Testing the Standard Model with e+ e- collisions: Part 1

por Dr. Michael Tung (ITP, State Univ. of NY at Stony Brook)

martes 23 jun. 1998 16:00 → 17:00 Europe/Madrid

Sala Seminarios (Dpto. de Fisica Teorica (UVEG))

We consider $e^+e^-$ annihilation into massive quarks due to photon and $Z$--boson exchange, and present a general technique to compute analytically one-loop QCD corrections of the relevant production rates and asymmetries. Particularly interesting observables are the forward-backward asymmetry and spin-spin correlations for the massive quarks, especially for the top. These $O(\alpha_s)$ corrections are typically of the order of 3--$5 \%$. In this exposition, we first treat the fully analytical derivation of the virtual and real QCD corrections with massive quarks for this process. For the virtual corrections, this involves form factors in the quark-gluon vertices. Then, the basic techniques are explained to tackle the more involved real (bremsstrahlung) corrections in terms of the phase-space integrals in closed analytical form. Finally, explicit analytical and numerical results for the observables under consideration are provided.