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Hi Kerstin, 

I don't remember exactly the details, so perhaps Antonio and Roberto can
correct me if I am wrong... 


> The parameters fixed in these fits come from mesparsetting.dat.
> Where do these numbers in mesparsetting.dat actually come from?
> I assume they come from some high statistics fits - could you
> give some details about these (what kind of data/MC, cuts applied,
> all params floated?,...)?
> 

They are obtained on the relevant samples (data, vub, vcb, other) after
applying the SL event selection. 
Note also that in the VVF code we actually refit for the PDF parameters
after applying all cuts, and fix the fitted parameters in the subsequent
mes fits in bins of the kinematic variables involved (look at FitMes
method). 

> In the CM2 version of this file I see many comments of the sort
> "# not updated to CM2" - why is this? Did we actually have a look
> and see that the changes were negligible or has this simply not
> been looked at?
> 

I believe we planned to update them but at about the same time we
switched to Thorsten's model for the PDFs and consequently used
another .dat file (mesparsetting_thorsten.dat). 

> I see that we are fixing the width of the Crystal Ball function.
> Why is this fixed also in those fits which do have a quite
> large signal fraction? Has anyone ever tried to float this
> in say the high stat fits (like for the correctionratios) and/or
> the mES fits for the low mX bins? If not, why not?
> 

I think they were allowed to float when determining the PDF parameters
and fixed afterwards. Floating the mean and width of the CB function
should be simple, just run subVirFit.pl with the flag -fixshape (yes, I
know, it is reverse logic...). If you want to float the width only then
you need to modify VubMesUnb in VirUtil.icc at around here: 

    if (fixpar == 0) { // preset parameters only
      Rm->setVal(inputPar[VirClass::iMean]); 
      Rs->setVal(inputPar[VirClass::iSigma]);
      ar->setVal(inputPar[VirClass::iArgus]);
    } else if (fixpar == 1) { // set and fix all parameters (if
reasonable value is given)
      if (inputPar[VirClass::iMean]  > 0.)   { Rm->setVal(inputPar
[VirClass::iMean]);  Rm->setConstant(); }
      if (inputPar[VirClass::iSigma] > 0.)   { Rs->setVal(inputPar
[VirClass::iSigma]); Rs->setConstant(); }
      if (inputPar[VirClass::iArgus] > -55.) { ar->setVal(inputPar
[VirClass::iArgus]); }

Cheers, Concezio.