The precision Monte Carlo event generator KK for two-fermion final states in e(+)e(-) collisions

We present the Monte Carlo event generator KK version 4.13 for precision pr edictions of the Electroweak Standard Model for the process e(+)e(-) --> f (f) over bar + ny, f = mu, tau, d, u, s, c, b, at centre-of-mass enemies fr om tau lepton threshold to 1 TeV, that is for LEP, SLC, future Linear Colli ders, b, c, tau-factories, etc. Effects due to photon emission from initial beams and outgoing fermions an calculated in QED up to second order, inclu ding all interference effects, within Coherent Exclusive Exponentiation (CE EX), which is based on Yennie-Frautschi-Suura exponentiation. Electroweak c orrections are included in first order, with higher-order extensions, using the DIZET 6.21 library. Final-state quarks hadronize according to the part on shower model using JETSET. Beams can be polarized longitudinally and tra nsversely. Decay of the s leptons is simulated using the TAUOLA Library, ta king into account spin polarization effects as well. In particular the comp lete spin correlations density matrix of the initial-state beams and final state tau's is incorporated in an exact manner. Effects due to beamstrahlun g are simulated in a realistic way. The main improvements with respect to K ORALZ are: (a) inclusion of the initial-final state QED interference, (b) i nclusion of the exact matrix element for two photons, and (c) inclusion of the transverse spin correlations in tau decays (as in KORALB). (C) 2000 Els evier Science B.V. All rights reserved.