Setting a trigger in Delphes 3 to avoid exhausting disk space

[Rafael Delgado López]

In Delphes 1.8 there was a config file (trigger card) which allowed to simulate a trigger in a easy way. It can we seen at

​http://arxiv.org/pdf/0903.2225.pdf

Is there something similar in Delphes 3? I need it in order to avoid exhausting disk space. Should I modify the code of readers/DelphesXXX.cpp to set my own trigger? What is the recommended way?

Thanks in advance for your answer,
yours sincerely,

[Michele Selvaggi]

Hello,

we did not implement Trigger cards in Delphes 3 as this is equivalent to applying some cuts. If you are concerned by disk space, I suggest you tighten the cuts relative to your interesting objects in the detector_card.

Also, a big fraction of the space is taken by particle-flow constituents and genparticle.
If you don't need these things in your analysis, I suggest you remove the related branches from your output, in the TreeWriter section of your data card.

For instance, commenting the following lines will save you a huge amount of space:

#add Branch TrackMerger/tracks Track Track
#add Branch Calorimeter/towers Tower Tower
#add Branch Calorimeter/eflowTracks EFlowTrack Track
#add Branch Calorimeter/eflowTowers EFlowTower Tower

Cheers,
Michele

[Rafael Delgado López]

Hello,

This helps me. I can easily divide the hard disk consumption by a factor of 50. And I think I will be able to reduce it even more. Setting cuts into some parts of the reconstruction machinery can also reduce the space consumption.

However, what I would like to do is not only set a cut which avoids writing some parts of the event into disk (this is what cuts in detector_card do, isn't it?). But one which "discards completely" the majority of events, based on the lack of a particle (including, maybe, the missing transverse momentum) which fulfill certain constraints in the reconstruction of the event. For example, the presence of at least one photon with Et>=XXGeV.

This would simplify certain analysis. Is it possible? Or, would be necessary to modify, for example, DelphesHepMC.cpp or DelphesPythia8.cpp in order to avoid writing such events into disk?

Cheers,
Rafael.