[Eg1_run] Latest version of Proton Long Paper

[Kuhn, Sebastian E.]

Hi Keith and Rob,

I gave the draft a quick once-over - hopefully you will also get feedback from others. For obvious (selfish) reasons, I concentrated on Section IV, since I hope that this can be used to placate the deuteron paper referee that we did everything correctly. However, I also have a few general observations:
1) The addresses of the first 3 and the last author are all outdated
2) Please turn on line numbers for future versions so it’s easier to comment on specifics
3) The abstract and sections I-II are of course nearly flawless (since I wrote most of that ;-). However, there are several places where the maximum beam energy is listed as 5.8 GeV (and others where it is correctly 5.7) - those need to be fixed (e.g., 3rd line abstract, 4th line from bottom p. 1 left column). Some references need to be added or updated, e.g. 2nd line from bottom p. 1 c2 (“will be presented elsewhere”). 
4) Fig. 1 should be removed (as well as the reference to it in the text) - in its present form, it is unacceptable and there is really no need to explain CEBAF in this paper. ALL OTHER FIGURES need to have “(Color online)” added to their captions. Fig. 2 needs a better caption (or the whole figure could be left out, as well). 
5) p. 7, c2, 2nd para: Moller misspelled, and “Located” capitalized
6) Before I get into Section IV, let me reiterate that I am most keen to get an update of Fig. 35 with eg1-dvcs data included. See the corresponding figure in the deuteron paper for format.

Now Section IV:
p10,c1,p1,l5: Again, 5.8 should be changed to 5.7
p10,c2,p2: “The electron count rate in each sector (normalized TO the Faraday cup CHARGE)”. Right before Fig. 6: “…ensured that the false physics asymmetry due to this effect was much smaller than 10^-4”.
Fig. 6: The caption is really confusing. In particular the sequences “1-4” and “2-3” need to be explained more clearly. 2nd line below Fig. 6: “OPPOSITE”, not “opposing”
p.10c1.p2.l4: “that FIRED the CC/EC triggers”. 2 lines later, remove “further” before “purify”.
Fig. 8: Ideally, we would remove the “pi^\pm” from the legend inside the plot; in any case, the caption needs to have more explanation what kind of cuts we are talking about.
Subsection C.2. (bottom p. 11): The explanation would be better if you added (at the end of the first paragraph) what the minimum ionizing signal in the ECin is, to justify the particular cut on 220 MeV. p.12c1 line 4 from bottom: replace “p.3” with “p>3”
Figs. 10&11: I vaguely remember that we discussed this before, but the black lines are hard to see (would light grey work better?). If it’s too hard to change, we can leave it, but there DEFINITELY aren’t any arrows, so the captions must be updated.
p13 1st paragraph: “The pion contamination was estimated using samples of scattered pions that were obtained during runs without CC trigger and by reversing all other electron selection cuts on the EC. These samples were scaled to the remaining background described in the previous paragraph at low CC signals. The correspondingly scaled number of pion events above
the CC 2-photo-electron cut was divided by the total number of counts passing all electron cuts to yield the contamination fraction $R(\theta,p)$. “
Fig. 12: Caption needs to explain the jump around E = 2.8 GeV (CC becomes efficient for pions).
p13c2p1l1: Remove the 2nd “with”. At the end of the same paragraph, formulate more clearly: “Then, Eq. 44 (with …) was used to determine a multiplicative background correction factor, $C_{back} \ident….$, to convert the raw asymmetry to the background-free physics asymmetry. Here, we assumed $A_{e^+}=0$ consistent with the average from our measurements (see Fig. 13).” (I would leave out any reference to Eq. 48 at this point - rather refer back to explain each term in it when you get there. The next paragraph is also confusing. Starting with the 2nd sentence: “R was changed by 1/2 of the difference between two equivalent determinations, for the case with outbending electrons and inbending positrons, vs. the reversed case.” or similar. Also, when you discuss changing Ae+ by 3 sigma, you should quote the numerical value and - ideally - indicate it by a line on Fig. 13, so that the reader gets an idea how reasonable our method is.
Section C.5: The 2nd paragraph is somewhat confusing in comparison to plots and later discussion. First off, in line 2, put “|M_p- W|” in absolute signs. I also don’t like “on the order 50 MeV” (at least an “of” should be added; better would be a more precise statement, like “30 MeV for 1.6 GeV up to 50 MeV for 5.7 GeV" or similar.) Line 4, Emiss is not defined but also the top panel of Fig. 15 is not labeled the same; the other panels are also badly labeled (one doesn’t know which particle’s theta and phi are being plotted there). 
p15c1p1l6: “deviations of the reconstructed kinematics of the scattered particles. An empirical method was developed []” yes, there needs to be a reference. Use CLAS-NOTE 2003-005.
p16c1p1l1: “$\theta_e” (add index to be clear).
Fig. 18: The quantity “DeltaE/E” is inconsistent between the axis label and the caption, and is not explained in the latter.
p16c2p2: “The (ungated) upstream Beam Position Monitors (BPM) were used to establish a relative CORRECTION on the FC signal for different targets. The BPM/FC ratio at 5.7 GeV (where multiple scattering is suppressed) provided an overall normalization…" End of next paragraph: “…extracted PHYSICS asymmetries”. 
p17c1p1l1: n^+ and n^- are defined confusingly; you want to make totally clear that “+” refers to beam and target polarization being OPPOSITE (anti-aligned), and “-“ parallel (aligned). Otherwise our definitions in other places don’t work. At the bottom of the paragraph, quickly refer back for Cback and then add “The remaining terms are now discussed in sequence.”.
p18c1p3: “To apply the model…were first SUMMED (or HISTOGRAMMED) in bins of W and Q2 for all runs IN each of the 12 data sets (see Fig. 21). From these sums, the ratios nMT/nC and nA/nC were formed. The ratio nMT/NC then determines…”. At the end of this para, add “...reanalysis and the resulting difference in FDF was used to estimate the systematic uncertainties due to these parameters.” 3 lines below that there is a weird citation (3 [][][] instead of 1 []).
E.2. at the bottom: “Because NMR measurements are dominated by the material near the edge of the target cell [81] which was not exposed to the beam and therefore had higher polarization than the bulk of the target, …”
Fig. 21: The gap between the 2 panels should be smaller, and/or the pictures reduced in size to avoid cramming the caption at the bottom.
Fig. 22: Caption needs more explanation, in particular the significance of the data points.
Fig. 23: Explain the 3 curves more explicitly (refer to pure hydrogen, not just “resulting difference”)
p19c1 4 lines from bottom: “Nuclear background contributed less than 5% of the events...”. Beyond this, I have a real PHYSICS question (arrrghh): As far as I understand, the true asymmetry was calculated from events within Delta-phi = 2 degrees. Yet, the background is normalize from 2-6 degrees? This seems too close for comfort - looking at Fig. 24, I clearly see an excess of elastic counts even out to Delta-phi = 3 degrees, which would yield the wrong normalization if included. Comment? Also, speaking about Fig. 24: It would be nice to indicated both the cut and the normalization region via vertical lines (and explain them in the caption).
E.3: In Eq. 53, you introduce the quantity “P_p” which is close to what we usually call “P_t”. In any case , in the last 2 lines of that column things get even further confused, as you introduce P_b as being an independent factor in Eq. 53 - which it isn’t. Maybe you can leave the P_p in Eq. 53, but then replace “P_b” by “$P_p = \frac{P_bP_t}{P_b}$”.
FINALLY, (phewww), for Table I, it would be nice to give the “typical” total systematic uncertainty for each column

As I said before, I don’t have time on Thursday for a meeting. However, feel free to meet “informally” and let me know if there are any new developments.
- Sebastian

On Aug 7, 2015, at 6:05 PM, Keith Griffioen <griff at jlab.org> wrote:

> Dear EG1b,
> 
> Please find the latest version of the long proton paper at 
> 
> https://www.jlab.org/Hall-B/secure/eg1/EG2000/griff/LongPpaper/
> click on eg1b_proton.pdf
> 
> We are still waiting on Rob to produce several figures, but the paper is starting to take its final form.  Any comments and suggestions are welcome.  Once the final figures are in place, we will modify the captions accordingly.
> 
> cheers,
> Keith
> 
> 
> 
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