Measurements of the continuum $R_{\rm uds}$ and $R$ values in $e^+e^-$ annihilation in the energy region between 3.650 and 3.872 GeV

TL;DR

This paper presents precise measurements of the $R$ values in electron-positron annihilation between 3.650 and 3.872 GeV, focusing on the continuum $R_{ m uds}$ near the $Dar D$ threshold, using data from BES-II detector.

Contribution

It provides new measurements of the $R$ values in a specific energy region, improving understanding of light hadron production near the $Dar D$ threshold.

Findings

$R_{ m uds}$ measured as 2.141 ± 0.025 ± 0.085 near 3.70 GeV

68 energy points analyzed in the 3.650-3.872 GeV range

Enhanced precision in $R$ values near the $Dar D$ threshold

Abstract

We report measurents of the continuum $R_{\rm uds}$ near the center-of-mass energy of 3.70 GeV, the $R_{{\rm uds(c)}+\psi(3770)}(s)$ and the $R_{\rm had}(s)$ 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 Collodier. We obtain the $R_{\rm uds}$ for the continuum light hadron (containing u, d and s quarks) production near the $D\bar D$ threshold to be $R_{\rm uds}=2.141 \pm 0.025 \pm 0.085$.