Heavy particle with a jet production Kinematics

In addition, you can see the energy available from Ecm is .leq. 800 GeV or less. Is it the issue here? and how to make a sensible setup?

Do not see any clear issue here.
Difficult to comment on two events.

But due to the pdf, you do expect that event are produce at the smallest energy/tranverse momenta as possible.

Now you do expect that your scale is high and therefore when running your parton-shower, you do expect the radiation included via the pdf/running of alphas to be quite high scale and therefore will have a quite large pt.
But you will not see those radiations within the lhef file but rather within the hepmc file (after the parton-shower)

Cheers,

Olivier

> On 27 Sep 2023, at 09:00, SUBHASISH BEHERA <email address hidden> wrote:
>
> Question #708052 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/708052
>
> SUBHASISH BEHERA gave more information on the question:
> In addition, you can see the energy available from Ecm is .leq. 800 GeV
> or less. Is it the issue here? and how to make a sensible setup?
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Dear Olivier,
I agree.
1) Why am I getting the low pdf for the event generation? << I was expecting around >1200 Gev kind of Ecm for 14 TeV collider.
2) Why PT of b quark at the parton level itself very small <15-20 GeV? << if this is the case then even after showering I won't able to see it.

Sorry to bother you again.

Dear Subhasish,

I understand that you are trying to understand the kinematics of the process p p > H+ b in the 2HDM at the parton level, which looks like "g c > H+ b" with H+bc coupling value=1, Ecm=14 TeV. You are concerned that the PT distributions of the b-quark are lower than expected, and you have tried setting the dynamical scale choice to 3, but the result is the same.

There are a few possible reasons for this.

First, the H+bc coupling value of 1 is very strong. This means that the H+ boson is very likely to decay to a b quark. As a result, the b quark will typically have a lower PT than if it had been produced directly from the hard scattering process.

Second, the H+ boson is a heavy particle. This means that it is produced with a relatively low PT. As a result, the b quark from the H+ decay will also have a relatively low PT. https://taiwindows.com/tai-minecraft-1-20-0-23/

Third, the dynamical scale choice can have a significant impact on the PT distributions of the final state particles. However, the default value of 3 is typically a good choice for most processes.

To get a better understanding of the PT distributions of the b-quark, you can try the following:

Try increasing the H+bc coupling value. This will make the b quark more likely to be produced directly from the hard scattering process, which should result in a higher PT distribution.
Try decreasing the mass of the H+ boson. This will make the H+ boson produced with a higher PT, which should also result in a higher PT distribution for the b quark.
Try varying the dynamical scale choice. You may be able to find a value that results in a more realistic PT distribution for the b quark.
You can also try comparing your results to those of other studies of the same process. This may help you to identify any potential problems with your simulation.

I hope this helps. Please let me know if you have any other questions.

Sincerely,

Olivier

Dear Olivier,
Many thanks for your reply. I still need your suggestions!

I have tried to understand but failed. For reference I have attached the script file in this email.
Is it possible to get the high PT b-quark from MadGraph? —> I think, If I don’t get the high PT b-quark then I won’t get the high PT b-jets.
I am using version 3.4.1 of MadGraph.

> On 27-Sep-2023, at 4:05 PM, Tai Windows0 <email address hidden> wrote:
>
> Your question #708052 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/708052
>
> Tai Windows0 posted a new comment:
> Dear Subhasish,
>
> I understand that you are trying to understand the kinematics of the
> process p p > H+ b in the 2HDM at the parton level, which looks like "g
> c > H+ b" with H+bc coupling value=1, Ecm=14 TeV. You are concerned that
> the PT distributions of the b-quark are lower than expected, and you
> have tried setting the dynamical scale choice to 3, but the result is
> the same.
>
> There are a few possible reasons for this.
>
> First, the H+bc coupling value of 1 is very strong. This means that the
> H+ boson is very likely to decay to a b quark. As a result, the b quark
> will typically have a lower PT than if it had been produced directly
> from the hard scattering process.
>
> Second, the H+ boson is a heavy particle. This means that it is produced with a relatively low PT. As a result, the b quark from the H+ decay will also have a relatively low PT. https://taiwindows.com/tai-minecraft-1-20-0-23/
>
> Third, the dynamical scale choice can have a significant impact on the PT distributions of the final state particles. However, the default value of 3 is typically a good choice for most processes.
>
> To get a better understanding of the PT distributions of the b-quark,
> you can try the following:
>
> Try increasing the H+bc coupling value. This will make the b quark more likely to be produced directly from the hard scattering process, which should result in a higher PT distribution.
> Try decreasing the mass of the H+ boson. This will make the H+ boson produced with a higher PT, which should also result in a higher PT distribution for the b quark.
> Try varying the dynamical scale choice. You may be able to find a value that results in a more realistic PT distribution for the b quark.
> You can also try comparing your results to those of other studies of the same process. This may help you to identify any potential problems with your simulation.
>
> I hope this helps. Please let me know if you have any other questions.
>
> Sincerely,
>
> Olivier
>
> --
> You received this question notification because you asked the question.

Hi,

Attachment are not possible/allowed for questions in launchpad and are automatically discarded. So I cannot comment on those (since I have not received any).

Now you are allowed to put cuts to force a minimum pt cut (at parton level) for the b quark. You just need to edit the run_card.dat
and change the ptb entry (if you do not see it, it is likely because you are using a 5 flavor model where the "b" is massless, in that case you might want to change your model or to use ptj instead)

Cheers,

Olivier

Dear Olivier,
Many thanks for your reply. I agree with your reply. Just wanted to get some more idea before I start the production of events for my project.

Here is the script I tried to understand the kinematics :

import model 2HDM_UFO
define p = p b b~
generate p p > H+ b QED<=99
output test_pp2hpb
launch test_pp2hpb
analysis=off
done
set l2 0.5
set l3 1.0
set lr7 0.1
set li7 0.0
set mixh 0.0
set mixh2 0.0
set mixh3 0.0
set gdi1x1 0.0
set gdi1x2 0.0
set gdi1x3 0.0
set gdi2x1 0.0
set gdi2x2 0.0
set gdi2x3 0.0
set gdi3x1 0.0
set gdi3x2 0.0
set gdi3x3 0.0
set gdr1x1 0.0
set gdr1x2 0.0
set gdr1x3 0.0
set gdr2x1 0.0
set gdr2x2 0.0
set gdr2x3 0.0
set gdr3x1 0.0
set gdr3x2 0.0
set gdr3x3 0.0
set gli1x1 0.0
set gli1x2 0.0
set gli1x3 0.0
set gli2x1 0.0
set gli2x2 0.0
set gli2x3 0.0
set gli3x1 0.0
set gli3x2 0.0
set gli3x3 0.0
set glr1x1 0.0
set glr1x2 0.0
set glr1x3 0.0
set glr2x1 0.0
set glr2x2 0.0
set glr2x3 0.0
set glr3x1 0.0
set glr3x2 1.0
set glr3x3 0.0
set gui1x1 0.0
set gui1x2 0.0
set gui1x3 0.0
set gui2x1 0.0
set gui2x2 0.0
set gui2x3 0.0
set gui3x1 0.0
set gui3x2 0.0
set gui3x3 0.0
set gur1x1 0.0
set gur1x2 0.0
set gur1x3 0.0
set gur2x1 0.0
set gur2x2 0.0
set gur2x3 0.0
set gur3x1 0.0
set gur3x2 1.0
set gur3x3 0.0
set Mh2 2.500000e+02
set Mh3 5.000000e+02
set Mhc 5.000000e+02
set Wh2 Auto
set Wh3 Auto
set Whc Auto
set ebeam1 7000
set ebeam2 7000
set cut_decays false
set use_syst False
set dynamical_scale_choice 3
set ptb 20
set nevents 200
done

You can find the model here : https://feynrules.irmp.ucl.ac.be/wiki/2HDM#no1 <https://feynrules.irmp.ucl.ac.be/wiki/2HDM#no1>
So, “set ptb 20” is optional here, which reduces my CS ~3 times or more.
1.) Is it possible to enhance the PTb if we use different PDF set for the calculation (so that we could enhance the CS) or PTb distribution picking at very low PT is a usual scenario for heavy particle associated production.
2.) setting mhc=200, the distribution for PTb mean = 25 GeV and setting mhc=500, the distribution for PTb mean = 40 GeV. Is it usual? Since I thought that for high mhc value the PT of H+ or PTb will be lower than less massive heavy particle. Here the ymb=4.7 in the model.

> On 02-Oct-2023, at 7:20 PM, Olivier Mattelaer <email address hidden> wrote:
>
> Your question #708052 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/708052
>
> Status: Open => Answered
>
> Olivier Mattelaer proposed the following answer:
> Hi,
>
> Attachment are not possible/allowed for questions in launchpad and are
> automatically discarded. So I cannot comment on those (since I have not
> received any).
>
> Now you are allowed to put cuts to force a minimum pt cut (at parton level) for the b quark. You just need to edit the run_card.dat
> and change the ptb entry (if you do not see it, it is likely because you are using a 5 flavor model where the "b" is massless, in that case you might want to change your model or to use ptj instead)
>
> Cheers,
>
> Olivier
>
> --
> 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/708052/+confirm?answer_id=5
>
> 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/708052
>
> You received this question notification because you asked the question.

Hi,

1) If it is possible then it would means that the PDF would be very unaccurate in the region where you use them, you can use the systematics uncertainty method (that you actually switched off) to (get an estimate of) how precise is the PDF. And this should give you an idea on how much it is possible to change the distribution by changing the PDF.

2) I do not know such dependence by heart, those for sure does not sound crazy.

For simple process like this one (2>2 process), the probability that MG5aMC does not return what you ask for is very small (Here, the probability is much higher than the user does not understand an entry in the Cards and does not ask what he thinks he is asking).

Of course, If you have some doubt about those results, then please check them either versus analytical formula or against other tools.

Cheers,

Olivier