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.
@article{arxiv.0707.1489,
title = {Is there an eta-3He quasi--bound state ?},
author = {C. Wilkin and M. Buescher and D. Chiladze and S. Dymov and C. Hanhart and M. Hartmann and V. Hejny and A. Kacharava and I. Keshelashvili and A. Khoukaz and Y. Maeda and T. Mersmann and M. Mielke and S. Mikirtychiants and M. Papenbrock and F. Rathmann and T. Rausmann and R. Schleichert and H. Stroeher and A. Taeschner and Yu. Valdau and A. Wronska},
journal= {arXiv preprint arXiv:0707.1489},
year = {2008}
}