Nuclear PDF in LHAPDF

Asked by Xiaojun Yao on 2017-10-27

In LHAPDF, there are some nuclear PDF's. For example, the EPS Pb one. The LHAPDF ID is 901300. But when I set the ID to be this number. The Madgraph system reports error. Does Madgraph support nuclear PDF in LHAPDF ? Will it support?

Cheers,
Xiaojun

Question information

Language:
English Edit question
Status:
Solved
For:
MadGraph5_aMC@NLO Edit question
Assignee:
No assignee Edit question
Solved by:
Olivier Mattelaer
Solved:
2017-10-27
Last query:
2017-10-27
Last reply:
2017-10-27

HI,

Like this i do not see any reason why it should crash.
Can you be more specific about the crash?

Cheers,

Olivier
> On Oct 27, 2017, at 21:03, Xiaojun Yao <email address hidden> wrote:
>
> New question #660059 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/660059
>
> In LHAPDF, there are some nuclear PDF's. For example, the EPS Pb one. The LHAPDF ID is 901300. But when I set the ID to be this number. The Madgraph system reports error. Does Madgraph support nuclear PDF in LHAPDF ? Will it support?
>
> Cheers,
> Xiaojun
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Xiaojun Yao (colo4k) said : #2

Thank you for your response Olivier. Here is the error:

MadGraph5Error : lhaid 901300 not valid input number for the current lhapdf

The ID number is what I got from the LHAPDF website: https://lhapdf.hepforge.org/pdfsets.html

Hi,

This sounds to be a pure lhapdf issue.
This pdf is not present inside the PDFsets.index
So you need to check which version of lhapdf you are using since it is likely to be a too old one for that set to be included.
(Note that we do not have full support for lhapdf6.2 so far)

Cheers,

Olivier

> On Oct 27, 2017, at 21:53, Xiaojun Yao <email address hidden> wrote:
>
> Question #660059 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/660059
>
> Status: Answered => Open
>
> Xiaojun Yao is still having a problem:
> Thank you for your response Olivier. Here is the error:
>
> MadGraph5Error : lhaid 901300 not valid input number for the current
> lhapdf
>
> The ID number is what I got from the LHAPDF website:
> https://lhapdf.hepforge.org/pdfsets.html
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Xiaojun Yao (colo4k) said : #4

It is inside the PDFsets of lhapdf6.1, which is the version Madgraph is using. I checked that the ID is the same as in version 6.2: https://www.hepforge.org/archive/lhapdf/pdfsets/6.1/pdfsets.index
My lhapdf version is 6.2. It has the same pdf set with the same pdfID.

I have successfully used this PDF set from lhapdf in FONLL. So can you tell me how to fix the problem in Madgraph? Say download the pdf set myself and add a path to where?

Hi,

My advise is to edit the file pdfsets.index from your lhapdf to add the line associate to that set.
And to download the set manually.
I hope that it will be enough but I’m not an lhapdf expert to know all the details here.

Cheers,

Olivier

> On Oct 27, 2017, at 22:32, Xiaojun Yao <email address hidden> wrote:
>
> Question #660059 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/660059
>
> Status: Answered => Open
>
> Xiaojun Yao is still having a problem:
> It is inside the PDFsets of lhapdf6.1, which is the version Madgraph is using. I checked that the ID is the same as in version 6.2: https://www.hepforge.org/archive/lhapdf/pdfsets/6.1/pdfsets.index
> My lhapdf version is 6.2. It has the same pdf set with the same pdfID.
>
> I have successfully used this PDF set from lhapdf in FONLL. So can you
> tell me how to fix the problem in Madgraph? Say download the pdf set
> myself and add a path to where?
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Xiaojun Yao (colo4k) said : #6

Adding the pdfID in the pdfsets.index works!
Thanks!

Xiaojun Yao (colo4k) said : #7

Thanks Olivier Mattelaer, that solved my question.

Xiaojun Yao (colo4k) said : #8

I want to make a final comment and hope it will be useful to others. In my .local directory where PDF sets are downloaded and linked, the pdfsets.index file is not exactly the same as that in the LHAPDF directory. That is why the problem above happens.