[Hybrid baryons] Proposal Draft - reorganized
Viktor Mokeev
mokeev at jlab.org
Sun Apr 17 17:18:51 EDT 2016
Dear Colleagues,
Please find the proposed a partial response to the comment:
------------------------------------
3) The two existing elements of the CLAS12 N* program (E12-09-003 and E12-06-108A) should be described somewhere in
the introduction in a concise fashion with appropriate references.
---------------------------
in the edited Sections 2.3 and 2.4 in the attached file. The edits are shown in bold.
Best Regards,
Victor
----- Original Message -----
From: "Daniel Carman" <carman at jlab.org>
To: "hybrid baryons" <hybrid_baryons at jlab.org>
Sent: Sunday, April 17, 2016 12:52:12 PM
Subject: Re: [Hybrid baryons] Proposal Draft - reorganized
Annalisa et al.,
I have just finished reading the available draft of the hybrid baryon proposal that was circulated yesterday. I have extensively
marked up my copy, but I wanted today to share only my “highest" level of comments as we work to shape a "presentable”
version of this proposal to meet the CLAS Collaboration review deadline of next Monday.
1) The proposal as it stands, while still rough and hastily written in some areas, is not all that bad. In fact, I am certain that we
can converge this week on a draft that will represent us well for the collaboration review.
2) One area of weakness that needs to be addressed is that there are no references to the extensive existing measurements
published by CLAS for KY electroproduction. These measurements needs to be described in some level of detail and proper
references included. I can provide this part along with references.
3) The two existing elements of the CLAS12 N* program (E12-09-003 and E12-06-108A) should be described somewhere in
the introduction in a concise fashion with appropriate references.
4) The proposal draft will need extensive clean-up with respect to grammar, syntax, and style. As I will be responsible for this,
I would like to get the “frozen” proposal draft (and all files) no later than Friday afternoon (Apr. 22) so that I can complete this
work over the weekend. I will finish my work by Apr. 24 and send the draft to the hybrid group for a final chance to look at it
before submission on Apr. 25.
5) Section 3. I found the "Old Version" much better written and more complete than the paragraphs that follow in the “New
Version". I propose to keep the text highlighted in blue and to delete the text on pp. 12 and 13 starting from "As discussed in
section 2.2, according ...” until "... channels such as $\phi(1020N$, $K^+\Lambda$.".
6) The first bullet of Section 3.1 makes no sense to me.
7) Explain the curves on Fig. 7 and Fig. 8.
8) Section 3.3. At the top of pp. 20 is a bit about "In collaboration with the JPAC ..." that does not seem to fit. Lots of words but the
relevance to the discussion does not seem to fit.
9) Section 5. The intro paragraph is all about KY and should be moved to Section 6.
10) The acceptance of CLAS12 for eppi+pi- and eK+ppi- can be misleading if a proper cut on the momentum for low momentum
tracks in the Central Detector is not considered. The minimum momentum tracks accepted by the CTOF is ~300 MeV. Is there a
pmin cut in effect?
11) Section 5.4. The second paragraph here makes no sense to me.
12) What is the purpose of Fig. 21? It should be better integrated into the text and redone with I=-3375A torus current.
13) Replace Fig. 25 and Fig. 26 with I=+/-3375 A for the torus.
14) Section 6.3. This business about "Lambda Separation %” and "Sigma0 Separation %" should be eliminated. For cross section
observables the hyperons can be separated with a proper line-shape analysis such as has been done in our existing CLAS
publications. So, remove the vertical lines on Figs. 27 and 28 and eliminate this discussion.
15) Section 6.4. Rate estimates should be shown only for final torus current choice of -3375 A. All of the other conditions listed only
serve to distract.
16) Section 6. Somewhere in the section a crisp argument has to be made about value added at running at both 6.6 GeV and 8.8 GeV.
What are the different kinematic ranges accessible at each beam energy and why are these different ranges essential for a successful
experiment?
17) Section 7. Nowhere are the different observables that will be measured succinctly laid out, especially for K+Y. The plan is to measure
the differential cross sections and to separate the structure functions sigU, sigLT, sigTT, and possible sigLT', as well as to measure the
induced and transferred hyperon polarization. This needs to be clearly discussed and why these observables are important. Also it needs
to be mentioned that the interference structure functions and polarization observables might be even more sensitive to hybrid baryons
that measurements of differential cross sections alone. Certainly they can only add additional sensitivity in the search for new baryon
states (hybrid or conventional). These observables and their potential sensitivities are not really mentioned or discussed at all in the
proposal.
18) Section 7.6. The discussion here is a bit muddy and misleading. Table 5 shows the minimal value of the A1/2 electrocouplings vs. Q2,
but under the condition that only the scattered electron is used to define the trigger. A tepid statement is made that with a two- or
three-prong trigger this minimal value improves. I think that some additional table must be included on what this improvement is with
our expected trigger condition for the experiment.
19) Section 7.7. Replace Tables 7 and 8 with values for I=-3375 A torus current.
20) Replace Figs. 34, 35, 36, 37 with I=-3375 A torus current.
21) Section 7.8 needs some attention to introduce this approach to define our sensitivity to finding hybrids. This includes mentioned the
use of this chi-squared approach from Bonn-Gatchina. The section should also be expanded following Volker' recent suggestion of
scanning the chi-squared space assuming different quantum numbers for the resonance than were used to generate it.
22) Section 8. The justification of the 30 days at each beam energy needs to be made more complete. We need to carefully define our
statistical requirements based on a certain minimum threshold value for the hybrid electrocoupling. The running time needs to be justified
showing how the minimum electrocoupling value increases as a function of reduced beam time.
23) Page 59. Figs. 39 and 40 are not referenced in the text.
24) Section 9. The summary should include explicit mention to the two existing elements of the CLAS12 N* program, E12-09-003 and
E12-06-108A, at 11 GeV.
25) Are Appendices A and B needed for this proposal? This is fairly elementary stuff. If deemed to be helpful to the proposal, the formalism
section on KY should follow what I have developed as the RPR formalism is based on what I have defined in our published KY papers from
CLAS.
Let me know if folks have any questions or comments on this.
Regards,
Daniel
***********************************************************************************
* *
* Dr. Daniel S. Carman e-mail : carman at jlab.org *
* Staff Scientist office : (757)-269-5586 *
* Jefferson Laboratory web: http://userweb.jlab.org/~carman *
* *
***********************************************************************************
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