Using MadSpin to decay NLO process events

Asked by teddym on 2018-09-18

Hi:
   I use a NLO version of GM model to produce events as:

generate p p > H5p H5p~ [ all= QCD]
==========
After I generate the events using all default setting, I decay events using madspin with

decay H5p > w+ a
decay H5p~ > w- a

and other default setting.
However it generate following errors:

INFO: generating the production square matrix element
INFO: generate p p > H5p H5p~ --no_warning=duplicate;define pert_QCD = ;add process p p > H5p H5p~ pert_QCD --no_warning=duplicate;
Command "decay_events " interrupted with error:
InvalidCmd : "define" command requires at least one particles name after "="

But if I use
set spinmode none

then there is no further problems.

So is that mean I must use spinmode none ?

Best
ycwu

Question information

Language:
English Edit question
Status:
Solved
For:
MadGraph5_aMC@NLO Edit question
Assignee:
No assignee Edit question
Solved by:
Olivier Mattelaer
Solved:
2018-09-18
Last query:
2018-09-18
Last reply:
2018-09-18

Hi,

This seems to be a problem related to your model.
MadSpin fails to determine the list of massless QCD particles for your model.
Would you be able to tell me the name of your model (if this is one available on the FR website)
or give me a way to download it?

> So is that mean I must use spinmode none ?

Well if your H5p has a very small width, then this is a good option otherwise i would not advise it.

Cheers,

Olivier

> On 18 Sep 2018, at 02:22, teddym <email address hidden> wrote:
>
> New question #674072 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/674072
>
> Hi:
> I use a NLO version of GM model to produce events as:
>
> generate p p > H5p H5p~ [ all= QCD]
> ==========
> After I generate the events using all default setting, I decay events using madspin with
>
> decay H5p > w+ a
> decay H5p~ > w- a
>
> and other default setting.
> However it generate following errors:
>
> INFO: generating the production square matrix element
> INFO: generate p p > H5p H5p~ --no_warning=duplicate;define pert_QCD = ;add process p p > H5p H5p~ pert_QCD --no_warning=duplicate;
> Command "decay_events " interrupted with error:
> InvalidCmd : "define" command requires at least one particles name after "="
>
> But if I use
> set spinmode none
>
> then there is no further problems.
>
> So is that mean I must use spinmode none ?
>
> Best
> ycwu
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

teddym (niepanchongsheng) said : #2

Hi Olivier:

>>This seems to be a problem related to your model.
>>MadSpin fails to determine the list of massless QCD particles for your model.

Does this means that I should directly set the mass of light quarks to be zero in the FeynRule ? Or I can also use a restrict file when I load the model files in MG5?

The model files are not available right now. We plan to upload it to FR website, but before that we want to check that it has no problem running with MG5.

However, this problem reproduced when I use loop_sm model in MG5 with all default settings.
>>>>>>>>>>>>>>>>>>>>>>>>>.
INFO: generating the production square matrix element
INFO: generate p p > t t~ --no_warning=duplicate;define pert_QCD = ;add process p p > t t~ pert_QCD --no_warning=duplicate;
Command "launch auto " interrupted with error:
InvalidCmd : "define" command requires at least one particles name after "="
<<<<<<<<<<<<<<<<<<<<<<<<

Am I doing something wrong?

Best
ycwu

Hi,

Indeed I was able to reproduce the problem with the SM.
The problem is that the syntax [all=...] is not supported by MadSpin,
just use [QCD] instead of [all=QCD] and this will work.

Cheers,

Olivier

> On 18 Sep 2018, at 15:37, teddym <email address hidden> wrote:
>
> Question #674072 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/674072
>
> Status: Answered => Open
>
> teddym is still having a problem:
> Hi Olivier:
>
>>> This seems to be a problem related to your model.
>>> MadSpin fails to determine the list of massless QCD particles for your model.
>
> Does this means that I should directly set the mass of light quarks to
> be zero in the FeynRule ? Or I can also use a restrict file when I load
> the model files in MG5?
>
> The model files are not available right now. We plan to upload it to FR
> website, but before that we want to check that it has no problem running
> with MG5.
>
> However, this problem reproduced when I use loop_sm model in MG5 with all default settings.
>>>>>>>>>>>>>>>>>>>>>>>>>> .
> INFO: generating the production square matrix element
> INFO: generate p p > t t~ --no_warning=duplicate;define pert_QCD = ;add process p p > t t~ pert_QCD --no_warning=duplicate;
> Command "launch auto " interrupted with error:
> InvalidCmd : "define" command requires at least one particles name after "="
> <<<<<<<<<<<<<<<<<<<<<<<<
>
> Am I doing something wrong?
>
> Best
> ycwu
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

teddym (niepanchongsheng) said : #4

Hi Olivier:
   Thanks so much. That solves my problems!

Best
Yongcheng

teddym (niepanchongsheng) said : #5

Thanks Olivier Mattelaer, that solved my question.

I have pushed a fix in the development version, the problem was not the "all=" but the presence of a space after the equal that was preventing MadSpin to react accordingly.

Cheers,

Olivier

> On 18 Sep 2018, at 16:01, Olivier Mattelaer <email address hidden> wrote:
>
> Hi,
>
> Indeed I was able to reproduce the problem with the SM.
> The problem is that the syntax [all=...] is not supported by MadSpin,
> just use [QCD] instead of [all=QCD] and this will work.
>
> Cheers,
>
> Olivier
>
>> On 18 Sep 2018, at 15:37, teddym <email address hidden> wrote:
>>
>> Question #674072 on MadGraph5_aMC@NLO changed:
>> https://answers.launchpad.net/mg5amcnlo/+question/674072
>>
>> Status: Answered => Open
>>
>> teddym is still having a problem:
>> Hi Olivier:
>>
>>>> This seems to be a problem related to your model.
>>>> MadSpin fails to determine the list of massless QCD particles for your model.
>>
>> Does this means that I should directly set the mass of light quarks to
>> be zero in the FeynRule ? Or I can also use a restrict file when I load
>> the model files in MG5?
>>
>> The model files are not available right now. We plan to upload it to FR
>> website, but before that we want to check that it has no problem running
>> with MG5.
>>
>> However, this problem reproduced when I use loop_sm model in MG5 with all default settings.
>>>>>>>>>>>>>>>>>>>>>>>>>>> .
>> INFO: generating the production square matrix element
>> INFO: generate p p > t t~ --no_warning=duplicate;define pert_QCD = ;add process p p > t t~ pert_QCD --no_warning=duplicate;
>> Command "launch auto " interrupted with error:
>> InvalidCmd : "define" command requires at least one particles name after "="
>> <<<<<<<<<<<<<<<<<<<<<<<<
>>
>> Am I doing something wrong?
>>
>> Best
>> ycwu
>>
>> --
>> You received this question notification because you are an answer
>> contact for MadGraph5_aMC@NLO.
>