Hadron Production by Electron - Positron Annihilation at 5 GeV Center - of Mass Energy

Abstract

We have measured the cross section \ensuremath{\sigma} for electron - positron annihilation into three or more hadrons, with at least two charged particles in the final state, at 5 GeV center-of-mass energy. We find a model-independent lower limit of $\ensuremath{\sigma}>9.1\ifmmode\pm\else\textpm\fi{}1.0$nb; assuming invariant phase-space production of pions, we calculate the detection efficiency of our detector to be (45 \ifmmode\pm\else\textpm\fi{} 11)%, yielding a cross section $\ensuremath{\sigma}=21\ifmmode\pm\else\textpm\fi{}5$nb. The average charged hadron multiplicity is found to be $\overline{n}=4.3\ifmmode\pm\else\textpm\fi{}0.6$.