The differential cross section for the $p\overrightarrow{d}{}^3\mathrm{He}\eta$ reaction has been measured at four beam energies 930, 965, 1037, and 1100 MeV. The total cross section is nearly constant throughout the whole energy region, despite the c.m. angular distribution becoming more anisotropic with increasing energy. The data join smoothly onto the results of near-threshold measurements, which are dominated by the S-wave $\eta {}^3\mathrm{He}$ final state interaction. At all the energies the differential cross section is maximal for $\cos {\theta }_{\eta }\approx +0.5\mathrm{}$ and this may provide a clue to the reaction mechanism and, in particular, to two-step contributions.

• Received 15 December 2001

DOI:https://doi.org/10.1103/PhysRevC.65.044608