Leptons Faking Photons using JetFakeParticle Module

[Sam Homiller]

Hi Experts,

I have two quick questions about the JetFakeParticle module in Delphes. I've used this for awhile to simulate light jets faking photons, but I was wondering if it could also be used for Leptons Faking Photons as well?

For example, if I just switch the input array to be the output of the ElectronIsolation module, could I then just turn on a probability for these electrons to convert to photons?

Also, for the JetFakeParticle module as it's normally used, does the jet that gets converted from a photon get removed from the output jet array? Many of the examples I've found seem to continue using jet output array from earlier modules after the JetFakeParticle module, as opposed to using the JetFakeParticle/jets array. Are these examples simply incorrect?

Thanks very much

Sam

[Michele Selvaggi]

Hi,

have a look at the identification map module:

​https://github.com/delphes/delphes/blob/master/cards/delphes_card_LHCb.tcl#L175-L257

And yes, one should use the JetOutputArray collection, which does not contained the fake particle as a jet.

Michele

[Sam Homiller]

Thanks -- that perfectly answers my question for the fakes, and the identification map looks like just what I needed.

A last quick question -- it says in the description that the incoming and outgoing particles should have the same charge, which is clearly not the case for a single electron faking a photon in the calorimeter. If I try to implement this anyway, would it return some kind of error or just a miscounting of the total charge?

Thanks again,

Sam

[Michele Selvaggi]

No error should be returned. Actually the outgoing pdgcode of the photon will be signed in that case, indicating the charge of the original electron/positron. Please note that with this module you also need to specify an efficiency for the incoming particles that are not "faked", as in the example I linked earlier.

Michele