A Determination of the Centre-of-Mass Energy at LEP2 using Radiative 2-fermion Events

TL;DR

This paper presents a method to determine the LEP2 centre-of-mass energy using radiative 2-fermion events, providing an independent cross-check of the nominal energy measurements.

Contribution

The study introduces an energy and momentum constraint method to measure the centre-of-mass energy from radiative events, aligning with existing estimates.

Findings

Results agree with LEP Energy Working Group estimates

Method provides an independent energy measurement

Compatible with previous data sets from 1997 to 2000

Abstract

Using 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.