[Eg6_analysis] Coherent DVCS paper from eg6 run group

[Liuti, Simonetta (sl4y)]

Dear All,
I received a copy from Mohammed a few days ago, I will send my comments shortly.
Simonetta
------------------------------------------
Prof. Simonetta Liuti telephone ++1 434 9822087
Physics Department
University of Virginia
382, McCormick Rd.
PO Box 400714
Charlottesville, VA 22904-4714

________________________________________
From: Whitney R. Armstrong [warmstrong at anl.gov]
Sent: Monday, February 20, 2017 3:47 PM
To: dupre
Cc: Hattawy, Mohammad (mhattawy at anl.gov); Nathan Baltzell (baltzell at jlab.org); Kawtar; Stepan Stepanyan; Stephen Bueltmann (sbueltma at odu.edu); Raffaella De Vita (raffaella.devita at ge.infn.it); alaoui.ah71 at gmail.com; Lamiaa El Fassi (elfassi at jlab.org); Hovanes; Fxgirod; David Jenkins; Liuti, Simonetta (sl4y); perrin at jlab.org; btorayev at jlab.org; ERIC VOUTIER; eg6_analysis at jlab.org
Subject: Re: [Eg6_analysis] Coherent DVCS paper from eg6 run group

Hello,

In general I think there are too many figures for a PRL.
Figures 1-5 can probably be removed or reduced.

Here are my specific comments.

Abstract:

Extra capitalization for potential acronyms.

"Deeply Virtual Compton Scattering" -> "deeply virtual Compton
scattering (DVCS)"

"Radial Time Projection Chamber" -> "radial time projection chamber
(RTPC)"

"Beam Spin Asymmetries" -> "beam spin asymmetries"

"Compton Form Factors" -> "Compton form factors"

"Generalized Parton Distribution" -> "generalized parton distribution"

Line 17: "Quantum Chromodynamics (QCD)" -> "quantum chromodynamics
(QCD)"

Line 19: "development of the Generalized Parton Distributions (GPDs)
..." -> "development of the generalized parton distribution (GPD) ...",
assuming the acronym isn't already defined in abstract.

Line 23: Unnecessary comma.

Line 23: Last sentence in paragraph could be improved. It is at a
critical location in the paper so you might want to reword for clarity.

"In impact parameter space, the GPDs are indeed interpreted as a tomography of the
transverse plane for partons carrying a certain longitudinal momentum"

Perhaps ...

"Impact parameter GPDs provide a tomographic image of the partons
carrying fixed values of longitudinal momentum."

Line 28: "Deeply Virtual Compton Scattering" -> "deeply virtual Compton
scattering" and remove "(DVCS)" if acronym defined  in  abstract.

Line 29: ", i.e. the " -> ", \textit{i.e.}, the"

Line 34: Technically "JLab" isn't an acronym since it has lower case
letters -- it is just another name. Furthermore, if you are going to
define the JLab acronym anyway, shouldn't you do the same for CERN and
HERA? I suggest just leaving it as "JLab" or "Jefferson Lab".

Line 48: "Figure 1" -> "FIG. 1"

Line 50: Sentence is hard to read. Maybe define the invariants Q^2 and t
in one sentence. Then describe the kinematic regime for factorization.

Line 59: Oxford comma?  "x, \xi, and t"

Line 59: "Figure 1" -> "FIG. 1"

Line 61: " with M the proton mass ..." ->
", $\nu = k^0-k^{\prime0}$, and M is the proton mass." Note that t is
already defined defined (see Line 50 comment).

Line 65: "Compton Form Factors" -> "Compton form factors"

Line 66: "... defined as" -> "... defined at leading order as"
The coefficient function is the LO one and it should be noted.

Line 69: Paragraph needs improved. Perhaps get to the point quickly ...
"The HERMES experiment measured this process with a few nuclear targets
(N, Ne, KR, and XE), however, they did not measure the recoil nucleus.
Therefore, the coherence of the reaction possibly suffers from large
contaminations ..."

Line 79: Shouldn't "CLAS" have already been defined in the abstract?

Line 83: Is this the first definition of RTPC? (But note the correct
capitalization of "radial time projection chamber")

Line 85:  The sentence beginning here seems out of place. "... while it
is subject to significant nuclear effects". Is this accidental mixing
with the incoherent paper?

Line 100: "at energy of " -> "at an energy of"

Line 115: "In Figure 2 a picture of RTPC installed in the experimental
hall, and the rendering showing detector components and the 4 He
detection concept are presented." ->
"Presented in FIG. 2 are a picture of RTPC installed in the experimental
hall and a diagram showing the basic detection technique."

Line 134: "The photons are detected in either the IC or
the CLAS electromagnetic calorimeter." Is this true?


Line 146: "events with ... " -> "events with $Q^2$ > 1 GeV$^2$/c$^2$."

Line 160: "After these requirements, we ... " -> "About 3200 events pass
these requirements and are shown in FIG. 4..."


I am going to take a break. Will pick up on this later.

Cheers,
Whit




On Mon, Feb 20, 2017 at 07:09:32PM +0100, dupre wrote:
>Hopefully with attachment this time.
>
>On 2017-02-20 19:05, dupre wrote:
>>Hello,
>>
>>We are now in the final part of the process for the eg6 analysis on
>>coherent DVCS off helium-4 and will soon submit a paper to the CLAS ad
>>hoc committee. We tried to group on the paper attached all the people
>>involved directly in the experiment or analysis. This list will of
>>course be supplemented by the rest of the CLAS collaboration and is
>>there to reflect the fact that some people had a more significant
>>involvement in the eg6 run group or the coherent DVCS analysis (the
>>incoherent DVCS paper will be coming soon).
>>
>>Please let us know if you have any remarks on the text of the paper or
>>about the author list by the end of the week.
>>
>>Best regards,
>
>--
>
>Raphaël Dupré
>Institut de Physique Nucléaire d'Orsay


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Whitney R. Armstrong