SM is diverging (especilay b and B quarks) at if sqrt{s} is very high

Asked by Yusuf Oğuzhan Günaydın on 2020-08-03

Hi,
in calchep version 3.8.5, my setting is;
SM Model
Process m,p->m,j
j: G,d,D,u,U,c,C,s,S,b,B
In State
S.F: Off
S.F.:cteq6l1(proton)
First Particle Momentum (GeV): 20000
Second Particle Momentum (GeV): 50000
on subprocesses;
m,b->m,b
m,B->m,B
although I applied cuts final state particles, cross-section values are diverging. This problem does not appear if I deal with lower center of mass energies.

Also, when I try to obtain N(m) and N(j) distribution plots with a different version of calchep e.i calchep3.6.25 vs calchep3.8.5, both distributions are inconsistent. That is, distributions are switching each other, which version is giving correct distribution?
 Thanks.

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Launchpad Janitor (janitor) said :
#1

This question was expired because it remained in the 'Open' state without activity for the last 15 days.

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Yusuf Oğuzhan Günaydın (yusufgunaydin) said :
#2

Yes, I still have this problem.
Dr.Yusuf Oğuzhan Günaydın
Kahramanmaras Sutcu Imam University
Faculty of Science and Letters
Department of Physics

> On Aug 19, 2020, at 4:20 PM, Launchpad Janitor <email address hidden> wrote:
>
> Your question #692193 on CalcHEP changed:
> https://answers.launchpad.net/calchep/+question/692193
>
> Status: Open => Expired
>
> Launchpad Janitor expired the question:
> This question was expired because it remained in the 'Open' state
> without activity for the last 15 days.
>
> --
> If you're still having this problem, you can reopen your question either
> by replying to this email or by going to the following page and
> entering more information about your problem:
> https://answers.launchpad.net/calchep/+question/692193
>
> You received this question notification because you asked the question.

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Launchpad Janitor (janitor) said :
#3

This question was expired because it remained in the 'Open' state without activity for the last 15 days.

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Yusuf Oğuzhan Günaydın (yusufgunaydin) said :
#4

I guess that you cannot solve this problem. I think I need to migrate to
other HEP phenomenology simulation softwares. Thank you for your interest!

4 Eyl 2020 Cum 16:05 tarihinde Launchpad Janitor <
<email address hidden>> şunu yazdı:

> Your question #692193 on CalcHEP changed:
> https://answers.launchpad.net/calchep/+question/692193
>
> Status: Open => Expired
>
> Launchpad Janitor expired the question:
> This question was expired because it remained in the 'Open' state
> without activity for the last 15 days.
>
> --
> If you're still having this problem, you can reopen your question either
> by replying to this email or by going to the following page and
> entering more information about your problem:
> https://answers.launchpad.net/calchep/+question/692193
>
> You received this question notification because you asked the question.
>

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Yusuf Oğuzhan Günaydın (yusufgunaydin) said :
#5

Finally, we find out the solution that is PDF we changed cteq6l1 to CT10. Then, diverging in the distribution plot has gone by this choose of PDf.

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Alexander Pukhov (pukhov) said :
#6

Thank you for your mail and  sorry for delayed response.

I tested your point and at  first run indeed have got divergent cross
section.  The only that I  have  managed to understand  is sqrt(s)
distribution was concentrated at M=5170. But after some changes  the
problem disappears and now I can not  see it again in spite of all my
efforts.

I use GUY interface with Pt cut 10GeV.  My answers for steq6l1 and CT10
are    2.44E4 pb  and    2.01E4 pb. The difference looks reasonable.

I'll  make a new attempt  to catch the bug later on.

Best

     Alexander Pukhov

On 03.08.2020 18:45, Yusuf Oğuzhan Günaydın wrote:
> New question #692193 on CalcHEP:
> https://answers.launchpad.net/calchep/+question/692193
>
> Hi,
> in calchep version 3.8.5, my setting is;
> SM Model
> Process m,p->m,j
> j: G,d,D,u,U,c,C,s,S,b,B
> In State
> S.F: Off
> S.F.:cteq6l1(proton)
> First Particle Momentum (GeV): 20000
> Second Particle Momentum (GeV): 50000
> on subprocesses;
> m,b->m,b
> m,B->m,B
> although I applied cuts final state particles, cross-section values are diverging. This problem does not appear if I deal with lower center of mass energies.
>
> Also, when I try to obtain N(m) and N(j) distribution plots with a different version of calchep e.i calchep3.6.25 vs calchep3.8.5, both distributions are inconsistent. That is, distributions are switching each other, which version is giving correct distribution?
> Thanks.
>
>
>
>
>
>
>