Getting no.of background events in signal region

[dsahoo]

Dear Experts,

I have fitted the Bs mass(it’s PDG mass 5.367 GeV) with gaussian(for signal) and exponential function(for combinatorial background). The fitted plot isattached with this post. I want to get the no.of background events in the signal region. Could you please tell me how to do this?

Thanks,
Deepak

[Wile_E_Coyote]

Try to calculate the integral of your background function using, for example, something similar to (instead of “gaus” use the name of your “red dots” background function):

Entries under a gaussian?

std::cout << hspectrum->GetFunction("gaus")->Integral(2, 45) / hspectrum->GetBinWidth(1) << std::endl;

[dsahoo]

I tried "std::cout << Bmass->GetFunction("bkgExpo")->Integral(5.287, 5.447) /Bmass->GetBinWidth(1) << std::endl;". It is showing error as below.

Error: Can't call RooRealVar::GetFunction("bkgExpo") in current scope bstophimumu_data.cc:70:
Possible candidates are...
(in RooRealVar)
(in RooAbsRealLValue)
(in RooAbsReal)
(in RooAbsArg)
(in RooPrintable)
(in RooAbsLValue)
Error: non class,struct,union object GetFunction("bkgExpo") used with . or -> bstophimumu_data.cc:70:
Error: operator '/' divided by zero bstophimumu_data.cc:70:
*** Interpreter error recovered ***

Thanks,
Deepak

[Wile_E_Coyote]

This is a question for some RooFit expert.