[Clascomment] OPT-IN: Upper limits for the photoproduction cross section for the Phi--(1860) pentaquark state off the deuteron

[Daniel Carman]

					July 28, 2011


Dear Hovanes et al.,

I have read through your Phi pentaquark paper and include my comments
below. I just have a few minor things to bring up. The paper is well
written overall. Let me know if you have any questions.


			   Regards,

				  Daniel

********************************************************************
Page 1:
 Left column.
  Paragraph 1.
   Line 9. Use "... as part of a spin 1/2 anti-decuplet ...".
  Paragraph 2.
   Line 7. Use "anti-decuplet" for consistency with usage elsewhere.

Page 2:
 Left column.
  Paragraph 2.
   Line 7. Use "... experiment results is from the decay sequence ...".
  Paragraph 3.
   Line 6. Use "... mass of the $\Xi^-(1321)\pi^-$ composite ...".
 Right column.
  Fig. 1. I think it would be good to indicate a size scale on this
    figure. Also an indication of the target location and the beam
    direction would be relevant.
  Paragraph 1.
   Line 1. Use "cross-checked".

Page 3:
 Left column.
  Fig. 2 caption. Why do you use Ref.[37] for the PDG when you use
    Ref.[4] for all other PDG references in this paper?
  Paragraph 3.
   Line 9. You discuss the DOCA cut here but do not provide information
    on the CLAS tracking resolution about the target.
 Right column.
  Paragraph 2.
   Line 1. Use "... pair for the $\Lambda(1116)$, ...".
  Paragraph 4.
   Line 2. Use "... Table II, with the exception of the cascade mass cut ...".

Page 4:
 Left column.
  Paragraph 1.
   Line 1. Use "... mass for the $\Xi^-(1321)$ and ...".
   Line 2. Use "We apply the 1.3175 ...".
   Line 8. Use "... reported mass of the $\Phi^{--}(1860)$.".
 Right column.
  Fig. 6 caption.
   Line 2. Use "mass bin. The error bars ...".
  Paragraph 1.
   - Here you mention acceptance and detector efficiencies but not
     trigger efficiencies. I assume that is because you do not factor
     them in any way into the acceptance and just leave them in your
     systematics. Is this assumption correct?
  Paragraph 2.
   Line 3. Use "... with an event configuration as in the first row ...".

Page 5:
 Left column.
  Fig. 7 caption. 
   Line 2. I suggest "... using restrictive cuts (see text for details) 
    and from the GEANT-based simulations (b).".
  Paragraph 2.
   Line 1. I suggest "Because we do not know how the photoproduction
    cross section of the $\Phi^{--}(1860)$ depends on kinematics ...".
   - The discussion here and the references to "rows" in Table III are
     unnecessary confusing. You refer to row 1, but row 1 is a column
     label. Does the 2nd reaction cover rows 2 and 3 then? Anyway, to
     clean this up, give each reaction a number and refer to this
     number through the paper (in this section and in other references to
     Table III).
 Right column.
  Fig. 8 caption.
   Line 5. Use "... indicates the position of the peak seen by ...".
  Paragraph 1.
   Line 8. Use "... 1.862 GeV that decays only through the ...".
   Line 27. Use "... of the cross section and its upper limit.".
  Paragraph 2.
   Line 4. Use "... 1.862 GeV, the acceptance does not ...".

Page 6:
 Left column.
  Paragraph 1.
   Line 5. Use "... so that the data acquisition system could cope ...".
  Paragraph 3.
   Line 22. Use "$\pm$15\%" for clarity.
 Right column.
  Table IV.
   - I suggest you draw a line across the table above the quadrature sum.
   Line 2. Use "... The overall systematic uncertainty ...".
   Line 3. Use "... as the square root of ...".
  Paragraph 1.
   Line 3. Use "... did not result in any qualitative change ...".
  Paragraph 5.
   Line 1. Use "... upper limits for the cross section for a ...".
   Line 4. Use "... bin as the mean value of a Gaussian ...".
   - Here you describe the Gaussian + polynomial fit. Is this a
     log-likelihood fit? Whatever, be specific here with your fitting
     details.

Page 7:
 Left column.
  Paragraph 1.
   Line 5. Use "... around the center of each bin.".
  Paragraph 2.
   Line 10. Use "... prescription of the Feldman-Cousins ...".
   Line 12. Use "For a comparison, we assumed ...".
 Right column.
  Paragraph 1.
   Line 7. Use "... level for the photoproduction cross section of the
    reaction $\gamma d \to \Phi^{--}X$ multiplied by the branching ratio
    for ...".
  Citations. Why do you include a preprint number for some references?
  Usually once something is published, you just use the journal reference.

Page 8:
 Left column.
  - Ref.[27] is incomplete. If this is a private communication, this should
    be stated.
  Paragraph 1.
   Line 1. Use "The number of events in the mass range of the 
    sideband-subtracted spectrum in Fig. 6 is distributed ...".  Actually
    this sentence is not fully clear to me. Are you saying that if I
    project Fig. 6 onto the y-axis that I will see a Gaussian distribution
    offset from zero?
 Right column.
  Paragraph 1.
   Line 3. Use "... according to the normal distribution:".
  Line 11 after Eq.(3). Use "... For the uncertainty in the value of ...".

Page 9:
 Left column.
  Fig. 10 caption.
   Line 2. Use "$x$-axis".
 Right column.
  Paragraph 2.
   Line 12. Use "... showed that the coverage probability of this ...".