Blinding in Background modelling

[wamorkar.t]

Dear experts,

In my unbinned paramteric analysis, I create PDF’s to model background and fit those to data. I do this by generating various PDF’s like Bernstein polynomials, power law etc and fit them to the entire data i.e without blinding. Later while making a plot of the background fits I blind my signal region using Roofit cutrange.

My first question: Is this the right approach? Or should the data be blinded first and the fitting be performed on blinded data? I will eventually be using the Envelope method for background modeling.

Second question: On using Roofit cutrange

    data_RooDataSet.plotOn(frame,RooFit.Binning(tpmass_high-tpmass_low),RooFit.CutRange("unblindreg_1"))
    data_RooDataSet.plotOn(frame,RooFit.Binning(tpmass_high-tpmass_low),RooFit.CutRange("unblindreg_2"))

to remove my signal region from the plot, the outputs I get look like this:

with points at the bottom. Is there a way to avoid these points?

Thanks in advance,
Tanvi

[moneta]

Hi,

The first question is more an analysis and experiment specific question and you should ask to your colleagues in CMS.

For the second one, I done;t understand which points you would like to remove ? It is not clear to me looking at the picture

Lorenzo