Measurement of R and determination of the charged-particle multiplicity in e+e- annihilation at 13-113-113-1around 10 GeV

Abstract

We have measured the R value in non-resonant e+e- annihilation using the ARGUS detector at the storage ring DORIS II. At a centre-of-mass energy {Mathematical expression} GeV the ratio of the hadronic cross-section to the μ-pair cross section in lowest order QED has been determined to be R=3.46±0.03±0.13. In addition, we have measured the charged-particle multiplicities in non-resonant hadron production at {Mathematical expression} GeV just below the B {Mathematical expression} threshold and in Υ{hooked} (4 S) resonance decays. For the average charged-particle multiplicities in continuum events and Υ{hooked}(4 S)→B {Mathematical expression} decays we obtain cont=8.35±0.02±0.20 and Υ{hooked}(4 s)=10.81±0.05±0.23. © 1992 Springer-Verlag.