Unable to apply cuts in NLO

Asked by Jhuma Ghosh on 2018-10-11

Hi,
I am trying to generate p p > b b~ g [QCD] with madspin off.
But, when I am looking into the run card, there is no option to put a Pt and eta cut on b and b bar.
I tried to add set etabmin 2.5 on the shell and added it to the run card also. But, it is not taking any cut on b or b bar.

But, in LO it is possible to apply. Am I missing something?

Thanks in advance.

Question information

Language:
English Edit question
Status:
Expired
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MadGraph5_aMC@NLO Edit question
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Last query:
2018-10-23
Last reply:
2018-11-08

Hi,

1) your syntax "p p > b b~ g [QCD] " does not make sense for a NLO computation.
You should not use "g" in the final state with [QCD]
As stated in the following warning:

> WARNING: Process: g/u/c/d/s/u~/c~/d~/s~ g/u/c/d/s/u~/c~/d~/s~ > b b~ g WEIGHTED=3 [ all = QCD ] can have real emission processes which are not finite.
> To avoid this, please use multiparticles when generating the process and be sure to include all the following particles in the multiparticle definition:
> g, c, s, u, d, d~, u~, s~, c~

You should rather use "p p > b b~ j [QCD]"

2) Cut at NLO are more complicated than LO cut since they need to be infra-red save.
So indeed the list of cut that you can use at NLO is not the same as the one of LO.

Now you can put pt cut on the b via the command
set pt_min_cut {5:10}

Such command does not exists for the rapidity.

Cheers,

Olivier

> On 11 Oct 2018, at 13:57, Jhuma Ghosh <email address hidden> wrote:
>
> New question #675034 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/675034
>
> Hi,
> I am trying to generate p p > b b~ g [QCD] with madspin off.
> But, when I am looking into the run card, there is no option to put a Pt and eta cut on b and b bar.
> I tried to add set etabmin 2.5 on the shell and added it to the run card also. But, it is not taking any cut on b or b bar.
>
> But, in LO it is possible to apply. Am I missing something?
>
>
>
> Thanks in advance.
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Jhuma Ghosh (jhuma) said : #2

Hi,

Sorry for my delay in reply. Thank you for your answers. They helped me a
lot.
As I need rapidity cut, I will try to apply them using Pythia.

Best regards,

Jhuma Ghosh

On Thu, Oct 11, 2018 at 6:16 PM Olivier Mattelaer <
<email address hidden>> wrote:

> Your question #675034 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/675034
>
> Status: Open => Answered
>
> Olivier Mattelaer proposed the following answer:
> Hi,
>
> 1) your syntax "p p > b b~ g [QCD] " does not make sense for a NLO
> computation.
> You should not use "g" in the final state with [QCD]
> As stated in the following warning:
>
> > WARNING: Process: g/u/c/d/s/u~/c~/d~/s~ g/u/c/d/s/u~/c~/d~/s~ > b b~ g
> WEIGHTED=3 [ all = QCD ] can have real emission processes which are not
> finite.
> > To avoid this, please use multiparticles when generating the process and
> be sure to include all the following particles in the multiparticle
> definition:
> > g, c, s, u, d, d~, u~, s~, c~
>
> You should rather use "p p > b b~ j [QCD]"
>
> 2) Cut at NLO are more complicated than LO cut since they need to be
> infra-red save.
> So indeed the list of cut that you can use at NLO is not the same as the
> one of LO.
>
> Now you can put pt cut on the b via the command
> set pt_min_cut {5:10}
>
> Such command does not exists for the rapidity.
>
> Cheers,
>
> Olivier
>
>
> > On 11 Oct 2018, at 13:57, Jhuma Ghosh <
> <email address hidden>> wrote:
> >
> > New question #675034 on MadGraph5_aMC@NLO:
> > https://answers.launchpad.net/mg5amcnlo/+question/675034
> >
> > Hi,
> > I am trying to generate p p > b b~ g [QCD] with madspin off.
> > But, when I am looking into the run card, there is no option to put a Pt
> and eta cut on b and b bar.
> > I tried to add set etabmin 2.5 on the shell and added it to the run card
> also. But, it is not taking any cut on b or b bar.
> >
> > But, in LO it is possible to apply. Am I missing something?
> >
> >
> >
> > Thanks in advance.
> >
> > --
> > You received this question notification because you are an answer
> > contact for MadGraph5_aMC@NLO.
>
> --
> If this answers your question, please go to the following page to let us
> know that it is solved:
>
> https://answers.launchpad.net/mg5amcnlo/+question/675034/+confirm?answer_id=0
>
> If you still need help, you can reply to this email or go to the
> following page to enter your feedback:
> https://answers.launchpad.net/mg5amcnlo/+question/675034
>
> You received this question notification because you asked the question.
>

Launchpad Janitor (janitor) said : #3

This question was expired because it remained in the 'Open' state without activity for the last 15 days.