Photon and light meson production in hadronic Z$^0$decays

Abstract.

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 $\pi^0$, $\eta$, $\rho(770)^{\pm}$, $\omega(782)$, $\eta'(958)$and a$_0(980)^{\pm}$. The particle multiplicities per hadronic Z$^0$decay, extrapolated to the full energy range, are: \begin{eqnarray} \langle n_{\gamma} \rangle & = & 20.97 \pm$ 0.02 \pm1.15 , \nonumber \\ \langle n_{\pi^0} \rangle & = & 9.55 \pm 0.06 \pm 0.75 , \nonumber \\ \langle n_{\eta} \rangle & = & 0.97 \pm 0.03 \pm 0.11 , \nonumber\\ \langle n_{\rho^{\pm}} \rangle & = & 2.40 \pm 0.06 \pm 0.43 , \nonumber \\ \langle n_{\omega} \rangle & = & 1.04 \pm 0.04 \pm 0.14 , \nonumber \\ \langle n_{\eta'} \rangle & = & 0.14 \pm 0.01 \pm 0.02 , \nonumber \\ \langle n_{{\mathrm a}_0^{\pm}} \rangle & = & 0.27 \pm 0.04 \pm 0.10 , \nonumber \end{eqnarray}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.