QCD corrections to e+ e- --> 4 jets
The main project of my Ph. D. thesis was the computation of the QCD corrections to e+ e- -> 4 jets. In collaboration with Z. Bern, L. Dixon and D.A. Kosower I calculated the one-loop amplitudes for e+ e- -> q qbar Q Qbar (hep-ph/9610370). These amplitudes were obtained by using a number of technical advances in the computation of one-loop amplitudes, like the spinor helicity method, colour decomposition and taking into account constraints derived from unitarity and the factorization in collinear limits. In a second step I have written a general purpose numerical program, called ``Mercutio'', which can be used to calculate any infrared safe four-jet quantity in electron-positron annihilation at next-to-leading order (hep-ph/9901277).
An algorithm for an "NLO partonic event generator"
Merging the benefits of an NLO calculation with event generators is a topic of current interest. As a step in this direction, I showed how to set up a computer program, which generates a sequence of unweighted momentum configurations, each configuration containing either n or n+1 four-vectors, such that for any infrared safe observable the average over these configurations coincides with the NLO calculation up to errors of a resolution variable. The algorithm can be implemented on top of existing NLO calculations (hep-ph/0106146).
Talks on this subject:
Talk given at the UK Phenomenology Workshop on
Collider Physics, Durham, 19-24 September 1999
(hep-ph/9911529).
Talk given at the International Europhysics Conference on High-Energy Physics
(HEP 97), Jerusalem, Israel, 19-26 Aug 1997
(PostScript).
Talk given at the 5emes Journees des Jeunes Chercheurs, Autrans, 1996
(in french, PostScript).