doc/v616/PhaseSpace_8C.html

void PhaseSpace() {


   TLorentzVector target(0.0, 0.0, 0.0, 0.938);

   TLorentzVector beam(0.0, 0.0, .65, .65);

   TLorentzVector W = beam + target;


   //(Momentum, Energy units are Gev/C, GeV)

   Double_t masses[3] = { 0.938, 0.139, 0.139} ;


   TGenPhaseSpace event;

   event.SetDecay(W, 3, masses);


   TH2F *h2 = new TH2F("h2","h2", 50,1.1,1.8, 50,1.1,1.8);


   for (Int_t n=0;n<100000;n++) {

      Double_t weight = event.Generate();


      TLorentzVector *pProton = event.GetDecay(0);


      TLorentzVector *pPip    = event.GetDecay(1);

      TLorentzVector *pPim    = event.GetDecay(2);


      TLorentzVector pPPip = *pProton + *pPip;

      TLorentzVector pPPim = *pProton + *pPim;


      h2->Fill(pPPip.M2() ,pPPim.M2() ,weight);

   }

   h2->Draw();

}

Int_t
int Int_t
Definition: RtypesCore.h:41

Double_t
double Double_t
Definition: RtypesCore.h:55

TGenPhaseSpace
Utility class to generate n-body event, with constant cross-section (default) or with Fermi energy de...
Definition: TGenPhaseSpace.h:15

TGenPhaseSpace::SetDecay
Bool_t SetDecay(TLorentzVector &P, Int_t nt, const Double_t *mass, Option_t *opt="")
Input:
Definition: TGenPhaseSpace.cxx:192

TH1::Draw
virtual void Draw(Option_t *option="")
Draw this histogram with options.
Definition: TH1.cxx:2974

TH2F
2-D histogram with a float per channel (see TH1 documentation)}
Definition: TH2.h:250

TH2::Fill
Int_t Fill(Double_t)
Invalid Fill method.
Definition: TH2.cxx:292

TLorentzVector
TLorentzVector is a general four-vector class, which can be used either for the description of positi...
Definition: TLorentzVector.h:32

TLorentzVector::M2
Double_t M2() const
Definition: TLorentzVector.h:491

n
const Int_t n
Definition: legend1.C:16