[Clascomment] OPT-IN: Measurement of the nuclear multiplicity ratio for K0s hadronization at CLAS

[Daniel Carman]

					June 7, 2011


Dear Aji, Ken et al.,

I have read through your draft paper on K0 hadronization. I include
my comments and questions below. My general impression is that this
doesn't measure up to the level of a letter due to the lack of detailed
theoretical interpretation of the data. It might more seamlessly go 
through as a PRC or PRD submission, but I will support you whatever
your decision is. If you have any questions on what I include below, 
let me know. 


			   Regards,

				  Daniel

********************************************************************
Page 1:
 Abstract.
 - Line 3. Use "... at Jefferson Lab and a 5.014 GeV electron beam.".
 - Line 3. I find the second sentence quite awkward. I suggest "We
    report the $K_s^0$ multiplicity for targets of C, Fe, and Pb
    relative to deuterium as a function of the fractional virtual
    photon energy $z$ and transverse momentum squared $p_T^2$ of
    the $K_s^0$". Note I do not think the word "differential" is
    needed here as it is never used again in this work. I am not sure
    what a "differential multiplicity" is anyway.
 - Line 8. "... to be broadened in the nucleus ...". Broadened relative
    to what?

Page 1:
- Line 1. I do not care for the first sentence, "Hadronization is the
   process whereby a quark is struck by a virtual photon from DIS of
   an electron." This statement certainly has nothing to do with
   hadronization. Hadronization is related to the hadron formation after
   a quark in a hadron is given a momentum kick and string breaking
   occurs. I think this should be tidied up.
- Line 3. "... as the quark propagates away ...". Away from what?. Again,
   this first sentence needs some attention. It is not a good idea to
   start off a paper in a sloppy manner.
- Line 5. I suggest "... observed at SLAC [1], followed by the EMC [2]
   and E665 collaborations, and more recently at HERMES [4-6]. The ...".

Page 2:
 Paragraph 1.
  - Line 1. Use "... ion collisions, as well as the study of ...".
 Paragraph 2.
  - Line 3. Use "... and its tranverse momentum squared, $p_t^2$."
     Eq.(1). I am confused by the definition of R_A^h. Why do the DIS
     normalization factors in the numerator and denominator not have
     the same functional definition as the N_h terms? In other words,
     why isn't N_e-^DIS a function of z, pt2, Q2, nu?
  - Eq.(1). Add a comma at the end of the equation.
  - Line 5 after Eq.(1). I suggest "... produced hadron flux in nuclei
     relative to deuterium, although ...".
  - The last sentence of this paragraph (defining formation lengths)
    seems kind of tacked on. It doesn't fit with the discussion in the
    paragraph.
  - Last sentence. You define the formation length as the characteristic
     distance over which hadrons form. Does this distance imply the
     distance from which the bare q-qbar pair is first formed until it
     becomes a fully dressed hadron?
  - Put Ref.[10] at the end of the sentence.
 Paragraph 4.
  - Line 2. The part "one must employ various models to explain the
     observed nuclear dependence". The observed nuclear dependence of what?

Page 3:
 Paragraph 1.
  - Line 1. I suggest "... the $z$ dependence of the multiplicity ratio
     in the nuclear medium for ...".
  - I find the discussion starting with "This can be explained simply
     by noting ..." to the end of the paragraph obtusely written and
     not fully clear. I think you need to revisit this discussion and
     rewrite.
 Fig. 1 caption.
  - Line 1. Use "... dependence of the multiplicity ratio ...".
  - Line 2. You do not mean "of $z$ for heavy nuclei". You mean $Z$",
     as in atomic number.
 Paragraph 2.
  - Line 1. This sentence is awkward. The word "also" is the problem.
     How about "While the HERMES measurements for the hadronization effects
     in $\pi^0$ production looked very similar to $\pi^\pm$, they did not
     report any $K^0$ hadronization result to compare against their
     $K^\pm$ data.".

Page 4:
 Paragraph 1.
  - Line 1. Use "Of course, the $K_s^0$ is a mixture ...".
 Paragraph 2.
  - Line 8. O.K. now I am confused by "The scattered electron and the
     produced hadrons were detected in coincidence by the CLAS detector"
     and the definition of Eq.1. It seems like from the requirement that
     you have an electron - "kaon" trigger requirement, that the
     N_e^DIS normalization is trivial in Eq.1. What is the difference
     between N_h(A)/N_h(D) and (N_h/N_e) (A) / (N_h/N_e) (D)?
 Paragraph 3.
  - Line 2. Use "... x= Q^2/(2 M \nu)$, where ...".
  - You should state the z range of your data for clarity in this
    discussion. In fact, I am not sure why you chose the plots in Fig. 2
    as you did. Why not show Q2 vs. z and Q2 vs. p_T^2, the plots in the
    relevant variables. Maybe in addition to what you do show.

Page 5:
 Paragraph 2.
  - Line 5. You explicity mention the p_T cuts on the lower plots in the
     text, but you do not mention the z cuts on the upper plots in the text.
     Seems like you should.

Page 6:
 Fig. 4 caption.
  - Line 2. Use "... experiment, along with the results ...".
  - Line 4. Use "... symbols as given in the legend.".
 Paragraph 1.
  - Line 5. Use "... studies, the data presented are ...".
  - Line 6. Use "... from target fragmentation and ...".

Page 7:
 Paragraph 1.
  - Line 7. Use "... the multiplicity ratio vs. $z$ results and a 5\% ...".
  - Line 8. Use "vs.".
 Paragraph 3.
  - Line 12. Use "... times is found to best fit ...".

Page 8:
 Paragraph 1.
  - Line 5. Why did you put "formation length" in quotes? Seems like this
     is not appropriate.

Page 9:
 Paragraph 1.
  - Line 3. Missing units on p_T^2.
 Paragraph 3.
  - Line 3. Use "... $K_s^0$ in the CLAS detector ...".
  - Line 5. I suggest "... because the data on both the deuterium and
     nuclear targets were acquired simultaneously. The targets were
     separated by ...".
  - Line 7. "The K_s^0$ counts come from fitting ... with a scattered
     electron.". Again, I guess that I still don't understand your definition
     in Eq. 1.

Page 10:
 - Ref. [7], two authors separated by "and".
 - Ref. [10], two authors separated by "and".
 - Ref. [12], "B.A. Mecking".

Page 11:
 - Ref. [17], "102, (2011).".