Author/Authors :
Abreu، نويسنده , , P and Angelis، نويسنده , , A.De and Ricca، نويسنده , , G.Della and Fassouliotis، نويسنده , , D and Grefrath، نويسنده , , A and Kjaer، نويسنده , , N and Henriques، نويسنده , , R.P and Mulders، نويسنده , , M and Pimenta، نويسنده , , M and Vitale، نويسنده , , L، نويسنده ,
Abstract :
The photon radiation in the initial state lowers the energy available for the e+e− collisions; this effect is particularly important at LEP2 energies (above the mass of the Z boson). Being aligned to the beam direction, such initial state radiation is mostly undetected. This article describes the procedure used by the DELPHI experiment at LEP to estimate the effective centre-of-mass energy in hadronic events collected at energies above the Z peak. Typical resolutions ranging from 2 to 3 GeV on the effective center-of-mass energy are achieved, depending on the event topology.
