Measurements of the ContinuumRudsandRValues ine+e−Annihilation in the Energy Region between 3.650 and 3.872 GeV

Abstract

We report measurements of the continuum $R_{uds}$ near the center-of-mass energy of 3.70 GeV, the $R_{uds(c)+\psi (3770)}(s)$ and the $R_{\mathrm{had}}(s)$ values in $e^{+}{e}^{-}$ annihilation at 68 energy points in the energy region between 3.650 and 3.872 GeV with the BES-II detector at the BEPC Collider. We obtain the $R_{uds}$ for the continuum light hadron (containing $u$, $d$, and $s$ quarks) production near the $D\overline{D}$ threshold to be $R_{\mathrm{uds}}=2.141\pm 0.025\pm 0.085$.