the result of strong interactions unlike the pionic atoms, are a new kind of atomic nuclei and their research has fundamental significance in studying in-medium properties of hadrons, in particular, medium modification of meson masses. The experimental confirmation of the existence of such η-bound system will lead to new possibilities of studying the interaction between a nucleus and the short lived ( 10-18 s) η meson.
The in-beam testing of the detector in full assembled condition was done at COSY, Juelich in March 2004. Different nuclear reactions (pp elastic scattering, p + p → d + π+, p + ’heavy target’) were used, in addition cosmic ray data were collected.
During the beamtime in May 2005 data on p + 27Al → 3He + 25Mgη where obtained. Big Karl was used to spectroscopy and get η-nucleus missing mass spectra. ’ENSTAR’ was used to reduce the background, making triple coincidences with η-mesic nucleus decay products through the chain η + N → N* → p + π−.
Preliminary results of the analysis will be presented.
Supprted in part by FZ Jülich, DAAD D/04/25575 and Int. Büro BMBF (DLR) contract IND 01/022