OPT-IN:Extraction of A^sin(Ï)_LU moments from the hard exclusive Ï^+ channel off the unpolarized hydrogen target in a wide range of kinematics

[Daniel Carman]

Dear Stefan et al.,

I have read through the draft of your pi+-n electroproduction paper include my comments
below. Most of what I have provided below will serve to improve the grammar and readability
of the paper. If you have any questions, let me know.

Regards,
Daniel
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General:
 - APS does not use "Color online" anymore. This should be eliminated from figure captions.
 - I think that adding parentheses about the argument of trigonometric functions makes the
   notation more cumbersome. I suggest that you eliminate these parenthesis throughout the
   paper
 - Units should be in roman font throughout.
 - Use "JLab" throughout and not "JLAB".
 - When a figure reference begins a sentence, you should use "Figure" instead of "Fig.".

Page 1:
- Title: This title definitely does not pull the reader in. I recommend that you revisit this and
   try to include something about the physics that you are accessing.
- Abstract:
  - Line 2. Use "... region, with nearly full ...".
  - Line 6. Use "Generalized Parton Distributions" and "Transition Distribution Amplitude".
  - Line 8. Use "GPD-based".
  - Line 10. Use "... we found $A_{LU}^{\sin \phi}$ to be negative, while ... near 90$^\circ$ in the
    center-of-mass.".
  - Line 12. Use "... mechanisms that can help ...".
- Left column:
  - Paragraph 1:
    - Line 4. Use "... and the four-momentum transfer to the nucleon $t$.".
    - Line 8. Use "... factors (defined at $t = -Q^2$)."
  - Paragraph 2:
    - Line 2. Use "... $-t/Q^2 \ll 1$), hard exclusive pseudoscalar meson ...".
    - Line 5. Use "... elements that can be expressed ...".
    - Line 7. Use "Distribution Amplitude".
    - Line 11. Use "3-dimensional".
    - Line 13. Use "... of the partons to their ...".
    - Line 17. I recommend that the sentence beginning "Although the DVCS process ..." starts a new paragraph.
    - Line 22. Use "... spin that is difficult ...".
    - Line 25. Use "... recent years have shown that the naive ...".
- Right column:
  - Paragraph 1:
    - Line 3. Use "... photons that are asympotically ...".
    - Line 7. Use "... and $\eta$ electroproduction, ...".
    - Line 9. Use "... to explain the cross section ...".
    - Line 10. Use "... and the large beam- and ...".
  - Paragraph 2:
    - Line 8. Use "Transition Distribution Amplitudes".
    - Line 18. Use "... the mesonic cloud of the nucleon."
    - Line 21. Use "Recent publications on exclusive $\pi^+$ ...".

Page 2:
- Left column:
  - Paragraph 1:
    - Line 1. Use "... and on $\omega$ electroproduction ...".
    - Line 2. Use "... kinematics have shown a first ...".
  - Fig. 1. Poor quality - grainy in appearance.
  - Paragraph 2:
    - Line 5. Use "... domains that are well ...".
    - Line 13. "We present a pioneering measurement ...". I really object to calling your own work "pioneering".
      That is really for others to decide. I am certain that nothing in this paper is "pioneering".
    - Line 15. Use "... $ep \to e'n\pi^+$ for full $\pi^+$ center-of-mass (CM) angular coverage ...".
  - Paragraph 3:
    - Line 2. Use "... cross section $d\sigma/dt$ in terms of structure functions is given by:'
    - Eq.(1). Trig functions should be in rm font (e.g. use \cos and \sin in math mode). End the equation with a "," for
      proper punctuation.
    - Line 1 after Eq.(1). Trig function in rm font (\tan). epsilon is the transverse virtual photon polarization not the
      longitudinal polarization.
    - Line 2 after Eq.(1). Use "polarization".
- Right column:
  - Paragraph 2:
    - Line 2. Use "... and the unseparated cross section ...".
    - Line 3. Use "... \epsilon d\sigma_L$, the cross section of Eq.(1) can be expressed as:".
    - Eq.(2). End the equation with a "," for proper punctuation.
    - Line 1 after Eq.(2). Use "... where the subscripts $ij$ represent ... and the target, respectively.".
    - Line 3 after Eq.(2). Use "... (BSA) of hard exclusive pion ...".
    - Eq.(3). End the equation with a "," for proper punctuation.
    - Line 1 after Eq.(3). Use "cross section".
    - Line 2 after Eq.(3). Use "... each beam helicity state ($\pm$).".
  - Paragraph 3:
    - Line 2. Use "CEBAF Large Acceptance Spectrometer".
    - Line 7. Use "The CLAS detector consisted of ...".
    - Line 10. Use "drift chambers".
    - Line 12. Use "... based on a lead-scintillator ...".
    - Line 14. Use "... with a Cherenkov counter.".
  - Paragraph 4.
    - Eq.(4). End the equation with a "," for proper punctuation.

Page 3:
- Left column:
  - Paragraph 1:
    - Line 2. Use "center-of-mass".
    - Line 1 after Fig. 2. Use "... cut limits was extracted."
    - Line 2 after Fig. 2. Use "This ratio slowly decreases for ...".
  - Fig. 2 caption. Line 3. Use "... (left) and in the backward region (right).".
  - Paragraph 2:
      - Eq.(5). End the equation with a "," for proper punctuation.
      - Line 2 after Eq.(5). Use "beamline".
      - Line 3 after Eq.(5). Note that the uncertainty of 2.4% is statistical. There is also a 3% systematic
        uncertainty due to the target foil polarization uncertainty.
  - Paragraph 3:
    - Line 5. Use "... events in the forward and ...".
    - Line 11. Use "cannot".
    - Line 15. Use "... background that spreads under ...".
- Right column:
  - Fig. 3. Poor quality - grainy in appearance.
  - Fig. 3 caption:
    - Line 2. Use "... emitted in the forward (left) ...".
    - Line 4. Use "statistical uncertainty".
    - Line 5. Use "Eq.(3)".
    - You have not differentiated between the vertical "error bars" and the horizontal "bin widths". This needs
      to be clarified.
  - Paragraph 1:
    - Line 2. Use "... determined in the same way as for ...".
    - Line 8. Use "bin-by-bin".
  - Paragraph 2:
    - Line 1. Use "... systematic uncertainty were ...".
    - Line 2. Use "... including particle identification, background subtraction, beam polarization, and the ...".
    - Line 11. Use "bin-by-bin".

Page 4:
- Left column:
  - Fig. 4 caption:
    - Line 1. Use "... as a function of ...".
    - Line 4. Use "GPD-based".
  - Paragraph 1:
    - Line 6. Use "... for both the longitudinally ...".
    - Line 8. Use "... contribution to the transversely ...".
  - Paragraph 2:
      - Eq.(6). End the equation with a "," for proper punctuation.
      - Eq.(8). End the equation with a "," for proper punctuation.
- Right column:
  - Paragraph 4:
    - Line 6. Use "... kinematics is clearly negative.".
    - Line 8. Use "$u$-channel".
    - Line 9. Use "TDA-based".

Page 5:
- Left column:
  - Paragraph 1:
    - Line 3. Use "However, calculations ...".
  - Paragraph 3:
    - Line 2. Use "... $x_B$ in the top plots and as a ...".
    - Line 3. Use "... $Q^2$ in the bottom plots, for pions ...".
    - Fig. 6 caption. Line 1. Use "... $Q^2$ (top) and $x_B$ (bottom)".
- Right column:
  - Paragragh 2:
    - Line 8. Use "cannot".
    - Line 9. Use "GPD-based".
    - Line 15. Use "... observed around $\theta_{CM} = 90^\circ$".
  - Paragraph 3:
    - Line 6. Use "U.S. Department of Energy".

References:
  - Give Collaboration names with all references as appropriate. (e.g. F.X. Girod {\it et al.} {\it (CLAS
    Collaboration)}, ...".
  - [17]. Spurious parenthesis after "et al.".
  - [18]. Typo on author's name.
  - [35]. If only two authors, separate names with "and" instead of ",".
  - [42]. Use "B.A. Mecking".
  - [43]. Typo on author's name. Use "Eur. Phys. J C {\bf 65}, 137 (2010)".
  - [46]. Pire et al. reference not used in the text
  - Put references in the order in which they are cited in the text.
  - I found typos on 2 authors names (see above). Please check the rest to catch any other problems.