[Clascomment] OPT-IN: Subthreshold photoproduction of phi mesons from deuterium

[Daniel Carman]

						October 18, 2010


Xi and Haiyan et al,

I have read through the latest draft of your phi meson paper. I have 
a few comments that I pass along below. Let me know if you have any 
questions or need any clarification. I am assuming that you intend
to submit this for publication in PRL. Given the very modest result with
no real interpretation, I would strongly bet that it will be rejected.


				      Regards,

				      Daniel

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Page 2.
  Abstract.
    Line 2. Use \"tagged-photon beam\".
    Line 6. Use \"... predictions based on a quasifree mechanism.\".
  Left Column.
    Paragraph 1.
      Line 3. Use \".. between two interacting ...\".
    Paragraph 2.
      Line 13. Use \"... magnitudes of the $K^+$, $K^-$, and $p$, which ...
      Line 13. You never state what this total momentum cut is. Seems like
        this would be appropriate.
      Line 14. You mention the simulation studies, but it is not clear what
        studies you are talking about. I would suggest something like
        \"... is confirmed by our detailed simulation studies (discussed
         below).\" to put this in better/more complete context.
      Line 15. Use \"... is less than that from backgroun ... for example,
        subthreshold/near-threshold $\\phi$ ...\".
  Right Column.
    Paragraph 1.
      Line 1. Use \"... of a bound state and direct $K^+K^-$ production ...\".
      Line 2. Use \"... and as such, it allows for ...
    Paragraph 2.
      Line 5. The sentence beginning \"The reconstructed $\\phi$ event
        originated from photoproduction ...\" reads quite awkwardly. It 
        sounds like you are saying that the associated high-momentum
        proton was reconstructed only because you required a triple
        concidence and because the detector is not perfect in its
        coverage. Both of these statements don\'t make full sense.
    Paragraph 3.
      Line 2. Remove the sentence containing the reference to the Theta+
        It is not necessary to mention and cite anything to do with that
        work here. It is distracting and irrelevant for this work.
      Line 8. Use \"... photon-tagging system ...\".

Page 3.
  Table II caption.
    Line 1. Use \"A comparison of the g10 and g11 ...\".
    Line 2. Use \"... is for the $E_\\gamma$ range of ...\".
    Line 3. Use \"... the target center of the g11 ...\".
    Line 4. Use \"... upstream from the nominal center ...\".
  Left Column.
    Paragraph 1.
      Line 6. Use \"... period for calibration purposes.\".
      Line 7. The sentence beginning \"This finding is consistent ...\" is
        quite awkward. You are trying to say that you also looked in a
        much higher statistics data set in the same photon energy bin
        and saw no strong phi peak. But g11 is mentioned without any
        introduction. You mention nothing about the relative sizes of
        the g10 vs. g11 hydrogen data sets and provide no information
        that allows me to understand how Fig. 1 right came about.
     Line 11. Use \"... data set, where the $\\phi$ peak ...\".
     Line 12. Use \"... panel) is the corresponding spectrum from the g11 ...\".
     Line 14. I have no idea what you are getting at or implying with the
       sentence \"The difference in the acceptance between the g10 and g11
       ...\". Is this an affect that I need to consider as important to
       appreciate what you are showing here?
     Line 15. Use \"... the g10 and g11 data sets has not been ...\".
     Line 19. You discussion on relative acceptances in terms of magnetic
       field and target position is very hand-waving and qualitative. Without
       some quantitative perspective, it provides nothing of real value.
     Line 23. The sentence beginning \"The g11 yield from hydrogen around ...\"
       is not a proper sentence. Please review.
     Line 28. Use \"... kinematic settings of g10 and g11.\".
   Paragraph 2.
     Line 6. You allude to the experimental resolution but never give a
       value. You should state it here explicitly.
  Right Column.
    Fig. 1 caption. The statement \"The unit is number of events ...\" is
      awkward. I suggest that you provide a y-axis label with events/2.5 MeV.
    Paragraph 1.
      Line 2 after Eq. 1. Use \"Such a fit was ...\".
    Paragraph 2.
      Line 18. Use units with c=1 here for consistency throughout this
        paper.

Page 4.
  Left Column.
    Fig. 2 caption.
      Line 3. Use \"$\\phi-N$\".
    Paragraph 1.
      Line 2. Use \"... which is the four-momentum ...\".
      Line 6. What was incident beam energy for g11? I don\'t know what
       the \"g11 kinematic region\" is based on what has been written here.
      Line 16. Use \"$N-N$\".
    Paragraph 2.
      Line 1. Use \"... as input to the ...\".
  Right Column.
    Paragraph 1.
      Line 15. Use \"... and the $\\phi-N$ FSI ...\".
      Line 21. Provide a reference to the input cross section model.
      Line 25. You state a maximum sys. uncertainty of 44%. However,
        according to Table 2, it is 32%. Please check.

Page 5.
  Left Column.
    Paragraph 1.
      Line 1. The discussion of the QF calculation is too scant to know
        what to make of it. Therefore I don\'t know what to make of the 
        curve provided in Fig. 3 or the ensuing discussion here.
      Line 3. Use \"... calculation is based on ...\".
      Line 7. Use \"... in the MC\".
    Paragraph 2.
      Line 3. Here you use the words \"below the production threshold\". I
        assume that this is a remnant from your last draft. The title is
        near threshold, not subthreshold. Please review.
      Line 4. Use \"... for protons accessible ...\".
      Line 6. Use \"... for protons.\".
  Right Column.
    Ref. [8]. Journal name is in italics. 
    Ref. [14]. Not cited in this work.