[Clascomment] OPT-IN:Exclusive eta electroproduction at W > 2 GeV with CLAS and Transversity GPDs

[Daniel Carman]

Ivan et al.,

I have read through the draft of your paper draft on eta electroproduction and my comments
are included below. I think that the presentation and the writing is fairly clear in most
places. Let me know if you have any questions.


					        Regards,
						
						Daniel

************************************************************************************
General:
 - You are not consistent with usage of "Fig." vs. "Figure" in the text.

Page 1:
 - Abstract:
   - Line 4. Use "... with those previously measured for ...".
   - Line 6. Use "Generalized Parton Distribution". 
 - Line 18. Use "... specifically for pseudoscalar meson ...".
 - Line 23. Move citations [3,4] from line 27 to the end of the sentence on line 23.
 - Line 28. Use "... and $t$, where $x$ ...".

Page 2:
 - Fig. 2 caption. Line 2. Use "... CLAS detector in the plane of the beamline as constructed by ...".
 - Fig. 2. Add an indication of the beamline and the beam direction. Add a scale on the drawing also.
 - Line 11. Use ".. the beam axis that divided the detector into six sectors.".
 - Line 26. Use "... [19] that was used ...".
 - Fig. 3 caption. Line 3. Use "DC Region~1".
 - Line 31. Add a suitable reference for the IC.
 - Line 34. Move the sentence on lines 34-36 to after the sentence on line 31 (and part of that paragraph).
   So, "... from the target. The IC consisted of 424 ...".
 - Line 54. Use $W$.
 - Line 59. Minor notation issue here. How about "... about $20\times10^3$ events, ...">

Page 3:
 - Line 2. Use "Particle identification".
 - Line 36. Use "... sectors are shown in ...".
 - Line 58. I am confused regarding $\sigma_t$. Is this number paddle dependent or do you use a single
   value for the entire TOF system?
 - Line 60. Use "Section IV B below) ...".

Page 4:
 - Fig. 5 caption. Line 1. Use "Yield distributions for ...".
 - Line 5. Use "... Section IV B below.".

Page 5:
 - Line 4. Use "... problematic SC counters, ...".
 - Line 40. Use "... in Fig.~8.".
 - Line 53. Use "... shown in the insert ...".

Page 6:
 - Fig. 8 caption.
   - Line 2. Use "... $M(\gamma\gamma)$, after ...".
   - Line 8. Use "... sidebands that ...".
 - Line 22. Use "... cross sections, the data were ...".
 - Line 25. Use "... Fig.~4.".
 - Line 25. Use "... For each $Q^2 - x_B$ bin there are nominally 8 bins ...".
 - Line 27. Use "... -x_B$ bin, as well as ...".
 - Last line. Use "... radiative contributions to the ...".

Page 7:
 - Fig. 10. Include bin values on the plot.
 - Third line in left column. Use "... [20]. The radiative corrections, $\delta_{RC}$, for the
   experiment are given by
 - Line 4. Use "... EXCLURAD [21], which has been ...".
 - Line 25. Use "... indicate that the measured cross sections were $\sim$13\% lower than the
   available published cross sections over a wide kinematic range.".
 - Fig. 11. Change plot label to "Relative systematic uncertainty".
 - Fig. 11 caption. Use "systematic uncertainties".
 - Line 29. Use "... SC counters, which was ...".
 - Line 31. Use "... factors that are not ...".
 - Line 41. Use "... can be estimated separately for each kinematic bin $(Q^2,x_B,t,\phi_\eta)$.".
 - Line 43. Use "... not possible, global values ...".
 - Line 48. Use "systematic uncertainty".
 - Line 50. Use "... constant $\delta_{Norm}$ was obtained separately for electrons ...".
 - Line 51. Use "... resulting in a mean value ...".
 - Line 54. Use "systematic uncertainty".
 - Line 55. Use "... systematic uncertainty excluding the uncertainty on the absolute ...".
 - Line 58. Use "... on all of the sources of systematic uncertainty that were studied. Finally, ...".

Page 8:
 - Line 41. Put data in the CLAS physics database as well and include reference to the database.

Page 9:
 - Add comma after Eq. 6 for proper punctuation.
 - Line 5. Use "... is a fit to $d^2 ...".
 - Line 6. Use "... the $\cos \phi_\eta$ and $\cos 2\phi_\eta$ terms.".
 - Line 13. Use "... functions initiated by ...".
 - Line 25. Use "... shown in Fig. 13 ...".
 - Line 27. Use "... obtained in the fitting procedure ...".
 - Line 28. Use "... statistical uncertainties on the individual ...".
 - Line 42. Use "... shown in Fig. 14.".
 - First line after line 48. Use "After the structure functions were obtained, fits were ...".
 - Second line after line 48. Use "$t$-dependence".
 - Line 51. Your values 1 to 1.8 GeV-2 do not agree with Fig. 15. Here we see values from 0.1 to 2.5 GeV-2.

Page 10:
 - Fig. 13. What is the big plot in the upper left corner? It is not referenced in the caption.
 - Fig. 13 caption. Line 1. Use "... $(Q^2,x_B)$ bin extracted from ...".

Page 11:
 - Fig. 14. What is the big plot in the upper left corner? It is not referenced in the caption.
 - Fig. 14 caption. Line 2. Use "... handbag calculations~[26] asymptotically predict ...".

Page 12:
 - Fig. 15. Missing units on the key values.
 - Line 6. Use "... on Fig. 13.".
 - Line 7. Use "GPD-based".
 - Line 25. Use "$\theta_\eta=0^\circ$".
 - Line 26. Use "... (GFFs) that denote ...".
 - Line 42. Use "... GPDs that are responsible ...".
 - Line 46. Use "... production as compared to $\pi^0$ production), ...".

Page 13:
 - Fig. 16 caption.
   - Line 2. Use "The top row presents data ...".
   - Line 6. Use "systematic uncertainties".
 - Line 2. Use "... data, and Eqs. 10 and 11 above, one ...".
 - Line 8. Use "... to underestimate the ...".
 - Line 17. Use "... for $\eta$ and $\pi^0$, the ...".
 - Line 18. Use "... higher than the theoretical prediction, which is ...".
 - Line 34. Use "... of the quark composition of the $\pi^0$ ...".

Page 14:
 - Line 15. Add a reference to this proposal or experiment.
 - Table V. You are not consistent with your significant figures for the values in this table.

References:
 - Do not list preprint numbers if a paper is published.
 - You should be consistent with your listing of collaborations, (CLAS) vs. (CLAS Collaboration).
 - [11] is not a CLAS Collaboration paper.
 - [15] Use "Wolin".
 - [17] Use "G.S. Adams".