{
  using namespace RooFit;

  // Model built with Low Level Factory
  RooWorkspace w("CMGWs","CMG workspace");
  w.factory("Gaussian::signal(imass[105,140],sigmean[115,105,120],sigwidth[1,0,4])");
  w.factory("Exponential::background(imass,exppar[-.1,-1,0])");
  w.factory("SUM::model(nsig[150,0,10000]*signal,nbkg[1000,0,10000]*background)");

  // Generate a toy sample according to the expected number of events
  RooRealVar* imass= w.var("imass");
  RooAbsPdf* model = w.pdf("model");
  RooDataSet *data = model->generate(*imass,Extended());
  
  // ML fit of the model to the data
  model->fitTo(*data);
  
  // Plot everything on a frame
  RooPlot* imassframe = imass->frame();
  data->plotOn(imassframe);
  model->plotOn(imassframe);
  model->plotOn(imassframe,Components(*w.pdf("background")),LineStyle(kDashed));
  
  imassframe->Draw();
  }