Precision study of the eta-3He system using the d+p->3He+eta reaction
/ Authors
T. Mersmann, A. Khoukaz, M. Büscher, D. Chiladze, S. Dymov, M. Hartmann, V. Hejny, A. Kacharava, I. Keshelashvili, P. Kulessa
and 16 more authors
Y. Maeda, M. Mielke, S. Mikirtychiants, H. Ohm, M. Papenbrock, D. Prasuhn, F. Rathmann, T. Rausmann, R. Schleichert, V. Serdyuk, H. Stein, H. Ströher, A. Täschner, Y. Valdau, C. Wilkin, A. Wro'nska
/ Abstract
The differential and total cross sections for the d+p->3He+eta reaction have been measured in a high precision high statistics COSY-ANKE experiment near threshold using a continuous beam energy ramp up to an excess energy Q of 11.3 MeV with essentially 100% acceptance. The kinematics allowed the mean value of Q to be determined to about 9 keV. Evidence is found for the effects of higher partial waves for Q>4 MeV. The very rapid rise of the total cross section to its maximum value within 0.5 MeV of threshold implies a very large eta-3He scattering length and hence the presence of a quasi-bound state extremely close to threshold.
Journal: Physical Review Letters