SecondVertexFit.h

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#ifndef VertexFit_SecondVertexFit_H
#define VertexFit_SecondVertexFit_H
#include "VertexFit/TrackPool.h"
#include "VertexFit/VertexFit.h"
 
//--------------------------------------------------------------------------------
//
// Fitting Parameters Format:  (px, py, pz, E, xd, yd, zd, xp, yp, zp)
//
// Author   Date         Comments
// K.L He   11/21/2005   original version
// Xu Min   11/30/2006   Add interface of production vertex and decay vertex
// Martin   09/02/2010   Add some kindly comments 
// 
//--------------------------------------------------------------------------------
 
// You can find the corresponding tutorial on the following web page:  
// http://docbes3.ihep.ac.cn/~offlinesoftware/index.php/Vertex_Fit
 
class SecondVertexFit : public TrackPool 
{
public:
 
    // constructor & deconstructor
    static SecondVertexFit *instance();
    ~SecondVertexFit();
 
    // initializtion must be called before SecondVertexFit each time
    void init();
 
    // set iteration number and chisq cut
    void setIterNumber(const int niter = 10) {m_niter = niter;}
    void setChisqCut(const double chicut = 500, const double chiter = 1.0e-2) {m_chicut = chicut;m_chiter=chiter;}
    // set decay point
    void setVpar(const VertexParameter vpar) {m_vpar_secondary = vpar;}
    // set production point
    void setPrimaryVertex(const VertexParameter vpar) {m_vpar_primary.setVx(vpar.Vx());m_vpar_primary.setEvx(vpar.Evx());}
    // set magnet correction factor
    void setMagCorrFactor(const double factor = 1.000) {m_factor = factor;}
 
    // fit function
    bool Fit();
 
    // fit results
    double              chisq() const {return m_chisq;}
    double              decayLength() const {return m_lxyz;}
    double              decayLengthError() const {return m_lxyz_error;}
    double              ctau() const {return m_ctau;}
    double              ctauError() const {return m_ctau_error;}
    double              factor() const {return m_factor;}
 
    HepLorentzVector    p4par() const {return m_p4par;}
    WTrackParameter     wpar() const {return m_wtrk;}
    VertexParameter     vpar() const {return m_vpar_secondary;}
    inline HepPoint3D   crossPoint() const;
    inline Hep3Vector   crossVector() const;
  
private:
 
    int    m_niter;       // number of iteration for second vertex fitting
    double m_chisq;       // fitting chisquare
    double m_chicut;      // chisquare upper limit
    double m_chiter;      // precision of iteration
    double m_lxyz;        // decay length
    double m_lxyz_error;  // error of decay length
    double m_ctau;        // c times tau
    double m_ctau_error;  // error of ctau
    double m_factor;      // B Field correction factor
 
    HepVector          m_crxyz;          // decay vertex in HepVector format
    HepLorentzVector   m_p4par;          // HepLorentzVector of particle at decay vertex
    WTrackParameter    m_wtrk;           // WTrackParameter of particle at decay vertex 
    VertexParameter    m_vpar_primary;   // production vertex
    VertexParameter    m_vpar_secondary; // decay vertex
 
    // Singleton Design
    SecondVertexFit();
    static SecondVertexFit * m_pointer;
};
 
inline HepPoint3D SecondVertexFit::crossPoint() const 
{
    return HepPoint3D(m_crxyz[0], m_crxyz[1], m_crxyz[2]);
}
 
inline Hep3Vector SecondVertexFit::crossVector() const 
{
    return Hep3Vector(m_crxyz[0] - m_vpar_primary.Vx()[0], 
                      m_crxyz[1] - m_vpar_primary.Vx()[1],
                      m_crxyz[2] - m_vpar_primary.Vx()[2]);
}
 
#endif  // VertexFit_SecondVertexFit_H