/////////////////////////////////////////////////////////////////////////
//
// 'ADDITION AND CONVOLUTION' RooFit tutorial macro #209
//
// Decay function p.d.fs with optional B physics
// effects (mixing and CP violation) that can be
// analytically convolved with e.g. Gaussian resolution
// functions
//
// pdf1 = decay(t,tau) (x) delta(t)
// pdf2 = decay(t,tau) (x) gauss(t,m,s)
// pdf3 = decay(t,tau) (x) (f*gauss1(t,m1,s1) + (1-f)*gauss2(t,m1,s1))
//
// 07/2008 - Wouter Verkerke
//
/////////////////////////////////////////////////////////////////////////
#ifndef __CINT__
#include "RooGlobalFunc.h"
#endif
#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussModel.h"
#include "RooAddModel.h"
#include "RooTruthModel.h"
#include "RooDecay.h"
#include "RooPlot.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "TH1.h"
using namespace RooFit ;
void rf209_anaconv()
{
// B - p h y s i c s p d f w i t h t r u t h r e s o l u t i o n
// ---------------------------------------------------------------------
// Variables of decay p.d.f.
RooRealVar dt("dt","dt",-10,10) ;
RooRealVar tau("tau","tau",1.548) ;
// Build a truth resolution model (delta function)
RooTruthModel tm("tm","truth model",dt) ;
// Construct decay(t) (x) delta(t)
RooDecay decay_tm("decay_tm","decay",dt,tau,tm,RooDecay::DoubleSided) ;
// Plot p.d.f. (dashed)
RooPlot* frame = dt.frame(Title("Bdecay (x) resolution")) ;
decay_tm.plotOn(frame,LineStyle(kDashed)) ;
// B - p h y s i c s p d f w i t h G a u s s i a n r e s o l u t i o n
// ----------------------------------------------------------------------------
// Build a gaussian resolution model
RooRealVar bias1("bias1","bias1",0) ;
RooRealVar sigma1("sigma1","sigma1",1) ;
RooGaussModel gm1("gm1","gauss model 1",dt,bias1,sigma1) ;
// Construct decay(t) (x) gauss1(t)
RooDecay decay_gm1("decay_gm1","decay",dt,tau,gm1,RooDecay::DoubleSided) ;
// Plot p.d.f.
decay_gm1.plotOn(frame) ;
// B - p h y s i c s p d f w i t h d o u b l e G a u s s i a n r e s o l u t i o n
// ------------------------------------------------------------------------------------------
// Build another gaussian resolution model
RooRealVar bias2("bias2","bias2",0) ;
RooRealVar sigma2("sigma2","sigma2",5) ;
RooGaussModel gm2("gm2","gauss model 2",dt,bias2,sigma2) ;
// Build a composite resolution model f*gm1+(1-f)*gm2
RooRealVar gm1frac("gm1frac","fraction of gm1",0.5) ;
RooAddModel gmsum("gmsum","sum of gm1 and gm2",RooArgList(gm1,gm2),gm1frac) ;
// Construct decay(t) (x) (f*gm1 + (1-f)*gm2)
RooDecay decay_gmsum("decay_gmsum","decay",dt,tau,gmsum,RooDecay::DoubleSided) ;
// Plot p.d.f. (red)
decay_gmsum.plotOn(frame,LineColor(kRed)) ;
// Draw all frames on canvas
new TCanvas("rf209_anaconv","rf209_anaconv",600, 600);
gPad->SetLeftMargin(0.15) ; frame->GetYaxis()->SetTitleOffset(1.6) ; frame->Draw() ;
}