MadGraph5_aMC@NLO

Wrong jet masses

Asked by HH

Dear experts,

I use MadGraph5 interfaced with PY8 and Delphes 3.4.2 to generate events. The delphes card I use is the card for Muon collider https://github.com/delphes/delphes/blob/master/cards/delphes_card_MuonColliderDet.tcl. The model I use is sm_full with TauDecay_UFO added. The process I am studying is mu- mu+ > tau+ tau-. My delphes card uses the inclusive Valencia algorithm to reconstruct jets. Obtained jets are then tau-tagged. One of the important variables in my study is the jet mass. My problem is that jet masses obtained using this delphes card are wrong. Half of the masses are positive and half of them are negative in a symmetric discrete pattern. Using another delphes card, the ILD delphes card, to generate a sample for the same process jet masses are correct! I don't know if this issue is related to MG5 or Delphes. I wanted to make sure about the MG5 side.

Thanks in advance for your help

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HH
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Olivier Mattelaer (olivier-mattelaer) said : 		#1

I would say that you need to contact Delphes author first, then if they say that the issue is in the PY8 file, then you need to contact PY8 autthor and if they say that the issue is within the lhef file, then you will need to go back to us.

Cheers,

Olivier

> On 22 Jan 2021, at 07:25, HH <email address hidden> wrote:
>
> New question #695138 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/695138
>
> Dear experts,
>
> I use MadGraph5 interfaced with PY8 and Delphes 3.4.2 to generate events. The delphes card I use is the card for Muon collider https://github.com/delphes/delphes/blob/master/cards/delphes_card_MuonColliderDet.tcl. The model I use is sm_full with TauDecay_UFO added. The process I am studying is mu- mu+ > tau+ tau-. My delphes card uses the inclusive Valencia algorithm to reconstruct jets. Obtained jets are then tau-tagged. One of the important variables in my study is the jet mass. My problem is that jet masses obtained using this delphes card are wrong. Half of the masses are positive and half of them are negative in a symmetric discrete pattern. Using another delphes card, the ILD delphes card, to generate a sample for the same process jet masses are correct! I don't know if this issue is related to MG5 or Delphes. I wanted to make sure about the MG5 side.
>
> Thanks in advance for your help
>
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Revision history for this message
HH (hh-madgrapher) said : 		#2

Okay thanks for your answer.