CbmLitPolarizedGenerator.h

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// -------------------------------------------------------------------------
// -----             CbmLitPolarizedGenerator header file                 -----
// -----              Created 11/09/09  by E. Kryshen                  -----
// -------------------------------------------------------------------------
 
#ifndef CBMLITPOLARIZEDGENERATOR_H
#define CBMLITPOLARIZEDGENERATOR_H
 
#include "FairGenerator.h"
#include "TF1.h"
#include "TVector3.h"
 
class FairPrimaryGenerator;
 
class CbmLitPolarizedGenerator : public FairGenerator {
public:
  typedef enum { kNoPol = 0, kColSop = 1, kHelicity = 2 } Frame_t;
  typedef enum { kDiElectron = 1, kDiMuon = 2 } DecayMode_t;
 
  CbmLitPolarizedGenerator();
 
  CbmLitPolarizedGenerator(Int_t pdgid, Int_t mult = 1);
 
  virtual ~CbmLitPolarizedGenerator() {};
 
  Bool_t GenerateDaughters(const TVector3 p, FairPrimaryGenerator* primGen);
 
  inline void SetPDGType(Int_t pdg) { fPDGType = pdg; };
  inline void SetMultiplicity(Int_t mult) { fMult = mult; };
 
  // Set temperature for transverse momentum distribution in GeV
  inline void SetDistributionPt(Double_t T = 0.154319, Double_t mass = -1.) {
    fT          = T;
    fPtDistMass = mass;
  };
 
  // Set rapidity distribution parameters (y0 - mid rapidity, sigma - Gaussian width)
  inline void SetDistributionY(Double_t y0    = 1.98604,
                               Double_t sigma = 0.617173) {
    fY0    = y0;
    fSigma = sigma;
  };
 
  // Set range
  inline void SetRangePt(Double_t ptMin = 0, Double_t ptMax = 3) {
    fPtMin = ptMin;
    fPtMax = ptMax;
  };
  inline void SetRangeY(Double_t yMin = 0, Double_t yMax = 4) {
    fYMin = yMin;
    fYMax = yMax;
  };
 
  // Set polarization parameter
  inline void SetAlpha(Double_t alpha = 0) { fAlpha = alpha; }
 
  inline void SetRefFrame(Frame_t frame = kColSop) { fFrame = frame; }
 
  inline void SetDecayMode(DecayMode_t decayMode = kDiMuon) {
    fDecayMode = decayMode;
  }
 
  inline void SetBeamMomentum(Double_t mom) { fBeamMomentum = mom; }
 
  inline void SetBox(Bool_t box) { fBox = box; }
 
  Bool_t Init();
 
  virtual Bool_t ReadEvent(FairPrimaryGenerator* primGen);
 
private:
  Int_t fPDGType;          
  Int_t fMult;             
  Double_t fT;             
  Double_t fPtDistMass;    
  Double_t fY0;            
  Double_t fSigma;         
  Double_t fPtMin;         
  Double_t fPtMax;         
  Double_t fYMin;          
  Double_t fYMax;          
  Double_t fPDGMass;       
  TF1* fDistPt;            
  Double_t fAlpha;         //< Polarization parameter in the helicity frame
  Frame_t fFrame;          //< Choice of decay products
  DecayMode_t fDecayMode;  //< Reference system for polarization
  Double_t fBeamMomentum;  //< Beam momentum in lab frame
  TF1* fPol;               
  Bool_t fBox;  // fBox = 1 Box generator, fBox = 0 - termal pt and gaussian y
 
  CbmLitPolarizedGenerator(const CbmLitPolarizedGenerator&);
  CbmLitPolarizedGenerator& operator=(const CbmLitPolarizedGenerator&);
 
  ClassDef(CbmLitPolarizedGenerator, 1);
};
 
#endif