[Clascomment] OPT-IN:Flavor Dependence of qq-bar Creation Observed in the Exclusive Limit

[Daniel Carman]

Mac and Kijun,

I have read through the draft of your cross section ratios paper. I think the paper is
written in a clean manner and your main conclusions are not muddied down by lots of
extraneous or tangential remarks. Your main conclusions on the ratios are relatively
qualitative, but the data presented allows the reader to appreciate them for what they
are. My comments on the draft are given below. Let me know if you have any questions.


				        Regards,

				        Daniel

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Page 1:
 - Your first paragraph amounts to only a single sentence. I would not split the first
   two paragraphs, but join them as one.
 - Line 19. I suggest ".. pair being produced during the flux-tube breaking was estimated ...".
 - Line 22. Missing period after "string tension".
 - Line 43. Sentence structure a bit awkward. I suggest "... 0.05 to 0.3. To extend these
   results we have measured the ratio of ...".
 - Line 46. You state that these studies allow for investigation in a new kinematic region,
   but you don't say what that region is. I would explicitly make this clear here.
 - Line 55. You do not define nu.
 - Line 56. Here you use CM and later you use c.m.. Pick one and stay consistent. You might
   also define CM the first time that you use it.
 - Line 59. I suggest "... scattering plane. The differential cross section can be expressed as:"
 - Eq.(1) is not consistent with Ref.[10] as claimed. To be consistent, remove the factor of 2
   in the epsilon pre-factor for sigLT. Also I am not a supporter of the $\phi^*$ notation as the
   * superscript is associated with c.m. notation. I would suggest to use the $\Phi$ notation as
   was used in Ref.[10].
 - Line 60. epsilon is not the transverse polarization of the virtual photon, but the ratio of
   the transverse to longitudinal polarization. I think the standard term is that epsilon is the
   "polarization parameter" of the virtual photon.
 - Line 61. The terms sigL, sigT, sigLT, and sigTT are not response functions, but structure functions.
   I suggest "... photon, and the terms $\sigma_T$, $\sigma_L$, $\sigma_{TT}$, and $\sigma_{LT}$ are
   the transverse and longitudinal structure functions and the two interference terms, respectively.".
 - Line 70. I suggest "... creation probabilities as a function of $Q^2$, $W$, and $\cos \theta_m^*$.

Page 2:
 - Line 87. Use "... identification, and scintillators and ...".
 - Line 95. Use "... momentum and path length from the drift ...".
 - Line 101. Use "... charged hadron, and determined ...".
 - Line 118. You state that you use a Gaussian for the signal fits. What about the radiative tail? Doesn't
   this noticeably affect the quality of the fits?
 - Line 149. You use the term "judged reliable". This sounds awfully qualitative. Was this based on the
   distributions of chi**2/nu matching expectations for your sample of fits?
 - Line 159. Use "... corrected yields in our two $Q^2$ ...".

Page 3:
 - Line 166. Units in rm font and spaces after the value.
 - Line 167. Use "... independent of $W$ for each of our $\cos \theta_m^*$ bins." (This is important to add to
   not give a false impression about the clear angular dependence.
 - Line 193. The notation here as written within a paragraph is a bit clunky. I suggest that you make each rate
   expression have its own line.
 - Fig. 1. What is the blue dashed line? This is not described in the caption. Also your thin blue line is quite
   hard to see.
 - Line 199. Do not begin a paragraph with this line (it appears indented). Also replace the semi-colon with a comma.

Page 4.
 - Fig. 2 caption. Line 2. Use "... as in Figure 1, but plotted ...".
 - Line 210. Use "... 0.07, depending on ...".
 - Line 224. You state that "one ... can do explicit corrections for two-body phase-phase". It is not clear what
   you are trying to say here. Are these corrections important? Did you do them?

Page 5.
 - Refs. [2] and [3] are switched (see your text where you explicitly list author names with the reference).
 - Refs. [6] and [8] are not complete. You have listed the journal, but not the authors.
 - While I am a fan of Ref. [13], I did not see it referenced in the text.