Hallo, everybody,

Here I try to summarize the comments which were voiced last Friday
with respect to the Draft of the Charm paper. 
For time reasons, we had no discussion on any of the remarks which
were made. After the meeting I received further input from some of you.

Here is my summary. I hope it takes into account all comments which
were made. Please, react soon before Marcel sends it to the Editors.


1) Reference to private communications in the introduction is misplaced.
   Check with the people of the private communication references
   if the interpretation of their information has been done correctly.

2) Structure the LHCb note as in the draft per topic and not per
   charm decay.

3) Make sure that the authors of the theoretical calculation cited are
   happy with the chosen presentation. In fact, the data are integrated
   cross sections in bins of p_t and y, whereas the calculations are
   differential cross sections.

4) The analysis section is very detailed, but rather technical and  
   therefore too long. Either shorten it, or provide a few more plots to  
   illustrate things.

5) Analysis part has a good structure but fails to show how the  
   parameter values, on which cuts are applied, are distributed.

6) Make more explicit which part of the efficiency determination  
   relies only on data, and which rely on a comparison with MC. 
   We suggest to be more explicit in separating these two, and to provide 
   some plots of Data/MC comparison for the variables through which 
   efficiencies are  estimated.

7) It is strange to present results as ratios to calculations of which 
   you give the predicted cross section, in stead of giving the measured 
   cross section and a comparison with the calculations. 
   Plotting the data points into the plots of the theoretical predictions 
   (e.g. Figs. 1-3) makes a much better  comparison.
   In addition, the question whether there is a steeper or softer slope 
   in the p_t spectra seems to become eliminated in this way.

8) At the end of the result section, change the wording for the  
   discussion of the f(c->D+)/f(c->Ds) result. 
   As it is, it is funny because it seems to make the point that the result
   is NOT in disagreement with the PDG value, but this latter has larger 
   uncertainties than our own measurement.
   How sure are we that the ratio value R=2.32 will not change by further
   refinements of the D_s analysis?

9) The note can gain in clarity by discussion all selections in a  
   similar way:
   -  selection of basic final states: kinematics, track quality, PID;
   -  quality of common vertex fit ;
   -  kinematic criteria for charmed particles ;
   -  pointing/separation/topological criteria for charmed particles.
   In this way one can more clearly emphasize common features of all analyzes
   and stress the differences. 
   Also it will make clear that cuts, being very different, still are based 
   on some general properties.

Thomas S. Bauer
NIKHEF                                                                
email: thomas @ nikhef.nl
P.O. Box 41.882                           tel. : (+31)-20- 5 92 20 50
1009 DB  Amsterdam,  The Netherlands      fax  : (+31)-20- 5 92 51 55