Dear experts,
I am trying to fit range with Bernstein polynomials:
// background model
RooRealVar a0("a0","coefficient a0",0.0,1.0);
RooRealVar a1("a1","coefficient a1",0.0,1.0);
RooRealVar a2("a2","coefficient a2",0.0,1.0);
RooRealVar a3("a3","coefficient a3",0.0,1.0);
RooRealVar a4("a4","coefficient a4",0.0,1.0);
//
RooBernstein bkg("bkg","background",dimuonmass2sideband,RooArgList(a0,a1,a2,a3,a4));
//
RooRealVar norm("norm","bkg normalization",1700.,0.0,3000.0);
RooAddPdf model("model","model",RooArgList(bkg),RooArgList(norm));
dimuonmass2sideband.setRange("R1",12.,25.);
dimuonmass2sideband.setRange("R2",30.,70.);
RooFitResult* r = model.fitTo(data,Range("R1,R2"),Save());
and I got a stupid result. All coefficients are set to 0.5 and curve does not describe my data at all
Number of data events = 1601
-log(L) at minimum = -3880.96
chi2 = 9.41812
- RooRealVar:: a0 = 0.499798 +/- 0.000166767
- RooRealVar:: a1 = 0.500182 +/- 9.49789e-09
- RooRealVar:: a2 = 0.499923 +/- 3.1032e-06
- RooRealVar:: a3 = 0.500068 +/- 7.51931e-07
- RooRealVar:: a4 = 0.499655 +/- 9.76319e-06
- RooRealVar:: norm = 1638.55 +/- 0.313795
norm = 1638.55 +/- 0.313795
Can you help, please.
Thanks, Sasha.