[Clascomment] OPT-IN:First Measurement of the Polarization Observable E in the p(gamma, pi+)n Reaction up to 2.25 GeV

[Daniel Carman]

Steffen,

I have read through the draft of your FROST pi+n E asymmetry paper. Included below are
my comments on the draft dated January 26. Let me know if you have any questions.


					        Regards,
						
						Daniel

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Page 1:
 - Eq.(2). The minus sign out in front stands out. Is this a universally accepted
   convention or do different folks use different notation? Perhaps a reference for
   this formalism should be included.
 - Line 46. Use "The consistency of the helicity ...".
 - Line 52. What "poorly known resonance" are you talking about? No need to be obtuse
   here.
 - Line 55. Use "... the interpretation will be presented ...".
 - Line 64. Use "... electrons from the CEBAF ...".

Page 2:
 - Line 5. The Moller polarimeter foil polarization is only known to 3%. Your uncertainty
   here is far too small.
 - Line 15. Use "... aligned along the beam axis ...".
 - Line 30. Use "Data from this experiment ...".
 - Line 50. Is alpha independent of kinematics? Also you never explicitly give the uncertainty
   on alpha (statistical or systematic).
 - Line 55. Use "... kinematic bin were then selected ...".
 - Line 58. Use "... distribution taken from a fit.".
 - Line 60. Use "The observable $E$ was finally extracted from the polarized yields ...".
 - Line 62. Use "..., and the average beam and target polarizations,".
 - Line 69. Is kappa independent of kinematics? You never explicitly give the uncertainty on
   kappa (statistical or systematic).

Page 3:
 - Line 6. Is 7.5% +/- 7.5%?
 - Line 7. Is 1.5% +/- 1.5%?
 - Lines 8-10: Are these uncertainties independent of kinematics?
 - Line 17. Use "... < 1.5 GeV, the data are well ...".
 - Line 28. The statement "making small amplitude changes that produce large changes in the 
   polarization observables" is not strictly true for fine-tuning changes. Small changes in
   amplitudes are more likely to have small effects on the observables. I am not sure why this
   parenthetical statement is included.
 - Line 41. Use "... parameters, while the ...".
 - Line 83. Use "... are larger than for the SAID analysis.".
 - Line 90. Use "$W$ = 2.3 GeV".
 - Line 100. The statement "... for a new state in the BnGa re-analysis." is frustratingly vague.
   What state are you referring to here?

Page 4:
 - Fig. 2 caption. Last line. Use "They will be presented in a follow-up paper.".

Page 5:
 - Table I caption. Line 1. I suggest "Fits including the new CLAS data (labeled E) and those
   without the new data."

Bibliography:
 - The bibliography has a number of problems. 
   > First, do not include the preprint numbers for already published papers.
   > et al. should not be underlined.
   > Many of the journal names are listed without appropriate spacing (e.g. Phys.Rev.Lett. 
     instead of Phys. Rev. Lett.).
   > Ref.[11] is not a CLAS Collaboration paper.
   > With many authors, use the first author followed by "et al.", do not list a handful of
     names then put "et al.".