update on reading event files

Asked by Graham on 2019-06-26

Hi

I am trying to analyze some events with madgraph

on the website this instruction on how to read them seems out of date

http://madgraph.phys.ucl.ac.be/Manual/lhco.html

Compare the event format

   # typ eta phi pt jmass ntrk btag had/em dummy dummy
   0 3 3599
   1 1 -0.060 2.878 359.51 0.00 -1.0 0.0 0.02 0.0 0.0
   2 1 0.398 6.041 368.07 0.00 1.0 0.0 0.01 0.0 0.0
   3 4 3.516 4.651 25.72 36.62 5.0 0.0 1.44 0.0 0.0
   4 4 -0.036 1.763 13.38 10.65 1.0 0.0 0.83 0.0 0.0
   5 4 -2.793 3.500 12.06 7.75 5.0 0.0 12.24 0.0 0.0
   6 4 1.068 1.243 10.00 4.53 3.0 0.0 7.71 0.0 0.0
   7 4 -3.969 0.688 9.79 3.79 5.0 0.0 7.78 0.0 0.0
   8 6 0.000 2.612 11.76 0.00 0.0 0.0 0.00 0.0 0.0

to what you have now (I removed sig figs to help readability)

<event>
 8 1 +4.44e-12 9.12e+01 7.55e-03 1.18e-01
       23 -1 0 0 0 0 +0.0e+00 +0.0e+00 +9.9e-15 9.1e+01 9.1e+01 0.0e+00 0.0e+00
       16 1 1 0 0 0 +9.4e+00 -1.1e+01 +3.2e+00 1.5e+01 0.0e+00 0.0e+00 -1.0e+00
      -24 2 1 0 0 0 -7.2e+00 +9.5e+00 -5.2e+00 7.3e+01 7.1e+01 0.0e+00 0.0e+00
      -11 1 1 0 0 0 -1.8e-01 +1.5e-01 -4.1e-02 2.4e-01 0.0e+00 0.0e+00 1.0e+00
      -12 1 3 3 0 0 +2.4e+01 -1.7e+01 -1.2e+01 3.2e+01 0.0e+00 0.0e+00 1.0e+00
      -16 1 1 0 0 0 -1.1e+00 +1.4e+00 +1.9e+00 2.6e+00 0.0e+00 0.0e+00 1.0e+00
       11 1 3 3 0 0 -3.1e+01 +2.6e+01 +7.1e+00 4.1e+01 0.0e+00 0.0e+00 -1.0e+00
       12 1 1 0 0 0 -8.7e-01 -6.4e-02 +7.6e-02 8.7e-01 0.0e+00 0.0e+00 -1.0e+00
</event>

Not sure what the first row is, but the 2nd to the last rows are clearly information on the in and out states. The order however doesn't appear to correspond to Jesse Thaler's instructions so I was wondering what the order is today?

Question information

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English Edit question
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MadGraph5_aMC@NLO Edit question
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Last query:
2019-06-26
Last reply:
2019-06-26

You are reading the manual for reading lhco format (the output of PGS and an optional one for Delphes, and the one use as input for MadWeight).

This format has nothing to do with the lhe format which is the standard format for event at parton level.
(Another standard is HepMC but this is for file after pythia).
We do not link that documentation in our page since this is available much more easily than the lhco description.

The format has three paper associated to it:
lhef version 1: https://arxiv.org/pdf/hep-ph/0109068.pdf
lhef version 2: http://home.thep.lu.se/~torbjorn/preprints/cern0603.pdf
lhef version 3: https://arxiv.org/pdf/1405.1067.pdf

if you are looking at the definition of the momenta, then you need to read the first paper.
The two other paper are mainly adding some conventional meta-data information.

Cheers,

Olivier

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