Hello,

looks like a nice piece of work;
it is remarkable how much one can get out of these data!

Scanning the paper, I noticed a few things, partly trivial, partly not quite.

Abstract: "have been measured" appears twice. Replace second by
"are given for" or so.

Page 2, line 6 from bottom "50 mm^2" should read maybe "(50 mm)^2" ?

Section 3: active and passive voice mixed in paper. Mostly
"was performed" but there are a few "we demanded" etc. Suggest to
search document for "we" and rephrase.

Page 4, line ~8 from bottom: "Taking into account ... the limited
acceptance of the detector ... one finds sizeable backgrounds".
I don't think small acceptance makes backgrounds worse!

Page 5, line ~9 of 3.1: change to "and pions: While"

Middle of page, zeta cut: the cut is described as cut on pt of
D0 daughters but as defined includes D0 momentum?

Table 2: in the caption, define what is what (b, d, zeta, L), e.g.
"L_pi is the Pion likelihood, with the normalization L_pi + ... = 1".
"not optimized" -> "chosen a priori"
"optimized" -> "optimized using background data and signal MC"

By the way, in the low-statistics limit, optimizing on Signal_Mc/
sqrt(background_data + ...)is almost as dangerous as optimizing on
signal_data, since one selects downward fluctuations in the background.
Works only in case of good background statistics.

Fig. 3 and associated text: should mention that a Poisson-statistics
likelihood fit is used, otherwise the low counts and
empty bins would cause trouble

Section 4: does the MC generate multiple interactions to simulate
their effect on efficiencies? Should be mentioned.

Page 11, text after eq. (8): mention that one indeed finds alpha
\approx 1 in the data, and refer to section 5.5

Page 12, "The sum of D cross sections accounts for 89+-4% of charm
cross section. Unfortunately I cannot look up ref 22 right now,
but I don't understand how this is calculated. Relative to an independently
measured charm cross section? Unlikely, then the error would much much
larger! Using a charmed baryon cross section? This needs to be explained!

Dito at the end 5.1: "The resulting charm cross section per nucleon is..."
Again, not clear where this number comes from.

Fig. 5:
Our data agree with models for D0 but fall well below the model curve
for D+. On the other hand, we say that D+/D0 is understood in simple
isospin models (I guess, feeddown from D*). This is inconsistent
unless the model curves violate the isospin arguments!

Page 14, Description of how the Pt cross section is obtained: as far as
I understand (it's hard to understand from the description), a fit in pt
is used to get the background? If yes, all the resulting data points are
correlated, and not independent.

I believe it is "we fit" and not "were fitted"

Page 15, first lines: we use x_b = 0.062 from E791. On the other hand,
I would expect that the cutoff of the power law at x_b is related to mass
effects, and I would guess that X_b scales more or less as 1/sqrt(s). Indeed
x_b is of order m_b/E_cm. I don't see a good reason why x_b should be
the same for E791 and us.

Page 15, last line: "It is similar to the world average value of 0.1"
Yes it is "similar" in some sense but it's about 1.5 sigma away and
that should be mentioned. If might well be that the true value differs
for e+e- and pp since the mechanisms are not 100% identical.

Line 9 of section 6: always a "," before "respectively"

a few lines down: again "0.27+-0.09+-0.05 is in agreement with".
Should not go uncommented, see above. "... marginal agreement..."?

Reference: none of the initials has a ".". Is this the journal style?

Greetings,
Werner