During 1993 and 1995 LEP was run at 3 energies near the Z(0) peak in order
to give improved measurements of the mass and width of the resonance. Durin
g 1994, LEP operated only at the Z(0) peak. In total DELPHI accumulated dat
a corresponding to an integrated luminosity of approximately 116 pb(-1). An
alyses of the hadronic cross-sections and of the cross-sections and forward
-backward asymmetries in the leptonic channels used the most precise evalua
tions of the LEP energies. In the dimuon channel, events with a photon radi
ated horn the initial state have been used to probe the cross-sections and
asymmetries down to PETRA energies. Model independent fits to all DELPHI li
neshape and asymmetry data horn 1990 to 1995 have been carried out giving v
alues of the resonance parameters:
M-Z = 91.1863 +/- 0.0028 GeV
Gamma(Z) = 2.4876 +/- 0.0041 GeV
sigma(0) = 41.578 +/- 0.069 nb
R-iota = 20.730 +/- 0.060
A(FB)(0) = 0.0187 +/- 0.0019.
These values are significantly more precise than those previously published
. The results are interpreted in terms of the Standard Model.