Dear experts,
I got a problem with fitting my unbinned data with signal model and RooProdPdf which is convolution of Gaussian and Polynomial of 1st order. I got unnormous amount of wornings like this:
[#0] WARNING:Eval – RooAbsPdf::getLogVal(model) WARNING: large likelihood value: 1.30437e+142
and absolutely stupid result of fit. When I fit separately by Gaussian or by Polynomial there is no problem with fit.
Here are lines of code I use:
RooRealVar dimuonmass11(“dimuonmass11”,“mass interval”,12.0,70.0);
// signal model
RooRealVar mean(“mean”,“BW mean”,27.3,25.0,30.0);
RooRealVar width(“width”,“BW width”,1.4,0.0,5.6);
RooRealVar sigma(“sigma”,“dimuon resolution”,0.45,0.45,0.45);
RooVoigtian sig(“sig”, “signal”, dimuonmass11, mean, width, sigma);
RooRealVar nsig(“nsig”,“signal normalization”,30.,0.0,300.0);
// background model
// Gaussian
RooRealVar a1g(“a1g”,“coefficient a1g”,14,0.0,30.0);
RooRealVar a2g(“a2g”,“coefficient a2g”,21,0.0,30.0);
RooGaussian bkg_gauss(“bkg_gauss”," background gaussian",dimuonmass11,a1g,a2g);
// Poly1
RooRealVar a1p(“a1p”,“coefficient a1p”,0.002,-0.03,0.03);
RooPolynomial bkg_poly1(“bkg_poly1”,“background poly1”,dimuonmass11,RooArgList(a1p));
// Gauss x Poly
RooProdPdf bkg(“bkg”,“Gaussian x Poly1”,RooArgSet(bkg_gauss,bkg_poly1));
// bkg normalization
RooRealVar nbkg(“nbkg”,“bkg normalization”,3380,3280,3480);
// define model
RooAddPdf model(“model”,“model”,RooArgList(sig,bkg),RooArgList(nsig,nbkg));
// define data
RooDataSet data(“data”,“my data”,tree,dimuonmass11);
//fit
RooFitResult\* r = model.fitTo(data,Range(12.0,70.0),Save());
Can you help, please. I guess it is a simple, stupid error I do in code but I can’t see it.
Thanks, Sasha.
