2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/206140Using e+e- -> mu+mu-(gamma) and e+e- -> qqbar(gamma) events radiative to the Z pole, DELPHI has determined the centre-of-mass energy, sqrt{s}, using energy and momentum constraint methods. The results are expressed as deviations from the nominal LEP centre-of-mass energy, measured using other techniques. The results are found to be compatible with the LEP Energy Working Group estimates for a combination of the 1997 to 2000 data sets.20 pages, 6 figures, Accepted by Eur. Phys. J. CHigh Energy Physics - Experimenttext