No lhe file output

Asked by Anton Stepennov on 2018-11-01

Dear experts,

When I'm trying to generate some process with fixed order e.g.
generate p p > Z c [QCD]
output Zc_NLO
launch Zc_NLO NLO

there is no lhe file in output Events directory, only banner and some logs, the same is for LO. But when I don't specify the order ,

generate p p > Z c [QCD]
output Zc
launch Zc

everything is fine , and in the end in Events directory there is lhe file with events.

I couldn't find any information in documentation, whether in fixed order generating there shouldn't be any lhe file output.
Does one have to specify, that there should be lhe file , while using fixed order ?

thank you,
Anton

Question information

Language:
English Edit question
Status:
Solved
For:
MadGraph5_aMC@NLO Edit question
Assignee:
No assignee Edit question
Solved by:
Olivier Mattelaer
Solved:
2018-11-01
Last query:
2018-11-01
Last reply:
2018-11-01

Hi,

This is the correct behaviour since you can not generated un-weighted events at fix-order.
(and that such events would be not compatible with ANY parton-shower)

For such type of generation, you are expected to write your analysis (we have various format for that) and generate your plot right away. You need to define which analysis to use in the FO_analyse_card.dat

This being said it is also possible to ask MG5aMC to generate some WEIGHTED lhe file (version 2 of the convention: including couter-events). For that you have to set in the FO_analysie_card file the parameter:
FO_ANALYSIS_FORMAT to LHE

Cheers,

Olivier

PS: Note that this is a LHE file version 2 (that version allow event file for fix order).
Note that such convention, implies you can not apply cut/ decay event/... independently for event and counter-event.

> On 1 Nov 2018, at 20:07, Anton Stepennov <email address hidden> wrote:
>
> New question #675857 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/675857
>
> Dear experts,
>
> When I'm trying to generate some process with fixed order e.g.
> generate p p > Z c [QCD]
> output Zc_NLO
> launch Zc_NLO NLO
>
> there is no lhe file in output Events directory, only banner and some logs, the same is for LO. But when I don't specify the order ,
>
> generate p p > Z c [QCD]
> output Zc
> launch Zc
>
> everything is fine , and in the end in Events directory there is lhe file with events.
>
> I couldn't find any information in documentation, whether in fixed order generating there shouldn't be any lhe file output.
> Does one have to specify, that there should be lhe file , while using fixed order ?
>
> thank you,
> Anton
>
>
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Thanks Olivier Mattelaer, that solved my question.