Karlsruhe 2011 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 12: QCD (Theorie) / Quantenfeldtheorie
T 12.9: Vortrag
Freitag, 1. April 2011, 16:05–16:20, 30.23: 10-1
All tree-level amplitudes in massless QCD — Lance Dixon1,2, Johannes Henn3, Jan Plefka3, and •Theodor Schuster3 — 1Theory Group, Physics Department, CERN, Ch-1211 Geneva 23, Switzerland — 2SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94309, USA — 3Institut für Physik, Humboldt-Universität zu Berlin, Newtonstraße 15, D-12489 Berlin, Germany
We derive compact analytical formulae for all tree-level color-ordered gauge theory amplitudes involving any number of external gluons and up to three massless quark-anti-quark pairs.
A general formula for all gluon-gluino tree amplitudes is presented, based on the combinatorics of paths along a rooted tree and associated determinants. Our results are obtained by projecting the previously-found expressions for the super-amplitudes of the maximally supersymmetric super Yang-Mills theory (N = 4 SYM) onto the relevant components.
We show how these results carry over to the corresponding QCD amplitudes, including massless quarks of different flavors as well as a single electroweak vector boson.
The public Mathematica package GGT is described, which encodes the results of this work and yields analytical formulae for all N = 4 SYM gluon-gluino trees. These in turn yield all QCD trees with up to four external arbitrary-flavored massless quark-anti-quark-pairs.