OPT-IN:Differential cross sections for Î(1520) using photoproduction at CLAS

[Daniel Carman]

Dear Utsav, Ken, et al.,

I have read through the draft of your paper on Lambda(1520) from analysis of the
CLAS g12 data and include my comments below. If you have any questions, let me know.
Good luck with the rest of the process and the submission to the journal.

Regards,
Daniel

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General:
- You have written the paper in the present verb tense. This is not standard and
makes the paper read awkwardly. Most of your verbs should be in the past tense
and I indicate this below.
- You are not consistent with your speed of light units throughout. Personally, I
prefer to let c=1, which also simplifies the notation.
- Your style is to overuse the comma. Sometimes this is not only grammatically incorrect,
but it makes the sentence structure awkward. I have flagged where I think you should
make some changes.

Page 1:
 - Author section: The address for Seung-il Nam is not complete. You should check with
   him, but at least use "Department of Physics, Pukyong National University, Busan
   48513, Republic of Korea".
 - Author section: Your asterisk designation footnote should be "$^*$Corresponding
   author. email: us810916 at ohio.edu".
 - Line 22. Use "... these ground and excited state baryons ...".
 - Line 36. The first time you introduce the notion of "missing resonances", it is
    fine to use the quotation marks, but I do not think it is necessary to continue
    to use the quotation marks for any subsequent usage of this term.
 - Line 56. Use "... of the $\Lambda(1520)$ ...".
 - Line 65. Use "... discussed and our conclusions are provided ...".
 - Line 71. Use "... photon beams in the energy range ...".
 - Line 75. Use "Another photoproduction study [9] for this hyperon by LEPS with
    liquid hydrogen and ...".
 - Line 85. Use "... modes, measuring the kaon angular ...".

Page 2:
 - Line 86. Use "... and forward peaked at energies ...".
 - Line 90. Use "Event though Moriya's result compared well with the model ...".
 - Line 98. Use "$\Lambda(1520)3/2^-$".
 - Line 100. Use "... they use the Rarita-Schwinger ...".
 - Line 109. Use "Regge theory accounts for the ...".
 - Line 111. You have not defined the variable s to this point.
 - Line 122. Use "... $\Lambda(1520), which takes into ...".
 - Line 123. Use "... exchanged in the $t$ channel, which has proven ...".
 - Line 126. Use "... $t$ channels have important contributions at ...".
 - Line 128. You should use modern notation for this state, N(2080)3/2^-.
 - Line 129. Use "... another resonance at a nearby mass.".
 - Line 141. Use "... (in the $s$-channel) ...".
 - Fig. 1. This figure is not reference in Section II at all. In fact, it is not
    reference until the very end of the paper (line 618).
 - Fig. 1 caption.
   - Line 2. Use "... $\Lambda^*$ here represents ...".
 - Line 144. Use "$\Lambda(1520)$ Photoproduction".
 - Line 146. Use "... $\Lambda(1520)$, which can decay via ...".
 - Line 147. Use "{\it e.g.}".
 - Section III.A. section heading. Use "The CLAS Detector".
 - Line 156. Use "CLAS Collaboration".
 - Line 161. Use "The CLAS detector was installed in Hall~B and was decommissioned
    in 2012.".
 - Line 162. Use "The design of the CLAS detector was based on a toroidal ...".
 - Line 163. Use "... that had the ability ...".
 - Line 165. Use "... particles over a large laboratory angular range, and ...".
 - Line 169. Use "... the beamline produced a field in the azimuthal direction."
 - Line 172. Use "... scintillation counters for time-of-flight (TOF), and ..."
 - Line 174. Use "... and neutrons, were the major ...".
 - Section III.A. Here you should also introduce the Tagger and the Start Counter as
    you refer to them later in the paper.

Page 3:
 - Line 177. Use "... this analysis was acquired ...".
 - Line 178. Use "... $g12$ experiment that was performed ...".
 - Line 180. Use "... high-energy, real-photon run.".
 - Line 182. Use "The photons continued forward ...".
 - Line 186. Use "... standard procedures for ...".
 - Line 188. Use "... Systematics} document [15].".
 - Line 191. Use "... n\pi^\pm\pi^\mp$, were ...".
 - Line 193. Use "... $n$ were reconstructed ...".
 - Line 197. Use "... delivered electrons ...".
 - Line 198. Use "... into Hall~B, where ...".
 - Line 199. Use "... photons were then produced.".
 - Line 200. Use "... target was triggered by ...".
 - Line 201. Use "... event was recorded when ... reaction was associated ...".
 - Line 202. Use "Since there were several ...".
 - Line 204. Use "... it was necessary to ...".
 - Line 207. Use "... was defined per photon ...".
 - Line 208. Here you mention the Tagger and the Start Counter but you did not include
    these elements in your description of CLAS.
 - Line 212. Use "... a photon reached the point ...".
 - Line 217. Use "Figure~2" (do not use the abbreviation if Figure is the first word in
   the sentence).
 - Line 223. Use "... < 1$~ns. This is ...".
 - Line 224. You do not explicitly mention whether you require $N_\gamma$=1 in this
    analysis.
 - Fig. 2 caption.
   - Line 1. Use "The photon coincident-time distribution ...".
   - Line 3. Use "particles. The 2-ns bunching ...".
   - Line 4. Use "... beam is apparent. Events with ...".
 - Line 225. Use "... 1.03, was obtained by ...".
 = Line 226. Use "... and was applied in the ...".
 - Line 229. Use "... process used the information ...".
 - Line 230. Use "... when it hit a detector ...".
 - Line 232. Use "... identification was vital to ...".
 - Line 233. Use "The PID information was accessed ...".
 - Line 234. Use "... data were passed through ...".
 - Line 235. Use "... that included the topologies ...".
 - Line 236. Use "... particles were selected. The PID process was refined ...".
 - Line 239. Use "... an event was compared ...".
 - Line 243. Use "... used the measured and calculated $\beta$ values, $\beta_{meas}
    and ...".
 - Line 244. Use "$\beta_{meas}$ was obtained from ...".
 - Line 248. Use "The time difference ($\Delta t$) between the ...".
 - Line 254. Use "... $\pi^-$, were selected with a timing cut of ...".

Page 4:
 - Fig. 3 caption.
   - Line 1. Use "The timing versus momentum distributions used for particle identification
      for $K^+$, ...".
   - Line 3. Use "$\pm 2.5\sigma$". Use "... each momentum bin are employed ...".
 - Line 255. Use "momentum-dependent".
 - Line 256. Use "... cuts were applied ...".
 - Line 259. Use "... function for $\pi^\pm$ or a Gaussian ...".
 - Line 260. Use "... background for $K^+$.".
 - Line 261. Use "$\pm 2.5 \sigma$".
 - Line 263. Use "Figure~3".
 - Line 264. Use "... momentum distributions ...".
 - Line 267. Use "The detection efficiency of low momentum particles was not large and
     not so accurately known. Such particles were eliminated by applying minimum momentum
     cuts $\vert p_{K^} \vert < 0.35$~GeV/$c$, ...".
 - Line 272. Use "... 0.17~GeV/$c$, where $\vert p \vert$ represents the ...".
 - Line 273. Use "... magnitude of the particle momentum.".
 - Line 277. Use "... $z$=0~cm, but was shifted 90~cm upstream in order to increase the
    detector acceptance in the forward direction. Charged tracks from the target were
    selected in reconstruction by requiring that they came from the $z$ range (coordinate
    along the beamline) from -110 to -70~cm.".
 - Line 281. Use "The geometry of the CLAS detector ...".
 - Line 282. Use "... presence of the toroidal magnetic field could cause ...".
 - Line 283. Use "... of particle tracks at the edges of the drift chambers, thereby
      resulting in uncertainties in the detector efficiency. We introduced fiducial ...".
 - Line 287. Use "well-behaved".
 - Line 291. Use "... [15] was applied for ...".
 - Fig. 4 caption.
   - Line 1. Use "The missing mass ...".
   - Line 3. Use "... cut to select neutrons is indicated by the ...".
 - Line 294. Use "Scintillation counters were used to determine ...".
 - Line 295. Use "... of charged particles. Counter with very low photomultiplier gain
     resulted in poor timing resolution and ...".
 - Line 297. Use "These bad paddles were identified ...".
 - Line 301. Use "... cuts was applied ...".
 - Line 302. Use "... two topologies for the ...".
 - Line 303. Use "In both of its charged decay channels, the $\Lambda(1520)$ branches ...".

Page 5:
 - Fig. 5 caption.
   - Line 3. Use "... indicated by the dashed lines.".
 - Line 307. Use "was constructed to select the ...".
 - Line 308. Problem with subscript on $P_{\pi^+}$.
 - Line 312. Use "... events with a $n$ were selected ...".
 - Line 314. Use "... $n$ peak in Fig.~4 is due to $\pi^+ tracks incorrectly reconstructed
    as $K^+$ tracks."
 - Line 327. Use "... from the $\Sigma^\pm ...".
 - Line 328. Use "... channel were excluded ...".
 - Line 333. Use "above-mentioned".
 - Line 335. Use "... for the $\Lambda(1520)$ ...".
 - Line 336. Use "This was done by plotting the missing ...".
 - Line 337. Use "... $MM(K^-\pi^+$) for the $\Sigma^+$ ...".
 - Line 338. Use "Straight cuts were applied ...".
 - Line 342. Use "... form a peak at the ...".
 - Line 345. Use "... such as $\gamma p ...".
 - Line 348. Use "Now the $\Lambda^*$ resonances ...".
 - Line 350. Use "... correspond to the ...".
 - Line 352. Use "... resonances $\Lambda(1670)$ and ...".
 - Line 358. Use "Figure~8".
 - Line 360. Use "... channels of the ...".
 - Line 365. Use "... $\Lambda(1520)$. Therefore, these predictions provide an
     explanation to the contrasting backgrounds in the two channels, ...".
 - Line 369. Use "Very similar mass distributions of the $\Lambda^*$ for the ...
     decay channels can be seen ...". This sentence also should not begin a new
     paragraph. It belongs in the paragraph started on line 356.
 - Line 371. Use "... \pi^0$ for the $\Sigma^+ ...".
 - Line 372. Use "... final states by J. Griselin ...".
 - Line 374. Use "The $\Lambda(1520)$ events were selected by cutting on the $MM(K+)$
    distribution in the range from 1.44 to 1.60~GeV.".
 - Line 377. Use "... for the $\Lambda(1520)$ ...".
 - Line 378. Use "... with the range of ...".
 - Line 380. Use "... for the two decay branches.".
 - Line 381. Use "Dalitz Plots".
 - Line 384. Use "... our reaction were used ...".
 - Line 386. Use "... \pi^+\pi^-$ were studied by ...".
 - Line 387. Use "... $IM(n\pi^-)$ vs. $IM(n\pi^+)$ for both data and simulation as shown
    in Fig.~9.".
 - Line 390. Use "Figure~9".
 - Line 393. Use "Events were assigned to ...".
 - Line 394. Use "... $IM$ was closer to ...".

Page 6:
 - Fig. 6 caption.
   - Line 1. Use "Selection of the $\Sigma^+$ (a) and $\Sigma^-$ (b) in the event
       distributions by making ...".
   - Line 2. Use "The cuts are shown by the dashed lines.".
 - Fig. 7 caption.
   - Line 1. Use "... resonances for the $\Sigma^+$ and ...".
   - Line 2. Use "... resonances $\Lambda(1405)$ ... to higher-mass resonances
          $\Lambda(1670)$ and ...".
 - Line 396. Use "... of events were misclassified, ...".
 - Line 397. Use "... the leakage was the same ...".
 - Line 398. Use "vs.".
 - Line 401. Use "... cut was made to eliminate these events, which improved the ...".
 - Line 404. Use "A GEANT3-based Monte Carlo (MC) [17] was used to simulate events ...".
 - Line 408. Use "... of the $\Lambda(1520)$, the ... \pi^+$, was independent generated
    for the processes ...".
 - Line 412. Use "... generator was based on ...".
 - Line 421. Use "... so that it matched our data, different values of $b$ were used ...".
 - Line 423. Use "... simulations, which were compared with ...".
 - Line 425. Use "... was calculated with simulated ...".

Page 7:
 - Line 426. Include proper units on the b-slope (GeV$^{-2}$).
 - Line 430. Use "... events were recorded with three charged particles ...".
 - Line 431. Use "... different sectors of CLAS.".
 - Line 432. Use "Due to the complex trigger configuration, the efficiency of the
    trigger was studied and accounted for by including it into the MC simulation."
 - Line 441. Use "... $\Lambda(1520)$, were sorted into bins ...".
 - Line 443. Use "... angle for the $K^+$ in the CM ...".
 - Line 444. Use "... and the mass of the proton ...".
 - Line 446. Use "Events were also binned ...".
 - Line 447. Use "... and squared four-momentum transfer $t$."
 - Line 449. Use "... $t$-variable for the reaction ...".
 - Line 450. End the equation with a comma for proper punctuation.
 - Line 454. Use "... $W$-bins were taken ...".
 - Line 455. Use "Each $W$ bin was studied ...".
 - Fig. 9 caption.
   - Line 1. Use "The $IM(n\pi^-$) vs. $IM(n\pi^+$) distributions for ...".
   - Line 2. Use "... (b) with the vertical and horizontal ...".
 - Line 457. Use "... as a function of $t$, nine $W$-bins were taken in ...".
 - Line 460. Use "... $W$ bin was studied ...".
 - Line 462. Use "... photon Tagger scintillators ..." to be consistent with notation
    used earlier.
 - Line 464. Use "... fourth $W$-bin has a 50~MeV width ...".
 - Line 468. Use "... distribution was fit with a ...".

Page 8:
 - Fig. 10.
   - Your plot labels are non-standard. Use "MM(K^+)".
 - Fig. 10 caption.
   - Line 1. Use "The yield extract fits for the $\Lambda(1520)$ peak in the ...".
   - Line 2. Use "... two decay channels $\Lambda(1520) \to ...".
   - Line 3. Use "The sum of the signal fit with a Voigtian ...".
   - Line 4. Use "... curve), gives the total fit function (solid curve). The yield
      of the signal events is given by the integral of the signal fit curve.".
 - Line 470. Use "... function was chosen ...".
 - Line 471. Use "Figure~10".
 - Line 474. Use "... 16.6~MeV. Both parameters are related ...".
 - Line 476. Use "... for the $\Lambda(1520) [3].".
 - Line 477. Use "... or $t$) was obtained by ...".
 - Line 481. Use "... out of the total generated event from the MC simulation provide ...".
 - Line 485. Use "... or $t$), was calculated ...".
 - Line 486. Use "... that were accepted to ...".
 - Line 491. Use "The accepted event distributions were obtained ...".
 - Line 493. Use "... files underwent a similar treatment to that ...".
 - Line 494. Use "Since the MC generates ...".
 - Line 496. Use "... distribution was fit using ...".
 - Line 497. Use "... function was kept fixed ...".
 - Line 499. Use "... width of the $\Lambda(1520)$, ...".
 - Line 501. Use "... $L(W)$, was evaluated as,".
 - Line 504. Use "... $W$ range, ...".
 - Line 509. Use "The differential cross sections for the reaction $\gamma p \to
    K^+\Lambda(1520)$ were calculated in $\cos ...".
 - Line 512. Use "... the yield value and $A(W, ...".
 - Line 516. Use "The differential cross sections were also ...".
 - Line 519. Use "... the yield value and $A(W, ...".
 - Line 521. Use "... 0.2~GeV$^2$/$c^2$, represent the size of ...".
 - Line 523. Use "... factor, $\gamma_{corr}$, is 1.03.".

Page 9:
 - Figs. 11, 12 notation on subplots. Your notation of "$W(K^+,\pi^+,\pi^-)$" on the
   subplots is certainly non-standard (and kind of meaningless to me). I would just
   use "W". Also, include the units on the energy range on each plot.
 - Fig. 11 caption.
   - Line 1. Use "... as solid circles for 10 center-of-mass energies ($W$) ...".
   - Line 2. Use "... 3.25 as a function of ..." and "... show the previous CLAS results
       by ...".
   - Line 3. Use "... are shown by the dashed curves.".
 - Line 524. Use "The decay modes of the $\Lambda(1520)$ ...".
 - Line 528. Use "The $\Sigma^+$ decays to a $n$ and $\pi^+$ with a b.r. factor ...".
 - Line 529. Use "... whereas the $\Sigma^-$ decays ...".
 - Line 530. Use "... used in Eqs.~9 and 10 for the $\Lambda(1520) ... 0.0672, whereas
    the branching ...".
 - Line 533. Use "... $\tau$, were applied separately ...".

Page 10:
 - Fig. 12 caption.
   - Line 1. Use "... as solid circles for 9 center-of-mass energies ($W$) ...".
   - Line 2. Use "... 3.25 as a function of ...".
   - Line 3. Use "... are shown by the dashed curves.".
 - Line 548. Use "... also shown ( as the dashed curves) in ...".
 - Line 550. Use "Similarly, the differential cross ...".
 - Line 552. Use "... (as the dashed curves) ...".
 - Line 555. Use "The systematic uncertainties for this study were estimated ...".
 - Line 556. Use "... variations on the different ...".
 - Line 561. Use "... parameters was done by ...".
 - Line 564. Use "... polynomial function was taken as ...".
 - Line 567. Use "... detector were used as ...".
 - Line 568. Use "... deviation from the nominal cut on ...".
 - Line 569. Use "... due to the fiducial cut.".
 - Line 570. Use "... variations were used for the other parameters.".
 - Line 571. Use "The systematic uncertainties for ...".

Page 11:
 - Line 581. Use "... accounts for the variations of the pressure and temperature
    throughout the $g12$ data-taking period.".
 - Line 589. Use "Discussion and Conclusions".
 - Line 590. Use "As seen in Figs.~11 and 12, ...".
 - Line 594. Use "The calculations indicate ...".
 - Line 596. Here you are trying to tell the reader that the inclusion of s-channel
    exchanges in the reaction mechanism are not so important because the t-channel
    model already agrees quite well with the data. But you then you state that this
    remark is only true just above threshold, and is limited to the first W bin. Why
    do you think this is true only a threshold and not over the full energy range?
    I am certainly confused by what you are trying to say here.
 - Line 598. You go on to say "This is because only N* resonances with mass below
    2.2 GeV are included in such calculations." This does not help me. What do you
    mean by "such calculations"? There is only one model being discussed and I thought
    you stated that it is purely t-channel model.
 - Line 599. Use ".. where there is intermediate $\Lambda^*$ exchange, such an ..."
 - Line 604. Use "Consequently, even for the higher-energy region ...".
 - Line 617. Use "... with a $K$-exchange diagram, ...".
 - Line 628. Use "... although the theoretical uncertainties, such as the EM transition
    couplings between the hyperons, are considerable for the $u$-channel.".
 - Line 630. Use "Also, some small deviations of the model compared to the data at
     forward angles for ...".
 - Line 633. Use "... that these differences could be explained ...".
 - Line 637. I recommend that you start a new paragraph with the sentence "Even though ...".
 - Line 640. Use "... at higher $W$ there is the need ...".
 - Line 640. Why do you claim there is a need for K* exchange or some interference
    contribution?
 - Line 644. Use "Hence, this study can contribute to a better understanding of the
      $\Lambda(1520)$ using higher-energy photoproduction data.".
 - Line 647. Use "... our results do not show ...".
 - Line 651. Use ".. whether an $N^*$ could ...".
 - Line 664. Use "... carried out with the CLAS12 detector ...".
 - Line 665. Include a reference to the CLAS12 spectrometer. V.D. Burkert {\it et al.}
   {\it (CLAS Collaboration)}, Nucl. Inst. Meth. A {\bf 959}, 163419 (2020)".
 - Table II caption.
   - Line 2. Use "The uncertainties represent only the statistical contributions."

Page 13:
 - Table III caption.
   - Line 3. Use "The uncertainties represent only the statistical contributions."

Page 14:
 - [6]. You should replace this with: "V.I. Mokeev {\it et al.}, Phys. Lett. B {\bf 805},
    135457 (2020)".
 - [14]. Use "CEBAF Large Acceptance Spectrometer (CLAS)".