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

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 $α_s^{(3)}(s)$ and $α_s^{(5)}(M_Z^2)$ are determined from the $R$ values.

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