Coherent exclusive exponentiation for precision Monte Carlo calculations of fermion pair production/precision predictions fo.stable W/sup +/W/sup -/ pairs

We present the new coherent exclusive exponentiation (CEEX), in comparison to the older exclusive exponentiation (EEX) and the semi-analytical inclusive exponentiation (IEX), for the process e/sup +/e /sup -/ to ff + n gamma , f = mu , tau , d, u, s, c, b, with validity for centre of mass energies from the tau lepton threshold to 1 TeV. We analyse 2f numerical results at the Z-peak, 189 GeV and 500 GeV. We also present precision calculations of the signal processes e/sup +/e /sup -/ to 4f in which the double resonant W/sup +/W/sup -/ intermediate state occurs using our YFSWW3-1.14 MC. Sample 4f Monte Carlo data are explicitly illustrated in comparison to the literature at LEP2 energies. These comparisons show that a TU for the signal process cross section of 0.4% is valid for the LEP2 200 GeV energy. LC energy results are also shown.