Hello Peter, Bernhard,
Below are comments on version 5.1 (July 16); some are a matter of taste
(just suggestions). It may be most efficient to make these changes in a 
colored font (e.g., via \usepackage{color} and \textcolor{green}{}) so 
the paper can be proofread quickly.

Global comment: for "GeV" vs. "GeV/c" or "GeV/c2", does the journal have 
	a convention? We are not always consistent (e.g., see p2 par 2).

--> corrected, we will stick to GeV/$c$. We were not consistent in our 
--> revious papers.

regards, Alan
			------------

p1, abstract, last sentence: "were measured" -> "are presented"
		(the simple past tense looks awkward here)

--> done

  par 1: no comma after "and 800 GeV"
	  (because the clause following is not an independent clause)
		
		"More data could" -> "More data would"  (right?)

		"is essential" -> "is important" (a matter of taste; 
						"essential" is rather strong)

--> done

  par 4: I suggest something like
	"The HERA-B detector is a fixed target spectrometer (see Fig. 1) 
	that uses the 920 GeV proton beam of the HERA e-p collider.
	Interactions occurred in two groups of four target wires each; 
	the groups were separated by 4 cm in z, and the typical wire 
	transverse dimension was 50-500 microns."	
	(the current text is ambiguous)

--> has already been changed, please have a look at the present version
	
	"located in" -> "positioned in"
	(a matter of taste)


--> done

  par 5: need a comma after "With this system"

  par 6: "in front of the magnet" -> "upstream of the magnet"
	 "behind the magnet...downstream of the interaction region"      
	-> "downstream of the magnet...from the interaction region"
		(a matter of taste)

	"fine-grained" (add hyphen)

--> all done


p2, par 1: "coarse-grained" (add hyphen)

--> done

  par 2: better to add a comma after "(ECAL)"
	(this "serial comma" is not required but helps the reader;
	most grammar guides recommend it when listed items become long)

	"in the momentum range from slightly"  (add "from")

	add commas after "up to 70 GeV/c" and "and 45 GeV/c"

	"with a pion misidentification rate" (add "rate")

--> all done

  par 5: "The study" -> "The analysis"  
	 (a matter of taste - "study" connotes a lesser piece of work)

	"with a total of 182 million interactions" is not in the correct
	place in the sentence; if you want to keep it you should say, e.g.
	"...were considered; the resulting sample consisted of 
	182\times 106 interactions."

	"with the total inelastic cross section \sigma_inel" seems 
	redundant with "for inelastic interactions" appearing 
	immediately before it

	"within a two-week minimum bias run" -> 
		"within a two-week running period."  (a matter of taste)

--> all done

  par 6: "Taking into account also the" -> "Taking into account the" 

	"one finds sizeable" -> "one expects sizeable"
	(the latter is what you mean, yes?)

--> all done

p3, par 1: "from particles originating"  (drop "the")

	no comma after "a detached secondary vertex"

--> all done

  par 3, I suggest something like:
	"...final-state kaons and pions. We required L_K > 0.33 (0.50)
	for kaon daughters of D_s+ (D0 and D+) candidates. This 
	requirement has an efficiency of XX% (YY%) and a pion 
	misidentification probability of Y% (Z%). For pion daughters
	only a mild cut Le+Lmu+Lpi > 0.05 was applied, where Lx denotes
	the RICH likelihood for particle type x. This requirement has 
	an efficiency of X%. No particle identification.."

--> The eff. and fake rate have been discussed in the apparatus section.
--> I do not think we have to go into details here. Also: how would you
--> define fakes in the specific decay channel? For details on PID see
--> http://www-hera-b.desy.de/subgroup/detector/rich/rich/pid_effi_2002/

  par 4: "between the K+ and \pi+"  (add the + to the "\pi" since this 
					is for D+)
-->  done

	after "\pm 75 MeV" it would strengthen the paper to add 
	"(X sigma in resolution)"

--> done


  par 5: "A common vertex for each track combination was fitted."
	 This is unclear to me: it means all pairs of tracks (e.g., 
	 for the phi), or all track triplets (for the Ds), or both?
	 If track pairs, presumably they must have opposite charge...

--> tracks from a D candidate, text changed


  par 7, bullets: 
	"of the secondary vertex with respect to the associated"
			(add "with respect")

	"of a pion or kaon with respect to the primary vertex"
			(add "with respect" & drop "a")

  par 8: need a comma after "We found that" 
	(because "for the three-body..." is a parenthetical clause)
					is for D+)
-->  all done

  pars 8 and 9 should be merged (both discussing impact parameter product 
	cut). As this cut is esoteric, I suggest giving its efficiency.
	 
--> efficiency of the cut is about 10%. Do we want to give this detail?

	footnote, use a colon: "is equal to one: Le + Lmu +..."
					is for D+)
-->  done

p4, par 2: "After applying the selection cuts" ->
		"After applying the selection criteria"
	(strictly speaking, "cuts" is colloquial and should be 
	 avoided if possible)

-->  done

	you should give the fraction of multiple candidates

-->  done


  par 4: "Poissonian statistics" -> "Poisson statistics" 
	 (I've never seen this - check an online dictionary)

-->  done

  par 8: "a simultaneous likelihood fit of events in the signal window
		and in the sidebands was used."
	This is unusual wording: "simultaneous fit" usually describes 
	a fit to independent data samples with one or more common fit
	parameters. Your fit satisfies this, but, e.g., in Belle/BaBar
	it would be described as a single fit to a large mass region 
	including sidebands on either side of the signal peak
	(if I've understood what you've done)

--> It is OK here: you fit e.g. pt distribution for both the (mass) signal 
--> window events and (mass) sideband events.

  Table 2: as Sasha noted, this table has an unusual format; is it 
	difficult to make this more standard?

--> improved to 2 columns

p5, Figs. 2,3: the vertical units seem better as "per 0.010 GeV" 
	to be consistent with the horizontal units. 

--> OK, we will change it

	Figs. 2-4 captions: mention what the smooth curves represent.

	Fig. 3 caption, I suggest:
	"Besides the Ds+ peak at 1.96 GeV, a D+ peak at 1.87 GeV is 
	 also visible. This peak corresponds to the..."

-->  done

  par 2: I suggest
	"..is in reasonable agreement (1.4\sigma higher) with the
	estimated number, 4.2 \pm 1.2."   (a matter of taste)

p6, par 1: "was assumed to be The influence"  some words are missing

-->  a % sign too much, done

	"of expression Eq. 2" -> "of Eqs. (1) and (2)" or
				 "of expressions (1) and (2)"

--> done

  Eq. (3): "i" is undefined	(the reader must wait until Eq. (5))

--> done

  par 3:  "for a specific decay channel" looks odd with a citation...
	  You could write something like
	"...is the PDG branching fraction for a specific decay channel."

 	penultimate sentence:
	"...a linear $A$ dependence of the cross sections was assumed, and
	\alpha was set equal to one in Eqs. (7) and (8)."

--> done

*** physics question: rather than use Eq. (6), we could have done a 
	simple 1-parameter fit to the three values of Eq. (3), no?
	(just a question; do not change the text)

--> Marko showed on one of the meetings that the two approaches are
--> equivalent.


  par 4: "Furthermore, the uncertainty of the reconstruction 
	efficiency can be divided..." ->
		"The uncertainty of the reconstruction efficiency can 
		be further divided.."   (a matter of taste)

--> done


	"from the reweighting of kinematical distributions." ->
		"from the reweighting of kinematic distributions
			based on pT and xF."

	"Table 4 and Table 5" -> "Tables 4 and 5."

	"in two ways:"  (use a colon)

	At the end of this paragraph I suggest adding:
	"The change in the resulting cross section is taken as
	 the corresponding systematic uncertainty."

--> done

p7, you could swap the order of Tables 4 and 5 such that
	they correspond to their order in the text.

--> done

  par 1: "using the expression Eq. 2" ->
		"using Eq. (2)" or "using expression (2)"

	better to add a citation after "xb = 0.062" 

  par 2: the last sentence should be
	"Our results provide the most accurate measurements at high
	energies and are consistent with those of previous studies."

	(plural, no comma, add pronoun)

  par 3: "hadronisation" -> "hadronization"

--> all done

*** physics question: does the "0.891 \pm 0.041" also include D0's 
	produced via D*+ ? 

--> yes

	This value should probably have a better reference than 
	just the generic PDG (e.g., is there a PDG page number)?

--> done; I am just not sure I am quoting it in the right way -> will check it

  	"as measured in the present study" is unnecessary
	 (and makes the reader wonder if this is something
	  different from that mentioned in the previous sentence)


--> done

  par 4: "by using the expression Eq. 8" -> "by using Eq. (8)" or
			 		    "by using expression (8)"

--> done

	perhaps (?)
	"...for the production of D0 and D+ mesons (together) are..."

--> left

  par 5: "a direct fit to the data points of Fig. 6 is not adequate."
	But the error bars in these plots look no worse than some
	Belle/BaBar fits, so this statement seems too strong.
	Perhaps "is not adequate" -> "gives relatively large errors." ?

--> 'is not adequate' is right: the statistics is low, so you cannot use
--> chi2, but since this is already a subratracted distribution, you 
--> also cannot use max.lik.

	"simultaneous fit"  This usage of "simultaneous" implies
	there is a common parameter in the pT2 and xF fits.
	I presume you're again referring to the signal window
	and mass sidebands? 

--> yes, and in the rest of the sentence this is explained

	"Poissonian" -> "Poisson" 

--> done

  par 6: "..from a fit to the data." -> "from the fit."
		(a matter of taste)

--> done




p8, Fig. 5: the non-HB data points and theory curves need references 
	somewhere (e.g., the caption)

--> curves are refered to in the caption, references for data points
--> were added

  par 2: "is within one standard deviation equal to the value" ->
		"is, within one standard deviation, equal to the value" or
		"is within one standard deviation of the value"

	better to write
	"....fixed value of \beta=6, i.e., the value that was used for 
	our study of..."

	last sentence, better to write
	"In this case the fit yielded the same value of <pT>, and the
	 chi2/ndf was unchanged."


--> all done

  par 3: "The experimental observation made by E791...also shows" ->
		"The measurements made by E791...also show"
		(a matter of taste)

  par 4: "is too small to be sensitive to" ->
		"is too small to determine"
	(the former implies it doesn't matter - so why 
		bother with it?)

	"the error in our study is much larger." ->
	   "the statistical error in our result is much larger."
		(a matter of taste)

--> all done

p9, Fig. 6a: some error bars/range bars are missing

--> negative entries (after subtraction), logarithmic y scale

  Fig 6	caption: "of expression Eq. 1" -> "of Eq. (1)" or 
					  "of expression (1)"

	"with a fit of function Eq. 2" ->
		"with the fit of Eq. (2)"

--> all done

  par 1: better to write
	"..simple prediction based on isospin symmetry and the measured 
	ratio of vector to scalar meson..."

  par 2: "is again" -> "is also" 

	no comma after "in pA reactions"
	
	"and is in good agreement"  (insert "is")

	"(see [1] and references therein)"  (insert "see")

	"one gets" -> "one obtains"

	"0.62 \pm 0.09 \pm 0.05 is obtained."  (add "is obtained")

  par 3: "of measurements in" -> "from measurements in"

  par 4: "\sigma_{nonLP}" -> "\sigma_{{\rm non}LP}"
		(Phys. Rev. convention)

	"reweighting in respect to" -> "re-weighting with respect to"

  par 5: "measured D meson production cross sections"  
			(add "cross sections")

	"of the relation Eq. 4" -> "of relation (4)" or
				   "of Eq. (4)"

--> all done

	"simultaneous maximum likelihood fits" 
	This usage of "simultaneous" implies there 
	is a common fit parameter alpha (but there 
	isn't - you take the average of separate fits)

--> It is indeed a simultaneous fit to three mass plots (one per target) for 
--> each D species. 

p10, par 1: "...two contributions:"  (use a colon here)

	 better to have a comma after "(about 2.5%)"

  par 3: "were measured to be:"  (add "to be")


--> all done

	I would list the differential cross sections (i.e., directly 
	measured) first, and the total cross sections (i.e., obtained by 
	extrapolation) second (a matter of taste, but also then the ccbar 
	result follows naturally)

--> left as it is

  par 4: no comma after "in pA reactions" 
	(because the clause following is not an independent clause)

--> changed already 

  par 6: this sentence should be added to the end of par. 5
	(it shouldn't be its own paragraph)

--> I am not sure about it: this sentence actually referes to all 
--> measurements we made, not only the ones in par.5. What about moving
--> it up to the end of paragraph 1 of the summary. 

	"and in (most/the majority of) cases provides the most" 
	(reads better to me to put the verb next to the object)

	"Aknowledgements" -> "Acknowledgements" 
	(use a spell-checker - again) 

--> sure...