[Clascomment] OPT-IN:Differential Cross Section for gamma d -> omega d using CLAS at Jefferson Lab

[Daniel Carman]

Dear Taya and Ken,

I have read through your draft of the omega photoproduction paper dated
Jan. 18, 2018 that was circulated for Collaboration-wide review. In general,
the paper is well laid out and the presentation and discussion are clear. I
have just a few comments on grammar/english/style to be considered. If
you have any questions, let me know.

Regards,
Daniel
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Page 1:
  - Typo in title (reaction listed twice)
  - Line 36. Use "... QCD, which can now extract ...".

Page 2:
  - Line 80. Use "... system consisted of six ...".
  - Line 82. Use "... that covered ...".
  - Line 91. Use "The three-momenta were reconstructed by the drift chambers
     and the particle identification was determined by ...". (The charge determination
     is mentioned in the next paragraph.)
  - Line 97. Use "... [12] that surrounded the target ... scintillator paddles that
     surrounded the exterior ...".
  - Line 101. Use "... g10 data set to optimize ...".
  - Line 115. I am a bit confused by the discussion. Multiple hypotheses for PID
     could be satisfied for a single charged hadron with the approach that you
     described. Is this possible with your approach? If so, how did you handle this?
     If not, please revisit the text for clarity.
  - Line 119. Use "The photon with the time that most closely matched with the
     vertex time was selected.".
  - Line 125. "A tagger energy correction was also applied to the selected photons."
    You should say what you were correcting for, the scale of the correction, and
    the associted systematic uncertainty.
  - Line 145. Use "... rejection and $\omega$ yield ...".
  - Line 149. Use "... missing mass from the deuteron ...".
  - Line 154. Use "... Lorentzian for the peak and a second-order polynomial for the
     background.".

Page 3:
 - Fig. 2 caption.
   - Line 2. Use "... shows the distribution of the missing mass ...".
   - Line 5. Use "... fit shown by the solid-red curve.".
 - Line 159. Use "... GeV, which were further ...".
 - Line 160. You have switched here your convention of units. I suggest that you
   let c=1 throughout and list momentum transfer with GeV^2 units.
 - Line 165. Use "... 782.65~MeV and 8.49~MeV, respectively.
 - Line 177. Use "... cross section required a ...".
 - Line 178. Use "... based upon the geometrical ...".
 - Line 179. Use "... of the detector subsystems.".
 - Line 192. Use "cross sections".
 - Line 200. Use "... propagated from the uncertainties of each ...".
 - Line 201. Use "cross section".
 - Line 209. Use "systematic uncertainties".

Page 4:
 - Fig. 4. Missing units on the key on the upper left.
 - Fig. 4 caption. Last line. Us "statistical uncertainties".
 - Line 214. Use "cross section".
 - Line 223. Use "... $b_{\omega N}$, to be equal.".
 - Line 226. Use "... amplitudes, are kept fixed ...".
 - Fig. 5 caption. Line 2. Use "... compared to that of a calculation ...".
 - Line 233. Use "... values as an input parameter ...".
 - Line 235. Use "The outputs were ...".
 - Line 247. Use "... shows contributions from ...".

References:
 - Standard style is to not include a comma before "et al.".
 - Ref. 19 is out of order. It should be the last in your list to put the references
   in the order cited.