Section 3

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Section 3.1.1

Par 1

L3/4 : ”while leptonic decays can be indirectly studied from the decay products when processing the DELPHES output” is very vague a sentence, with no real meaning. Suggestion is to drop it. The rest of the section is extremely verbose, and could be replaced by one sentence stating that electron and muon energy/momentum is smeared with resolutions parameterized as a function of pT and eta (and mention that these parameterizations can be changed by the user?). The convoluted explanations about what a typical collider experiment is actually doing is of no interest for the reader, as DELPHES does not do the same anyway. This text could be replaced by a figure showing the resolutions used to reproduce the CMS and ATLAS performance for electrons and muons, as well as a comparison with the actual detector resolutions.

Section 3.1.2

Last line : ”Neutral pions are automatically classified as photons”. As al- ready mentioned, neutral pions are not long-lived particles in any generator. Instead they decay promptly to two photons, which obviously are classified as photons. The authors might want to drop the comments about neutral pions.

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Section 3.2.2

L2/3: ”as these might indicate the production of heavy unstable particles” carries little meaning is the context of this article (and probably in a wider context too) without additional explanation. Suggestion is to drop it.

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Section 3.2.2

Par 1:

L1/2 : It is not useful to indicate what is done in real experiments. Instead, it is important to describe what is done in DELPHES. 1.8.2 Section 3.1.3

As a general comment, the isolation definition chosen here is very much hadron collider biassed. One would not do the same in e+e- collisions. This comment supports the initial request that the abstract includes a sentence stating that DELPHES is aimed at simulating hadron collider experiments (so far).

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”Charged pile-up subtraction”

There are several problems in this paragraph.

• It is not stated if this paragraph is specific to PF or not. If it’s not, the

procedure to remove charged particles from the event in which purely calorimetric jets are reconstructed needs to be spelt out clearly.

• Even if the paragraph is PF specific, it is not clear what ”subtracted

from the event: means. For example, are the pile-up charged hadrons removed from the event before computing the missing transverse en- ergy ? To the best of my knowledge, it is not what is done in LHC experiments.

• The criterion ”a distance |z| > Zvtx” is obscure. What if the hard

interaction is produced with |z| > Zvtx ? and what is the definition of this ”distance” ? If is is the distance between the vertex of a PU interaction with respect to the vertex of the hard interaction, the use of ”z” instead of ”z” (with the proper definition in the text) is in order.

”Residual pile-up subtraction”

• It is not clear how ”rho” is obtained in DELPHES

• ”mainly the jet energies and the isolation” : is ”rho” used for anything

else ? if yes, it should be stated. If not, ”mainly” should be removed.

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Par 2:

L4: It would be useful to mention one of the advantages of the PF recon- struction in the context of PU mitigation, namely the fact that the calorime- ter energy deposits associated to PU charged hadrons are ”automatically” removed. In DELPHES, however, this does not happen when a charged hadron and a neutral deposit fall in the same calorimeter tower, because the charged hadron is then ignored by DELPHES.