Near-threshold η-meson production in the dd↦He η reaction
/ Authors
A. Wrońska, A. Wrońska, V. Hejny, C. Wilkin, S. Dymov, S. Dymov, C. Hanhart, V. Komarov, H. Koch, A. Kulikov
and 8 more authors
A. Magiera, T. Mersmann, S. Mikirtytchiants, H. Ohm, D. Prasuhn, R. Schleichert, H. Stein, H. Ströher
/ Abstract
Abstract.The dd↦4Heη reaction has been investigated near threshold using the ANKE facility at COSY-Jülich. Both total and differential cross-sections have been measured at two excess energies, Q = 2.6 MeV and 7.7 MeV, with a subthreshold measurement being undertaken at Q = - 2.6 MeV to study the physical background. While consistent with isotropy at the lower energy, the angular distribution reveals a pronounced anisotropy at the higher one, indicating the presence of higher partial waves. Options for the decomposition into partial amplitudes and their consequences for the determination of the s-wave ηα scattering length are discussed.
Journal: The European Physical Journal A - Hadrons and Nuclei