god day …

i am excuting this code, and when it finishied it is supposed to plot a PDF of some variable(cos_theta) with its components

but i always have a wired looking line in the Canvas at the biginnig of the range(wich is not a part of my distribution)

i think it is the RooAddPdf who causes this problem??

thank you for your help!.

using namespace RooFit;

int angle(){

RooRealVar *cos_theta = new RooRealVar(“cos_theta”,“cos_theta”,-1.,1.);

RooRealVar *Rt = new RooRealVar(“Rt”,“Rt”,0.2,0.,1.);

RooRealVar *a = new RooRealVar(“a”,“a”,0,-2.,2.);

RooAbsPdf* Pdftheta_odd = new RooGenericPdf(“Pdftheta_odd”,“Pdftheta_odd”," 1 - cos_theta**2 " , cos_theta);**2 )/2",

RooAbsPdf Pdftheta_even = new RooGenericPdf(“Pdftheta_even”,“Pdftheta_even”," ( 1 + cos_theta

*cos_theta);*

RooAbsPdfbkg_ang = new RooGenericPdf(“bkg_ang”,“bkg_ang”,“1 + a*cos_theta**2”,RooArgList(*a,*cos_theta));

RooAbsPdf

RooAbsReal *B_S_fitt = new RooRealVar(“B_S_fitt”,“B_S_fitt”,0.26,0.,10.);

RooAbsPdf *pdf_sig_mix_ang = new RooAddPdf(“pdf_sig_mix_ang”,“pdf_sig_mix_ang”,*Pdftheta_odd,*Pdftheta_even,*Rt);

RooAbsPdf *pdf_sig_mix_ang_bkg = new RooAddPdf(“pdf_sig_mix_ang_bkg”,“pdf_sig_mix_ang_bkg”,*bkg_ang,*pdf_sig_mix_ang,*B_S_fitt);

RooDataSet *data = pdf_sig_mix_ang_bkg->generate(*cos_theta,78363);

RooPlot *cadre1 = cos_theta->frame();

pdf_sig_mix_ang_bkg->plotOn(cadre1);

pdf_sig_mix_ang_bkg->plotOn(cadre1,Components(“Pdftheta_odd”),LineColor(kBlack));

pdf_sig_mix_ang_bkg->plotOn(cadre1,Components(“Pdftheta_even”),LineStyle(kDotted),LineColor(kBlack));

pdf_sig_mix_ang_bkg->plotOn(cadre1,Components(“bkg_ang”),LineStyle(kDashed),LineColor(kBlack));

cadre1->Draw();

return 0 ;

}