Measurement of π⁰ and η meson production ine ⁺ e ⁻ annihilation at$\sqrt s$ near 10 GeV

Abstract

We present a study of inclusive π⁰ and ŋ production ine ⁺ e ⁻ annihilation at$\sqrt s \approx 10 GeV$. Our analysis is based on integrated luminosities of 46.2 pb⁻¹ taken at the υ (1 S) resonance and 42.1 pb⁻¹ taken in the neighboring continuum. We measure the inclusive π⁰ and ŋ spectra for direct υ (1 S) → 3g decays and continuum processes$e^ + e^ - \to q\bar q$ and obtain the following mean particle multiplicities per event:

$$\begin{array}{*{20}c} {Continuum:} \\ {\begin{array}{*{20}c} {\left\langle {n_{\pi ^0 } } \right\rangle = 3.64 \pm 0.21 \pm 0.36} & {\left\langle {n_\eta } \right\rangle = 0.22 \pm 0.04 \pm 0.03} \\ \end{array} } \\ {\Upsilon (1S) \to 3g:} \\ {\begin{array}{*{20}c} {\left\langle {n_{\pi ^0 } } \right\rangle = 3.39 \pm 0.14 \pm 0.34} & {\left\langle {n_\eta } \right\rangle = 0.35 \pm 0.04 \pm 0.04.} \\ \end{array} } \\ \end{array}$$

We compare our results with predictions of different fragmentation models and with other measurements performed ine ⁺ e ⁻ annihilation at similar center-of-mass energies.