Measurement Of The Running Of Effective Qed Coupling At Large Momentum Transfer In The Spacelike Region

The q(2) running of effective QED coupling alpha(q(2)) is measured in a spacelike region, (10 GeV)(2) less than or equal to -q(2) less than or equal to (54 GeV)(2), using Bhabha-scattering and muon-pair production data at e(+)e(-) collisions with a center-of-mass energy of 57.77 GeV. The result verifies the prediction of a theoretical estimation with a precision of better than 1% in terms of alpha(q(2))/alpha(t(0)) with t(0) = -(10 GeV)(2).