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Eta-Helium Quasi-Bound States

N. Willis·Y. Le Bornec·A. Zghiche·C. Wilkin·R. Wurzinger·O. Bing·M. Boivin·P. Courtat·R. Gacougnolle·F. Hibou·J. M. Martin·F. Plouin·B. Tatischeff·J. Yonnet
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Abstract

The cross section and tensor analysing power t_20 of the d\vec{d}->eta 4He reaction have been measured at six c.m. momenta, 10 < p(eta) < 90 MeV/c. The threshold value of t_20 is consistent with 1/\sqrt{2}, which follows from parity conservation and Bose symmetry. The much slower momentum variation observed for the reaction amplitude, as compared to that for the analogous pd->eta 3He case, suggests strongly the existence of a quasi-bound state in the eta-4He system and optical model fits indicate that this probably also the case for eta-3He.

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N. Willis, Y. Le Bornec, A. Zghiche, C. Wilkin, R. Wurzinger, O. Bing, M. Boivin, P. Courtat, R. Gacougnolle, F. Hibou, J. M. Martin, F. Plouin, B. Tatischeff, J. Yonnet. 1997-03-12. Eta-Helium Quasi-Bound States. https://doi.org/10.1016/s0370-2693(97)00650-3

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