THE MONTE-CARLO PROGRAM KORALZ VERSION-4.0 FOR LEPTON OR QUARK PAIR PRODUCTION AT LEP/SLC ENERGIES

A Monte Carlo program for tau pair production and decay applicable to the experiments in e+e- colliders in the Z resonance energy range is presented. The program includes initial and final state bremsstrahlung corrections up to the O(alpha2) (with exclusive exponentiation), and O(alpha) electroweak corrections. More than twenty distinct tau decay modes can be generated: (a) leptonic modes tau- --> nunue-BAR(gamma) and nunumu-BAR(gamma); (b) one-meson modes, nutau- and nuK-; (c) two-meson modes, nu(pi-pi0}rho-, nu(K-pi0}K*- and nu{K0pi-}K*-: (d) three-meson modes, nu{pi-2pi0}a1-, nu{2pi-pi+}a1-, nuK+K-pi-, nuK0K0pi-BAR, nuK-K0pi0BAR, nuK-pi0pi0, nuK-pi-pi+, nuK0pi0pi- and nunpi-pi0; (e) four-pion modes, nupi-3pi0, and nu2pi-pi+pi0 (including the omegapi- contribution); (f) multi-pion modes, nun +/-,0 with n > 4; and finally the decay tau- --> nupi- pi0gamma from the omega --> pigamma Complete O(alpha) QED corrections are included in the leptonic decay channels, and for other decay channels an interface is provided to the PHOTOS Monte Carlo generator for approximate simulation of the QED corrections. The program includes three libraries of pure electroweak corrections from three independent groups of authors. The program can also be used for the generation of final states different from tau+tau- pairs, i.e., it is able to generate mu+mu-, nunuBAR, and under some restrictions uuBAR, ddBAR, ccBAR, ssBAR and bbBAR final states.