Measurement of the dp → 3 He η reaction near threshold

Total and differential cross sections for the dp → 3Heη reaction have been measured near threshold for 3He center-of-mass momenta in the range from 17.1 MeV/c to 87.5 MeV/c. The data were taken during a slow ramping of the COSY internal deuteron beam scattered on a proton target detecting the 3He ejectiles with the COSY-11 facility. The forward–backward asymmetries of the differential cross sections deviate clearly from zero for center-of-mass momenta above 50 MeV/c indicating the presence of higher partial waves in the final state. Below 50 MeV/c center-of-mass momenta a fit of the final state enhancement factor to the data of the total cross sections results in the 3He–η scattering length of |a| = 4.3 ± 0.5 fm. © 2007 Elsevier B.V. PACS: 14.40.-n; 21.45.+v; 25.45.-z