Key error when trying to run photo production at NLO

[James Howarth]

I am trying to simulate photo-produced ttbar at NLO in QCD using loop_sm, with the command:

> generate p a > t t~ [QCD]

and setting beam two to type 2 (lpp2 = 2). The process compiles but as it starts to run I get the error:

> Command "launch auto " interrupted with error:
> KeyError : 2

Is it possible to run this process at NLO with the photon coming from the beam? If I use both beams with beam type 1 (i.e. getting the photon from the PDF) then it runs fine. I can also run photo production at LO in QCD without any problems, it only seems to fail at NLO.

Any help (or clarification on if what I'm trying to do is possible) would be appreciated.

Cheers,

Jay

[Rikkert Frederix (frederix)]

Dear Jay,

Indeed, for NLO running only colliders with fixed s-hat (like lepton-lepton collisions) or collisions that require PDFs for both incoming particles (your typical proton-proton collisions) are supported.

best,
Rikkert

[James Howarth (jhowarth)]

Dear Rikkert,

Okay thanks, then this is clear and not a bug. Thanks for the clarification.

Cheers,

Jay

[Olivier Mattelaer (olivier-mattelaer)]

Hi Rik,

Just want to ask a question on this topic:

I guess that handling p a would not be trivial (with elastic photon).
But am I correct to say that including a a > t t~ [QCD] with elastic photon should be quite simple?

Cheers,

Olivier

> On 26 Feb 2018, at 14:19, James Howarth <email address hidden> wrote:
>
> Dear Rikkert,
>
> Okay thanks, then this is clear and not a bug. Thanks for the
> clarification.
>
> Cheers,
>
> Jay
>
> --
> You received this bug notification because you are subscribed to
> MadGraph5_aMC@NLO.
> https://bugs.launchpad.net/bugs/1751761
>
> Title:
> Key error when trying to run photo production at NLO
>
> Status in MadGraph5_aMC@NLO:
> New
>
> Bug description:
> I am trying to simulate photo-produced ttbar at NLO in QCD using
> loop_sm, with the command:
>
>> generate p a > t t~ [QCD]
>
> and setting beam two to type 2 (lpp2 = 2). The process compiles but as
> it starts to run I get the error:
>
>> Command "launch auto " interrupted with error:
>> KeyError : 2
>
> Is it possible to run this process at NLO with the photon coming from
> the beam? If I use both beams with beam type 1 (i.e. getting the
> photon from the PDF) then it runs fine. I can also run photo
> production at LO in QCD without any problems, it only seems to fail at
> NLO.
>
> Any help (or clarification on if what I'm trying to do is possible)
> would be appreciated.
>
> Cheers,
>
> Jay
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/mg5amcnlo/+bug/1751761/+subscriptions

[Rikkert Frederix (frederix)]

Hi Olivier,

Yeah, I think you are right. That should not be too complicated.

Cheers,
Rik