Can we use initial radiation particle to generate process?

Asked by Li on 2017-11-06

Hi,

For a process like wb > th, can I generate this process in Madgraph like " generate w+ b > t h" ? ( this gives me zero result after launch.)

The w is the initial radiation particle.

Best,
Li

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2017-11-06
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2017-11-07

Hi,

Did you set the PDF to None (lpp=0) in that case?
Looks like the default for that process is lpp1=lpp2=1 which means PDF from proton which are zero.

Cheers,

Olivier

> On Nov 6, 2017, at 07:23, Li <email address hidden> wrote:
>
> New question #660388 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/660388
>
> Hi,
>
> For a process like wb > th, can I generate this process in Madgraph like " generate w+ b > t h" ? ( this gives me zero result after launch.)
>
> The w is the initial radiation particle.
>
> Best,
> Li
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Li (huangli-itp) said : #2

Hi Olivier,

    Set lpp=0 works. It calculated the cross section. But I guess this is not the "real" cross section from p radiate a w and wb->th in pp collider? Is there any way to ask MadGraph do the radiation and use the radiation particle to react?

Best,
Li

Hi,

No we do not have that built-in.

My first question here is how do you compute that?
Do you have an analytic formula for the “PDF” of the photon (like for the elastic photon?)
or are you using some special pdf for that?

In both case, it should be possible to hack MG5 to accommodate it (but you are likely to meet efficiency problem with the phase-space integrator which are not trivial to solve)

Cheers,

Olivier

> On Nov 6, 2017, at 15:57, Li <email address hidden> wrote:
>
> Question #660388 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/660388
>
> Status: Answered => Open
>
> Li is still having a problem:
> Hi Olivier,
>
> Set lpp=0 works. It calculated the cross section. But I guess this
> is not the "real" cross section from p radiate a w and wb->th in pp
> collider? Is there any way to ask MadGraph do the radiation and use the
> radiation particle to react?
>
> Best,
> Li
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

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