include/EvtGenModels/EvtBtoKD3P.hh

0001
0002 /***********************************************************************
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0020
0021 #ifndef EVT_BTOKD3P
0022 #define EVT_BTOKD3P
0023
0024 class EvtParticle;
0025 #include "EvtGenBase/EvtComplex.hh"
0026 #include "EvtGenBase/EvtDecayAmp.hh"
0027
0028 // Decay model that does the decay B+ -> K+ D , D -> 3 psudoscalars.
0029 //
0030 // The B- daughters specified in the decay file should be K-, D0, D0,
0031 // where the first D0 is produced via b->c decay and the second via b->u.
0032 // In reality, only one D daughter exists, so the first two
0033 // daughters must be defined to decay to the same final state using
0034 // the EvtPto3P model, but with CP-conjugate amplitudes.
0035 //
0036 // For a given point in the Pto3P Dalitz plot,
0037 // the total amplitude is \propto [A1 + A2 r exp(i(phase))], where
0038 //
0039 // A1 & A2 are the amplitudes of the D0 and D0bar to decay into that
0040 // Dalitz plot point,
0041 //
0042 // r is the (positive) ratio between the A(B->B0bar K) and A(B->D0 K)
0043 // B decay amplitudes,
0044 //
0045 // phase is the total phase difference (weak phase + strong phase) between
0046 // A(B->D0bar K) and A(B->B0 K).
0047 //
0048 // Note that this model knows nothing about your convention for the
0049 // sign of the phase, so when specifying the decay of a B- you need to
0050 // change the order of D0 and D0bar and change the total phase so that
0051 // the sign of the weak phase flips with respect to the parameters of B+.
0052
0053 class EvtBtoKD3P : public EvtDecayAmp {
0054   public:
0055     EvtDecayBase* clone() override;
0056
0057     // Initialize model
0058     void init() override;
0059     void initProbMax() override;
0060     void decay( EvtParticle* p ) override;
0061
0062     // we really have two daughters, although three are listed in the .dec file:
0063     int nRealDaughters() override { return 2; }
0064
0065     std::string getName() override;
0066
0067   protected:
0068     // parameters:
0069     double _r;
0070     EvtComplex _exp;
0071
0072     // other:
0073     const EvtDecayBase* _model1 = nullptr;
0074     const EvtDecayBase* _model2 = nullptr;
0075     bool _decayedOnce = false;
0076 };
0077
0078 #endif