1301.0843 (P. Adlarson et al.)

Search for the eta-mesic 4He with WASA-at-COSY detector    [PDF]

P. Adlarson, W. Augustyniak, W. Bardan, M. Bashkanov, T. Bednarski, F. S. Bergmann, M. Berlowski, H. Bhatt, M. Buescher, H. Calen, H. Clement, D. Coderre, E. Czerwinsk, K. Demmich, E. Doroshkevich, R. Engels, W. Erven, W. Eyrich, P. Fedorets, K. Foehl, K. Fransson, F. Goldenbaum, P. Goslawski, A. Goswami, K. Grigoryev, C. -O. Gullstroem, F. Hauenstein, L. Heijkenskjoeld, V. Hejny, F. Hinterberger, M. Hodana, B. Hoeistad, A. Jany, B. R. Jany, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, F. A. Khan, A. Khoukaz, S. Kistryn, J. Klaja, H. Kleines, B. Klos, M. Krapp, W. Krzemien, P. Kulessa, A. Kupsc, K. Lalwani, D. Lersch, L. Li, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, M. Mikirtychiants, H. -P. Morsch, P. Moskal, B. K. Nandi, S. Niedzwiecki, H. Ohm, I. Ozerianska, E. Perez del Rio, P. Plucinski, P. Podkopal, D. Prasuhn, A. Pricking, D. Pszczel, K. Pysz, A. Pyszniak, C. F. Redmer, J. Ritman, A. Roy, Z. Rudy, S. Sawant, S. Schadmand, A. Schmidt, T. Sefzick, V. Serdyuk, N. Shah, M. Siemaszko, R. Siudak, T. Skorodko, M. Skurzok, J. Smyrski, V. Sopov, R. Stassen, J. Stepaniak, E. Stephan, G. Sterzenbach, H. Stockhorst, H. Stroeher, A. Szczurek, T. Tolba, A. Trzcinski, R. Varma, P. Vlasov, G. J. Wagner, W. Weglorz, M. Wolke, A. Wronska, P. Wuestner, P. Wurm, A. Yamamoto, X. Yuan, L. Yurev, J. Zabierowski, C. Zheng, M. J. Zielinski, W. Zipper, J. Zlomanczuk, P. Zupranski, M. Zurek

An exclusive measurement of the excitation function for the dd->3Heppi- reaction was performed at the Cooler Synchrotron COSY-Juelich with the WASA-at-COSY detection system. The data were taken during a slow acceleration of the beam from 2.185 GeV/c to 2.400 GeV/c crossing the kinematic threshold for the eta meson production in the dd->4He-eta reaction at 2.336 GeV/c. The corresponding excess energy with respect to the 4He-eta system varied from -51.4MeV to 22MeV. The integrated luminosity in the experiment was determined using the dd->3Hen reaction. The shape of the excitation function for the dd->3Heppi- was examined. No signal of the 4He-eta bound state was observed. An upper limit for the cross-section for the bound state formation and decay in the process dd->(4He-eta)bound->3Heppi- was determined on the 90% confidence level and it varies from 20nb to 27nb for the bound state width ranging from 5MeV to 35MeV, respectively.

View original: http://arxiv.org/abs/1301.0843