include/EvtGenBase/EvtDalitzPoint.hh

0001
0002 /***********************************************************************
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0020
0021 #ifndef EVT_DALITZ_POINT_HH
0022 #define EVT_DALITZ_POINT_HH
0023
0024 #include "EvtGenBase/EvtCyclic3.hh"
0025 #include "EvtGenBase/EvtDalitzCoord.hh"
0026 #include "EvtGenBase/EvtDalitzPlot.hh"
0027
0028 // This class describes the complete kinematics of the Dalitz decay.
0029 // It holds all the six invariant momentum products, three daughter
0030 // particle masses and three invariant masses of pairs of particles.
0031 // This description is completely symmetric with respect to particle
0032 // permutations.
0033 //
0034 // Another way to slice the six coordinate is to make a transformation
0035 // to the mass of the decaying particle. The four masses make up a
0036 // Dalitz plot. The other two are coordinates of a point in the plot.
0037
0038 class EvtDalitzPoint final {
0039   public:
0040     EvtDalitzPoint();
0041     EvtDalitzPoint( double mA, double mB, double mC, double qAB, double qBC,
0042                     double qCA );
0043     EvtDalitzPoint( double mA, double mB, double mC, EvtCyclic3::Pair i,
0044                     double qres, double qhel, double qsum );
0045     EvtDalitzPoint( const EvtDalitzPlot&, const EvtDalitzCoord& );
0046
0047     EvtDalitzCoord getDalitzPoint( EvtCyclic3::Pair i, EvtCyclic3::Pair j ) const;
0048     EvtDalitzPlot getDalitzPlot() const;
0049
0050     double q( EvtCyclic3::Pair ) const;
0051     double bigM() const;
0052     double m( EvtCyclic3::Index ) const;
0053
0054     // Zemach variables
0055
0056     double qres( EvtCyclic3::Pair i ) const;
0057     double qhel( EvtCyclic3::Pair i ) const;
0058     double qsum() const;
0059
0060     // Kinematic quantities
0061     //
0062     // pp  - 4 momentum product
0063     // e,p,cosTh - energy/moementum in rest-frame of j
0064
0065     double qMin( EvtCyclic3::Pair i, EvtCyclic3::Pair j ) const;
0066     double qMax( EvtCyclic3::Pair i, EvtCyclic3::Pair j ) const;
0067     double pp( EvtCyclic3::Index i, EvtCyclic3::Index j ) const;
0068     double e( EvtCyclic3::Index i, EvtCyclic3::Pair j ) const;
0069     double p( EvtCyclic3::Index i, EvtCyclic3::Pair j ) const;
0070     double cosTh( EvtCyclic3::Pair pairAng, EvtCyclic3::Pair pairRes ) const;
0071
0072     bool isValid() const;
0073
0074     void print() const;
0075
0076   private:
0077     double _mA, _mB, _mC;       // masses
0078     double _qAB, _qBC, _qCA;    // masses squared
0079 };
0080
0081 #endif