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 http://​cms.cern.ch/​cds/​EGM-13-001 http://​cms.cern.ch/​cds/​EGM-13-001
 +
 +**Commenti di Marco C**
 +
 +The paper is too long and hard to read  although its physical content is quite good
 +
 +The language is often too much "cms slang" with expressions not of general
 +understanding outside CMS 
 +
 + It has still the structure of  an analysis note as it collects a list of useful and
 +important informations but as a paper it should be more synthetic and coherent
 +
 + ​giving to a reader the possibility to select the relevant numbers, that should be
 +for example summarised at the end of each main section.
 +
 + More emphasis should be put into linking the performance of the electron
 +reconstruction and selection with the main CMS analysis papers where
 + these numbers are used to build up the systematics
 +
 + 
 + More work is needed to make it mature to be published
 +
 +
 +**Commenti di Stefano A**
 +
 +The Torino group would like to acknowledge the authors for this extensive and
 +detailed documentation of electron reconstruction in CMS. The task was not a trivial
 +one, given the complexity and the multifaceted nature of the problem and the many
 +slightly different ways in which various analyses exploited the available tools for
 +reconstruction,​ identification and selections of electrons. ​
 +
 +However, the reading of the CWR draft left us with a few serious concerns (Type B
 +comments):
 +
 +1. We are afraid the use of scientific English in this document does not quite meet
 +the CMS standards required for a journal paper submission. Grammar is shaky,
 +repetitions can be often avoided, symbols and quantities are not always properly
 +defined and in several occasions the text is simply incomprehensible. We warmly
 +suggest a careful reading of the excellent guidelines for preparing CMS publications
 +available at  https://​twiki.cern.ch/​twiki/​bin/​view/​CMS/​Internal/​PubGuidelines .
 +
 +2. Connected to the above, the manuscript is very technical, which perhaps
 +facilitated excessive use of CMS jargon. CMS jargon should be completely removed
 +before going to FR. With this respect, the document as it stands is a very good CMS
 +Analysis Note, but unacceptable for a journal publication.
 +
 +3. The document is  very long. We feel there are several opportunities to make it
 +more terse by avoiding repeated text and concepts. Also, the number of figures could
 +be reduced either by merging several plots into one or by avoiding showing many
 +flavours of the same plot (e.g. when showing efficiencies for several working
 +points).
 +
 +
 +Below we provide some suggestions. We started by providing line-by-line comments,
 +but realised it was an impossible task within the given time : after a couple
 +sections we marked only  the most important problems. We are sure the LE has a lot
 +of useful comments and can help making this a top-quality paper.
 +
 +A curiosity : the residual trend in pt in Fig 15 left is ascribed to the fitting
 +function. We believe the fitting function should bias simulation and data in the
 +same way, so we are left wondering if the explanation is sound. ​
 +
 +
 +
 +Good luck for the implementation of comments and FR !
 +
 +
 +
 +Type A comments :
 +
 +Abstract: ​
 +
 +“A few 100 GeV” - A few hundreds GeV
 +
 +“cluster energy in the calorimeter” -> the word “cluster"​ is jargon and must be
 +defined or avoided ​
 +
 +“combining the measured energy in the calorimeter and the measured momentum in the
 +tracker” -> combining the energy measurement in the calorimeter with the momentum
 +measurement in the tracker.
 +
 +“The observed distributions of relevant observables are found to be well reproduced
 +through Monte Carlo simulation” -> The spectra of the observables relevant to
 +electron reconstruction are well reproduced in Monte Carlo simulations,​ as well as
 +selection and reconstruction efficiencies.
 +
 +“The data to simulation efficiency ratios …” -> We suggest to remove this convoluted
 +sentence.
 +
 +“The effective energy resolution .. changes “ -> The energy resolution [you don’t
 +explain what “effective” means just yet] for electrons produced in Z decays ranges
 +from 1.7% to 4.5%, depending on pseudorapidity and  energy losses via bremsstrahlung
 +radiation.
 +
 +Introduction:​
 +
 +L27: “such as those ..” -> such as Higgs searches and properties, standard model
 +precision measurements and searches for new physics.
 +
 +L30 : "the basics ..  established for” ​ Rephrase, suggestion: The basic principles
 +of offline electron reconstruction in CMS were outlined in the PTDR (ref), and rely
 +on the combination of the energy measurement performed by the Electromagnetic
 +Calorimeter (ECAL) and of the momentum measurement performed by the silicon tracker.
 +This strategy delivers optimal performances over a wide range of transverse momentum
 +(pt). 
 +
 +L32-33: consequently,​ remove this repetition (you already said the reconstruction
 +combines E(ECAL)/​p(TK))
 + 
 +L34: “In this paper .. means” -> Throughout the paper, ​ “energy” and “momentum” are
 +used to refer to the energy of the electromagnetic shower initiated by the electron
 +in ECAL and track momentum measurement in the tracker, respectively,​ while the term
 +“electron energy” is used to refer to the combined information.
 +
 +L36 There is no such thing as “the performance of the energy calibration” .
 +Suggestion: ”The performance of ECAL in terms of calibration precision and
 +resolution was reported in Ref , while track reconstruction is discussed in Ref 5
 +
 +L38 “were some aspects .. also discussed” : drop
 +
 +L40 “performance of the resolution” , again there is no such thing. Suggestion: “In
 +this paper, electron reconstruction algorithms are described and their performance
 +in terms of resolution, accuracy and identification capabilities is discussed, based
 +on 19.7 fb-1 of data … " ​
 +
 +
 +L44 “The ​ needs for electron performance ..” Electron performance cannot “need”
 +anything. Rephrase. Suggestion: “The cutting-edge physics analyses foreseen by the
 +CMS scientific program demand high electron reconstruction and selection efficiency,
 +small misidentification probability,​ and high accuracy and precision of the energy
 +measurement over a large pt range.“
 +  ​
 +L46-7 “The most challenging physical process is the Higgs ..“ this is not at all
 +true, as there is a plethora of low-energy decays which would be far more
 +challenging. ​ Suggestion “A crucial and challenging physical process to study, which
 +is used as a benchmark in the present report, ​ is the decay of the Higgs into four
 +electrons or two muons and two electrons, where one of the electrons can have a pt
 +as low as 5 GeV. At the other extreme, electrons with pt above ..."
 +
 +
 +L52 “Fig 1 shows the overall “ -> “Fig 1 shows the full-range spectrum of
 +uncorrected dielectron invariant-mass derived from data collected using [remove
 +“relatively”] high pt dielectric triggers. ​
 +
 +L53 “No correction … to these data” drop, it can be replaced by using the adjective
 +“uncorrected” in the sentence above. If you really want to be specific, add
 +“uncorrected for efficiency” at the end of the previous sentence.
 +
 +L54 : “The drop of the spectrum” , well, it’s arguably an increase rather than a
 +drop, unless you look backwards ! Suggest : “The step around 40 GeV” , or “the
 +feature around 40 GeV"
 +
 +L58 : remove “in front of the calorimeter”
 + 
 +L59 : “the tracker material … lead to significant emission of bremsstrahlung “ -> “
 +cause significant bremsstrahlung emission along..”
 +
 +L64: Add the sentence: ” The paper is organised as follows”
 +L69 : “are shown” ->  are presented ​
 +
 +Caption to Fig 1 : ->   ​“The full-range spectrum of uncorrected dielectron invariant
 +mass ..” Drop “ No correction .."  ​
 +
 +Section 2
 +Line 80: the new CMS publication rules allow dropping the definition of pseudorapidity
 +
 +L80-85: very convoluted. Just say how the coordinate system is defined, and then
 +that its center can be placed either in the geometrical center of the detector or in
 +a primary vertex (we believe this is what you mean ?). A direction cannot be
 +measured relative to a point, this is plain wrong. ​
 +
 +L83 : “unless specified to the contrary” -> unless otherwise specified ​
 + 
 +L90-91 : “offering for eta<2.5 an active detection region (the acceptance) “ : 
 +sorry, what ?
 +
 +L101:" A consequence of the silicon tracker” -> “A consequence of the presence of
 +the silicon tracker”
 +
 +L107-109: these  concepts have already been discussed in L58.
 +  ​
 +In summary, we wonder if Section 2 could be made shorter, since it does not really
 +say anything new.
 +
 +Section 3
 +
 +L143 “in a fixed time interval of less than 4 us” -> in 3.6 us 
 +
 +L146-157: please rewrite this paragraph explaining properly what a trigger tower is,
 +defining “cluster”,​ etc.
 +
 +L 158-160 : the sentence says nothing, the reader does not know what a L1 or HLT
 +electron candidate is.
 +
 +L 165 “unbiased sample relative to the consider efficiency” not clear
 +
 +L167 “cluster in the ECAL that forms an invariant mass with the first electron” a
 +cluster does not form an invariant mass
 +
 +L173 drop the word “dedicated”
 +
 +L177 “their results compared to evaluate the systematic uncertainties” : please
 +clarify. The results from MadGraph and Powheg are compared with each other ? Which
 +systematics are evaluated ?
 +
 +L184 after .. reweighting good agreement is found “ isn’t this obvious form the
 +definition ​ of reweighing ?
 +
 +L195 “previous bunch crossings” ​ : previous to what ?
 +
 +Section 4
 +
 +L 197 “a track in the tracker” -> a track reconstructed in the silicon detector
 +L 197  “ a cluster of energy” : we believe “cluster” was never properly defined
 +L 199  “used to maximise both the performance and the similarities with the trigger
 +stand-alone strategy” : this sentence is really obscure to the non-initiated
 +
 +L207 “this spread can be quite restricted”:​ rephrase
 +L215 “along the phi direction relative to the initial direction of the electron”
 +what does it mean ? Radiation is emitted along the phi direction, period.
 +
 +L217 “two super clustering algorithms” : supercluster is not defined
 +
 +L220 -249 : these paragraphs are full of jargon (“dominoes”,​ “seed”),​ undefined
 +symbols (N_steps, etc),  unreported values (value of ET^min_seed e.g.)
 +
 +L266 “makes this a non optimal” -> a sub-optimal
 +L267 “there is a too large of a change in curvature due” -> when the change in
 +curvature is large because of bremsstrahlung
 +
 +L281 “general tracks” : please check if they were ever defined
 +L290 “a subset of the seeds leads eventually to tracks “ ??
 +L339 “the track stops collecting hits” : it’s hard to believe that tracks can
 +“collect hits”
 +L357 “a dedicated Bethe-Heitler function” : what is a dedicated Bethe-Heitler ​
 +
 +L399 “emit high fractions of their energies” -> rephrase
 +
 +L403 “difference in the material” -> imperfect modelling of the material budget in
 +simulation
 +L404 “access” -> assess
 +L407 define ”service region" ​
 +
 +L423 “ECAL-driven seeded” : convoluted expression. BTW , we think “seeding” was
 +never explained
 +L433 “it is therefore not very restrictive in the direction along which … “ : puzzling
 +
 +L449 “transition region” -> boundary between EB and EE
 +
 +L463-464: try to explain better
 +L483   : “felt needed for the alignment procedure” : it’s not a matter of feelings,
 +please rephrase
 +
 +
 +
 +L536 “ observables sensitive” -> suited to identify
 +
 +L556 “ the end of the encaps” -> the highest eta endcap regions ​
 +
 +L581 “laser monitoring system” -> add Ref
 +
 +L611 it’s not the number that is reconstructed,​ but the vertices, flip the terms
 +(“number of reconstructed interaction vertices”)
 +L622 “CB with different parameters .. below and above the peak position” : explain
 +better, the peak position is a parameter itself ​
 +
 +L654 “can cause the corrections” calls for the introduction of the corrections ..
 +
 +L659-660 : “The SC energy is corrected by changing …” : put in this way it is quite
 +puzzling
 +
 +L675 “The resolution of a SC energy is also affected by the sources of discrepancy” ​
 +???
 +
 +
 +L681-682 “smeared energy simulation” , define (we believe this is not the right
 +expression)
 +L684 “inflated” -> increased
 + 
 +L687 “after all the steps are taken” -> after the refinements explained in the
 +previous sections
 +
 +L716 “must be corrected further on top of ..” please rephrase
 +
 +L726 “the breadth of performance in data”
 +
 +L744 “the resolutions are smeared in simulation” : resolutions are not smeared
 +
 +L756-757 “used ..used” . 
 +
 +L759-763: unclear
 +
 +L772 “through of a method”
 +
 +L786 : “electrons produced within ..” -> originating form the decay of the b and c
 +quarks
 +
 +L807 “reconstructed electrons that match generated electrons …” rephrase
 +
 +L809 “enough purity” rephrase
 +
 +L831  etc: explain why sigma_ietaieta is effective in discriminating signal from
 +background electrons
 +L834-835 “obtained by counting crystals” rephrase
 +
 +L852 “shape information is expanded “ ?
 +
 +L891: “significant energy flow near their trajectories” perhaps “significant
 +activity” ?
 +
 +L897 : Introduce the paragraph by saying “Two techniques are employed …”
 +
 +L908-909 :  “the calibration that corresponds … used to define their contribution”
 +really obscure
 +L915-918 : obscure as well
 +
 +Formula: please ensure you write a sound mathematical formula
 +
 +L928: “among the most sensitive observables” -> among the observables more sensitive…
 +L932  A_eff not defined
 +
 +L989-990 :  please check if d0 and dz are defined
 +
 +L994 “90,​80,​70%” we lost track of what the three numbers may refer to
 +L1015, L1023 add Reference
 +
 +
 +L1072 “dependence.. on the number of bins used “ ?
 +
 +L1087 : "to select ​ both the events and the probe “ ?
 +
 +Fig25/25 perhaps can be merged ?
 +
 +
 +Section 7 “Summary and conclusions"​
 +
 +In this section it is particularly important to avoid CMS jargon
 +
 +L1155/56 “with a single-cluster supercluster” ,  “multi-cluster supercluster” ,
 +perhaps we could refer to high-brem and low-brem electrons ?
 +
 +
 +References ​
 +
 +References should be uniformly presented. E.g , Ref 25 has “Vol”, “No” while others
 +have not (remove Vol, No, ). Some references have start and end page, others only
 +start page (remove end pages from refs 25,31,36).
 +
 +
 +