electron proton collision

Hi,

I'm not an expert in this type of physics, Is this an deep inelastic collision?
or is it in the elastic regime?

In any case such type of computation can not be done at NLO accuracy.
Note our default model neglect the electron mass.
So if you want to keep the electron mass effect (I guess it makes sense for your process)
you need to change the model and therefore use the sm-full model

If you are in the deep inelastic mode you should similate it with a script like this

import model sm-full
define p = p a # maybe ?
generate p e- > e- j
output
launch
set lpp1 1 # pdf from lhapdf (or internal)
set lpp2 0
set pdlabel lhapdf
set lhaid XXXX

In this case, you need to be very carefull about the photon contribution since the physical content of the photon is not the same for all pdf set (some exclude the elastic contribution while some other include it)

And in the elastic mode, you should use

generate a e- > e- a
output
launch
set lpp1 2 # elastic photon from a proton
set lpp2 0

In both case, you might need to worry to the scale choice, especially since by default they are a cut if the dynamical scale is assigned lower than 2 GeV. So it is probably needed to pass to a fix scale choice
set fixed_scale YYY

Finally you need to be carefull with the default cut that might be by default too strong for your process ( In the massless case, you need for sure cuts in the final case, I'm not 100% sure for the massive case)

Now I have never run such type of computation myself. I have a student starting to look in this direction but we do not have yet started the above process.

Cheers,

Olivier

> On 9 Aug 2021, at 17:40, wilds9 <email address hidden> wrote:
>
> New question #698304 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/698304
>
> Dear MadGraph experts,
>
> I am a novice. I want to calculate the momentum transport cross section of low-energy (keV ~ MeV) electrons scattered by protons. I am not sure whether MadGraph5_aMC@NLO can simulate such low energy electrons. How can I learn? Are there similar examples?
>
> Best regards,
> wilds9
>
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Hi Olivier,

    Thank you so much for answering my doubts patiently.

Really thanks!
wilds9