• We think the motivation of the measurement is not stated clearly. In the introduction, the reader doesn't receive a sense why is this measurement important. There is only one sentence on the theory (QCD), that we suppose makes predictions of the measured cross-section, and we think these should be mentioned. Therefore, we think the introduction should be reformulated and present clearly the motivation of the measurement. For instance, some sentences which seems irrelevant should be omitted, such as the mention of the mass and width of the J/psi, and the mention that the J/psi is useful for B tags and spectrometer calibration, since this is not related in any way with the present paper.

  We disagree.

• We think the paper uses too much jargon and technical details, especially in the FMU hardware and trigger descriptions. These were difficult to read to us, and will be certainly more for a non-CDF reader. For example, mentionning the "Commercial STRUCK latches" and "RABBIT ADC's" is probably inappropriate in a PRD. We'll give more examples in the specific comments.

  Technical details are necessary. Jargon is defined. There are references to the hardware.

• The results are quoted: 197.3 +- 9.3 +- 28, but we think the use of decimals is irrelevant with an uncertainty of 28, instead: 197 +- 9 +- 28.

  OK, we've dropped the .3, 28 is the systematic error.

• The paper flips between eta and polar angle, we recommand the consistent use of pseudorapidity. Also, both "event vertex" and "primary vertex" is used, again, we recommand to use only one of them.

  Eta and theta are properly used. "Primary vertex" has been adopted as universal.

• CDF is not defined, and the 0 in D0 should be "slashed" (and D0 should be also defined).

  We don't know what CDF stands for. D0 without the slash is the usual term in the literature.

• The words "central" and "forward" when talking about detectors should be defined.

• We thought it was difficult to understand the luminosity section. The first paragraph talks about saturation, but it is not stated how we correct for it. The second paragraph talks about rate limit. The connection between the two paragraph is not clear for the reader, maybe starting the 2nd paragraph by "However, the whole CDF luminosity was not all available..." would help. At the beginning, there is mention of "total cross section for these hits", which doesn't make sense.

  Sure it does. The CDF luminosity is referenced. The wording has been changed to define a 'store'.

• The disposition of figures and tables seems randomly distributed throughout the paper, some of them were within the text, others were after references. We suppose this will be corrected for the final version.

  PRD editors can shuffle things.

(When reproducing the text, I put corrections between <>)

• Abstract
  • Typo: a space missing between 5.2 and pb^-1.

    fixed

  • "The measurements extend...": measurement should be singular.

    there are several measurements, as a function of pt.

• Introduction
  • See general comments, we believe it needs to be rewritten.

    We don't think so.

• Section 2.1
  • The title should be changed, it is "Central Detector", but it talks about wall, plugs and forward calorimeters.

    Wall and plugs were part of the central detector. Forward cals were not, but are included anyway.

  • "The distribution of the ppbar colisions was Gaussian...": Instead: The distribution of the primary vertex of ppbar colisions was Gaussian about the nominal center of the detector."

    Original wording is fine.

  • p.2-3: "... on extrapolation of tracks from the central tracking chamber - CTC.". Instead, should add column: "...chamber: CTC".

    ???

  • p.3: "The vertex time projection chamber<:> VTX..."

    Clear as is

  • p.3: It is stated that the prim. vertex was found using SVX, CTC and VTX, but unless we're wrong the VTX wasn't used for that. Also, the sentence saying that "all available information" was used is awkward, for instance the calorimeter wasn't used.

    The VTX was used in calculating the vertex.

  • p.3: "There were several instrumented components to the calorimeter, both electromagnetic and hadronic": This formulation of this sentence is awkward ("both electromagnetic and hadronic"). The continuation: "covering polar angles from 90 degrees down to 3 degrees" gives the impression half of the detector is missing.

    It is explicitly stated that the detector is symmetric.

• Section 2.2
  • p.3: "... had two iron toroids <with> 7.6m <of> outer diameter, <a> 1m inner diameter and <a thickness> of 1m".

    OK as is.

  • p.3: "The ratio of multiple scattering angle to bend angle ... was 16.6%". Two comments: 1) we believe a ratio should not be quoted in %. 2) We don't understand this sentence since the average of multiple scattering is 0%?

    We added 'rms', which has been defined earlier, and dropped the %.

  • p.3: The quotation of position of drift chambers has inconsistent precision.

    Fixed.

  • p.3: We believe the word "road" is jargon and should be defined.

    Road is a good English word with clear meaning.

  • p.5: In left figure, lines are identified but not the blocks (not obvious for common readers).

    Sentence added to caption.

  • p.5: " Going clockwise from horizontal..., next is the patern of ...". This is an example of a difficult sentence to read, we recommand separating it into two.

    Reads OK.

  • p.6: This figure is blurred, is it possible to scan a nicer version?

    Best one available.

  • p.7: ", <where> the <triggered> muon was in ...". Also, triggered muon is an example of jargon and needs to be defined.

    The meaning is clear.

• Section 2.3
  • p.7: "The pads divided the wedge into three <5 degree wide> segments in phi...". Also, no segmentation in eta is quoted.

    Phrase added regarding eta segmentation.

  • p.8: The "rate limit" of the trigger: We think you need to define that.

    Rate limit means rate limit.

• Section 3 (see general comments also)
  • p.8: A "collider run" is jargon, and needs to be defined as something like: "a period of data-taking defined as a continuous store for the beam".

    Sentence added.

  • p.9: "Matching this list to the runs in the J/psi analysis": Needs to be more precise about which J/psi analysis, there are many, and add a reference probably.

    'the' changed to 'this'

• Section 4.1
  • p.9: The issue of the ratio of multiple-scattering to magnet bend angle: Better to state explicitly (if we understand this point correctly): the UNCERTAINTY in the bend angle arising from multiple scattering effects is about 0.16 of the total bend arising from the magnetic field.

    That is correct. It is in the formula on page 7 for the momentum resolution.

  • p.10: There is quite a bit of space spent talking about the SVX, but the conclusion is that it cannot be used, thus we suggest to shorten it to a single concise sentence.

    It is as concise as practical.

  • p.10: If you keep it: "The high spatial resolution of the SVX..." should be changed to "good resolution", right now it is misleading...

    Done

  • p.10: Same paragraph: we think the discussion about the J/psi-jet balancing should be either omitted, or more explained why it is done, because in the current form it seems irrelevant.

    A phrase was added.

  • p.10: We think the discussion about the cassette tapes is unnecessary.

    It is true, and does no harm.

  • p.10: "These events were retracked": the word "retracked" is jargon and needs to be explained.

    Removed.

• Section 4.2
  • The list of selection criteria contains the opposite sign cut, but it is stated that after "the like sign background was ... after quality selection criteria", therefore it should be omitted in the list of cuts? This is also misleading in the caption of figure 7.

    The procedure is clearly described.

  • p.11: The cut #9: "Two FMU level 3 trigger" is unclear, probably better: Both muons to pass the FMU trigger selections.

    The two FMU level 3 trigger is described earlier.

  • p.11: "...the efficiency dropped off sharply for pt < 10 GeV/c, <as shown in figure 5>, because of the limited solid angle of the FMU..."

    Word order in the text is preferred.

  • p.11: The cut on the chi^2 is at 11.6, one could ask why such a value (why not 12)?

    Because 11.6 is the ideal chiprob>98%.

  • p.12: "this number was the product of wires, pads...": This sentence needs to be rewritten (wires and pads are not numbers).

    Fixed.

  • p.12: The "like sign <background> substraction".

    OK.

  • p.12: Probably better to talk about the explanation for the shift peak to 3.2 GeV/c^2 the first time this value is mentioned on p.12.

    ???

  • p.12: The Monte Carlo is not described.

    Yes it is.

  • p.16: "... the other two, with a good chi^2". Better:" with a good fit".

    'Good chi^2' is an acceptable term.

  • p.17: "Quantization axis" needs to be defined.

    OK, done.

  • p.17: dE/dx is undefined, better to use something like energy losses through ionization of material.

    A phrase was added, but dE/dx is a universal expression for energy loss through ionization.

• Section 5
• p.17: "Table 2 begins the calculation of...": Reads awkwardly. Also, there is a typo later in the word calculation.

  Fixed

• p.19: In table 2: 1) MCgen and MC accept are not defined. 2) Last column, the value have wrong uncertainties.

  The authors and godparents independently verified the calculations. The MC terms are defined in the text.