MadGraph5_aMC@NLO

Questions about the matching scale choice with Ht cuts implemented at parton level

Asked by Da Liu

Hi,

Recently, I have implemented a Ht cut which includes the pt of the top. Now if I divide the phase space of tt + jets into different region according to the Ht cut at parton-level, then do the matching, how does the match scale should vary according to the Ht cut? Is it reasonable to do this? For example, divide the Ht into three bind 0-500, 500-1000, 1000- Infinity at the parton-level and then do the matching into to different bins?

Thanks a lot.

Best wishes,

Da

PS: How many jets in the matrix element are allowed for the MadGraph5 to work well?

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

Hi Da,

I would personally use the same matching scale for each value of the cut, which is then equivalent to just populate the different part of the phase-space with different luminosity.
For the validation of the matching/merging, you need to recombine all the sample (and scale the sample to have a unique multiplicity)

Cheers,

Olivier

On Aug 25, 2014, at 6:16 PM, Da Liu <email address hidden> wrote:

> New question #253588 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/253588
>
> Hi,
>
> Recently, I have implemented a Ht cut which includes the pt of the top. Now if I divide the phase space of tt + jets into different region according to the Ht cut at parton-level, then do the matching, how does the match scale should vary according to the Ht cut? Is it reasonable to do this? For example, divide the Ht into three bind 0-500, 500-1000, 1000- Infinity at the parton-level and then do the matching into to different bins?
>
> Thanks a lot.
>
> Best wishes,
>
> Da
>
> PS: How many jets in the matrix element are allowed for the MadGraph5 to work well?
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Revision history for this message
Da Liu (liuda) said : 		#2

Thanks Olivier Mattelaer, that solved my question.