rf310_sliceplot.C: 'MULTIDIMENSIONAL MODELS' RooFit tutorial macro #309

//////////////////////////////////////////////////////////////////////////
//
// 'MULTIDIMENSIONAL MODELS' RooFit tutorial macro #309
// 
// Projecting p.d.f and data slices in discrete observables 
//
//
//
// 07/2008 - Wouter Verkerke 
// 
/////////////////////////////////////////////////////////////////////////

#ifndef __CINT__
#include "RooGlobalFunc.h"
#endif
#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussModel.h"
#include "RooDecay.h"
#include "RooBMixDecay.h"
#include "RooCategory.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "RooPlot.h"
using namespace RooFit ;


void rf310_sliceplot()
{


  // C r e a t e   B   d e c a y   p d f   w it h   m i x i n g 
  // ----------------------------------------------------------

  // Decay time observables
  RooRealVar dt("dt","dt",-20,20) ;

  // Discrete observables mixState (B0tag==B0reco?) and tagFlav (B0tag==B0(bar)?)
  RooCategory mixState("mixState","B0/B0bar mixing state") ;
  RooCategory tagFlav("tagFlav","Flavour of the tagged B0") ;

  // Define state labels of discrete observables
  mixState.defineType("mixed",-1) ;
  mixState.defineType("unmixed",1) ;
  tagFlav.defineType("B0",1) ;
  tagFlav.defineType("B0bar",-1) ;

  // Model parameters
  RooRealVar dm("dm","delta m(B)",0.472,0.,1.0) ;
  RooRealVar tau("tau","B0 decay time",1.547,1.0,2.0) ;
  RooRealVar w("w","Flavor Mistag rate",0.03,0.0,1.0) ;
  RooRealVar dw("dw","Flavor Mistag rate difference between B0 and B0bar",0.01) ;

  // Build a gaussian resolution model
  RooRealVar bias1("bias1","bias1",0) ;
  RooRealVar sigma1("sigma1","sigma1",0.01) ;  
  RooGaussModel gm1("gm1","gauss model 1",dt,bias1,sigma1) ;

  // Construct a decay pdf, smeared with single gaussian resolution model
  RooBMixDecay bmix_gm1("bmix","decay",dt,mixState,tagFlav,tau,dm,w,dw,gm1,RooBMixDecay::DoubleSided) ;
  
  // Generate BMixing data with above set of event errors
  RooDataSet *data = bmix_gm1.generate(RooArgSet(dt,tagFlav,mixState),20000) ;



  // P l o t   f u l l   d e c a y   d i s t r i b u t i o n 
  // ----------------------------------------------------------

  // Create frame, plot data and pdf projection (integrated over tagFlav and mixState)
  RooPlot* frame = dt.frame(Title("Inclusive decay distribution")) ;
  data->plotOn(frame) ;
  bmix_gm1.plotOn(frame) ;



  // P l o t   d e c a y   d i s t r .   f o r   m i x e d   a n d   u n m i x e d   s l i c e   o f   m i x S t a t e
  // ------------------------------------------------------------------------------------------------------------------

  // Create frame, plot data (mixed only)
  RooPlot* frame2 = dt.frame(Title("Decay distribution of mixed events")) ;
  data->plotOn(frame2,Cut("mixState==mixState::mixed")) ;

  // Position slice in mixState at "mixed" and plot slice of pdf in mixstate over data (integrated over tagFlav)
  bmix_gm1.plotOn(frame2,Slice(mixState,"mixed")) ;

  // Create frame, plot data (unmixed only)
  RooPlot* frame3 = dt.frame(Title("Decay distribution of unmixed events")) ;
  data->plotOn(frame3,Cut("mixState==mixState::unmixed")) ;

  // Position slice in mixState at "unmixed" and plot slice of pdf in mixstate over data (integrated over tagFlav)
  bmix_gm1.plotOn(frame3,Slice(mixState,"unmixed")) ;



  TCanvas* c = new TCanvas("rf310_sliceplot","rf310_sliceplot",1200,400) ;
  c->Divide(3) ;
  c->cd(1) ; gPad->SetLeftMargin(0.15) ; frame->GetYaxis()->SetTitleOffset(1.4) ; gPad->SetLogy() ; frame->Draw() ;
  c->cd(2) ; gPad->SetLeftMargin(0.15) ; frame2->GetYaxis()->SetTitleOffset(1.4) ; gPad->SetLogy() ; frame2->Draw() ;
  c->cd(3) ; gPad->SetLeftMargin(0.15) ; frame3->GetYaxis()->SetTitleOffset(1.4) ; gPad->SetLogy() ; frame3->Draw() ;


}