Distributions in Four-Fermion Processes

Abstract

The programs WPHACT and WTO, which are designed for computing cross sections and other relevant observables in the $e^{+}{e}^{-}$ annihilation into four fermions, are used to make detailed and complete predictions for the semi-leptonic and fully hadronic channels $e^+e^- \to \barq q lν, \barq q \barq q$. Both the total cross sections in the LEP~2 energy range and some of the most relevant distributions are analyzed. Particular algorithms are introduced for the fully hadronic channels in order to analyze the $WW$ physics and to properly define the signal versus the background. With appropriate kinematical cuts it has been shown that the Neutral Current background can be made vanishingly small when the problem of determining the $W$ boson mass is addressed. The remaining background from the complete Charge Current and Mixed processes is again small but not completely negligible. A detailed discussion is performed on the validity of the most relevant approximations such as the double-resonant one. The inclusion of final state QCD correction, in its {\it naive} form (NQCD), is discussed and various implementations are examined.

15 pages, 13 Postscript figures. Longer version to appear in Nuc. Phys. B

References in corpus (22)

• EXCALIBUR -- a Monte Carlo program to evaluate all four fermion processes at LEP 200 and beyond
• An Algorithm to Compute Born Scattering Amplitudes without Feynman Graphs
• All electroweak four fermion processes in electron-positron collisions
• Stable Calculations for Unstable Particles: Restoring Gauge Invariance
• Unstable particles in One Loop Calculations
• Finite Width Effects and Gauge Invariance in Radiative $W$ Production and Decay
• A New Method for Helicity Calculations
• Heavy Quarks and Leptons at $e^{+}{e}^{-}$ Colliders
• WPHACT 1.0 - A program for $WW$, Higgs and 4 fermion physics at $e^{+}{e}^{-}$ colliders
• HIGGS BOSON PRODUCTION IN $e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}b\bar{b}$
• $e^{+}{e}^{-}\to e^{-}{\bar{\nu }}_{e}u\bar{d}$ from LEP to linear collider energies
• Initial-state QED corrections to four-fermion production in e+e- collisions at LEP200 and beyond
• On the determination of the trilinear boson couplings in e^-e^+ --> lepton anti-neutrino quark anti-quark at LEPII
• WWGENPV - A Monte Carlo Event Generator For Four-Fermion Production in $e^{+}{e}^{-}\to W^{+}{W}^{-}\to 4f$
• Four quark processes at LEP 200
• WWF: a generator for e+e- to 4 fermions + gamma
• THE PROCESS $e^{+}{e}^{-}\to l\bar{l}q\bar{q}$ AT LEP AND NLC
• Off shell W pair production in e+ e- annihilation: The CC11 process
• WTO - a deterministic approach to $4$-fermion physics
• Semi-analytical and Monte Carlo results for the production of four fermions in $e^{+}{e}^{-}$ collisions
• Higgs production in $e^{+}{e}^{-}\to l\bar{l}q\bar{q}$ at LEP and NLC
• Complete O($\alpha$) QED corrections to the process $ep\to eX$ in mixed variables

Cited by in corpus (3)

• Semileptonic six fermion processes at future $e^{+}{e}^{-}$ colliders: signal and irreducible background for top and WWZ physics
• Reconstruction and approximation effects on W mass distributions at LEP2
• Uses of Covariant Formalism for Analytical Computation of Feynman Diagrams with Massive Fermions