MadGraph5_aMC@NLO

Stray electron neutrino in hadronized LHE files

Asked by Will Flanagan

Hi Madgraph Experts,

I have noticed that there is always an electron neutrino in the last line of each event in my hadronized LHE files. Is this something standard that I have never seen before? Of course it is not physical since it violates lepton number and has no parent.

For example, in the event below, we have a standard ttbar event with two extra jets. The W+ decays to a tau and an anti-tau neutrino. The W- decays to a down and an anti-up. So this last 'electron neutrino' is clearly an artifact of Madgraph or Pythia.

Any comments are much appreciated!
Will

<event>
 21 100 0.10000000E+01 0.00000000E+00 0.00000000E+00 0.00000000E+00
      21 -1 0 0 0 0 -0.80563805E+01 0.30647410E+01 0.30223681E+03 0.30235969E+03 0.00000000E+00 0. 0.
      21 -1 0 0 0 0 -0.11760525E+02 -0.12011705E+02 -0.58836164E+03 0.58860174E+03 0.00000000E+00 0. 0.
      21 2 1 1 0 0 -0.31533946E+00 -0.93099471E+01 -0.44149026E+03 0.44158852E+03 0.00000000E+00 0. 0.
      21 2 1 1 0 0 -0.51966829E+01 0.24664678E+01 0.52041110E+01 0.77570451E+01 0.00000000E+00 0. 0.
       6 2 2 2 0 0 0.36088849E+02 0.61963267E+02 0.16528235E+03 0.24977812E+03 0.17300000E+03 0. 0.
      -6 2 3 3 0 0 -0.50393733E+02 -0.64066752E+02 -0.15121041E+02 0.19183775E+03 0.17300000E+03 0. 0.
      24 2 5 5 0 0 -0.33308131E+02 0.71327127E+02 0.74549399E+02 0.13506486E+03 0.80547578E+02 0. 0.
       5 2 5 5 0 0 0.69396981E+02 -0.93638604E+01 0.90732955E+02 0.11471326E+03 0.48000000E+01 0. 0.
     -15 2 7 7 0 0 -0.38647195E+02 0.99568280E+01 0.59478492E+02 0.71649095E+02 0.17770000E+01 0. 0.
      16 2 7 7 0 0 0.54383004E+01 0.61264521E+02 0.15037398E+02 0.63316980E+02 0.00000000E+00 0. 0.
     -24 2 6 6 0 0 0.35476888E+02 -0.47179415E+02 -0.37150163E+02 0.10538575E+03 0.79003262E+02 0. 0.
      -5 2 6 6 0 0 -0.85788238E+02 -0.18154899E+02 0.91565425E+01 0.88295551E+02 0.48000000E+01 0. 0.
       1 2 11 11 0 0 -0.25366194E+02 -0.92694408E+01 -0.15772649E+02 0.31277015E+02 0.33000000E+00 0. 0.
      -2 2 11 11 0 0 0.59374072E+02 -0.37230847E+02 -0.20616738E+02 0.73051866E+02 0.33000000E+00 0. 0.
       5 1 0 0 0 0 -0.89644262E+02 -0.20667763E+02 0.79776186E+01 0.94798067E+02 0.21442503E+02 0. 0.
       5 1 0 0 0 0 0.69858851E+02 -0.10220415E+02 0.92977591E+02 0.11724894E+03 0.10851959E+02 0. 0.
      21 1 0 0 0 0 0.57843128E+02 -0.36099980E+02 -0.19376169E+02 0.71249155E+02 0.72090258E+01 0. 0.
      21 1 0 0 0 0 -0.29621144E+02 0.71532855E+01 0.43274598E+02 0.53069628E+02 0.38875290E+01 0. 0.
      21 1 0 0 0 0 -0.18276261E+02 -0.76690790E+01 -0.13155039E+02 0.24071457E+02 0.36801492E+01 0. 0.
      21 1 0 0 0 0 0.13122368E+02 0.13999991E+02 -0.24756864E+03 0.24835708E+03 0.47759195E+01 0. 0.
      12 1 0 0 0 0 -0.57489393E+01 0.64279972E+02 0.00000000E+00 0.64536540E+02 0.00000000E+00 0. 0.
</event>

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Olivier Mattelaer (olivier-mattelaer) said : 		#1

Hi,

This file actually include a small/simple/naive detector simulation (and jet algorithm) and should therefore be handle with a lot of care.
I guess that this correspond to a missing ET information or something like that.

Cheers,

Olivier

On Dec 24, 2013, at 9:36 PM, Will Flanagan <email address hidden> wrote:

> Question #241245 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/madgraph5/+question/241245
>
> Description changed to:
> Hi Madgraph Experts,
>
> I have noticed that there is always an electron neutrino in the last
> line of each event in my hadronized LHE files. Is this something
> standard that I have never seen before? Of course it is not physical
> since it violates lepton number and has no parent.
>
> For example, in the event below, we have a standard ttbar event with two
> extra jets. The W+ decays to a tau and an anti-tau neutrino. The W-
> decays to a down and an anti-up. So this last 'electron neutrino' is
> clearly an artifact of Madgraph or Pythia.
>
> Any comments are much appreciated!
> Will
>
> <event>
> 21 100 0.10000000E+01 0.00000000E+00 0.00000000E+00 0.00000000E+00
> 21 -1 0 0 0 0 -0.80563805E+01 0.30647410E+01 0.30223681E+03 0.30235969E+03 0.00000000E+00 0. 0.
> 21 -1 0 0 0 0 -0.11760525E+02 -0.12011705E+02 -0.58836164E+03 0.58860174E+03 0.00000000E+00 0. 0.
> 21 2 1 1 0 0 -0.31533946E+00 -0.93099471E+01 -0.44149026E+03 0.44158852E+03 0.00000000E+00 0. 0.
> 21 2 1 1 0 0 -0.51966829E+01 0.24664678E+01 0.52041110E+01 0.77570451E+01 0.00000000E+00 0. 0.
> 6 2 2 2 0 0 0.36088849E+02 0.61963267E+02 0.16528235E+03 0.24977812E+03 0.17300000E+03 0. 0.
> -6 2 3 3 0 0 -0.50393733E+02 -0.64066752E+02 -0.15121041E+02 0.19183775E+03 0.17300000E+03 0. 0.
> 24 2 5 5 0 0 -0.33308131E+02 0.71327127E+02 0.74549399E+02 0.13506486E+03 0.80547578E+02 0. 0.
> 5 2 5 5 0 0 0.69396981E+02 -0.93638604E+01 0.90732955E+02 0.11471326E+03 0.48000000E+01 0. 0.
> -15 2 7 7 0 0 -0.38647195E+02 0.99568280E+01 0.59478492E+02 0.71649095E+02 0.17770000E+01 0. 0.
> 16 2 7 7 0 0 0.54383004E+01 0.61264521E+02 0.15037398E+02 0.63316980E+02 0.00000000E+00 0. 0.
> -24 2 6 6 0 0 0.35476888E+02 -0.47179415E+02 -0.37150163E+02 0.10538575E+03 0.79003262E+02 0. 0.
> -5 2 6 6 0 0 -0.85788238E+02 -0.18154899E+02 0.91565425E+01 0.88295551E+02 0.48000000E+01 0. 0.
> 1 2 11 11 0 0 -0.25366194E+02 -0.92694408E+01 -0.15772649E+02 0.31277015E+02 0.33000000E+00 0. 0.
> -2 2 11 11 0 0 0.59374072E+02 -0.37230847E+02 -0.20616738E+02 0.73051866E+02 0.33000000E+00 0. 0.
> 5 1 0 0 0 0 -0.89644262E+02 -0.20667763E+02 0.79776186E+01 0.94798067E+02 0.21442503E+02 0. 0.
> 5 1 0 0 0 0 0.69858851E+02 -0.10220415E+02 0.92977591E+02 0.11724894E+03 0.10851959E+02 0. 0.
> 21 1 0 0 0 0 0.57843128E+02 -0.36099980E+02 -0.19376169E+02 0.71249155E+02 0.72090258E+01 0. 0.
> 21 1 0 0 0 0 -0.29621144E+02 0.71532855E+01 0.43274598E+02 0.53069628E+02 0.38875290E+01 0. 0.
> 21 1 0 0 0 0 -0.18276261E+02 -0.76690790E+01 -0.13155039E+02 0.24071457E+02 0.36801492E+01 0. 0.
> 21 1 0 0 0 0 0.13122368E+02 0.13999991E+02 -0.24756864E+03 0.24835708E+03 0.47759195E+01 0. 0.
> 12 1 0 0 0 0 -0.57489393E+01 0.64279972E+02 0.00000000E+00 0.64536540E+02 0.00000000E+00 0. 0.
> </event>
>
> --
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