Dear Peter and Bernhard,

Please find below comments for the open charm paper v.5.1.

Below I have some suggestions for arrangement of Figures and tables,
but the situation can be changed after inserting the authour list, so
I think it is time to put the complete authour list to the draft.
You can contact Mike about it.

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para 1: You mention that ratio of open charm to charmonium cross
sections in pA reactions is essential for quark-gluon plasma searches
and refer to [10], however I was not able to find this point there.
Where should I look? I would also like to know what non-perturbative
effects do you mean in the previous sentence.

--> Good point. In this reference there is indeed a very short discussion,
--> and only references are given to the original papers, e.g. Andronic
--> Barun-Munzinger, Redlich, Stachel plb 571 2003 36. Bernhard was in
--> contact with J. Stachel about it, and we changed this sentence 
--> and the reference.
--> Non-perturbative effect: the k-factor still seems to be a free variable... 

At the end of introduction you mention that a comparison with
theoretical expectations is made. However, I didn't find any
mentioning of this comparison in Summary. Should we add it?
In the paper, I found only Pv calculated assuming isospin invariance
(but here it is just assumed, but again no comparison is made).

--> The theoretical predictions actually heavily rely on experimental
--> input (e.g., k-factor for absolute values), and in case of Pv 
--> the use of isospin invariance cannot really be considered as a model.
--> I propose we drop that sentence in the introduction.

Section 3.1, end of para 3: put additional spaces in the definition of
zeta between three "p(...)".

--> Definition of zeta removed, we do not actually need it.

Table 2 looks a little bit non-structured and easy to read.
I would suggest to add vertical spaces between 4 parts of it
(possibly "\vfill" will work,
otherwise one can add something like "\vspace*{4ex}").
Another possibility is to use \begin{table*} instead of
"\begin{table}" for a table which occupies two columns
(example is in our psi' paper hep-ex/0607046).

--> We have tried with a second option. Please have a look at it.

In the current layout, I would propose to put Table 3 after Fig.2.
First of all, Table 3 is discussed after Figs.2-4, and secondly, then
Figs.2-4 could look like a complete block.

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p.6, col 1, middle of para 2 - Thank you for introducing this well-hidden
error in the middle of text. This will certainly test how many people
read the whole paper. After testing this, please finish the sentence.

--> found by almost all who sent comments; a % sneeked in...

end of p.6, col 1 and further: I would add brackets to references of
equations: "Eq.(4)"
I would add dots to the end of Eq.(5,7,8,10)

--> dots: done
--> brackets: we do not use it in the phi/K* paper. I left it as it was for
--> the time being.

p.6, col 2, the last but 2nd para: "Tables 4 and Tables 5"
                               --> "Tables 4-5"
p.6, col 2, the last para: "tables 6-8"
                       --> "Tables 6-8"
--> done

End of p.6, col.1:
You sum three f(D) from PDG page 200 to get (89.1+-4.1)% and probably
ignore statistical correlations between them.  LEP compilation paper
hep-ex/0412015 in Appendix B shows that there are correlations.
How much the statistical error 4.1% will reduce if correlations are
taken into account?
(I already asked this question, is there any answer to it?
Probably, statistical uncertainties from HERA-B cross sections anyway
dominate, so that influence of correlations is probably small, but
still we specify this number in the paper, so it should be correct.)

--> We assume the fractions are independent. The error is only a small 
--> fraction of the total systematic and thus the details should not
--> matter much for our result. We should, however, tell the reader
--> what we did, and I have added this in the text.
--> In case you have an idea how to improve the error estimate, we 
--> would of course appreciate your help!

End of Sect.5.1: probably we could show a plot of ccbar cross section
vs. sqrt(s) similar to Fig.1 of recent paper by C.Merino, C.Pajares
and Yu.M.Shabelsky arXiv:0707.0946 [hep-ph] (or corresponding plots of
review [1]). This would be another comparison with the theory.

--> I do not think this result is of central importance for this paper
--> to merit a special figure to compare with the others.
--> First it relies on the assumption taht we can use e+e- hadronization
--> data, and second neglects correlations. 


Sect 5.1, last line: "adding in quadrature the individual contributions"
                 --> "adding the individual contributions in quadrature"

--> I think both are OK, and would prefer to keep the original version.

p.8, col 1, para 2: In principle one could expect that chi2/ndf should
not change much if the number of ndf is large and the change of chi2
is small as here (I would expect increase by
(delta(beta)/sigma(beta))2 = (1/4.3)2 = 0.05). However, giving the
second chi2/ndf at the end of paragraph tempts to compare the two
numbers and adds possibly nothing, so one could exclude it.

--> right, the second chi2 removed from the text

Sect.5.2, last line: I would not consider that 3.2 is much larger than
1.4, so I would propose to change "much larger" to "larger".

--> done

p.8, col 2, last line: what is the last prediction of Pythia
                       for ratio sigma(D+)/sigma(D0)?

--> 0.41 for Pythia version 6.326  with default settings except for
--> PARP(91)=1.5 and PARJ(13)=0.6 (private communication, Lourenco+Woehri)

p.9, col 1, para 2: "([1]" --> "(see review [1]"

--> done

sect.5.3, last para: one can compare the result also with recent Zeus paper
"Measurement of D mesons production in deep inelastic scattering at HERA",
ZEUS Collaboration (S. Chekanov et al.), DESY-07-052, arXiv:0704.3562 [hep-ex],
Section 8.2. As far as I understand, their gamma(s)  should be divided by 2 to get
0.112 + 0.015 + 0.009 + 0.017 = sigma(D+s)/(sigma(D0)+sigma(D+))
              - 0.004 - 0.013

--> added 

Table 9: the table should look better after transposing it
         (and occupy less space).

--> done

Sect.5.4, middle: "the second systematic" --> "the second is systematic"

--> I think we do not have to duplicate 'is' in this case.

Sect.5.4: Can any statement be made about comparison with theory?
          e.g. some values from Lourenco?

--> I think we should avoid making too many comparisons with theory
--> (=Pythia) because the values depend very much on the version and
--> settings.

Summary, para 2, line 2: "were measure" --> "were measured"
                 line 5: "cross section are" --> "cross sections are"
         last line in col.1: "with existing measurements"
                         --> "with the existing measurements"
--> done

Summary, col 1: "in most cases the most..."
                "in the majority of case the most..."

--> done

References: a comprehensive list of corrections in punctuation was
            already provided by Dima.
I can add the following:
[2] Put spaces in the name of the journal.
[29] Other references have a dot at the end, except this one.

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In general, I would advise to look how References are made in a recent
published paper, e.g. our psi' paper Eur. Phys. J. C 49, 545-558 (2007)
and use this style. One can notice that they put the year in brackets
at the end of reference. They don't put a dot at the end of reference.

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