[Clascomment] OPT-IN: Target and Beam-Target Spin Asymmetries in Exclusive pi0 Electroproduction for Q2>1 GeV2

[Daniel Carman]

Peter et al.,

I have read through the draft of your latest paper on the pi0N asymmetries for 
larger Q2 and include my comments below. Let me know if you have any questions.


					        Regards,
						
						Daniel

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Page 3:
 - Do not use all capitals for "Lexington, KY".

Page 4:
 - Line 74. Add the standard "Mecking et al." CLAS reference here.
 - Line 82. Use "... inclusive electron scattering ...".

Page 5:
 - Line 99. Your notation for the reactions is awkward and internally inconsistent.
   You put particles in parentheses that are not detected in the event reconstruction
   and you simultaneously use parentheses to indicate a parent particle that is
   reconstructed from its decays. Also I do not know what you mean by the second
   reaction in the list. Is this a reaction with one of the pi0 photons missed? I
   think this notation throughout the paper needs attention.
 - Line 106. Use "... by requiring a positively charged track with a time-of-arrival
   at the scintillation counters within 0.7 ns of that predicted ...". Also, why 0.7 ns?
   Is this a 3sig cut? If so I would add this after the 0.7 ns.
 - Line 112. Give here the length of the target and the vertex resolution of CLAS.

Page 6:
 - Line 117. Use "... at the EC in agreement with the ...".
 - First line after 122. Use "... by requiring a deposited energy of at least ...".
 - Second line after 122. The proper abbreviation for nanoseconds is "ns" not "nsec".
   Check this through the paper.
 - Add a period after your reaction listing before line 123.
 - Line 124. Use "... or other mesons.".
 - Line 133. "There is considerably more background under ...". But comparison of 
   Fig. 1a and Fig. 1b shows distributions that are essentially identical in the signal
   and tail regions. There is no evidence here to support your statement that there is
   considerably more background under the pi0 peak here.

Page 7:
 - Put a period after Eq.(1).
 - Eq.(1) is not intuitive to me and I have no idea what your chi2 construct here is
   based on. What does this distribution look like and why do you choose chi2 < 4?

Page 8:
 - Fig. 1. How can Fig. 1a and Fig. 1b have the same statistics given the fact that one
   includes the CLAS proton acceptance? Also, you do not state where the photons are
   detected in CLAS to make these plots. For EC-EC, EC-IC, and IC-IC configurations, these
   plots should be different (and this motivate different cut limits) due to the different
   resolutions of the two calorimeters.
 - Line 154. Here are several times in the paper you say "All other applicable exclusivity
   cuts have been applied." or "All other relevant exclusivity cuts have been applied.".
   These statements are vague and they should not be. What cuts have been applied for all
   plots should be made clearer.
 - Line 157. You state "that matches the wings on the ammonia distributions on the low-mass
   side of the peak". However as seen in Fig. 2b, there is no matching on the low-mass side
   of the peak. In fact the matching on either side of the peak is quite similar and not
   particularly indicative that the background is fully accounted for.
 - Line 161. No negative sign on Mx cut.
 - Line 162. Use "... with $A > 2$ and 90\% from ...".
 - Here you are talking about the ammonia and carbon in your target but you have not said in
   this paper what your target is. I shouldn't have to read Ref.[1] to know this. I suggest
   that you add a couple of sentences to describe to the reader what your experimental
   configuration is.

Page 10:
 - Line 186. Use "Fig. 4".
 - Line 194. Missing period at the end of the sentence.

Page 11:
 - Line 3 after 200. Use ".. (Fig. 6a), with weaker population in this region for lower photon
   energies ...".

Page 12:
 - Eq.(2) and (3). Use "degrees". End Eq.(3) with a period.

Page 13:
 - Fig. 5 caption. Use "... topology for a) 1.1 ...".

Page 14:
 - Line 218. Use " ... 1.5~GeV were used, as mentioned above.".

Page 15:
 - Lines 223, 226, 227, 228. You use a different number of significant figures for you
   different angle limits. Then for your different W limits. Then for your different cos theta
   limits. Be consistent.
 - Line 225. Use "... gradually increase to achieve ...".

Page 17:
 - Line 240. Use "... and target polarization ($P_T$), as well as the value of $P_B$, is listed
   in Table I for the two Parts of the experiment.".

Page 19:
 - Line 283. This bit is confusing as written. How about "... forming the asymmetries, the
   expectation is that the acceptance functions should be fully compatible statistically."?
 - Line 285. What was verified by forming the chi2? What is the chi2 that you are talking about 
   here?
 - Line 286. Can events belong to more than one topology in your analysis? I should think not
   if you are combining the computed asymmetries. However, this should be stated explicitly
   in the paper.

Page 20:
 - Line 297. Spurious "as" at the of the sentence.
 - Line 310. Use "... electron scattering rates, fits to the ... spectra, and the value ...".

Page 22:
 - Fig. 9 caption. Use "... [10] and the blue dashed curves ...".
 - Line 350. Use "... data and in Fig. 12 for the ...".

Page 25:
 - Fig. 25 caption. Typo on "rowss" in second line.

References:
 - Put references in the order cited in the paper.
 - Ref.[2], [3]. Space after comma and before page number.
 - No comma after author and before "et al.".
 - Ref. [8]. Use "Phys. Rev. C".