Parton Distribution Functions in MG5

Hi Andrew,

> I know I can alter the run-card with either 0,1, or -1 (corresponding to leptop, p, and pbar beams respectively).

0 is in fact no pdf but indeed this is the correct value for a lepton beam.

> I was curious to know what method MG used to calculate the PDFs? Can I see the parameters of that method? Can I call on different methods? Where is the code stored? Is it accessible? Etc..

MadGraph can use different set of PDF, you can specify one of the pre-build value in the run_card.dat.
If your favorite pdf set is not present, it's possible (see the README file for instructions) to link MG to lhapdf libraries.

Different collaborations/set of PDF are based on different method.
The best would be to read the associated papers.

Cheers,

Olivier

On Jul 12, 2012, at 4:36 PM, Andrew Chegwidden wrote:

> New question #202949 on MadGraph5:
> https://answers.launchpad.net/madgraph5/+question/202949
>
> Hello,
>
> I was wondering what, if any, control I have over the Parton Distribution Functions in MG. I know I can alter the run-card with either 0,1, or -1 (corresponding to leptop, p, and pbar beams respectively). I was curious to know what method MG used to calculate the PDFs? Can I see the parameters of that method? Can I call on different methods? Where is the code stored? Is it accessible? Etc..
>
> I use MG local on my machine so I have all the code available to me.
>
> Thank you for your time,
>
> Andrew Chegwidden
> Michigan State University
>
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