$R$ value measurements for $e^{+}{e}^{-}$ annihilation at 2.60, 3.07 and 3.65 GeV

Abstract

Using a data sample with a total integrated luminosity of 10.0 pb${}^{-1}$ collected at center-of-mass energies of 2.6, 3.07 and 3.65 GeV with BESII, cross sections for $e^{+}{e}^{-}$ annihilation into hadronic final states ($R$ values) are measured with statistical errors that are smaller than 1%, and systematic errors that are about 3.5%. The running strong interaction coupling constants ${\alpha }_s^{(3)}(s)$ and ${\alpha }_s^{(5)}(M_Z^2)$ are determined from the $R$ values.

14 pages, 4 figures, 3 tables