[Clascomment] OPT-IN:Target and Beam-Target Spin Asymmetries in exclusive Ï+ and Ïâ electroproduction with 1.6 to 5.7 GeV elec trons

[bosted at jlab.org]

Dear Igor,
That is really impressive work.  I have several comments and suggestions
for your
consideration...

1) Abstract: You do not have en-->epi-p data.  You did not collect data on
free but bound neutron.  One cannot possible to measure pionEPR on the
"neutron" target you have to take into account FSI corrections to convert
ed-->epi-pp into en-->epi-p. There are no FSI calculations for pionEPR.
FSI for asymmetries could be small but
still unknown. CHANGED to "...kinematic bins
for $\pi^+$ and 35,000 bins for $\pi^-$ production."

2) Abstract: Most of "previous world data" are CLAS measurements
(according to the SAID database - CLAS collected about 85% of the world
database) and I would  punch this fact. NOT DONE (doesn't seem appropriate
to me).

3) Abstract: I do not think that last phrase is necessary here.  No
resonance couplings are presenting in the manuscript. CHANGED to
"When combined with cross section measurements,
the present results will provide powerful constraints
on nucleon resonance amplitudes at moderate and large
values of $Q^2$, for resonances with masses as high as 2.3 GeV."

4) line 16: your list of pi- measurements is uncompleted, check the SAID
database which has all available data. I cannot seem to get there: when I
click on "data Base" on
http://gwdac.phys.gwu.edu/analysis/epr_analysis.html
nothing happens. Can you send any pi- reference you consider essentail.
Meanwhile, I've change to say "references include..."

5) line 45: I am not sure that one can possible to prove that your
treatment for en-->epi-p is good enough.  We published several PRC papers
for pionPR analyses which allows to get gn-->pi-p from CLAS (g10) and
MAMI-B gd-->pi-pp measurements. inSpire can give you appropriate refs.
ANSWER: Text has been changed to be very
careful to say that we present measured asymmetries on deuteron target. No
neutron response functions are extracted in this paper.

6) line 143: How is about a neutron-detection efficiency?  How your took
it into account? ANSWER: There is no need to account for any efficiencies
in asymmetry measurements (the efficiency cancels in the ratio)

Let me suggest to add more curves to your data-plots using EBAC and SAID
predictions which will obviously benefit this manuscript.
ANSWER: The JANR fit is from the EBAC group (Inna). I tried using SAID but
ran into difficulties, and decided two curves were enough to illustrate
the point that new fits are needed now that we have more data.

BTW I am not sure if I am familiar with JANR treatment but MAID07 does not
fit available g*n-->pi-p data (they used some relationships between p and
n targets) ANSWER: Inna (JANR) did not consider pi- production. She only
does
pi+ and pi0.