Running Delphes over Pythia stdhep NLO

[Juanpe]

Hello,

I am running a simple ttbar process in NLO with Madgraph5_aMC@NLO and then I make the showering with Pythia. After that I want to run Delphes (version 3.1.2) over the hep file Pythia produces but I get a segmentation fault which I don't know why is happening. This is the output:

$ ../../../Delphes/DelphesSTDHEP ../../../delphes_myATLAS.dat delphes.root events.hep
** INFO: adding module        ParticlePropagator       ParticlePropagator
** INFO: adding module        Efficiency               ChargedHadronTrackingEfficiency
** INFO: adding module        Efficiency               ElectronTrackingEfficiency
** INFO: adding module        Efficiency               MuonTrackingEfficiency
** INFO: adding module        MomentumSmearing         ChargedHadronMomentumSmearing
** INFO: adding module        EnergySmearing           ElectronEnergySmearing
** INFO: adding module        MomentumSmearing         MuonMomentumSmearing
** INFO: adding module        Merger                   TrackMerger
** INFO: adding module        Calorimeter              Calorimeter
** INFO: adding module        Merger                   EFlowMerger
** INFO: adding module        Efficiency               PhotonEfficiency
** INFO: adding module        Isolation                PhotonIsolation
** INFO: adding module        Efficiency               ElectronEfficiency
** INFO: adding module        Isolation                ElectronIsolation
** INFO: adding module        Efficiency               MuonEfficiency
** INFO: adding module        Isolation                MuonIsolation
** INFO: adding module        Merger                   MissingET
** INFO: adding module        Merger                   ScalarHT
** INFO: adding module        FastJetFinder            GenJetFinder
** INFO: adding module        FastJetFinder            FastJetFinder
** INFO: adding module        EnergyScale              JetEnergyScale
** INFO: adding module        BTagging                 BTagging
** INFO: adding module        TauTagging               TauTagging
** INFO: adding module        UniqueObjectFinder       UniqueObjectFinder
** INFO: adding module        TreeWriter               TreeWriter
** INFO: initializing module  Delphes
** INFO: initializing module  ParticlePropagator
** INFO: initializing module  ChargedHadronTrackingEfficiency
** INFO: initializing module  ElectronTrackingEfficiency
** INFO: initializing module  MuonTrackingEfficiency
** INFO: initializing module  ChargedHadronMomentumSmearing
** INFO: initializing module  ElectronEnergySmearing
** INFO: initializing module  MuonMomentumSmearing
** INFO: initializing module  TrackMerger
** INFO: initializing module  Calorimeter
** INFO: initializing module  EFlowMerger
** INFO: initializing module  PhotonEfficiency
** INFO: initializing module  PhotonIsolation
** INFO: initializing module  ElectronEfficiency
** INFO: initializing module  ElectronIsolation
** INFO: initializing module  MuonEfficiency
** INFO: initializing module  MuonIsolation
** INFO: initializing module  MissingET
** INFO: initializing module  GenJetFinder
#--------------------------------------------------------------------------
#                         FastJet release 3.0.6
#                 M. Cacciari, G.P. Salam and G. Soyez
#     A software package for jet finding and analysis at colliders
#                           http://fastjet.fr
#
# Please cite EPJC72(2012)1896 [arXiv:1111.6097] if you use this package
# for scientific work and optionally PLB641(2006)57 [hep-ph/0512210].
#
# FastJet is provided without warranty under the terms of the GNU GPLv2.
# It uses T. Chan's closest pair algorithm, S. Fortune's Voronoi code
# and 3rd party plugin jet algorithms. See COPYING file for details.
#--------------------------------------------------------------------------
** INFO: initializing module  FastJetFinder
** INFO: initializing module  JetEnergyScale
** INFO: initializing module  BTagging
** INFO: initializing module  TauTagging
** INFO: initializing module  UniqueObjectFinder
** INFO: initializing module  ScalarHT
** INFO: initializing module  TreeWriter
** Reading events.hep
Segmentation fault--------------------------------------------------] (0.00%)

If I do exactly the same procedure but with LO Pythia hep file it works fine. Is there something I need to spcify to Delphes to be able to run over the NLO hep file?

Thanks a lot in advance,
Juanpe.

[Pavel Demin]

Dear Juanpe,

A similar problem is reported in #292.

I've just committed a fixed version of the STDHEP reader to the Delphes code repository
and this fixed version will be available in the next release.

You can apply this fix by removing the following line from the 'DelphesSTDHEPReader::ReadSTDHEP4()' method in 'classes/DelphesSTDHEPReader.cc':

  xdr_string(fInputXDR, &fBuffer, 100);

Alternatively, you can download a snapshot of the Delphes code repository from

​https://github.com/delphes/delphes/archive/master.zip

Regards,

Pavel

[Juanpe]

Hi Pavel,

thanks for the answer. I am going to try your suggestion and let you know if I still find any issue.

Thanks a lot!
Juanpe.