Six-quark decays of off-shell $W^+W^-$ pairs via parton-level QCD in electron-positron annihilations

Abstract.

We study the decays into six quarks of off-shell pairs of $W^\pm$ bosons produced in electron-positron annihilations, through the ${\cal O}(\alpha_s^2)$ order in the strong coupling constant. We give explicit helicity amplitude formulae. We present numerical results in the context of phenomenological analyses of relevance at LEP2 and future Linear Colliders: such as $M_W$ determinations, New Physics and Higgs searches.