gluon fusion and quark-quark annihilation

Hi,

I would suggest to check that you indeed have the interaction in your model
For this you can type
display interactions u u~ NewParticle

if it is then you can try
generate p p > NewParticle QED<=99

Cheers,

Olivier

> On Feb 1, 2016, at 18:07, Keyhan <email address hidden> wrote:
>
> New question #284304 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/284304
>
> Hello,
>
> I have a model in which there are two ways for a new particle production.
> One is via gluon fusion (by adding an effective operator) and the other
> one is through quark anti-quark annihilation.
>
> When I run p p > "New Particle", I see that only through gluon fusion the production takes place!
> I played some with the "InteractionOrder" option, but I think I do still something wrong not to get what I expect.
>
> I would appreciate any hints.
> Best regards,
> Keyhan
>
>
>
>
>
>
>
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Hi Olivier,
Thanks a lot for the reply. The option "QED<=99" worked out.
However, another problem arises when I run for a process like

generate p p > h NP , h > a a QED<=99 (where h=Higgs decays effectively into a photon pair. NP = New Particle),

where, again I see that the above process undergoes only via gluon fusion while I expect it to undergo via quark anti-quark annihilation as well.

On the other hand, when I run like

generate p p > h NP QED<=99 ,

I realize that the above process takes place through both gluon fusion and quark anti-quark annihilation !

Would appreciate any further hints,

Best ,
Keyhan

Hi,

This is because the coupling restriction are specific to each piece for the decay process.
So the correct syntax is in that case:
> generate p p > h NP QED<=99, h > a a

Cheers,

Olivier

> On Feb 1, 2016, at 23:22, Keyhan <email address hidden> wrote:
>
> Question #284304 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/284304
>
> Status: Answered => Open
>
> Keyhan is still having a problem:
> Hi Olivier,
> Thanks a lot for the reply. The option "QED<=99" worked out.
> However, another problem arises when I run for a process like
>
> generate p p > h NP , h > a a QED<=99 (where h=Higgs decays
> effectively into a photon pair. NP = New Particle),
>
> where, again I see that the above process undergoes only via gluon
> fusion while I expect it to undergo via quark anti-quark annihilation as
> well.
>
> On the other hand, when I run like
>
> generate p p > h NP QED<=99 ,
>
> I realize that the above process takes place through both gluon fusion
> and quark anti-quark annihilation !
>
> Would appreciate any further hints,
>
> Best ,
> Keyhan
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Hi, thanks a lot for the help.
Best, Karim