The BZ angle in e+ e- -> 4jets: abelian vs non-abelian

Use MadGraph/MadEvent to produce two event samples, one for standard QCD and one with an abelian QCD model for

Run the collision on the peak of the Z boson and set a minimum invariant mass for the jets of $m_{jj}>10$ GeV. Plot the Bengtsson-Zerwas angle between the planes identified by the two lowest and to highest energy jets:

$\cos \chi_{BZ} = \frac{( {\bf p}1\times {\bf p}2) \cdot ({\bf p}3\times {\bf p}4)}{

{\bf p}1 \times {\bf p}2

{\bf p}3\times {\bf p}4

}\,.$

Comparison should be made with the plots of Ref. ​hep-ph/9503354, where various implementation of the abelian models are discussed. Our web implementation include the emission of abelian gluons as possible partons leading to jets.

-- Main.FabioMaltoni - 29 Aug 2007