Inclusive yields and transverse spectra of non-strange mesons

Recent data on the production ofη, ϱ0, ω and other mesons in hadron-hadron collisions at intermediate energies are studied. Their transverse spectra dσ/dpT2 are all found to be approximately exponential, with similar slopes, ∼3.4 (GeV/c)−2, up to about pT2 = 2(GeV/c)2. The inclusive yields of the mesons are broadly in agreement with quark model predictions. In the case of pions, a distimction is made between those directly produced and those produced indirectly via resonance decay. It is estimated that between 10% and 30% of pions are directly produced.