722 research outputs found
QCD corrections to e+ e- --> 4 jets
We report on the next-to-leading order QCD calculation for e+ e- --> 4 jets.
We explain some modern techniques which have been used to calculate the
one-loop amplitudes efficiently. We further report on the general purpose
numerical program ``Mercutio'', which can be used to calculate any infrared
safe four-jet quantity in electron-positron annihilation at next-to-leading
order.Comment: 4 pages, talk given at the UK Phenomenology Workshop on Collider
Physics, Durham, 19-24 September 199
A subtraction scheme for computing QCD jet cross sections at NNLO: regularization of real-virtual emission
We present a subtraction scheme for computing jet cross sections in
electron-positron annihilation at next-to-next-to-leading order accuracy in
perturbative QCD. In this second part we deal with the regularization of the
real-virtual contribution to the NNLO correction.Comment: 32 pages, LaTeX file, uses pstrick
QCD Sum Rules for Heavy Flavors
We give a short review of QCD sum rule results for B and D mesons and
Lambda_Q and Sigma_Q baryons. We focus mainly on recent developments concerning
semileptonic B->pion and D->pion transitions, pion couplings to heavy hadrons,
decay constants and estimates of the b quark mass from a baryonic sum rule, and
the extraction of the pion distribution amplitude from CLEO data.Comment: 12 pages, LaTeX, Talk given by O.Yakovlev at the 4th Workshop on
Continuous Advances in QCD, Minneapolis, May 12-14, 2000; to appear in the
Proceeding
Subtraction terms for one-loop amplitudes with one unresolved parton
Fully differential next-to-next-to-leading order calculations require a
method to cancel infrared singularities. In a previous publication, I discussed
the general setup for the subtraction method at NNLO. In this paper I give all
subtraction terms for electron-positron annihilation associated with one-loop
amplitudes with one unresolved parton. These subtraction terms are integrated
within dimensional regularization over the unresolved one-particle phase space.
The results can be used with all variants of dimensional regularization
(conventional dimensional regularization, the 't Hooft-Veltman scheme and the
four-dimensional scheme).Comment: 27 page
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