[Clascomment] OPT-IN: Determination of the Proton Spin Structure Functions for 0.05 < Q2 < 5 GeV2 using CLAS

[Reinhard Schumacher]

1-20-2017

Hello Keith et al.,

I have looked over your draft CLAS paper "Determination of the Proton
Spin Structure Functions...CLAS" dated 12-30-2016.   Since it is such
a long paper, I must admit not reading it word by word, but I really
like the overall effort and think it is a very nice paper.   It
clearly sums up a lot of work by your group. 

My comments on the paper are pretty sparse since I read sections
selectively, but here they are.

line 22: the list of reactions (e.g.....) is not well defined.  When
you say semi-inclusive scattering, the reader thinks "of what?",
Similarly "deeply virtual production..."  Presumably it would be
better for the reader to insert "electron" appropriately.

Line 45:  ungrammatical sentence.  "The data" cannot do anything by
themselves, so you need something like "...and they can BE USED TO test
...".   Similarly, the next sentence needs to read "They also can BE
USED TO..."

Line 59:  I would insert the reference to CLAS at this point,
currently item 84.   You use that reference much later in the paper,
but I think it would be good to put it here, too, so the casual reader
knows immediately where to find more information.

Fig 1 caption:  I cannot tell which direction this picture is taken
from.   Caption should mention is this is the beam-eye view or
something else.

Fig 13: small typo ".two"

Fig. 17 caption:  Instead of "various phi bins" would it be more precise to say
"five evenly spaced phi bins across one CLAS sector" ?  "Various"
sounds so ill-defined.

Fig. 27: The blue open circles and purple triangles mentioned in the
caption do not show up well:  too small and wring color in my
hardcopy. Either remake the figure or change the caption to reflect
the figure.

Fig. 27 caption:  Replace "systematic error" with "systematic
uncertainty" here.    You are quite inconsistent about this usage in
the paper.    I recommend changing "error" consistently to
"uncertainty" in many places in the paper.   I will not list them
all.

Fig 28:  Again, the markers and the caption are not consistent.


Fig 30:   Where are the "blue hollow circles"?  I see small solid blue
dots.

Fig. 31 and Fig 35 and Fig 36:  "error" --> "uncertainty"

Fig 32:  There seems to be a stray light blue line in the bottom
middle panel.


Finally, again, I think this is a good paper:   I (re)learned a number
of things from it.

Cheers,
Reinhard