New R Values in 2-5 Gev from the Beijing Spectrometer

Abstract

The values of $R=\sigma (e^{+}{e}^{-}\to hadrons)/\sigma (e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-})$ for 85 center-of-mass energies between 2 and 5 GeV were measured with the upgraded Beijing Spectrometer at the Beijing Electron-Positron Collider, with an average uncertainty of $\sim 7$.

4 pages, 1 figure, 1 table, talk given at XXXVIth Rencontres de Moriond, Electroweak Interactions and Unified Theories, Les Arcs, Savoie, France, March 10-17 2001