“…There have been numerous measurements of the pd → 3 He η reaction at low energies over the last 30 years, where the 3 He nucleus was detected and the η meson identified through the missing mass in the reaction [181,182,239,240,241,242,243,244,245,246,247,248]. The statistical precision is generally reasonable but the systematic uncertainties, mainly associated with the overall normalization, range from about 7% in the Saclay measurement [243] up to twice that in most of the other data, except for the large errors at COSY-11 [246].…”