Inclusive η production at low transverse momentum in 63 GeV ppcollisions at the cern intersecting storage rings

The inclusive production of η-mesons in pp collisions at √ s =63GeV and ϑ CM =90° has been measured for p T P T = 750MeV/c and η/π ≈ 0.01 at P T =300MeV/c, in a way that consistent with phase-space considerations, e.g. m T scaling. The η/π ratio, integrated from 0.2–1.5 GeV/ c , is found to be η/π=0.07±0.055.