[Clascomment] OPT-IN:Measurements of $gamma_{v} p ightarrow p' pi^{+} pi^{-}$ cross section with the CLAS detector for $0.4 GeV^{2} < Q^{2} < 1.0 GeV^2$ and $1.3 GeV < W <1.825 GeV$

Daniel Carman carman at jlab.org
Tue Feb 13 11:06:55 EST 2018


Dear Gleb et al,

I have read through the draft of your paper on 2pi electroproduction dated
Feb. 4. The paper from a presentation standpoint is in very good shape. I
have a number of comments on grammar/english/style for you to work through
before submission. If you have any questions, let me know. A very nice paper.

Regards,
Daniel
------------------------------------------------------------------------------------------
General:
 - Figs. 3, 4, 6, 8, 9, 10, 13, 15: I think that you make the presentation less complete
   when you present these 2D figures in B&W. I strongly recommend that you
   replace these figures with color versions.
   
Page 1:
 - Title: Use "Measurements of the ..."
 - Note: Throughout the paper you use "$\gamma_{\rm v}$". This really should
   be "$\gamma_v$.
 - Abstract:
   - Line 4. Use "... final hadronic system ...".
   - Line 6. Use "... experiments to date.".
   - Line 9.  Use "The data offer promising prospects to improve knowledge on ...".
 - Line 12. Use "During the last several decades, ...".
 - Line 19. Use "...  of the extracted observables ...".
 - Line 31. Use "...  new data for the full integrated ...".
 - Line 37. "They are also available on GitHub [3]." I do not think that it is appropriate
    to cite data on a private github repository for CLAS. The CLAS physicsdb is
    sufficient and appropriate. I recommend to remove this reference.
 - Line 39. Use "... in $W$), as well ...".
 - Line 40. Use "...  statistical uncertainties than were achieved ...".
 - Line 41. Use "...  cross sections [4-6].".
 - Line 58. Use "...  range, direct comparisons with these data are not straightforward
    and are not shown here.".
 - Line 66. Use "...  above the $\Delta(1232).".  
 - Line 71. Use "...  $Q^2$ binning, which is valuable ...".
 - Line 74. Use "The most common way ...".

Page 2:
 - Line 78. Use "This model, which aims at ...".
 - Line 87. Use "... on the kinematic region), which is a very promising ...".
 - Line 88. Use "... of the resonant ...".
 - Line 91. Use "... within the JM model, ...".
 - Line 97. Use "... were acquired at JLab in Hall~B ...".
 - Line 99. Use "... [1], which consisted ...".
 - Line 101. Use "... Drift Chambers (DC), a {\v C|herenkov ...".
 - Line 102. Use "... a Time-of-Flight ... and a sampling ...".
 - Line 105. Use "... allowed for the determination of their momenta  in the DC.".
 - Line 109. Use "... period that lasted from ...".
 - Line 112. Use consistent significant figures on beam energies.
 - Fig. 1 caption. Use "... during the CLAS "e1e" run period.".
 - Line 118. Use "... along the $z$-axis (near the center of CLAS), and ...".
 - Line 123. Use "The target cell had 15-$\mu$m-thick aluminum entrance and exit
     windows. In addition, an aluminum foil was located 2.0~cm downstream of the
     target center.".
 - Line 128. Use "... and served for both the estimation ... of events that originated ...".
 - Line 132. Use "... included runs with the target cell ...".
 - Line 140. Use "Both distributions are normalized to ...".
 
Page 3:
 - Line 147. Use "... target runs shows two peaks that correspond ...".
 - Line 150. Use "... a cut on the $z$-coordinate of the electron ...".
 - Line 151. Use "... by the two vertical ...".
 - Line 167. Use "... responses were analyzed.".
 - Line 168. Do not begin a new paragraph with this sentence.
 - Line 176. Use "In the next step, a so-called sampling fraction ...".
 - Line 184. Use "... of $P_{e'}$ should be nearly a fixed constant. This constant is
    roughly 1/3, since by the EC design ...".
 - Line 195. Use "... while the other two curves ...".
 - Line 196. Use "... cut that was determined ...".
 - Line 198. Use "... for the experimental data ...".
 - Line 208. Use "As was shown ...".
 - Line 210. Use "... photoelectrons (the so-called ...".
 - Fig. 4 caption. Last line. Use "... that was applied ...".

Page 4:
 - Left column:
   - Line 2. Use "... photoelectrons, shifted the measured CC spectrum towar zero ...".
   - Line 5. Use "... buy a more pronounced ...".
 - Line 214. Use "... denominator corresponds to the ...".
 - Line 223. Use "... As is seen in Fig. 4, ...".
 - Line 225. Use "... sector (shown in white).".
 - Line 230. Use "... originated from the black ...".
 - Line 233. Use "... signals from the inefficient ...".
 - Line 235. Use "... as shown in Fig.~5. This peak in the photoelectron ...".
 - Line 244. Use "... by the function:
     \begin{equation}
       y = ...   ,
     \end{equation}
    which is a slightly modified Poisson distribution where ...".
 - Line 250. Use "Finally, the correction factors defined as:
    \begin{equation}
     F_{ph. el.} = ... ,
    \end{equation}
    were applied as a weight for each event that corresponded to the particular PMT."
 - Line 253. Do not begin a new paragraph with this sentence.
 - Line 257. Use "... for a charged particle track, ...".
 - Line 258. Use "... candidate was calculated.".
 - Line 262. Use "... given by:".
 - Eq.(4) should end with a comma not a period.
 - Line 271. Use "... is given for scintillator 34 of CLAS sector 1.".
 
Page 5:
 - Line 287. Use "... bands in the experimental ...".
 - Line 294. Use "... the reconstructed momentum and ...".
 - Line 296. Use "... effects were of ...".
 - Line 297. Use "... they could not be simulated ...".
 - Line 298. Use "... procedure was needed ...".
 - Line 302. Use "It was shown ... position was shifted from the proton mass value
    and this shift depended on the CLAS sector.".
 - Line 306. Use "... effect depended on the ...".
 - Line 308. Use "... 2.039~GeV, there was a small shift ...".
 - Line 309. Use "... peak position, while Ref. [14] ...".
 - Line 319. Use "... momenta could be neglected.".
 - Line 323. Use "... correction, as well as an ...".
 - Line 332. Use "... due to their interaction ...".
 - Line 336. Use "... and, therefore, the effect ...".
 - Line 339. Use "... shifts in the distributions ...".
 - Line 342. Use "... low-energy protons ...".

Page 6:
 - Line 343. Use "... loss in the materials.".
 - Line 350. Use "... 4$\pi$ [1] as the areas covered ...".
 - Line 353. Use "In addition, the detection ...".
 - Fig. 8 caption:
   - Line 2. Use "... plot shows the ...".
   - Line 5. Use "... curves show the applied ...".
 - Line 365. Use "For these particles, sector ...".
 - Line 368. Use "... as a function of the angles ...".
 - Line 372. Use "... cuts that select ...".
 - Fig. 9 caption:
   - Line 2. Use "... plot shows the ...".
   - Line 5. Use "... curves show the applied ...".
 - Line 376. Use "... cuts were the best ...".
 - Line 386. Use "... areas were typically caused ...".
 - Line 391. Use "... were different for each CLAS sector.".
 - Line 395. Use "... run, variations of the experimental conditions, e.g. fluctuations
     in the target density or changes in the response of parts of the detector, ...".

Page 7:
 - Line 398. Use "Only the parts ...".
 - Line 401. Use "... per Faraday Cup (FC) charge ...".
 - Line 408. Use "The DAQ live time ...".
 - Line 412. Use "... is shown as a function of the DAQ live time and the yields ...".
 - Line 419. Use "... two final state hadrons ...".
 - Line 421. Use "... can be reconstructed using ...".
 - Line 423. Use "... between four different event topologies depending on the ...".
 - Line 425. Use "... final state hadrons ($X$ is the undetected particle):"
 - Fig. 11 caption:
    - Line 1. Use "... of blocks as a function of DAQ ...".
    - Line 2. Use "... and the yields ...".
    - Line 4. Use "... lines show the applied cuts.".
 - Line 431. Use "... conditions, topology 1 ...".
 - Line 434. Use "... among the other ...".
 
Page 8:
 - Fig. 12 caption:
   - Line 2. Use "... for the four event topologies ...".
   - Line 5. Use "... while the curves are from the simulation. The plot shows the ...".
 - Line 450. Use "cannot".
 - Line 455. Use "... and the absence of ...".
 - Line 461. Use "... 50\%), but also to ...".
 - Line 469. Use "... final state hadrons, ... four-momenta of the initial state ...".
 - Line 475. Use "... final state particles.".
 - Line 479. Use "... curves show the simulation. The plots in Fig. 12 represent
     topologies ...".

Page 9:
 - Line 498. Use "... calculations, experimental events ...".
 - Line 501. Use "... simulation, the reconstructed .... subject to the same summation.".
 - Line 506. Use "... final state hadrons were known ...".
 - Line 513. Use "... sections were obtained ...".
 - Line 527. Use "... final state hadrons ...".
 - Line 534. Use "... final state hadron description ...".
 - Line 537. Use "... pair of hadrons ...".
 - Line 539. Use "... pair of hadrons ...".
 - Line 542. Use "... between the two plans (i) defined by the ... and the first
     final state hadron and (ii) defined by the three-momenta of all final state
     hadrons ...".
 - Line 564. Use "... encompasses about 1.2 million ...".
 - Line 567. Use "... final state hadron ...".
 - Line 571. Use "... 1.22~GeV, as well as ...".
 - Line 574. Use "Special attention was required for ..."

Page 10:
 - Table I caption. Use "... final state hadron ..."
 - Line 582. Use "... $M_{upper}$ was calculated ...".
 - Line 607. Use "... extracting the cross sections, the event yield was divided .."
 - Line 608. Use "... width $\Delta M$, thus ...".
 - Line 612. Use "... data were not sufficient ...".
 - Line 616. Use "... which was different ...".
 - Line 620. Use "In addition to the above ...".
 - Line 622. Use "... variable was assigned ...".
 - Line 624. Use "... behavior, the ... size caused ...".
 - Line 627. Use "... applied that included ...".
 - Line 628. Use "... to 4\% for some ...".
 
Page 11:
 - Line 634. Use "... of this paper) ...".
 - Line 635. Use "... $\sigma_e$ via:"
 - Eq.(9) should end with a period.
 - Line 636. Use "Here $d^5\tau$ is ...".
 - Line 637. Use "... state that were described in Sec. IV A.".
 - Line 638. Use "... photon flux given by"
 - Eq.(11) should end with a period.".
 - Line 643. Use "Here $\nu = ...".
 - Line 651. Use "... event was weighted ...".
 - Line 660. Use "... hydrogen, and $N_A ...".
 - Line 664. Use "... simulation and $R ...".
 - Line 683. GENEV needs a reference.
 - Line 691. Use "... approach in Ref.~[15].".
 - Line 694. Use "... procedures. The efficiency ... was then calculated in ...".
 - Line 702. Use "... and increased up to a few ...".

Page 12:
 - Fig. 15 caption. Line 2. Use "... unertainty vs. efficiency.".
 - Line 710. Use "cannot".
 - Line 712. Use "... along with the other ...".
 - Line 714. Use "... and, therefore, some model ...".
 - Line 725. Use "Additionally, the efficiency in some ...".
 - Line 726. Use "... due to boundary effects, ...".
 - Line 729. Use "These cells could be differentiated from the cells with reliable
     efficiency by their larger relative ...".
 - Line 737. Use "As is seen in ...".
 - Line 740. Use "... efficiency was obtained ...".
 - Line 752. Use "... 22], as well as ...".
 - Line 753. Use "... and, therefore, provides ...".
 - Line 755. Use ".. describes in detail the approach ...".
 - Line 760. Use "... to the case when the ...".
 - Line 761. Use "... cells was ignored, and ...".
 - Line 762. Use "... for the case when the empty cells were taken into account ...".
 - Line 763. Use "The black curves represent the TWOPEG cross sections that were ...".
 - Line 766. Use "... from the empty cells ...".
 - Line 770. Use "... due to the negligible/zero CLAS acceptance in these regions.".
 - Line 776. Use "... total statistical uncertainty, as was done in Refs.~[6,22].".
 - Line 780. Use "... using the TWOPEG ...".
 - Line 781. Use "... [21], which accounts ...".
 - Line 783. Use "... known approach of Ref.~[15].".
 - Line 785. Use "... cross sections from the non-radiative cross sections.".
 - Line 787. Use "... in TWOPEG, the double-pion ...".
 - Line 790. Use "... electron (the so-called ...".
 - Line 792. Use "In Refs.~[15,21] the ...".

Page 13:
 - Fig. 16 caption:
   - Line 1. Use "... for the cases when the contribution ...".
   - Line 2. Use "... when it was taken into ...".
   - Line 3. Use "... while the latter are with the ...".
 - Line 814. Use "... final state hadron ...".
 - Line 817. Use "... final state hadron ...".

Page 14:
 - Fig. 17 caption. Line 1. Use "The quantity $1/R$ (see Eq.(15)) as ...".
 - Line 848. Use "... of the efficiency,".
 - Line 850. Use "... by Eqs.~(16) and (17) ...".
 - Line 857. Use "... sections, the total ...".
 - Line 876. Use "... as uncertainties in the electron registration ...".
 - Line 882. Use "... were summed up in ...".
 - Line 883. Use "... alternative method considers ...".
 - Line 889. Use "... includes the uncertainties due to ...".

Page 15:
 - Fig. 18 caption:
   - Line 1. Use "... shadowed area for each point is the total cross section ...".
   - Line 3. Use "... the total systematic uncertainty. The error ...".
   - Line 4. Use "... curves are the cross section prediction ... dashed curves
       correspond ..."
 - Line 916. Use "... extracted integrated cross ...".
 - Line 917. Use "... are shown by the black circles ...".
 - Line 918. Use "... shadowed areas correspond ...".
 - Line 921. Use "... systematic uncertainty."
 
Page 16:
 - Fig. 19 caption:
   - Line 2. Use "... curves are the cross section ...".
   - Line 3. Use "... dashed curves correspond ...".
 - Line 935. Use "... due to the high ...".
 - Line 942. Use "... sections. This model aims at ...".
 - Line 947. Use "... results is based on the JM model estimations of ...".
 - Line 949. Use "... differential), as well as ...".
 - Line 955. Use "... sections was obtained ...".
 - Line 957. Use "This generator employs the ...".
 
Page 17:
 - Line 962. Use "... of the model ...".
 - Line 975. Use "... for the integrated ...".
 - Fig. 20 caption:
   - Line 2. Use "... integrated double-pion ...".
   - Line 3. Use "... details). The different symbols ...".
 - Line 982 (and following). Use the updated PDG format for listing resonances,
    e.g $P_{11}(1440)$ --> $N(1440)1/2^+$.
 - Line 987. Use "... data on the $Q^2$-dependences of the resonance ...".
 - Line 988. Use "Additionally, the states ...".
 - Line 992. Use "... values of their electrocouplings ...".
 - Line 1004. Use "... for the integrated ...".
 - Line 1007. Use "These contributions were obtained as the ratio of ...".
 - Line 1011. Use "... with increasing $W$ and $Q^2$, consistent with ...".
 - Line 1012. Use "... 1.5~GeV, this contribution ...".
 - Line 1023. Use "... extracted integrated ...".
 - Line 1024. Use "... [4], which were obtained with a ...".
 - Line 1035. Use "... two in Ref. [4], the map of the empty cells ...".
 - Line 1039. Use "... binning in the hadron ...".
 - Line 1043. Use "CONCLUSIONS AND OUTLOOK".
 - Line 1044. Use "... on integrated and ...".
 - Line 1047. Use "The results are a significant improvement over previously ...
     in this kinematic region due to the extension in the $W$ coverage and due
     to the increased statistics, thereby ...".
 
Page 18:
 - Fig. 21 caption.
   - Line 2. Use "... and statistical uncertainties) ...".
   - Line 3. Use "... for the results from Ref. [4] ("e1c"), it is ...".
 - Line 1052. Use "... in the CLAS physics ...".
 - Line 1073. Use "... acceptance, in this way achieving a very ...".
 - Line 1088. Use "... contribution that grows ...".
 - Line 1091. Use "... extraction of the resonance electrocouplings.".
 
Page 19:
- Line 1133. Use "... from the other sets of variables are ...".
- Line 1135. Use "... between the two planes A ...".
- Line 1138. Use "... all final state hadrons.".
- Line 1140. Use "... the c.m.s. their ...".
- Fig. 22 caption:
  - Line 2. Use "... final state hadrons ...".
  - Line 3. Use "... of the $\pi^-$ and ...".
  - Line 4. Use "... of the auxiliary ...".
- Line 1146. Use "... along the $z$-axis.".
- Line 1149. Use "... plane B. The angle between the two planes ...".
- Right Column:
   - Line 8. Use "... and in the case of ...".
- Line 1161. Use "... to see that ...".
- Line 1163. Use "... about the kinematics of the reactions ...".

References:
 - Give URL for all CLAS-Notes.
 - You do not need to include arXiv listings for already published papers.
 - [2], [3]. You have an extra space before the period.
 - [15]. Use "... Rev. Mod. Phys. ...".
 - [22]. Use "... to be published ...".


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