[Clascomment] [EXTERNAL] Re: OPT-IN:First comprehensive measurement of spin observables and differential cross sections dsigma/dt in omega photoproduction off the proton for 2.7 < Egamma < 5.2 GeV using CLAS

[Keith Griffioen]

> On Mar 7, 2022, at 12:54 PM, Volker Crede <vcrede at fsu.edu> wrote:
> 
> Dear Stepan,
> 
> Please accept my apologies for the delay. First of all, thank you very much for your comments and efforts that help improve our manuscript. With one exception, I believe we have addressed all your comments. Please let me know if you have any additional questions or remarks:
> 
>> On Feb 3, 2022, at 11:06 AM, Stepan Stepanyan <stepanya at jlab.org> wrote:
>> 
>> - Laget’s affiliation with JLAB is incorrect.
>      —> I believe Jean Marc has clarified the situation. The affiliation with JLab is correct.
> 
>> - line 13, photons energy range, 2.7 GeV - in the text and the presented data have much lower photon energy ~1.55 GeV
>      —> The energy of 2.7 GeV is correct for all t-dependent observables which is the focus of this paper. For this reason, I left 2.7 GeV in the title. However, I have added a sentence to the abstract:
> 
> Moreover, differential cross sections d$\sigma$/d(cos\,$\Theta$) and the unpolarized spin-density matrix elements in the Adair frame are presented for the incident photon energy range 1.95--2.83~GeV. 
> 
>> - line 63, the sentence is unclear, “The low-energy regime close to the reaction threshold, where nucleon resonances dominate the photoproduction of ω mesons, and the Regge regime are analytically connected. “ either unfinished sentence or may be “and” must be removed?
>      —> I am not sure about this comment. The sentence looks good to me and would make little sense without the word “and."
> 
>> - line 66, why not “t-dependence”, do we need to have “-t”? It talks about momentum transfer dependence of the cross section
>      —> Since all data are presented in terms of -t, we decided to leave the sentence as is.
> 
>> - line 75, the lower photon energy limit is quoted as 1.6 GeV. In the abstract it is 2.7 GeV, and the lower W value corresponds to photon energy of 1.5 GeV. Must be consistent with quoting the energy range
>      —> The energy of 1.6 GeV is correct here since we are not specifying what the representation of the observables is. This is just a general comment on the analysis. If we had to repeat each time that the minimum of 1.6 GeV applied to the angular distributions and the minimum of 2.7 GeV to the -t representation, the paper would be more confusing, I believe.
> 
>> - line 103, either remove “at Jefferson Laboratory” or move it after earlier reference to the CLAS collaboration on line 99
>      —> Done, changed.
> 
>> - sentence starting at line 214, “The full set ...”, the supplemental material is not provided (no link), but it looks like data in Figures 5, 6, and 7 are what is referred here for d\sigma/dcos(\theta). So if that is the case, then the reference to 10 MeV and 20 MeV wide bins is reversed and generally messed up. In Fig.5, W range 1.95-2.35 GeV, the bin width is 20 MeV, Fig.6 and 7, W range 2.35-2.83 GeV, bin size is 10 MeV. Bin width is correct for d\sigma/dt figures.
>      —> The links for the supplemental material will be provided and inserted by Physical Review. I have corrected the sentence (thank you for pointing out the mistake):
> 
> The full set of differential cross sections d$\sigma$/d(cos\,$\Theta$) in 20-MeV-wide and 10-MeV-wide
> bins for the $W$~range \numrange{1.95}{2.35}~GeV and \numrange{2.35}{2.83}~GeV, respectively, and d$\sigma$/d$t$ in 20-MeV-wide bins for the $W$~range \numrange{2.45}{3.25}~GeV is provided as
> supplemental material~\cite{SuppMaterial:CrossSections}.
> 
>> -  line 247, “For each (E_\gamma ...”, change E_\gamma to W, the energy bins are quoted as W-bins on the figures and in the text before (specially Fig. 3 and 4)
>       —> Changed.
> 
>> - line 299, there is no magenta curve on Figs. 2 and 3. The predictions of [33] are reverend as “red curves” in the caption of Fig.2
>      —> Corrected, magenta has been replaced with red in the text. We changed the color of the curves in the analysis review but missed the subsequent mistake in the text.
> 
>> - caption of Fig.3, it does not look like the definition of red curves in Fig.2, and Fig.3 are the same
>      —> Can you please clarify why you think the definitions are different? Looks good to me.
> 
>> - line 312, should not “The” be a lower case after “:” 
>      —> I have double-checked and using an upper case “The” is correct since we start a proper sentence.
> 
>> - line 337, the W range is inconsistent with data, the lowest bin for data is 1.95 GeV, and why 3-digits. For the presented figures, W for cos\theta dependence is 1.95 to 2.83 GeV
>      —> We have changed the range to [1.95, 2.83] GeV as you suggested.
> 
> Best wishes,
> 
>        Volker 
>