MadGraph5_aMC@NLO

Im Trying to implement new particles in a event using pythia8 build in, yet im not able to change settings for my particle in the particle data table from pythia8

Asked by Jonathan Sanchez

Hi!

Im implementing long-lived particles BSM for a mc simulation. So far, I managed to correctly include the UFO-model for my particles, calculate widths and past the decay channels to pythia8. However, I want to actively configure the settings for my decay in the Particle data of pythia8 but I cant figure it out how. Specifically, I refer to changes in decay settings of pythia such as ("BSMpdg:mayDecay = off", or "BSMpdg:isResonance = off", or "BSMpdg:isVisible = off". So far, I figured out that you can do this changes with sm particles using the "pythia8_card" with no problem; yet since new particles id and Qnumbers are not written before "param_card" reading, all my attempts result in error because there is no such a particle registered in pythia. I hope you can help me to surpass this problem.
**************************************************************
Error obtained in the log for pythia8:
PYTHIA Error: input particle not found in Particle Data Table:
   556:isVisible=off
**************************************************************
I'm actually working with madgraph build in my personal pc and also in a CMSSW container with pythia8Simulations using LHE and SLHA files that i understand uses a similar pythia8 interface as the one implemented in madgraph

Thanks in advance,
Jonathan

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Olivier Mattelaer (olivier-mattelaer) said : 		#1

If you have the same issue in CMSSW, then it would make more sense to ask Pythia8 author. Since then the issue is likely on their side since CMSSW does not use the MG5aMC interface.

Cheers,

Olivier

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Jonathan Sanchez (jonajjsj95) said : 		#2

Hi Oliver!

Thanks for your answer. I had already deliver my issue to Pythia devs.
Besides the part involving cmssw, since I'm running mc simulations with Madgraph/pythia8 interface I Mus Insist if there is any way that allows me to modify my particles using Pythia _ard, or in another way if there is one.

Cheers,
Jonathan

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Olivier Mattelaer (olivier-mattelaer) said : 		#3

If this is a pythia8 issue, then nothing that I can do.
The only source of issue that we can have within MG5aMC is an ordering issue since we do modify the pythia8_card that you provide in order to customize add information. If your issue is due to an ordering issue bwtween the different pythia8 statement then this is likely a MG5aMC issue. But then I would not expect such issue in cmssw...

Cheers,

Olivier

> On 26 Jul 2021, at 16:01, Jonathan Sanchez <email address hidden> wrote:
>
> Question #698145 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/698145
>
> Status: Answered => Open
>
> Jonathan Sanchez is still having a problem:
> Hi Oliver!
>
> Thanks for your answer. I had already deliver my issue to Pythia devs.
> Besides the part involving cmssw, since I'm running mc simulations with Madgraph/pythia8 interface I Mus Insist if there is any way that allows me to modify my particles using Pythia _ard, or in another way if there is one.
>
> Cheers,
> Jonathan
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

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