Hi again !
I have a problem with background and signal. My fit for the signal+background is good but when I want to view the background only, it is always above the signal (see attached file).
I 'am trying to have something like the macro example rf201_composite.C.( And finally I want to subtract the background from the signal.)
Any ideas ?
Thanks in advance
Here is the code of my macro:
[code]
using namespace RooFit;
void All(char* treefile = “bntAnalysis_merged.root”, char* treename = “fTwoMuonNtuple”){
// Open the file
TFile *f = new TFile(treefile,“READ”);
// Connect to the tree
TTree* tree = (TTree*)f->Get(treename);
//Switch to the branch and fill the invariant mass histogram
Float_t m;
tree->SetBranchAddress(“m”,&m);
TH1F *hm = new TH1F(“hm”,“m distribution”,580,0,12);
Double_t nentries = (Double_t)tree->GetEntries();
for (Double_t i=0; i<nentries; i++)
{
tree->GetEntry(i);
hm->Fill(m);
}
RooRealVar mass(“mass”,“invariant mass (GeV/c2)”,0,12);
RooDataHist *data = new RooDataHist(“data”,“data x”,mass,hm);
//Breit-Wigner for the phi
RooRealVar mean_phi(“mean_phi”,“mean_phi”,1.0,0.9,1.1);
RooRealVar g(“sigma_phi”,“sigma_phi”,1,0,2);
RooBreitWigner *phi_BW = new RooBreitWigner(“phi_BW”,“Breit Wigner PDF”,mass,mean_phi,g);
//Crystal ball for the J/psi
RooRealVar mean_jpsi(“mean_jpsi”,“mean_jpsi”,3,2.9,3.2);
RooRealVar sigma_jpsi(“sigma_jpsi”,“sigma_jpsi”,0.07,0,0.1);
RooRealVar alpha(“alpha”,“alpha”,1);
RooRealVar n(“n”,“n”,5);
RooCBShape *jpsi = new RooCBShape(“jpsi”,“crystal ball PDF”,mass,mean_jpsi,sigma_jpsi,alpha,n);
//Crystal ball for the psi
RooRealVar mean_psi(“mean_psi”,“mean_psi”,3.6,3.4,3.8);
RooRealVar sigma_psi(“sigma_psi”,“sigma_psi”,0.07,0,0.1);
RooRealVar alpha_psi(“alpha”,“alpha”,1.5);
RooRealVar n_psi(“n”,“n”,1);
RooCBShape *psi = new RooCBShape(“psi”,“crystal ball PDF”,mass,mean_psi,sigma_psi,alpha_psi,n_psi);
//Crystal ball for the Upsilon
RooRealVar mean_up(“mean_up”,“mean_up”,9.4,9.3,9.5);
RooRealVar sigma_up(“sigma_up”,“sigma_up”,0.07,0,0.1);
RooRealVar alpha_up(“alpha_up”,“alpha_up”,1,0,5);
RooRealVar n_up(“n_up”,“n_up”,1,0,10);
RooCBShape *upsilon = new RooCBShape(“upsilon”,“crystal ball PDF”,mass,mean_up,sigma_up,alpha_up,n_up);
//Exponential background
RooRealVar a(“a”,“a”,-0.85,-0.8,-0.9);
RooExponential bkg(“exp”,“exp”,mass,a);
RooRealVar fsig(“fsig”,“signal”,0.1,0.,1.);
RooRealVar fsig2(“fsig2”,“signal2”,0.1,0.,1.);
RooRealVar fsig3(“fsig3”,“signal3”,0.1,0.,1.);
RooRealVar fsig4(“fsig4”,“signal4”,0.1,0.,1.);
RooAddPdf sum(“sum”,“sum”,RooArgList(*phi_BW,*jpsi,*psi,*upsilon,bkg),RooArgList(fsig,fsig2,fsig3,fsig4),kTRUE);
sum.fitTo(*data,Range(2.2,5));
RooPlot* mframe = mass.frame(Title(“Fit of invariant mass”));
data->plotOn(mframe);
sum.plotOn(mframe);
sum.plotOn(mframe,Components(bkg),LineStyle(kDashed));
mframe->Draw();
}[/code]
spectre.ps (83.8 KB)
