MadGraph5_aMC@NLO

tau lepton simulation in madgraph and delphes

Asked by han

Hi,

In madgraph5, I generated the process using the following command line
generate p p > z > ta+ ta-.
output
launch

For the switches determine which programs are run, I choose
1 Run the pythia shower/hadronization:
3 Run Delphes as detector simulator:

For the default pythia-pgs of madgraph5, we only use pythia to shower/hadronization, not use the PGS. Instead, I
use the delphes to perform the detector simulation of tau lepton. How should I edit the default cards or modify codes in order to perform the detector simulation of tau lepton using delphes. (tau width is 0 in the default param_card, how to deal with it)

Thanks.

Best

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MadGraph5_aMC@NLO Edit question
Assignee:
Kentarou Mawatari Edit question
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Kentarou Mawatari
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Kentarou Mawatari (kentarou-mawatari) said : 		#1

The pythia interface in MG5 uses TAUOLA for tau decays.
So, after shower/hadronization by pythia, all the taus are decayed.

Kentarou

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han (xfhan) said : 		#2

Dear Kentarou，
         Thank you for your reply . Do you mean that I keep the default pythia_card, param_card and width of tau = 0? Besides, I found the "tauola.f " is in the pythia-pgs/libraries/PGS4/src file, I am afraid that there maybe a problem if tau lepton simulation is performed by Delphes not using PGS4.
        Best.

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Best Kentarou Mawatari (kentarou-mawatari) said : 		#3

Yes. If there are taus in lhe event file, TAUOLA does tau decays. Kentarou

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han (xfhan) said : 		#4

Thanks Kentarou Mawatari, that solved my question.

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Saurabh Niyogi (saurabh12102003) said : 		#5

Hello,

 I am opening this old thread as my query is related to Tauola in MG5.

When I checked pythia log file (tag_1_pythia), I found tau with status code K(I,1) = 1 i.e. stable particle. The initial generated taus were with status 21, then 11 and finally 1 without any decayed daughter as can be seen parent line.
   15 (tau+) 11 -15 9 19 20 4.08723 -45.40078 -92.30326 102.96109 1.77700
   16 (tau-) 11 15 10 21 21 -72.52393 61.91669 -296.67893 311.63270 1.77700
   17 mu+ 1 -13 11 0 0 18.44565 -17.64150 -13.05391 28.66845 0.10566
   18 nu_mu 1 14 12 0 0 48.16263 -45.64914 -340.89563 347.29428 0.00000
   19 (tau+) 11 -15 15 24 24 4.06254 -45.33055 -92.04573 102.69828 1.77700
   20 (tau-) 11 15 16 22 23 -72.51522 61.90924 -296.64328 311.59525 1.77700
   21 tau- 1 15 20 0 0 -72.51521 61.90924 -296.64325 311.59522 1.77700
   22 tau+ 1 -15 19 0 0 4.06254 -45.33055 -92.04573 102.69828 1.77700

So, my question is: does Tauola inside pythia decay tau as mentioned above by Kentarou ?

Thanks,
Saurabh

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Kentarou Mawatari (kentarou-mawatari) said : 		#6

Hi Saurabh,

Yes. Please also look at

https://answers.launchpad.net/mg5amcnlo/+question/226476

Kentarou