Algorithm when pdfwgt == True

Asked by Junho Choi on 2018-07-07

Hi,

I study DrellYan ee process,

p p > e+ e-
p p > e+ e- j
p p > e+ e- j j

.

When I set

True = pdfwgt

in runcard,

ME level xsec values are different between v260 & v261 MG5.

v260 : 3.286e+03 +/- 7.039e+00

v261 : 3.875e+03 +/- 9.902e+00

As far as I know, if the "pdfwgt == True" , ISR is considered to set (x,Q^2). I mean if there's ISR, x, Q scale is changed and the change is considered when pdfwgt == True.

I guess algorithm related to pdfwgt = True is changed between v260 & v261. Is it true?

If you have any unclear thing in my description, please let me know.

Best regards,

Junho Choi

Question information

Language:
English Edit question
Status:
Solved
For:
MadGraph5_aMC@NLO Edit question
Assignee:
No assignee Edit question
Solved by:
Olivier Mattelaer
Solved:
2018-07-12
Last query:
2018-07-12
Last reply:
2018-07-11

Hi,

If you look at the UpdateNotes of 2.6.1 you will see the following:

> OM: Fix a bug in matching/merging forbiding the pdf reweighting for some processes (since 2.4.0)

So this difference is indeed expected and you should discard result from 2.6.0.

Cheers,

Olivier

> On 7 Jul 2018, at 08:13, Junho Choi <email address hidden> wrote:
>
> New question #670715 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/670715
>
> Hi,
>
> I study DrellYan ee process,
>
> p p > e+ e-
> p p > e+ e- j
> p p > e+ e- j j
>
> .
>
> When I set
>
> True = pdfwgt
>
> in runcard,
>
> ME level xsec values are different between v260 & v261 MG5.
>
> v260 : 3.286e+03 +/- 7.039e+00
>
> v261 : 3.875e+03 +/- 9.902e+00
>
>
>
>
> As far as I know, if the "pdfwgt == True" , ISR is considered to set (x,Q^2). I mean if there's ISR, x, Q scale is changed and the change is considered when pdfwgt == True.
>
>
> I guess algorithm related to pdfwgt = True is changed between v260 & v261. Is it true?
>
>
> If you have any unclear thing in my description, please let me know.
>
>
> Best regards,
>
> Junho Choi
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Junho Choi (junhochoi) said : #2

Thanks Olivier Mattelaer, that solved my question.

Junho Choi (junhochoi) said : #3

Thanks!

I should have read the node. Sorry.

Best regards,

Junho