Recent developments in calculating power corrections to hadronic event shapes

by Zoltan TROCSANYI (CERN)

Friday 10 Mar 2000, 14:00 → 14:15 Europe/Zurich

TH Auditorium (CERN)

The LEP experiments publish their data corrected to hadron level, while perturbative calculations result in cross sections at parton level. Non-perturbative hadronization phenomena are responsible for significant differences - in general comparable to the size of the next-to-leading order corrections - between the two results. In the talk, we shall review some recent developments in predicting these non-perturbative corrections to hadronic event shapes using perturbative techniques: the dispersive approach to power corrections. First, we shall discuss the status of the universality picture of the predictions. Next, we extend the universality assumptions to final states emerging from heavy quarks and present results for power corrections to the mean values of event shapes of tagged b events. We conclude with a lesson that may be drawn about the universality from the phenomenology of power corrections to event shapes of tagged samples.