Question about the QCD scale

Hi Sasha,

The default scale is dynamical and depends of the Feynman diagram under consideration.
(since we use the diagram_enhancement technique for the integration, we have a non ambiguous definition of which Feynman diagram is used).
For this diagram, we are able to tag unambiguously which jet should be consider as QCD jet from those which are tagged as QED jet (originated from a QED interaction).
Then we do the clustering of the jets.

Then in case of a s-channel diagram (like q q~ > t t~), we use the geometric average of the transverse mass associated to the splitting (e.g. the transverse mass of the top and anti-top)
In presence of T-channel with not QCD vertex, we use the geometric average between the transverse mass of the radiative particles and the mass of the non QCD particles.

For the renormalization scale, we use the geometric average of the above scale.

Cheers,

Olivier

On Feb 17, 2014, at 12:46 AM, Alexander Belyaev <email address hidden> wrote:

> New question #244098 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/244098
>
> Hello,
> could let me know, please,
> what is the default QCD scale for
>
> generate p p > z z j j QED=99, z > e+ e-, z > mu+ mu-
>
> process?
>
>
> Thank you,
> Sasha
>
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.