Dear experts,
I’m experiencing a problem with the definition of a RooFFTConvPdf on a large mass range.
First I define my dataset:
RooRealVar* mgg = new RooRealVar(“mgg”, “MASS”, 300, 6000, “”);
RooArgSet* ntplVars = new RooArgSet(*mgg)
RooDataSet signal(“signal”,“dataset”,sigTree,*ntplVars,"","");
then a Breit Wigner:
RooBreitWigner SigModelBW(“SigModelBW”,“SigModelBW”, *mgg, BWmean, BWwidth);
and then a doubleCrystalBall:
RooDoubleCB ResponseDoubleCB(“ResponseDoubleCB”,“ResponseDoubleCB”, *mgg, CBmean, CBsigma, CBalpha1, CBn1, CBalpha2, CBn2);
All the parameters of both the BW and the crystal ball functions are fixed.
Finally I define the convolution in this way:
mgg->setBins(5000, “cache”);
mgg->setBinning(RooBinning(5000,300,6000));
RooFFTConvPdf* ConvolutedRes;
ConvolutedRes = new RooFFTConvPdf(“sig”,“sig”, *mgg, SigModelBW, ResponseDoubleCB);
and when I plot it I get the result attached (largeRange.png).
If I restrict everything to a smaller range (eg 1250-1700) things look ok, see the attached plot (narrowRange.png).
Can you please help me in understanding what I’m doing wrong, and if there is a way to have my pdf on the full range?
Many thanks in advance for your help.
Cheers,
Chiara