[Clascomment] answers to your comments on the dvcs prd - eg1dvcs

[Silvia Pisano]

Dear Michel,

thanks a lot for your useful comments. We implemented most of them (and did
not report about the accepted ones, since we agree on them).

Below, you can find our answers on the points that need a more detailed
discussion.

Best regards,

Angela, Erin, Silvias

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- "Eqs 1 and 2 could (should?) be in line within the text, and there is a
minus sign missing in Eq 1."

Thanks for noting the sign, you are right! As to the positioning of the
equations, we preferred to leave them as they are, to give the right
resonance to the quantities introduced. We also slightly modified this part
following some suggestions from Volker.


- "L73-74: not quite correct. “The transverse part of t is the squared
Fourier conjugate of the transverse ….”.

Yes, you are right. We corrected it.


- "Eq8: to be consistent with Eq 6, is not there a factor –pi missing ?"

Yes, we included it.


- "L106: “With a finite number of measurements, a model input is necessary
to deconvolute…” (meaning that with an infinite number of integrals along
x, there are, or could be,  mathematical ways to get the x-dependence; this
may be compared to medical imaging reconstituting 3D images from 2D
measurements)"

We preferred to leave it as it is, since we will always have a finite
number of measurements only, and don't wanna be misleading with too many
details.


"L135: HERMES statistics on TSA are comparable to exploratory CLAS (see
Fig. 22). I would write: “….was also performed. The statistics obtained in
measurements [13,14] do not allow for a 4-dimensional binning of the data”.

We rephrased that paragraph, and the presentation of the previous
measurements has been reordered.


- "L 187-188: F1 and F2 already defined. Put a full stop at the end of Eq
16, skip “where…factors” and write “Due to the relative values of the
proton form factors F1 and F2,….”"

Thanks, it is way better now.


- "L190-191: this is not quite correct, and we had that discussion before
for the PRL and checks were made with VGG. The contributions of H and
H_tilde to A_UL are quite comparable. It is misleading to say that the
latter is dominant and the former minor. Please find another formulation."

Ok, we modified the text explaining better why there is a comparable
sensitivity to ImH and ImHtilde.


- "Section III: may be worth adding towards the end the beam helicity flip
frequency and a typical target polarization reversal frequency."

While we know that the helicity change is the usual one - i.e. 30 Hz - it
is hard to define a typical frequency in changing the target polarization,
since the changes were not regular at all. We preferred then not to mention
this information, not to create "asymmetry" among the two polarization
information.


- "About combining results from parts A and B, it would be instructive (and
maybe necessary) to add what is the expected beam energy dependence of the
3 observables from a given model (say VGG), for fixed xB, Q2, t. It is not
enough, as is done later, to show that the bin centers are nearly the same."

We did some studies through the VGG model, the results of which can be
found here:

http://www.lnf.infn.it/~pisanos/dvcs/prd/coll_wide_review/ebeam_test/

The two curves are the -t dependence of the three asymmetries in our 5 (Q2,
xb) bins for the two beam energies  (blue line is partA, red partB). Since
the difference is very small it is well beyond our statistical precision.


- "Table III: same number of significant digits everywhere ?"

To the best of our knowledge the significant figures are correct as is. For
statistical errors one usually retains only the first non-zero digit unless
the error is small (e.g. 0.015) and then it is common practice to keep two
digits. For these reasons all the PbPt and one of the Pb errors have two
digits, while the other ones have been rounded to one.


- "L853: $R_Acc, 1.3\times R_Acc, 0.7\times R_Acc$"

We explained it in words, to make the sentence more readable.


- "L891 and others: we call GK (from the original GPD parameterization) a
calculation of DVCS observables made by KMS (and for this paper by MS).
Although this is a bit heavier notation, why not replacing GK by GK-KMS ?
GK did not calculate DVCS, and it would be fair to our collaborators on
this."

Unfortunately, we cannot change it anymore since we used the same notation
for the PRL, and we need to be consistent among the two papers.


- "Fig.26 caption: is not it -ImH/pi and - ImH_tilde/pi which are plotted?
If yes, should be explicit in the caption."

The quantities that we plot in the figure are the actual imaginary parts of
the CFFs, because we keep into account the -pi factors.



- "Table V: strictly speaking, TSA, its errors and c (DSA and other c)
should have the same number of significant digits (4). I would leave it as
is, but make sure it is the case in the CLAS data base."

We adopted the convention to present all the results with 3 sig figures,
however being the TTSA correction so small we decided to report with 4 sig
figures to avoid zero values.


Thanks again!
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