NNLO QCD Corrections to the Forward-Backward Asymmetry
by
Mike SEYMOUR (Rutherford Laboratory)
→
Europe/Zurich
TH Auditorium (CERN)
TH Auditorium
CERN
Description
We calculate the second-order QCD corrections to the forward-backward asymmetry in e+e- annihilation. Using the
quark axis definition, we do not agree with either existing
calculation, but the difference relative to one of them is small and
understood. In particular, we point out that the forward-backward
asymmetry of massive quarks is enhanced by logarithms of the
quark mass. This implies that the forward-backward asymmetry of
massless quarks is not computable in QCD perturbation theory
and affected by non-power-suppressed corrections coming from
the non-perturbative fragmentation functions. We also calculate the
second-order corrections using the experimentally-preferred thrust
axis definition for the first time.
