OPT-IN:Target and Double Spin Asymmetries of Deeply Virtual Ï0 Production with a Longitudinally Polarized Proton Target and CLAS

[Reinhard Schumacher]

Hello Andrey,

I have read through your draft paper "Target and Double Spin
Asymmetries of Deeply Virtual... and CLAS" (undated), and I have the
following comments.  Overall the paper is pretty clear: a description
of your measurements of several spin asymmetries in deep inelastic pi0
electroproduction, and the connection of these observables, via models
that are named but not really explained, to GPD distributions.

I see that several people have made comments, and I am sure some of
mine will be redundant, but hopefully they are not totally a subset of
what has already been suggested.

Line 72, Eq (1): I am missing the connection between the "generic"
formula you give here and the asymmetry formulas given as Eq (2) and
Eq (3).  Later in the paper I don't see where you "close the loop" for
the reader and show how the measured A's get you information about the
F's.  Can you at least give one example in algebraic form of how they
are connected?  Also, you never come back to mention the nature of
what you call H(x,xi,Q2,t) the partonic subprocess amplitude.  Without
some explanation, the reader thinks the whole formulation of the
amplitude decomposition may be totally arbitrary and unconstrained.

line 80: remove "the" - this is an example of many instances where you
have an incorrect article in front of a noun.  I will not enumerate
them all, but you should recheck this.

line 96 - 102: You make some strong declarative statements here
without pointing the reader to where these statements are justified.
Is it supposed to be Ref [12]?  If so, maybe repeat this reference at
the end of this section.

Fig 1 caption: replace "markers" with something else like "points".
Also, did you explain HOW the 12C data were normalized to the 14NH3
data?  It looks like some choices were made and I didn't see them
itemized in the text (maybe I missed it, of course).  You need the
"color online" phrase.

line 144: ...allow rejection of events...

Fig 3:  This figure is too small, so I would try to make it full
page width, or break it into two figures, each one with one of the two
columns showing a Q2 xB bin.  I can barely read the figure when I hold
it close, so I fear it will get rejected.  Also, on this one you can
remove the "color online" phrase since the color is irrelevant.

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