Dear Peter,

On Mon, 11 Jun 2007, Peter Krizan wrote:

>>> >The fit quality in Fig 2a does not look especially good, 
>>> >i.e., the MC does not describe the peak at 1.58 GeV/c2. What
>>> >are those events (i.e., from the truth table)? What is the 
>>> >chi2/dof of the (presumably binned) fit? Do you include a 
>>> >systematic error to account for uncertainty in the background 
>>> >shape? (you should) The discussion of systematic errors on 
>>> >p11 is a bit terse; more explanation here would strengthen 
>>> >the paper. 
>>> >
>>> >  
>>> >
>
>> Please find enclosed a plot which shows the residuals (difference in the 
>> measured and fitted number of entries in units of sigma) for Fig 2a. 
>>  From the plot we deduce that the observed 'peak' at 1.58 is most 
>> probably a fluctuation. This is supported by the distribution for 
>> individual targets (Fig 8 in the note 
>> ,http://www-hera-b.desy.de/subgroup/physics/herab/analysis/mb2003/open_charm_articles/note_061017.pdf).  


Thanks for your answers.
Fig. 8 shows a qualitatively similar excess of data over 
MC at 1.58-1.60 GeV for W, Ti, and Gold targets. Usually 
such a trend indicates a systematic effect...
Anyway, as long as you include an appropriate systematic 
error for this in the signal yield, then there is no issue. 
But I would mention this systematic due to uncertainty in 
the background shape in the systematics paragraph.

regards, Alan