MadGraph5_aMC@NLO

Imposing Various Cuts

Asked by Han

Hi MadGraph team !

I have several questions on imposing various selection cuts in "run_card.dat" to get a sensible cross sections for processes I generate.

1) Is there a way that I can impose separate electron and muon's pt or rapidity cuts? When I see the run card, cuts are loosely defined for "charged leptons", not specifically on e- or mu-.

2) Can we impose the cut in ratio like "missing transverse energy/transverse energy sum <0.5"?

3) I know that I can apply various customized cuts after generating parton-level events (by reading "lhe" file), but then how can I get modified cross section? Surely the cross section for generated process is dependent on selection cuts right?

Cheers !

JeongHan Kim

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Olivier Mattelaer
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Best Olivier Mattelaer (olivier-mattelaer) said : 		#1

Hi,

> 1) Is there a way that I can impose separate electron and muon's pt or rapidity cuts? When I see the run card, cuts are loosely defined for "charged leptons", not specifically on e- or mu-.

For optimization reason, the computation of the cross-section for electron and muon are done only once and the result is multiply by two.
Therefore the cuts should be the same. Making two successive run will solve this.
In order to bypass such optimization, you need to have a model where the muon mass is not zero.
Then you will be able to add those cuts in cuts.f

> 2) Can we impose the cut in ratio like "missing transverse energy/transverse energy sum <0.5"?

you can add such type of cut. See instruction here:
https://cp3.irmp.ucl.ac.be/projects/madgraph/wiki/FAQ-General-1

> 3) I know that I can apply various customized cuts after generating parton-level events (by reading "lhe" file), but then how can I get modified cross section? Surely the cross section for generated process is dependent on selection cuts right?

The cross-section is just the ratio of events passing the cuts times the original cross-section.

Cheers,

Olivier

On Nov 11, 2013, at 3:06 AM, Jeong Han Kim <email address hidden> wrote:

> New question #239010 on MadGraph5:
> https://answers.launchpad.net/madgraph5/+question/239010
>
> Hi MadGraph team !
>
> I have several questions on imposing various selection cuts in "run_card.dat" to get a sensible cross sections for processes I generate.
>
> 1) Is there a way that I can impose separate electron and muon's pt or rapidity cuts? When I see the run card, cuts are loosely defined for "charged leptons", not specifically on e- or mu-.
>
> 2) Can we impose the cut in ratio like "missing transverse energy/transverse energy sum <0.5"?
>
> 3) I know that I can apply various customized cuts after generating parton-level events (by reading "lhe" file), but then how can I get modified cross section? Surely the cross section for generated process is dependent on selection cuts right?
>
> Cheers !
>
> JeongHan Kim
>
> --
> You received this question notification because you are a member of
> MadTeam, which is an answer contact for MadGraph5.

Revision history for this message
Han (jeonghan-kim) said : 		#2

Incredible!
Thank you

Cheers!

JeongHan Kim