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CWR QCD-10-029: Comments and Answers

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Final version of the draft paper before corrections


BLACK: Initial comments

BLUE: Comment taken into account or answer to question

GREEN: Still to be discussed among us or to be fixed

RED: Not done, and we explain why.

PINK: Partial agreement with the comment. Changed done for the agreed part.

BROWN: The comment needs further clarification to be answered.

Comments from Greg Landsberg

Dear Authors and the ARC Members,

I read with interest the paper on the jet energy flow. Congratulations on having this important measurement done and a nice paper! My only regret is that - alas - it comes some two weeks after an ATLAS measurement on the longitudinal and transverse shapes of jets - I really wish the order was reverse...

I have a few physics comments on the paper and a number of style suggestions, targeting a more uniform style of the paper. In what follows, suggested additions/modifications are sometimes CAPITALIZED for clarity.


0) My main physics comment is that after you defined the two types of jets used in the analysis (JPT and PF), the rest of the paper does not mention the jet type at all. It's absolutely unclear what measurements are done with the JPT jets. Figures 2-3 are the only place that mentions the type (PF jets), but all the subsequent figures, tables, and the text ignores the issue completely. Not only there is not enough information in the paper to figure out what jets have been used, but it is not clear at all why two algorithms were used to start with. What's the point of using anything beyond PF jets, which presumably give you the most precise information about the particle content of a jet? This needs to be reworked and either JPT approach should be removed from the paper or a clear explanation of what it was used for and why it's better than the PF jet approach should be included.

Our paper consists of two analyses: classical jet shape and charged component analysis- that were combined to the one paper at a very late stage. All results are presented for anti-kT particle level jets. We studied systematics in details for both type of jets. The uncertainty from conversion of the results from detector level to particle level observables are included into systematics in all cases. Both type of jets use informations from all subdetectors and are comparable in resolution and scale.

Using three different observable to characterize the jet structure make the paper much stronger than using just the classical jetshapes. In any case, the difference between charged tracks attached to the JPT jets from those clustered into PF jets should be small and would like to keep that discussion of of the paper.

1) The other comment is that dumping 40+ pages of meticulous tables on an unsuspecting reader is somewhat cruel. Do you really expect anyone to go and digitize this information by hand? Firstly, I hope that all the information in the tables is made available to theorists via Rivet interface or by some other electronic means. Secondly, if this is indeed the case, why include tables in the main body of the paper at all, when we could provide them as electronic supplement to the paper, which is much more useful than 40 pages of densely typeset numbers. I suggest that you consider this as a better way to disseminate this important information.

We will provide an electronic versions of the tables. Publication Committee will decide how to make them public.

2) L9: the statement begs references on the e+e- tunes.

We have amended this sentence to say "collider data". We think that is more in lne with current work. Individual tunes are referenced later.

3) L32: the choice of the momentum range is quite odd given that the paper focuses on rather low-pT jets. Suggest quoting resolution at 100 GeV, not 1000.


4) L38: the granularity in the forward HCAL region is not constant and some towers are larger than 0.175 x 0.175. Correct or drop.

Thanks for catching this. We have dropped the granularity description for the forward region as we only use jets with eta < 3.0.

5) L45: the term "uncorrected" is cryptic here; replace with "reconstructed" or "reconstructed at the trigger level". Since the trigger uses completely different jet algorithm, I'd not go into much detail here anyway. The paragraph begs an integrated luminosity of the sample to be quoted here, particularly since most of the triggers are prescaled. How do you merge data samples corresponding to various triggers? - Please add an explanation to the text.

We modified to ".... the event to have an online jet \pt of at least 15, 30, 50, 70, 100, or 140 \GeVc. These jets were reconstructed using an iterative cone algorithm only from the energy deposits in the calorimeters."

We don't merge trigger samples, we use only one trigger sample / pT bin. We added " These datasets are combined to measure the jet characteristics in bins spanning over the 20 \GeVc $<\pt<$ 1 \TeVc range such that the trigger contributing to each bin is fully efficient."

6) L62: mention the distance parameter of 0.5 here. You never mention it, apart from L94, where a different parameter R=0.7 refers to the cone size, not the anti-kT algorithm. Since you use the energy in a cone anyway, is there really any advantage of using anti-kT, and not SIScone algorithm, which would map more precisely on the cones you use for the analysis? Why do you use anti-kT with the distance parameter of 0.5 and not 0.7 to match the energy cones?

We use D=0.7 anti-kt jet of jetshape analysis and D=0.5 anti-kt for the charged particle multiplicity. We will make it clear. The difference is partially historical. However, it may be better to use smaller size to measure the fragmentation of the parent parton and thus can be used to differenciate between quark and gluons. Larger size includes more energy from the parent parton and from multi-parton interaction and thus may be better suited for MC tuning. We have not done an extensive study of these potential benefits and thus would not like to discuss in the paper. The main difference between anti-Kt and SIScone is the splitting and merging step which can make SISCone jets non-circular and we use cones to measure jetshapes. SISCone does not give any advantage and we prefer to use an algorithm which is used by all other analysis.

7) L104: add a reference to the D6T tune.


8) L214: given the ATLAS paper on jet fragmentation, I don't think you could claim the "first" measurement of jet shapes here.

It is true not "first" measurment of jet shapes (although it is a first measurement of jet shapes with PF jets). We have removed the "first" in the conclusions.


0) The paper is quite inconsistent in the use of an Oxford comma and the hyphenation rules. CMS style suggests the use of the Oxford comma, but this rule is violated as early as in the title, and you use it really at random through the paper. I'll point out particular occasions in the detailed comments. Ditto about the hyphenation rules, which also are followed more or less randomly. There is also remaining jargon in the paper: "fake", "errors", etc. Finally, while you correctly typeset averages inside the \langle, \rangle brackets in the equations on p.4, all the , <\delta R^2> are typeset with the "<", ">" signs, which make them look ugly. Please, use context search-and-replace feature of the editor to recast all of them using the \lange, \rangle notation.

Thanks for the comment. We hope we have fixed all these issues.

1) Title: add an (Oxford) comma before "and".


2) Abstract, LL2-3: ... proton-proton collision data SAMPLE collected with the CMS detector at the LHC in 2010 AND CORRESPONDING TO AN INTEGRATED LUMINOSITY OF 36 pb$^{-1}#. LL3-4: definition -> reconstruction; L7: QCD-based -> QCD (or QCD-inspired).


3) Introduction, LL3-4: split the long sentence in two: end the first one after the "TeV scale." and start the next one with "However, ..."; L7: add a comma after "Instead"; QCD-motivated; L11: provided THAT additional; L18: lead to DEVELOPMENT OF gluon ...


4) The CMS Detector, L26: add a comma before "and"; η=−lntantheta2; L35: hadron and hadronic calorimeter are used inconsistently through the paper; change to "hadron" here and elsewhere. L38: THE ECAL cells (can't start a sentence with an acronym); L40: test-beam data; LL40-41: ... 50 GeV pions that only deposit minimal energy in the ECAL is close to one.


5) Event Selection and Reconstruction, L44: single-jet high-level triggers; L45: add a comma before "or"; L50: add a comma before "and"; L52: HADRON calorimeter; L53: move "[12]" after "primary vertex"; L55: add a comma after "pion"; L59: add a comma before "and"; L60: jet-finding algorithm; L62: jet ALGORITHM [17]; L65: add a comma before "except"; L73: cuts -> requirements.


6) Jet Observables, L82: tracks ORIGINATING from A SINGLE primary vertex; L91: transverse MOMENTA; L92: swap the order of y_Jet, \phi_Jet in "described by ..." to match the order in the formula for r_i; L94: cone OF SIZE R=0.7; L97: missing extra closing parenthesis: (\rho(0.7)); L99: bin-by-bin; L104: add a comma before "and"; L110: jet energy scale; L112: add a comma before "and"; LL116,118: jet-energy-scale uncertainty; L125 and formulae below: finish the second set of equations with a comma and change "And" to "and"; L129: jet-energy-scale corrections; L131 and everywhere else in the paper: ⟨Nch⟩ and ⟨\deltaR2⟩; L136: fake -> misidentified; L143: jet-energy-resolution corrections; bin-by-bin; L144:Z2 Monte Carlo SAMPLES; cross-check.


7) Results, L149: In FIGS. 2 and 3; jet SHAPE measurement; L151: Tables 4-43 are out of order - they are mentioned before Tables 1-3; L159: function of JET pT in different JET rapidity regions. L160: add a comma before "and"; L162: pT-ordered; L167: angular-ordered; LL167-168: cluster-based; L190: add a comma before "and"; L205: add a comma before "while"; L211: THE {\sc PYTHIA6} TUNE Z2 ...

Done. The tables have been removed completely (they will be uploaded separately).

8) Conclusion, L213: suggest "Conclusions" in plural; L218: QCD-inspired; L219: Perugia2010 (no space); L224: no point in introducing the MC acronym here - this is the last time the term is used and the only time the acronym is used (not being defined). L228: qualitatively AGREE with.


9) Acknowledgement section is completely missing. I am surprised the paper went as far as CWR in the review process with this obvious omission unnoticed.

We were waiting to make sure we had the latest acknowledgements... It's now included.

10) References, Refs. [6,7,10]: add the arXiv reference; Ref. [9]: add the arXiv and journal info; Ref. [11]: JINST reference should be typeset properly; it's JINST {\bf 03} by the way; doi reference should not be in bold face; Ref. [13] show page range and not just the first page; also add the doi reference; Ref. [15]: use the same style as in Refs. [12,16]: CMS PAS {\bf JME-09-002} (2009); Ref. [17]: JHEP {\bf 04} (2008) add the page number; add the arXiv and doi references; Ref. [21]: JHEP {\bf 05}, add arXiv reference; Ref. [23]: suggest moving in the main text; at the very least add commas before "except" and "while"; Refs. [24,25]: add arXiv references; Ref. [26]: add doi reference (if it exists); Ref. [28]: add arXiv reference.

I don't think there is an arXiv reference for Refs. [6,7]. Added for Ref [10],[11], fixed JINST reference, Ref [13] couldn't find the doi, but added the arXiv reference, fixed Ref [15], [17],[21],[23],[24],[25],[28]. Could not find doi for Ref [26] but corrected author's name smile .

11) Figures. Remove "Preliminary" from all the figures. Add the integrated luminosity information to Figs. 2, 3, 5 either a la Fig. 4 or a la Figs. 6-10. In Fig. 7 separate "7" and "TeV" with a blank space. Figs. 2 and 3 captions, L1: particle-flow jets; L3: particle-level; L4: are shown AS ERROR BARS on the data points; Figs. 4, 5, captions, L2: particle-level; L4: are shown as ERROR BARS on the data points; Fig. 6 caption, L2: delete "Monte Carlo" after Herwig++; L3: Carlo SIMULATIONS with various tunes. Figs. 7, 8 captions, L5: of of -> of; Monte Carlo SIMULATIONS; L6: systematic UNCERTAINTIES. Fig. 9 caption, L1: bin-by-bin.

I will fix the style of the figures as it is suggested. Fixed captions.

12) Tables. Tables 4-43: column "Stat Error" should read "Stat Uncert." in all these 40 tables.

The tables have been removed.

That's all. Good luck with the final approval steps and fast publication!

Comments from Sijin Qian

Dear QCD-10-029 editors:

I have roughly read through the QCD-10-029-paper-v10.pdf, and would have some (large and small) questions and comments from a non-expert's point of view. I list them below, please make a note of it if any of them would be sound.

In case that these comments would not be displayed well, a simple text file is attached with the identical content.

Thank you and looking forward to hearing from you,


Thank you very much for reading the paper and submitting comments!

In general

(1) In all Figures, on the line above or inside the plots, the word of "preliminary" should be removed.


(2) It seems not necessary to list all 40 Tables in the paper. It can be referred to a CMS note; if the authors would not like to elimite all those Tables, it seems better to only mention 2-3 typical Tables in the paper at most.

The tables have been removed from the paper. They will stay in the PAS. The data will be uploaded separately.

(3) Throught out the paper, all Figures and Tables should be put inside the text instead of at the end of paper. The latter is very inconvenient for people to read.

I think papers are done both ways and there are pros and cons for embedding tables and figures or for putting them at the end.

(4) Throughout the paper (including the text and the table captions, etc.), the spaces inside and <delta(R2)> should be reduced in order to avoid the possible confusion between "trianglar quotation sign '<>'" and the greater ">" (and lesser "<") signs, i.e. to change from

"< Nch >" --> ""


"< delta(R2) >" --> "<delta(R2)>"

This is now fixed.

Page 0

(5) The 2nd line of the article's title

(a) To be consistent with the expression on L80 and many other CMS papers, it may be changed from "in pp(non-italic) Collisions" --> "in pp(italic) Collisions"


(b) It should be changed from "at 7 TeV" --> "at sqrt(s) = 7 TeV"


(6) In Abstract, the 1st-2nd lines, is seems sound slightly better if to change from "in 7 TeV center-of-mass-energy proton-proton collisions" --> "in proton-proton collisions at 7 TeV center-of-mass-energy"


Page 1

(7) L2, it seems clearer if a comma is added as "In the framework of quantum chromodynamics (QCD) jets arise ..." --> "In the framework of quantum chromodynamics (QCD), jets arise ..."

This part has been revised.

(8) L7, it seems clearer if a comma is added as "Instead phenomenological models based on QCD ..." --> "Instead, phenomenological models based on QCD ..."


(9) Between L19 and L20, at the end of Introduction Section, normally it has a paragraph to briefly introduce each of other Sections in the paper, e.g.

"In this paper, Section 2 is ...; Section 3 ...; ... are described in Section 4; ...; the conclusions are in Section 6".

But this paper seems missing this paragraph yet.

We think this depends on the length of the paper (and therefore the journal it is submitted to). But we put it in.

(10) L22-23, as the center of the LHC may refer to different things, it may be slightly clearer if two words of "ring" are added, i.e.

"the x-axis points towards the centre of the LHC and the y-axis points up, perpendicular to the LHC plane," -->

"the x-axis points towards the centre of the LHC ring and the y-axis points up, perpendicular to the plane of LHC ring,"


(11) L24, as the numerical value of the angle phi has been explicitly shown on L38 and implicitly at other places, and an angle can be measured in either the radians or degrees, therefore, the unit of phi should be specified as

"the azimuthal angle phi is measured with respect to the x axis and ..." --> "the azimuthal angle phi is measured (in radians) with respect to the x axis and ..."


(12) L32-33, it seems clearer if to change from "for pT = 1000 GeV in the central region [12]." --> "for pT = 1000 GeV in the barral region [12]."

This seems less clear... barrel is CMS jargon, while central describes what is meant by barrel.

(13) L41, would it be possible to briefly explain the "minimal" a little more quantatively, e.g. something like "only deposit minimal energy in the ECAL." --> "only deposit minimal (e.g. < xxx%) energy in the ECAL."

Revised to " the response for single 50 \GeVc pions that only deposit the minimum ionizing energy in the ECAL is close to unity."

Page 2

(14) L51, to be clearer and consistent with the expression on L57, it seems should be expanded (something like) from "In the first, called JPTjets [15], energy deposits ..." --> "In the first method, called (Jxxx Pxxx Txxx) JPTjets [15], energy deposits ..."

Agreed and fixed.

(15) L57, similar as the item (14) above, "In the second method, called PFJets, particle ..." --> "In the second method, called (Particle Flow) PFJets, particle ..."

Agreed and fixed.

(16) L71, the "MC" has been used in the figures later, so it should be explained at its first appearance here; also, since the data can be real data and MC data, therefore the line may be changed from

"using both data and Monte Carlo;" --> "using both real data and Monte Carlo (MC) data;

Added (MC). While you are right about (legacy) referral to Monte Carlo data, I think the reference is clear in the paper. I think Monte Carlo data means something different to what you are saying here -- before having real CMS data, some MC samples were treated as if they were data (with all unfolding corrections, etc). I don't think this applies anymore, and data should mean data and Monte Carlo should mean Monte Carlo...

Page 3

(17) L85, to be consistent with the capitalization of all other Sub-section titles in the paper, it should be changed from "4.2 Definition of the Jet Shape Variables and Their Corrections" --> "4.2 Definition of the jet shape variables and their corrections"

Revised. Deleted these lines.

(18) L86, it seems can be shortened from "As mentioned in the introduction of this paper, differential ..." --> "As mentioned in Section 1, differential ..."

Agreed and fixed.

(19) L92-93, the "cone size of R" has not been defined in the paper yet, it seems should be done here, i.e. "R is the cone size." --> "R is the cone size and defined as xxxxxxxx."

Changed the wording to make it clearer.

(20) L94, it will be clearer if a comma is added, also the variable "R" should be italic to be consistent with the expression elsewhere in this paper, i.e. "measurements of the tails a cone of R=0.7 is used." --> "measurements of the tails, a cone of R(italic)=0.7 is used."


(21) L97, an extra left bracket seems should be removed, i.e. "(rho(0.7)" --> "rho(0.7)"


(22) L102, if the word of "size" is single, the verb should be changed from "The size of the unfolding correction factors are a function ..." --> "The size of the unfolding correction factors is a function ..."

Absolutely! Fixed.

Page 4

(23) In 3 lines of formulae below L125,

(a) at the end of the 2nd line, the period sign may should be changed to a semi-colon sign, i.e. "<delta(eta2)> = ... ." --> "<delta(eta2)> = ... ;"

This was changed to a comma to reflect a previous comment.

(b) at the beginning of the 3rd line, the "and" should not be capitalized, i.e. "And" --> "and"


(c) at the end of formula for "Phi(C)", the period sign should be changed to a comma, i.e. "Phi(C) = = ... ." --> "Phi(C) = = ... ,"


(24) L136, to be consistent with all "pT"s elsewhere in this paper, the letter "p" should be italic, i.e. "high p(non-italic)T jet" --> "high p(italic)T jet"


Page 5

(25) L149, a letter of "s" is missing, i.e. "In Fig. 2 and 3," --> "In Figs. 2 and 3,"


(26) L151, as mentioned in the item (2) above, it may changed from "The complete set of results is tabulated in Tables 4 through 43." --> "The complete set of results is tabulated in Ref.[xx]." or "The complete set of results is tabulated in Ref.[xx], and two typical ones can be found in Tables 4 and 5."

We've removed the tables altogether. They will be uploaded separately.

(27) L153, I'm not sure whether it would sound a little more smooth if to change from "peaked at low r; that is, the jets are highly collimated ..." --> "peaked at low r; it means that the jets are highly collimated ..."

We think the first version is better.

Page 6

(28) L208, a "dot" is missing, i.e. "is shown in Fig 10." --> "is shown in Fig. 10."


(29) L225, it may sound slightly better if to change the order of words from "All these models predict mean charged particle multiplicity values slightly higher" --> "All these models predict the values of mean charged particle multiplicity slightly higher"

We think the original wording is better.

(30) After L232, a short version of Acknowledgment Section (without the Section Series number) should be added.


Pages 7-8, in the References Section,

(31) For the consistency in this Section, all references should have only one page number instead of two. The ones which need to be modified are Refs. [1]-[7], [18] and [25].

Instead we have added page ranges for all references, where possible. (See comments from Greg).

(32) L256, in [9], there is no journal name and other publication info yet.


(33) L260-261, in [11], to be consistent with other Refs. in this Section, it should be changed from

"JINST 3 (2008) S08004 doi:10.1088/1748-0221/3/08/S08004 (2008)." -->

"JINST 3(bold non-italic) (2008)(non-italic) S08004(non-italic). doi:10.1088/1748-0221/3/08/S08004(non-bold) (2008)."


(34) L268, in [15], to be consistent with other PAS Refs. (e.g. [12], [16] and [19], etc.), it should be changed from "CMS Physics Analysis Summary CMS PAS JME-09-002 (2009)." --> "CMS PAS(non-bold italic) JME-09-002 (2009)."


(35) L271-272, in [17], there is no page number yet, also to be consistent with Refs. in many other CMS papers, it should be changed from "JHEP 0804 (2008)." --> "JHEP 04 (2008) page number."


(36) L275, in [19], the word of "determination" seems should be capitalized as "Jet Energy Corrections determination at 7 TeV" --> "Jet Energy Corrections Determination at 7 TeV"


(37) L277, in [20], a bracket is missing, i.e. "Jet Performance in pp Collisions at sqrts = 7 TeV" --> "Jet Performance in pp Collisions at sqrt(s) = 7 TeV"


(38) L279, in [21], similar as the item (35) above, it should be changed from "T. Sjostrand, ... JHEP 0605" --> "T. Sjo(with two dots on the top of "o")strand, ... JHEP 05"


(39) L285, in [24], similar as the item (38) above, "T. Sjostrand" --> "T. Sjo(with two dots on the top of "o")strand"


(40) L290, in [26], there is no page number yet, i.e. "Physics of Atomic Nuclei 58 (1995)." --> "Physics of Atomic Nuclei 58 (1995) page number."


(41) L291, in [27], I'm not sure whether the word of "problems" should be capitalized, i.e. "Inverse problems of Mathematical Physics" --> "Inverse Problems of Mathematical Physics"

You're right, problems should be capitalized. Fixed.

(42) L293, in [28], I'm not sure whether the word of "the" should not be capitalized, i.e. "Tuning Monte Carlo Generators: The Perugia Tunes" --> "Tuning Monte Carlo Generators: the Perugia Tunes"

Since "The" is the first word of the subtitle, we think it should be capitalized.

Page 10

(43) Fig. 2, the lower part of each plot for "MC/Data" should be explained in caption.


Page 11

(44) Fig. 3's caption now is identical with the Fig.2's, I'm not sure whether it can be shortened from "Figure 3: Differential jet shapes for particle flow jets as a function of the ... the bin center; the horizontal bars show the size of the bin." --> "Figure 3: The similar plots as Fig.2 for the pT(jet) range from 140 to 1000 GeV."

Otherwise, both captions of Figs.2 and 3 seem should add a few words on the 2nd line, i.e.

for Fig.2, "axis for different ranges of jet transverse momentum." --> "axis for different ranges of jet transverse momentum from 20 to 125 GeV."

for Fig.3, "axis for different ranges of jet transverse momentum." --> "axis for different ranges of jet transverse momentum from 140 to 1000 GeV."

Namely, two captions of Figs.2 and 3 seem better to not be identical.


Page 19, Tables 1 and 2

(45) The right-most 2 columns of the 1st row should have the cell border lines.

(46) The left-most 2 columns of the 1st row, to be consistent with the expression of "pT" elsewhere in this paper, it should be changed from "Pt" --> "pT"

This change also should be made for Table 3 on Page 20

(47) In the captions, the unit of "pT" should be given as "GeV". This change also should be made for all Tables 3-40 on Pages 20-60.

All the tables have been removed. They are in the PAS, and we will add these corrections later to the PAS.

Comments from Albert De Roeck

Dear Editors Thanks for this new paper on the jets structure studies, which I personally find a very interesting topic,

Some general remarks

1- There is a bit of mix of variables used in the paper, without a clear justification (rapidity and pseudo rapidity). Are we in a postions to say why one was chosen for a given analysis, and the other for another analysis? In that case we should add that information to the paper. Or is this 'historical' ,because the analyses were done by different groups with a different a priori choice? In the latter case we still need some elegant way to say why we chose the variables the way we did, in this paper.

Both rapidity and pseudo rapidity are widely used for jet analysis. Namely for detector level Jets the energy scale corrections and their uncertainty are presented as function of pseudo rapidity while for final results are presented for certain bins in rapidity. For jet shape observables the fraction of jet transverse momentum in sub-cones in rapidity - azimuthal angle space was traditionally used. In the case of the charged multiplicity and the second moment the analysis was performed in pseudo rapidity - azimuthal angle space because these particular values are reconstructed for charged particle tracks and well matched to the similar values of the corresponding charged particles. It is also true that two analyses were done separately that it was decided to include these two different analysis in the single paper at the very late stage when both analyses were almost completed. We would like to avoid this discussion (differences between rapidity and psuedo-rapidity) in the paper but if some one can suggest a sentence or two, we will be happy to put it in.

2- Event selection: wouldn't wou want to select events where the two jets are always clearly separated? I think this is not done now but would seem like a natural selection requirement. What fraction of the jets you study actually overlap in 'cone' space to some extend?

Yes and no. We want to do an inclusive analysis and did not make any such requirement. We also repeated the analysis using only two leading jets for the same reason as you mention. The difference between the jetshapes was shown in approval talk and is negligible. We also compared the cone with clustered constituents and the difference <2% of energy in the annulus 0.6<r<0.7. Rest of jetshapes are identical.

For charged multiplicity and the second moments, we use constituents of as given by the clustering algorithm and thus there is not need for such a cut. It is part of the definition. We used inclusive jet sample for analysis in order to minimize any kind of biases caused by selections using detector level observables. We also compared these results with the similar results for di-jet sample where only two leading back-to-back jets were used. The difference for mean charged multiplicity and for dR2 was below 1% for these two selections at Jet Pt>50GeV. The results are available in the Analysis Note (CMS AN-10-123) as supported material (attached to QCD-10-014).

3- line 73 are the most recent 2010 JetMet corrections used as released a few months ago (you seem to refer to an older paper). If not, why not?

We use the latest corrections available for 2010 data. The two PASes referenced for JEC and jet id cuts are the only public PASes on the subject, as far as we know. However there is a paper to be published in JINST on JEC and pT resolution which is in arXiv. We have added this to the references.

4- Unfolding: only bin-to-bin corrections are used, so no real regularized unfolding. You get like 15% systematics uncertainties with the present method in some regions because of the model dependence. Can't you do better with a real full unfolding, which should not depend on the input? You say that the unfolding uncertainties dominate the systematic uncertainties! Was a full unfolding even tried?

For jetshapes analysis, the "unfolding" corrects for many effects which include (a) smearing between jet Pt bins, (b) inefficiency of the single particle reconstruction (c) smearing of jet axis and (d) smearing of single particle directions. These corrections combination of the convolution of jet fragmentation functions (pt spectrum and type of the particles) with detector response to these particles and jet resolution and the true inclusive jet Pt spectrum. In fact uncertainty on the corrections are dominated by differences in MC generators i.e. jet fragmentation function, used for unfolding. The jet energy scale uncertainty which related to smearing between Pt bins is smaller.

For charged particle analysis (using only tracks and track efficiency corrections are made separately), we tested the full unfolding using Tikhonov regularization method for solution of the integral equations. As far as the response matrix was calculated without any a-priori information on jet spectra a residual scale corrections based on the comparison unfolded MC results with particle level MC truth were required. The unfolded results for mean charged multiplicity and the second moments were found close to the similar results obtained with bin-to-bin corrections. The small difference was included in the systematics. The results of the Tikhonov resgulariztion together with the comparison bin-to-bin and regularization are available in the Analysis Note (CMS AN-10-123) as supported material (attached to QCD-10-014).

5- Is there an overview of all the systematics that have been included in these analyses? Shouldn't one add a table as we usually do in our papers?

There are a lot of corrections, since they are applited to jets in pT, eta bins. We're not quite sure how to make an overall table as you suggest. We do state systematic uncertainty ranges in the text... should we put those statements in a tabular form?

6- The table ordering in the paper is strange: first come the tables from section 5.2 and then those of section 5.1…

The tables have now been removed... although they are in the PAS also in this strange order. We will correct the PAS later.

7-line 177 The Perugia tune discussion here comes a bit late. but since it is proclaimed the 'best model' we have in Fig 6, wouldn't it make sense to show it more also in our comparisons/figures? The choice of models used for the plots looks random. What is the physics question you like to address exactly with these comparison and choices, and why different choices for different figures? If the choice has a definite logics then that would need some more explanation in the text.

We have added Perugia to all jetshape measurements and moved the discussion to beginning of the section along with other tunes.

8- line 195: only here we have something on the PDFs mentioned, as used in the models. Is this choice the same also for the model predictions used earlier in the paper? Then this information comes late! How relevant is the choice of the PDFs? In any case I propose that all information of all MC's should be given in a centralized way at one place, best before you start discussing the results.

We moved all discussion of MCs to the beginning of the section.

9- line 217. What do you mean with "the trends expected from QCD"? This sentence is rather vague and really does not say anything. Are you talking about the ratio quark jet/gluon jet? Then plaease also say a bit on why/how QCD predicts that ratio...

We have rephrased the text.

10- Fig 6: my conclusion from that plot would be that we have essentially always gluon jets the whole time. Not sure you can take the conclusions you make from this plot: I see no real 'approach to the quark jets'. The difference between quark and gluon jets just gets smaller.

We removed this plot from the paper as we are measuring the differences between quarks and gluons. The plot was for illustrative purposes only. The plot is approved and can be shown in public.

11- Figure 10: For what rapidity selection are the gluon/quark jet predictions shown in this figure?

The rapidity range for gluon/quark jets are now indicated in the figure caption.

Is this result consistent with eg Fig 6, so that we can claim we understand the full picture?

We have removed figure 6, since it really has very little content. However qualitatively the two figures agree in the sense that we see more quark jets than gluon jets as the jet pT increases. Figure 6 wasn't made for different rapidity ranges, so we can't comment on that.

Details 12- line 37: you describe only the central/endcap HCAL in line 35, but give the acceptance including HF, so you should say something on the HF specifically, since it is a different technology that is used.

This section has been updated.

13- lines 66-73: somewhere one should also mention we had a test-beam campaign, which is also used to tune the simulation

Modified to say "The ECAL is calibrated using test beam electrons, and photons from $\pi0$ and $\eta$ meson decays in the collider data. The ECAL cells are calibrated such that the response to non-converted photons is close to unity over the whole momentum range. The energy scale agrees with the simulation better than of 1\% in the barrel region ($|\eta|<1.5$) and better than 3\% in the endcap region ($1.3<|\eta|<3$)~\cite{pas_ecal}."

and have added reference for HCAL calibration.

14- line 76-84: Are pile up effects taken into account in this analysis? The pile-up in 2010 was low but not zero. Has this been studied?

We use one one vertex events for jetshapes. The pile up interaction in which the vertex is not reconstructed is generally very soft and thus does not effect the jet shapes. The high instantaneous luminosity data contributed preferentially to the high \pT jets and even there is the effect should be small as the pile-up energy is small compared to those jet Pts.

For charge particle multiplicity and second moment measurements, we use only the tracks which are associated with the main primary vertex. We compared results derived for events with different numbers of primary vertexes (1, 2 >=3) and were in agreement within statistical errors. The corresponding plots are included in AN.

15-line 87: do you want to say here 'at hadron colliders'? They have eg also be measured at HERA, as we discuss in the introduction..

added "at hadron colliders".

16- line 97: rho=0.9 bracket missing

We have removed this discussion.

17- line 116. Something wrong with 'distributions.' in this sentence

We think this is fixed (removed the "the").

18- line 136-138: how are these high density corrections determined? From Monte Carlo? Please explain in the paper.

These correction were determined as functions of transverse momentum and rapidity of reconstructed jets based on comparison of the values for and <dR^2> for the matched particle level and detector level jets for MC samples. This clarification is included in the updated draft.

19- line 164-168: we do not say anything on Herwig6 in this list, which I think is the only one we do not discuss… What underlying event model is used for Herwig (if any)? See also my 'general comment'.

We dropped Herwig6 from the analysis as we do not have full Pt range MC. In any case Herwig++ is new and improved MC

20- line 214 is not completely correct. ATLAS also measured some jet shape distributions and published them already (our reference 10). Just drop the 'first' to avoid complaints.

Thanks. We removed the "first".

21- fig 2: are the systematic excesses at Radius for Herwig in the middle pt range significant or affected by limited MC statistics?

The statistical uncertainties for MC (especially look at the ratio plots) is negligible.

22- Fig 7. Note that the data drop in the last bins on both figures, a bit unnatural and unexpected. The models do not show any intend for a drop. Are you sure this last data point is correct? The first and last bin in a distribution may suffer from edge effects on eg acceptance or unfolding effects, which when not properly taken into account, can be wrong. Or do you believe this drop? It's very strange. Also: what are the correlated errors (in size) for the data on this plot. Is it a large fraction of the total error?

The similar data drop in the last point was observed already for the results at the detector level (before any corrections were applied). Detector level plots were shown in the Analysis Note (CMS AN-10-123) as supported material (attached to QCD-10-014). We consider that drop as a statistical fluctuation of the data. The statistical error in different bins are uncorrelated because these results were derived using bin-to-bin corrections.

23- Figure 8: the scale for the ratio plot is different for the two plots in this figure, which is optically a bit misleading… How does the Perugia prediction do here?

The scales for the ratio were corrected to be the same for the updated plots. We did not compared these results with Perugia prediction.

24- Figure 9. Herwig shows a big deviation here… What do we learn from it?

This is very interesting question. A possible reason of that difference could be the difference in the showering or hadronization models (string for PYTHIA and cluster for HERWIG). We do not have any proofs for but assume that the authors of the HERWIG will be able to explain better that difference when our results will be published.

Good Luck


Comments from Yuichi Kubota


Thank you, authors, for the hard work which made it possible to complete this timely paper. We held a group-wide journal club of this paper draft, and came up with the following comments and suggestions. We hope they are useful to make the paper more perfect!

General comments

  1. It may be difficult to do, but it would be great if more physical interpretation of the results are included in the paper. It seems that for one observation some models fit better than others, while for other observations, another set of models fits better, and it feels that it would be great if we can add statements on what aspects of the models or tunes are responsible for the better fit, etc. Particularly, the paragraph spaning from L169-174, as well as in the conclusion section, will have more impact if physical implications are discussed.

We described the differences in various MC models in general. Determining which parameters are responsible for good agreement or disagreement is beyond the scope of this paper. In general all the tuning parameters are (loosely) correlated.

2. Regarding figure 10, discussion is made that "more forward jets look more quark-like". However, the difference between the two curves is small and the Gluon/Quark lines are shown for an undefined rapidity range -- is it excluded that the main effect is really detector-related (tracking efficiency changes as a function of eta)?

Predictions for quark and gluon jets are shown for |y|<1 but the difference between similar points for |y|<1 and for 1<|y|<2 is less that the size of the point markers (AN-10-123, attached to QCD-10-014). Corrections for tracking inefficiency as function of eta were applied appropriately and uncertainty was included in the systematics shown in the plots.


3. "Shapes, Transverse Size and Charged Hadron Multiplicity" sounds like a mixture of very specific to quite vague terms, and do not seem appropriate for a title. Can we say "Measurements of jet characteristics in pp Collisions at 7 TeV?" More specifically, "Shape is pretty vague and some of us thought it included many more variables than what's written in the paper. Meanwhile, "Multiplicity" is very specific and unambiguous.

Jet shape measurements have a long history in collider experiments. We prefer leaving the current title so that the scientific community interested in jet shape measurements can easily search for this result.


4. - First paragraphs should make it clearer what is measured in the paper. Some things are discussed (e.g. an actual separation of quark and gluon jets) which are not part of the actual outcome -- this is fine, but the introduction should make it clearer what can be expected in the paper in terms of physics outcomes. We believe we have improved the organization of the paper.

5. The organization of the first paragraph could be improved. Suggest that the first sentence should introduce jets (an observable which is not a consequence of the theory framework of QCD) and then the second sentence could discuss that the measurements can constrain our understanding of the phenomenon. We believe we have improved the organization of the paper.

6. L4 - after we say that jets are of prime interest, it would be nice to give a few examples of how they are used in physics. We have revised the introductory paragraph and we hope you like it.

7. - L11-12 - The latter part starting with "provided ..." is not clear. Perhaps something like "additional energy flow arising from the underlying event is included?" This description has been improved.

8.- L15 - suggest something like, "jet structure provide additional information which would further constrain these tunes"

This sentence has been rephrased.

9.- L16 - "Addition" does not sound appropriate. "Meanwhile" or "For example?"

Meanwhile and For example do not have the same meaning as In addition. We have changed "In addition" to "also".


10.- CMS is not brass out to |eta| < 5, but HF (iron/quartz) starts at |eta| > 3. HF is used when jets out to y=3 are considered.


11- Talk about muon system as muons are used in jet reco.


12- L39 and L41 - It's not clear what "close to one" in these lines mean. Do you mean the response is linear? Linear with the slope of one?

Close to one means almost = 1.0. A multiplicative correction of 1.0 means there is no need to correct the jet. Close to one means that the jet only needs small corrections.

Event Selection

13- L45 - uncorrected is jargon, a clearer description of how the jet energy is measured in HLT, how additional corrections are made off-line, and the implications of being "uncorrected" should be given.


14- L46 - "Jets ..." is not clear. Do you mean something like, "Some of the jets with lower transverse momenta are missed by these triggers but are kept with a minimum bias trigger and they are used to study low-energy jets." We don't think it's necessary to describe the min bias trigger, and in fact the current description is likely to confuse readers more than being helpful.

We think it is necessary to describe what min bias trigger mean. We have revised the text.

15- L62 - "jets were clustered" sounds like a few jets in an event are clustered together to form a super jet. How about "jets were defined" or "jets were reconstructed"?


16- L63 - well-known


17- L66 - again, "close to unity" is not clear.

This means the (multiplicative) corrections were close to 1.0. Can you suggest a better phrasing?

Jet Observables

18- L77 - " ... opf the makeup of jets by combining them"?


19- L82 - Unclear. Should make it clear if you are using only jets from 1 vertex, how the vertex is chosen We have added definition of primary vertex in the text and revised the text.

20- L83-84 - Unclear what you are referring to by "corrected back to particle level" For charged multiplicity, the observed number of tracks is corrected to generated number? How about Pt? corrections for the detection efficiencies as a function of Pt? As a function of Pt relative to the jet axis? How about for jet size measurement, what does this mean? The same comment applies to L99 (unfolded to particle level); L131 (at particle level); L192 (deconvoluted to the particle level)

These details for charged particle measurements are explained in the paper. They include: a) corrections to tracker acceptance and nuclear interactions as function of track Pt and eta b) corrections to track reconstruction inside the jets as function of jet Pt and eta c) correction for jet energy resolution (L143-148) The details of analysis can be found in AN-10-123, attached to QCD-10-014.

We improved the description of the correction procedure in the Paper.

21- L90 - since delta r cannot be brought to very small value, what value of "delta r" did you use? It would be nice to include this.


22- equations - Can you be specific about whether PTi's are relative to the beam, or to the jet axis? The comment applies to the equations for the jet size after L125.


22- L93 - "the jet cone size"


23- L94 - Use math mode for R=0.7.


24- L95 - Change to say, "These sums are calculated using a rigid cone around the jet axis, and the particles summed are therefore not necessarily clustered ... Also, in the previous paragraph, you start saying that the effect of underlying events are studies with R=0.7 and in this paragraph you continue to say that R=0.7 and floating cone size implied by anti-k_T are compared to study this effect. This suggest that these two paragraphs should be combined into one.

This has been rephrased.

25- is this only in the case of overlap of jets? (this should be made clear)

We think this is now clear.

26- L97 - paraenthsis issue, not closed and confusing with rho(0.7) (maybe use [rho(0.7)]).


27- L99 - bin-by-bin


28- L101-102 - merge paragraphs


29- L105 - what is the "difference" Is it RMS of the four values? The largest difference of the four?

It is the largest difference of the four. This is now explained in the paper.

30- L107-108 - merge paragraphs


31- L108 - have the results been verified that conclusions are the same when smearing the MC rather than unsmearing the data?

Here we assume you are worrying about the unfolding technique. In this case, there is no quantitative result, so there is no reason to believe that the conclusions will change. It is important to unfold the data for comparison with ATLAS/Tevatron results. For the charged particle analyses, different unfolding techniques were tried, and all agreed with the bin-by-bin unfolding presented in the paper.

32- L116 - stray period. Also, what is the impact larger than what?

Fixed. Larger refers to the single particle calibrations discussed in the paragraph above.

33- L124 - r = 0.5 should be R = 0.5. R is used for "cone size." Also "These include" but we don't have anything else. Why don't we say "They are"?


34- L125 - Perhaps remove _c variables (they are never mentionewd outside the equations) and put N_ch and deltaR2 in brackets. Also, change "with" with "where, "And" with "and", periods at the end of the second equation and middle of the last with commas. Finally, can we be clear if the second moment measurements done with only charged particles, or neutrals are included, too?

We did not remove the _c variables, as they are important to the definition of the observables. As for the rest, we have clarified the text with your comments. Indeed the 2nd moment measurements are done with charged particles only.

35- L131 - Everywhere fix how you use averages. (Use brackets as in equations, not greater or less than symbols)


36- L141 - put deltaR2 in brackets. We don't thing the use of "respectively" is standard here. How about "from 3 to 8% as the jet transverse momentum goes from 40 to 200 GeV, respectively, rising to 20% ..."


37- L143 - we don't understand what "energy resolution corrections" are, and how this is relevant to the measurements. Can we be clearer?

The corrected jets have finite energy resolution, so for example a jet with 50 GeV energy may have a resolution uncertainty of a few GeV, meaning it could be a 47 GeV jet or a 53 GeV jet. This may demote or promote the jet to the next pT bin, which, since the jet shapes are a function of jet pT, also affects the jet shape measurements. (The same is true also for other jet characteristics).


38- L151 - Tables should be referenced in the order they appear (or appear in the order they are referenced).

The tables have been removed.

39-L152 - At high jet PT.


40- L163 - hadronization; not "were" but "are" since this is a general statement. Then in the next sentence, we are discussing specific cases of Tevatron/LEP data or CMS data to come up with particular tunes.


41- L164 - how do we judge "better"?

Fixed. (removed "better")

42- L167 - cluster-based


43- L169 - "from HERWIG"


44- L175 - 1-psi is redefined again. (remove)


45- L190 - "The ratios of the MC" Do you mean data to MC ratios? This is not clear from this.

We mean ratio of Monte Caro to data for all the different Monte Carlos. We've rephrased this to hopefully make it clearer.

46- L191 - "central radial momentum" This is not defined and is not clear what you mean. Fixed.

47- L193 - "based on the PYTHIA ..."


48- L202 - why are we switching to "eta" from "y"? In this paragraph, are we talking about ratio of the delta eta and delta phi in terms of their averages over events, or taking the ratio for each event and average them over events? This should be clear. Also, mention of (lack of) B field on delta phi should be discussed - if the effect is very small, this should be at least mentioned.

We use $\eta$ for charge hadron multiplicity measurement and second moments. It is partially historical. All the measurements are done at the primary vertex and should not be effected by magnetic field.

49.- L210-212 - Why are we repeating this statement here based on previous figure of Fig 7? Are we prepared to say based on this that there are too many gluon jets predicted by these models based on these observations? If so, (1-psi(0.3) seems to say the opposite. Are we prepared to discuss here, too?


50- L212 - systematically?



51- L217 - "trend expected from QCD" Is this really from QCD? Not from kinematics based on the expectation that the Pt relative to the jet axis is more or less independent of the Pt of the jets? We do not understand the comment. We think parton showering is described by the QCD. We have rephrased the sentence.

52- L218 - QCD-inspired


53- L224 - just remove variable r, and MC


54- L226 - remove points from data points.



55- L271 - need DOI entry



56- Add color to lines to assist people who view in color. We preferred to present all the lines in Black color but different style 57- Standardize Pythia capatialization.

Being done.

58- all figures should read CMS, not CMS Preliminary, and styles should be standardized.


59- All figures should have the integrated lumi in a uniform format Done.

60- Are bin centering corrections applied? No, points are plotted in the center of the bin and the horizontal bin uncertainty bars represent the bin size covered by the point. The same is done for data and MC.

Figure 2,3

61- try hard to cut plots of at 0.4*10-2 and use space to make MC/Data bigger w.r.t. data. Done.

62- make it clear these are representative bins in caption.


Figure 4,5

63- The 2nd from the right most point in the data in the right bottom plot of Fig 5 seem to have large upward fluctuation from smooth curve expectation and the size of the error bar. Can we make any comment on this? Are there significant systematic uncertainties in the data which make this fluctuation acceptable? Also the plot title line as well as "CMS preliminary" and "sqrt(S)=7 TeV lines of these plots came out to be smudge on my printer (in Bat 27 at CERN), although they are fine on screen. Can you make sure that there is no defect in the PDF file? - vertical axes inconsistently labelled


64- make it clear these are representative bins in caption.


65- MC/Data comparison plots would be nice here -- consistent with other figures and useful

Added MC/Data ratio for Fig 4-5 and 6 as well.

Figure 6

66- From the writing, we understood that the data part of these two plots are the same. But when you look at the plots, they are not the same. The data in the upper plot start from ~0.44, while the bottom one starts from ~0.32. Can you clarify?

We removed qg plot from the paper but the difference was die to pT bins that we excluded for the qg plot. The up plot was presented starting from 20 GeV while qg plot was presented starting from 30 GeV.

67- make it clear gluon and quark jets are simulation in caption AND legend. Fixed. But this plot is removed from the paper.

68 Figure 7,8,9 - low quality bitmaps - legends not CMS-standard style - "Gluon" and "Quark" jets should be consistently labelled in the legends as from simulation (PYTHIA?)

69- not left/right for the two plots, but should be top/bottom (Fig 7/8)


70- remove extra "of" in the 2nd line from the bottom (Fig 7/8)


Comments from Anne-Marie Magnan

Dear authors,

Congratulations on a nicely summarised paper which contains a lot of very interesting results. Please find below the comments from the Imperial College London group, mainly minor, with a few suggestions to improve the fluidity of reading.

General comments:

1- Many "these" and "this" seem unnecessary. It seems they have been added in order to cut long sentences, but most of the time could be simply replaced by an article e.g. "the". Some of them are highlighted below in the detailed comments.

2- All the text should be moved to present tense unless there is a clear reference to the past. Basically from line 10 to the end, all the description of the analysis and results should be made in the present tense, as it is done in Section 2 for the description of the detector.

3- There seem to be two sets of results, one made with PF jets (jet shapes) and one with JPT jets (charged multiplicity and jet moments). It would make the text read more clearly to move section 4.3 after 5.1, and make section 4 "Jet shape" with 4.1 definition, 4.2 results, and section 5 for charged multiplicity and moments, with again 5.1 definition, 5.2 results. Along these lines, the description of the PF and JPT algorithms could be added to these respective sections instead of in section 3. More specific suggestions are given below in the detailed comments.

4- For the jet shapes, I wonder what the comparison with D6T brings except one additional set of lines which makes the plots harder to read. It seems however fully justified for the charged multiplicity/jet moments as there it gives better agreement with the data.

Although D6T is old but it is using Q2 showering and we would prefer to keep it.

5- the acknowledgements section is missing.


Detailed comments:

6. Abstract: add results, what is "the" conclusion(s) of the paper. It is hard to describe the agreement/disagreement in the abstract without describing the MC tunes etc.

7. Line 10: "these models" -> "the theoretical (or phenomenological) models".


8. Line 15: "describing jet" -> "describing the jet"; "these tunes" -> "the tunes".


9. Line 18: "these quantities" -> "such quantities"; "these predictions" -> "the predictions"

Fixed. .

10. Line 19: the Oxford Dictionary gives v, v. or vs as abbreviations of versus, not vs. Suggestion to spell it out "versus".

This has been reworded.

11. Line 35: "These calo" -> "The calo"


12. Line 44: add one line to describe the trigger system in CMS in Section2, with the definition of the HLT, instead of giving it here. Add that HLT jets are uncorrected calorimeter jets with iterative cone 5 clustering algorithm.

13. Line 50-65: I would suggest to move the specificities of JPT and PF jets to the new "section 4 and 5" suggested in the general comments. I would suggest to keep here only the general description of anti-kT jets, mention you will use two different reco algorithms described later, both use similar jet energy corrections as described in lines 66-73. The size of the jet algo is missing: is it 0.5 for both or 0.5 (JPT) and 0.7 (PF) ? Also, it is not clear from the text that JPT jets are first anti-kT calojets, from which the total energy is corrected using the tracks. It seems from the text that the anti-kT algo is used on corrected clusters, which is not true AFAIK.

14. Line 50: Repetition "...used...using..."


15. Line 51: "calorimeter subdetectors" -> add "information" ? ; "called JPT jets" -> "producing the so-called Jet-plus-track (JPT) jets"; same for PF.


16. Line 53: the PV is not defined, which one is taken if there are several ?

17. Line 54: "with these" -> "with the"


18. Line 62 : "anti-kt jet clustering." --> "anti-kt jet clustering algorithm."


19. Line 64 : " ... the weighting factor for the scaled distance". To the non-expert reader, its not obvious what the "scaled distance" is. Please give a reference or explain further.

The reference is just above (anti-kT jet clustering algorithm).

20. Line 67: "These corrections" -> "Multiplicative residual correction factors"

21 Line 69: "This multiplicative correction" -> "The corrections" or "They" ?


22. Line 73: add basic description of the ID criteria, and that their efficiency is close to 100%.

23. Lines 76-84: I suggest to move lines 78-80 together with the description of PF jets in the new section 4, and lines 80-82 with JPT jets in the new section 5. Lines 82-84 could go to the end of section 3. And lines 76-78 could be moved in the introduction after line 19, as an outline of the paper content. Like it is now, the variables are introduced in a sentence whose point is to describe a selection criteria, it appears clumsy.

24. Line 76 : "to characterise jet structure." --> "to characterise the jet structure".


Line 86: Instead of "As mentionned...", just give again the references after Tevatron and LHC ?

Line 90 : "The integrated jet shape psi(r) "


Line 91: "Here the sums" -> "The sums"


Line 92: parenthesis around (y_jet,phi_jet)

Line 95: "These particles" -> "The particles"


Line 97: typo with parenthesis around rho (0.7)


Line 98: spell out "less than"


Line 103: "0-20%" -> "0 and 20%". Are the corrections in both directions or leading to sysmetically lower/higher values ? "These .... this...." be more specific...

The corrections are only in one direction (hence we didn't put an absolute value or a negative sign...). There are many correction factors (as they depend on many jet variables), so "These" instead of "This" seems appropriate.

Line 104: ref for D6T ?


Line 116: typo ". because" -> ", because"


Line 117: "migration of events produced ... " -> "migration of events between pT bins". Currently it reads a bit unclear.


Line 122: Please use one symbol for psi(r) [i.e. here appears in capital letter].


Line 124: "These include..." -> "The mean charged.... are considered, defined as:"

reworded according to another comment.

Line 125 and everywhere, including caption of figures: make a choice between , <dR^2> or just Nch, dR^2 having them defined as the averages, or spell out "averages of Nch, dR^2" : currently there is a mix of all three...

Agreed and (hopefully) fixed.

Line 126-127: repetition of lines 53-55. If JPT description is moved in this section, can be merged.

Line 130: "these JPT jets": which ones ? The overlapping ones ?

No, this is for all JPT jets. This is fixed in the text.

Line 133: "First" -> "first" ; "corrections for the tracker acceptance" : what is meant by that ? Up to which rapidity does the measurement go ?

Lines 136-138: how are the residual corrections calculated ? With MC ? Data ? The method could be explained briefly, and the size of the corrections given. Also, the text is lacking detail about the systematics uncertainties either here or in the next paragraph.

These corrections were derived using matching between particle and detector jets for PYTHIA6 Z2 and HERWIG++ MC samples. The mean value of ratio for particle level to detector level observables for the same jets were used as correction factors. Te average values for two MC samples was used as the correction factors and the difference was used as systematics uncertainty. The description of systematics uncertainties is added to the text.

Line 139-142: could be rephrased in the form : " The total correction factors for (<dR^2>) range from about 2 to 5 % (3 to 8%) as the jet pT ..... Both correction factors rise to 20% for ..." In which direction are the corrections: always smaller or larger than 1 ? Add detail about systematics here ?

The details about systematics are added.

Line 145: add that Tikhonov regularisation method is a method using the inversion of the resolution matrix, taking into account more properly bin correlations. Is the 2% difference taken as a systematics?

This explanation will be added to the text. 2% difference was indeed taken as systematics.

Line 149: "measurement" -> "measurements"


Line 150: add fig 2 and 3 are for central rapidity region (|y|<1). Fixed

Line 160: Herwig is mentionned (also in figure caption) but not shown... Herwig6 has been removed from the figures already. The text is fixed accordingly.

Line 163: typo in "hadronization". About the different fragmentation models, it might be good to add a separate section somewhere and give a little bit more details.

Line 169: "As seen in the figures" -> "As seen in Fig. XX" not clear which figure shows that, could be a little bit more specific to help the reader understand. Also, "wider" is not specific enough: what does it mean in terms of the variables looked at ?

Line 171: tune Z2 and D6T show the same features...

Lines 173-174 : "in Fig.5, and ... with increasing ..." --> "in Fig.5 and show very small dependence, with jets becoming slightly narrower, with increasing ..."

Line 179: it is not clear at all for me that Perugia fits the data better: Z2 is much better at low pT... Can you be more specific, with a quantitative measurement of the agreement, e.g. Chi^2 or showing the ratio MC/data ?

Line 181: give the matching cone size (or other matching criteria).

Line 183-185: could it be rephrased to make clearer what are the expectations from QCD, what is the observation in data and what is the prediction from the tune compared to the data? It seems for the MC tune that the quark-initiated component could be over-estimated everywhere (and hence pulling the MC distribution lower than the data everywhere). Is that correct ?

Line 188: add that the figures are for two bins in rapidity.

Lines 188-190: the uncertainties should have been described in Section 4.3, with a numerical estimate of how much each of the sources contribute. From table 1, it seems the total uncertainty is around 3%: does that mean it is dominated by the unfolding (2% according to line 146 if I interprete that number correctly) ? Also, I cannot see anywhere in the text an explanation of how the influence of PU is taken into account.

Lines 195-196: add references for the PDF sets.

Line 196: "Both tunes" -> there are 3: all 3 ?

Lines 207-212: move after line 201 for better continuity of the variables used ?

Line 208: introduce also the theory curves in that plot: Pythia tune Z2 and gluon/quark components.

Line 209: "hypothesis": needs to be supported by some reference or further document. Currently it does not sound that intuitive why for example the fraction of quark-induced jets increases with increasing jet rapidity. Again, could it be rephrased to make clearer what are the expectations, the observation and the predictions from the tunes ? Connect with intro lines 16-18 ?

Line 210-212: 3 MC models mentionned, but only one is plotted in fig 10... Typo in "systematically".

Fixed typo.


Everywhere: sometimes only publication, sometimes publication+doi, others publication+doi+arxiv. Make uniform ?


Line 256: ref missing.


Line 263: was there a real publication ? Same for PF line 270, and JEC line 276.

Not as far as we know. There is now a JEC paper for CMS and we have added it to the bibliography.

Line 277: typo in sqrts



All: add that it is pp (proton-proton) Done.

Fig 1,2,3,5: add luminosity.


Fig 2,3: there is no Herwig++ for the low pT bin. Any reason ? In ratio plot, left axis max screwed up by min of plot above. Caption: mention in central rapidity region. It seems no uncertainty is considered on the MC predictions. Could this be motivated in the text?

Herwig++ is available for the pT bin in 30 GeV - 1 TeV. That is why Herwig++ is not shown for 20-25 GeV bin. The rest is fixed.

Fig 4: the line style for Pythia 8 is inverted with D6T compared to figure 2 and 3, except for the top-right figure. What about the ratio MC/data ? Caption mentions Herwig but it is not shown.


Fig 5: ratios MC/data ?


Fig 7, 8: caption: left-right -> top-bottom. Nch -> , typo "of of". Add "on the data measurement" at the end.


Fig 8 caption: first (right) to be removed.


Fig 9: caption, "the systematic uncertainty" add on the data measurement.


FIg 10: caption: left-right -> top-bottom.



- these tables should probably be removed and given in "computer-friendly" format e.g. database/Rivet... But nevertheless a few comments below.

The tables have been removed.

- stat uncertainties are increasing/decreasing/increasing. I suppose it comes from the different statistics available for the different triggers due to prescales. If so, it should be added somewhere in the main text in section 3. Also, how is the prescale taken into account, i.e. how are the different samples normalised to each others ?

- Table 3: the last pT bin is not given, compared to Tables 1 and 2. Any reason ?

- Tables 4-...: caption, typo in uncertainties. Explain what are CF, Frag, SPC.

The tables are removed based on classical jet shape results.

Comments from Nicola De Filippis


Note: the text we propose to include is underlined


- Could be useful to compare to ATLAS Phys.Rev.D83:052003 (2011), arXiv:1101.0070 (paper on the same subject that was submitted two weeks before this)

This is now in our list of references.

- Strongly recommend the full text to be edited by a native English speaker

- Too many tables (43) even for material support!

The tables have been removed.

- In the references you are referring to only two CMS papers. Really these are the only CMS papers that became publications or are you using the references to the PAS notes and not to the relative papers? Please check.

We have updated the references and they are complete as far as we know.


In the abstract: Line 1: specify which characteristics Line 4: is this charged particle the Charged Hadron of the title? If yes please specify charged hadron instead of charged particle Line 4: differential and integral -> since you are measuring something as a function of something or integrated over something, please specify simply jet shape distributions and give the two definitions in the text specifying which kind of informations can be extracted by the differential and integral jet shape and why it is important to measure both.


Line 5: put a comma after “however”


Line 9: properties in previous works on e+e-

We think the original wording is better.

between 19 and 20: At this point it would be nice and useful to define the framework of the paper (goals, kind of measurements etc.): In this paper…

Line 12: "tunes" is a jargon. Specify what is "tunes" Line 18: "may lead"-> that's not a very strong motivation for the analysis: specify what, how and why are you doing in a clearer way

Event Selection:

Line: 48: put a comma after “4.65”


Line 65: describe how jet look like when they overlap

That seems like too much detail -- when 2 anti-KT jets overlap, the energy in the overlap region is assigned to one of the jets depending on the kT of the jet. So one of the jets could be conical with the other a cone with a bite taken out, or more likely if the jets are close in energy, neither jet will be conical.

Jet Observables:

Line: 84: the explanation of the expression “back to particle level” is a bit too short, and could result to be unclear.

Line 86: delete “of this paper”


Line 87: actually in the introduction there is no reference to LHC previous measurements


Line 88: please specify in which range you have extended this measurement and what was the range

measured by previous experiments

We have added a reference to the ATLAS measurement, and think the text reads ok now.

Line 90: delta r value is not specified. Moreover: “and outer radius … delta r/2 around the jet axis. Line 90 (formulas): the meaning of ri, R is differed to lines 91-93, it’s a bit too far.

We have now written in the text the delta r value we use (0.1). The meanings of ri and R in the formulas is the same as in the text in lines 91-93.

Line 103: it is unclear how the QCD model can affect the detector response to the jet; of course the detector

response does not depend on the QCD model that you use to model the response itself

The QCD model affects which part(s) of the detector the jet populates, and the composition of the jet, which changes the detector's response to the jet. So the response depends on the QCD model of jet production. We have tried to clarify this in the text.

Line 116:remove full stop after “distributions”


Line 119: if you are quoting a maximum uncertainty do not say 2-3%, specify one number or the cases where it is 2% and where it is 3%

We think the original is fine and gives a flavor for the uncertainty due to JES.

Line 125 (formulas): use commas instead of full stops, where instead of with, and instead of And. Phi_c, eta_c are used only here, and are not defined in the text.

Line 139: factors would be quoted 1.02-1.05 better than 2% or 5%

We are happy to go with the consensus on this.


Line 149: delete comma after “2 and 3”. Un-personal form would be better than “we present”.


Line 150: put a comma after “uncertainties”.


Line 155: delte coma after “region”

The consensus seems to be that this comma is necessary. Line 158: again, un-personal form would be better than “we plot”.


Line 165: ref.9-> in the intro you said that this work was five pages later the work has been completed. Please clarify if the work is ongoin or already completed.

Agreed and fixed.


The discussion of the comparison data-MC generators should be improved.

Line 228: you cannot say "qualitatively" in the conclusions of a Physics paper. Specify better what is in agreement and what is not removing the word "qualitatively"!

Removed the word "qualitatively".

STYLE COMMENTS (1) 2.) The CMS Detector: Line 41: change "one" to "unity"


4.) Jet Observables Line 77: give us -> provide more complete -> complete: or is it complete or is it not. "More complete" doesn't exist! makeup-> constituents


Line 78: since you already defined "PFJets" as particle flow jets, use consistently PFJets in all the text


Line 82: one->the primary vertex


Line 85: use small letters for Jet Shape....; no emphasis needed


Line 90: the symbol used for the integral jet shape (psi) is sometimes written in capital letters (also in Figure 1) Please use consisten notation in ALL text AND figure

Fixed. All psi's are now capital.

Line 90: parenthesis missin at the very end of the line


Line 99: bin-by-bin


Line 102: are->is


Line 107: "lowest pt bins"->"lowest-pt bin"

We think the original is better.

Line 109: "Other sources of systematic uncertainties considered"-> remove considered

Line 110: "jet-energy scale" -> "jet energy scale (JES)"; do not use jet-energy scale with the hypen between jet and energy

We have gotten different comments on this. We are willing to use whatever the standard is. Right now, we are using "jet-energy-scale".

Line 116: "distributions. because" -> "distributions because"


Line 117: events->jets


Line 122 : "In addition to studying"-> in addition to the study


Line 123: psi symbol written in capital letters


Line 126: "associated with"-> associated to


Line 133 "steps: First" -> steps: first


Line 143: "bin by bin" -> bin-by-bin


Line 144: "cross check" -> cross-check


5.) Results

Line 152: "the data"-> data (in all the text)

Line 153: "the jets"-> jets


Line 154: "axis, and they"-> axis while they


Line 158: "where we plot the a function"-> where the amount of plotted as a function


Line 163: hadronizatoin -> hadronization


Line 166: if you already used ref.24 (and the same is valid for every reference) do not repeat the reference every time you are discussing something related to that paper. References only ONCE in all the text!

Line 176: "compared with"-> compared to


Line 190: remove "on"


Line 193: "predictions employing"-> predictions based on


Line 212: systemAtically


Line 212: "as already noted"-> so why are you repeating it? Are you adding something more? If not, remove it


6.) Conclusions fix it! units on x-axis are missing

Line 217: "trends expected from QCD" -> predictions based on QCD theory


Line 218: remove "inspired": nothig in Physics is "inspired"

Changed "inspired" to "based".

Line 219: "we observe that PYTHIA6"-> "it results that PYTHIA6"

We believe the original phrasing is better.

Line 220: "initial CMS soft pt data"-> unclear; splease specify better

remove "low" at the and of the line


Line 221:"those in the data"-> "those observed in data"


7.) References

Ref14-> why are you referencing a thesis? Why you didn't find a paper or article on the subject? Put a more serious reference

We will check into this.

Ref15: remove "CMS Physics Analysis Summary" and use only CMS PAS, as done for the other references Ref16: put CMS PAS in bold, as done for the other references

All CMS PAS references are now the same.

Ref23: put a proper reference to Pythia Z2 tune



Line 66 : jet p_T response :is it a well defined quantity or a qualitative one? in the second case might it be jargon?

We think "response" is well defined. At least the same word has been used in other CMS publications without explanation...

Line 68 : what do you mean by "in-situ measurements" ?

Measurements made during data taking.

Line 79 : reconstructed vertex -> reconstructed primary vertex

We think the original is better.

Line 82 : from one : which one? any choice criterium?

The main primary vertex in the event was defined as the vertex with the maximum sum of transverse momenta of reconstructed tracks. This clarification is added to the text.

Line: 89 : annulus -> ring

We think the original is better.

Line: 97-98 : ...edge (rho(R)) below the 2% level.


Line: 102 : are -> is ; vary -> varies [the subject is singular here: "size"]


Line: 103 : , as this -> since this


Line:107 : as high as 15% -> the 15% level

We think the original is better.

Line: 114 : resulting -> related

We think the original is better.

Line 114: was negligible -> resulted to be negligible

We think the original is better.

Line 114 : as this effect largely cancels out -> as expected since this effect should largely cancel out


Line 116 : . because it ->since it

We think the original is better.

Line 117 migration to higher p_T bins of events


Line 119 : results -> implies

We think the original is better.

Line 122 In addition to studying -> Beyond studying

We think the original is better.

Line 122 we have measured characteristics -> we have measured the characteristics

We think the original is better.

Line 124 These include -> These characteristics include


Line 125 defined via -> defined by


Line 125-126 2nd formula row : put "; and" instead ". And"


Line 125-126 formulas: why using p_T,i while before you used the notation p_Ti ?


Line 128 : with -> according to


Line 129 between the track -> between each track


Line 133 steps ; First -> steps. Firstly

We believe "First" is better.

Line 135 Next -> Secondly

We believe "next" is better.

Line 137-138 ranges : ... and applied -> ranges (...) and


Line 140 rise to 20% -> rise up to 20%

We believe "rise" is more correct than "rise up".

Line 142 : rising to -> rising up to

We believe "rising to" is more correct.

Line 152 : annulus ->ring

This was originally described as an annulus, so we believe the word "annulus" is less confusing.

Line 153 : low r ; that is -> low radius r, namely


Line 154 For the lowest p_T bins -> At low p_T bins

We think the original wording is better.

Line 156 : a radius r=0.1 around -> a cone of radius r=0.1 around


Line 169 : As seen in -> As depicted in


Line 169 : figures : which ones? better to specify (or say "all figures")

This referred to Fig. 4. It's now fixed in the text.

Line 169 : data are wider -> wider is vague, please re-express the sentence


Line 172 : than evidenced in data -> than found in the data


Line 179 : "clearly fits the data best": is it really clear or so evident? might be better a sentence like "seems to fit better the data"

Perugia2010 fits the data much better at low pT and follows the correct trend at high pT. We've left out the "clearly" but the statement is still stronger than "seems to fit better the data".

Line 212 : sistematically


Line 212 : at |y|<1 -> for |y|<1

<span style="color: #0000ff"> Fixed.

Line 218 : generators and tunes -> generators and related tunes


Line 226 : than the data points -> than the data



Fig.1: it is unclear if rho is the surface at that circle or the area of the cone that has as a basis that grey surface; same for psi in the figure below

We welcome ideas of how to make the figure more clear.

Fig2: Luminosity is missing; Herwig is mentioned in the caption but is missing in the upper left plot; what happened? Specify. Weird behaviour of the curve in the first two bins of the upper left plot. Label "1.0" on the y scale is "broken"; units on x-axis are missing; add it! Remove "Data points....size of the bin" phrase from the caption since it is explaining something too obvious

Luminosity info is added. Herwig++ sample is available for only 30-1000GeV. That is why it is not shown for the 20-25GeV bin. x axis unit is added.

Figure 2 (and other similar following): - x-axis label : why not "radius r" instead of "Radius" Done.

- why not minimum y value set to 10^-1 instead of 10^-2 (leaving maximum y unchanged) : it would help to compare curves

10^-1 would be too low for high pT bin figures where we have narrower shapes, and it is good to have identical y axis ranges so we cut it at 0.4*10^-2.

- uncertainties on the data points ? are they within the size of the markers? if so please say it explicitely! Uncertainties are shown with "green band" while statistical uncertainty is shown on top of data points as vertical error bars.

- in general: how the green area in MC/data ratio is calculated? shouldn't be 4 ratio curves with 4 shaded regions? if not - and you adopted a solution to help reading the plot - please explain this solution exactly in the caption.

For each MC line we determined the MC/Data ratio and plot it in the ratio pad. There is only one "green band around unit 1 and that represent the total systematic uncertainty on "data points". Notice that the ratio pad has "only total systematic uncertainty" while the original figures have "absolute errors" that is shown in the green band. We did not want to show 4 "green band" based one 4 MC type.

- in general : y minimum scale value on y-axis for the upper (rho(r)) plot comes out to be superimposed to the maximum value (1.5) fo the lower (ratio) plot -> please shift upwards the y minimum value of the upper plots.


Fig4: this does not really seem to depend on |y|, why are there 6 plots? There is a small dependence. It is a known fact that the fraction of quark jets increase with the increasing rapidity which cause narrower shapes as a function of rapidity.

Fig5: place labels consistently (example 20 GeV < pT < 25 GeV) in all the plots; Herwig is missing in the upper left plot

Herwig++ is not shown for 20-25GeV bin since this MC sample is not available below 30GeV.

Fig 6: extend the MC predictions lines to the borders of the plot!

Fig7: remove the shadow from the legend, left and right plots are probably top and bottom, "also shown are the predictions..."-> predictions ... are also shown; for luminosity symbol use L or integral(L); symbol "L" is used fo instantaneous luminosity!

Shadow were removed from the legends.

Fig8: delta R^2-> probably < delta R^2 >; "also shown are predictions"-> predictions are also shown


Fig 9: explain the behaviour of PYTHIA6 D6T at 200: is that an effect of low statistics? Errors? Why is the curve so irregolar?

This is a question for Olga/Vladimir.

Tables: too many significat digits: example 17.63 \pm 0.57-> 17.6 \pm 0.6 Ptmin and ptmax -> p_T^{\rm min} and p_T^{\rm max}

Agreed. Tables have anyway been removed.

Figure 8: top instead of left, bottom instead of right. Correct the double “of” in last sentence


Fig8: delta R^2-> probably < delta R^2 >; "also shown are predictions"-> predictions are also shown


Fig 9: explain the behaviour of PYTHIA6 D6T at 200: is that an effect of low statistics? Errors? Why is the curve so irregolar?

PYTHIA6 D6T sample has 10 times less statistics than other MC samples. We smoothed the MC lines shown in that figure.

Tables: too many significat digits: example 17.63 \pm 0.57-> 17.6 \pm 0.6 Ptmin and ptmax -> p_T^{\rm min} and p_T^{\rm max} Table 4 and others: remove "systematics uncertainties are added....uncertainty"

The tables have been removed. They will be uploaded separately. We will take into account your comment on the number of significant digits.

Comments from Paolo Azzurri



Dear Authors,

congratulations for this nice paper with very interesting results. We generally find the paper to be quite well written. You can find below some comments and suggestions from the CMS-Pisa group.

Best wishes

The CMS Pisa group

General: - we understand that may tables will be moved "outside" the paper: how will this be done and dealt with in the text ?

References to the tables have been removed from the paper. The data will be uploaded separately.

- the insets in all figures should be unified with similar fonts and amount of information.

- should some comment be added on the recently published atlas results ?

This has been added.

- we would prefer to use GeV/c and GeV/c2 units when appropriate (instead of GeV everywhere)

Very good point. We changed all references as you suggested.

Abstract: "… of jet characteristics in inclusive jet production from 7 TeV … " "… the anti-kT algorithm as a jet definition .." "...we measure the mean charged particle multiplicity, the differential .." "… a function of the jet transverse momentum." is the meaning of "corrected to particle level" clear enough ?

Incorporated all phrasing changes. We think "corrected to particle level" is clear, but will think about it.

Section 1 - line 7: "first principle" looks too ambitious

This phrasing has been changed to "analytically".

- line 8 : add comma after "models"


- line 12: "the Tevatron data"


- line 14: "higher energies" "at LHC" should be added for consistency with line 87


- line 19: "may lead to methods able to discriminate gluon by quark jets"


Section2 - line 22 : "in the counterclockwise beam direction"


- line 32 : 5% for pT=1TeV is too good, where did you find it ? Ref [12] does not have pT resolutions. Can we rather quote measured momentum resolutions ?

This has been changed to quote the momentum resolution at 100 GeV (1%). We can't find documentation for this number, however it is quoted in other CMS papers.

Section 3 - line 45: "15,30, … can you specify better how these triggers are taken simultaneously with different pre-scaling, and combined for the measurements ?

- line 66: "pT response " looks like a jargon and a definition should be desirable, you can also cite the jet response and resolution paper.

We put a small defining phrase in the text. We do cite the jet response and resolution paper later in the discussion of jet energy scale uncertainties.

- line 69 : "The correction is a multiplicative factor"


Section 4.2 - line 79: "reconstructed vertex" the definition of the vertex quality criteria should be desirable

- line 89-90: What is the value used for delta ? is it delta =0.1 ? Can you add this information ?

Yes, it is 0.1. This is added in the paper.

- line 97: [rho(07)]


- line 102: decide if "jet pT"or "pT with jet as superscript" as at line 129 and in other lines and formulas - line 102: "jet y"or "y with jet as superscript" as at line 92 and in other lines and formulas

Fixed both variables to be consistent.

- line 116 : "distribution, because it" Fixed.

Section 4.3 - line 123: How do the results change if the charged (add charged) track pT is lowered down to 300-200 MeV ?? Or made higher (1GeV)?

This is a question for Olga/Vladimir.

- line 124: use D=0.5 to avoid confusion with the other r and R variables. also why do you use 0.5 and not 0.7 for example ?

Fixed. Here D=0.5 is used to reduce ...

- formulae after line 125: use capital Delta or sigma to avoid confusion with the lowercase delta in the differential formulae from the previous section

- formulae after line 125: "… , and …"


- line 126: "calorimeter jet,"

Inserted comma.

- line 129-130 "The jet energy scale corrections for these JPT jets range between 2-3%." what jets are we referring to here ?

This means just for JPT jets in general. We removed the "these".

- line 136,137: pT jet, jet pT….


Section 5 - line 149 spell out Figure

We think the convention is to use the abbreviation. If we spell it out in one place it should be spelled out everywhere.

- line 150-151: add " for abs(y) less than 1" as in fig 2,3


- line 151 : "The complete set of results " add "for different abs(y) regions". Should be better if we say in more details: "...set of results is tabulated in tables 4 through 10 for 0-abs(y)-0.5, in tables 11 through 17 for 0.5-abs(y)-1.0, etc….

The tables have been removed.

- line 163: "event, radiation and hadronization were" (correct hadronizatoin)


- line 164: ".. of the collider data …"


- line 166: "improved diffraction model" one should specify better that in Pythia8 "single diffractive" and "double diffractive" generators are implemented, while in PYTHIA6 (and HERWIG ? ) generator the diffractive component is not at all implemented. - line 169 "… at low pT the data are wider than the Monte Carlo predictions…" can you explain better how to infer form which figure that the low-pT data jets are wider ?

- line 175: "...,the fraction of jet..." why the same definition is repeated here, it was already done at line 159


- line175: Fig. 6 is simply the sum of the first two bins in y of fig.4 with the addition of Perugia 2010 ?

The Perugia prediciton was added to any figures we have int he paper (fig2-6). Figure6 refers to central rapidity bin, |y|<1. Figure 4 is shown for different rapidity bins.

Yes. By adding two bins in rapidity we are still in the very central region and the data statistics are better for comparing with MC.

- line 179: if Perugia 2010 fits the data best why was not used to fit the other distributions? Done.

- line 187-188: Add "for two different abs(y) intervals". It should be better if the values of the two intervals would be specified.::j


- line 181: "initiated jets"


- line 182 : "from the two partons into two partons processes"


- line187: Add "the charged particles multiplicity Nch of the jet…"

We're not sure exactly where to add this.

- lines 193-197: Again why, if Perugia 2010 best describe the data (see again at line 219), is not used to fit the data and only PYTHIA and HERWIG are used to try to reproduce the data of fig. 7 and 8 ?

-line 212" "systematically"


Section 6 line 219: not really convincing that "PYTHIA6 with the Perugia 2010 tune best describes the data"

Figure 1. Caption: Change in something like "Pictorial definition of ......quantities. For analytical definition of these quantities see formula in the text"


Caption fig.2 and fig.3: Add "for abs(y) less than 1. Comment on the fact that HERWIG++ is missing in the lower pT jet bins.


Figure 4: L=36 pb-1 is quoted in this figure while in other figures is not quoted. Please unify…


Figure 6 bottom: specify in the inset that gluon and quark jets are still from Perugia2010 Done, but q/g figure is removed from the paper.

Figure 6 top: it is not clear here that the perugia tune really gives the best agreement with data also what is the prediction curve of perugia ? the full line in the bottom plot does not correspond to the dash-dotted line on the top plot, and actually does not seem to correspond to any of the curves on the top plot …

The ratio plot is added for Figure 6 as well so that one can see how these MC tunes deviate from the Data. And bottom figure has been removed from the paper so the inconsistency between the line styles are removed.

Figures 7,8: maybe mention that in the MC/Data windows the data points are relative to themselves (data/data) and therefore lay on the ratio=1 line.

Figure 8: caption: change (left) (right) to (top) (bottom)


Figure 9: Add in the inset "Abs(y) less than 1"

Figure 9: Is herwig dashed or dashed-dotted ? The definition in the caption does not match the figure legend.

Figure 9: what is the reason for the large fluctuations in the dotted (pythia6?) predictions ?

Figure 10: Add in the two insets "PYTHIA6Z2 Gluon (Quark) Jets"

Tables 4-43: Please define CF(Z2), Frag Sys, SPC Sys and possibly also all the others.

The tables have been removed. They are now in the PAS only and we will update the PAS with these comments.

-- PelinKurt - 23-Oct-2011 -- AnwarBhatti - 28-Oct-2011

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