arXiv:0707.1489·v1·Nuclear Experiment
Is there an eta-3He quasi--bound state ?
C. Wilkin · M. Buescher · D. Chiladze · S. Dymov · C. Hanhart · M. Hartmann · V. Hejny · A. Kacharava · I. Keshelashvili · A. Khoukaz · Y. Maeda · T. Mersmann
Abstract
The observed variation of the total cross section for the dp -> 3He eta reaction near threshold means that the magnitude of the s--wave amplitude falls very rapidly with the eta centre--of--mass momentum. It is shown here that recent measurements of the momentum dependence of the angular distribution imply a strong variation also in the phase of this amplitude. Such a behaviour is that expected from a quasi--bound or virtual eta-3He state. The interpretation can be investigated further through measurements of the deuteron or proton analysing powers and/or spin--correlations.
Comments: 10 pages with two eps figures