Photon and Light Meson Production in Hadronic Z^0 Decays
  The inclusive production rates and differential cross-sections of photons and mesons with a final state containing photons have been measured with the OPAL detector at LEP. The light mesons covered by the measurements are the \pi^0, \eta, \rho(770)+-, \omega(782), \eta'(958) and a_0(980)+-. The particle multiplicities per hadronic Z^0 decay, extrapolated to the full energy range, are:   <n_\gamma> = 20.97 +/- 0.02 +/- 1.15,   <n_\pi^0> = 9.55 +/- 0.06 +/- 0.75,   <n_\eta> = 0.97 +/- 0.03 +/- 0.11,   <n_\rho^+-> = 2.40 +/- 0.06 +/- 0.43,   <n_\omega> = 1.04 +/- 0.04 +/- 0.14,   <n_\eta> = 0.14 +/- 0.01 +/- 0.02,   <n_a_0+-> = 0.27 +/- 0.04 +/- 0.10.   where the first errors are statistical and the second systematic. In general, the results are in agreement with the predictions of the JETSET and HERWIG Monte Carlo models. 
The OPAL Collaboration, K. Ackerstaff et al