Finite-energy sum rules for the cross section of $e^+e^-$-annihilation into hadrons in quantum chromodynamics

Finite-energy sum rules are obtained for the cross sections of $e^+e^-$-annihilation into hadrons in quantum chromodynamics; for the standard model, these agree reasonably with the experimental results, and the best agreement is obtained for the five-quark model with charge $Q_5=-1/3$ of the fifth quark.