VFHelix Class Reference

VFHelix parameter class. More...

#include <Helix.h>

List of all members.

Public Member Functions
	VFHelix (const HepPoint3D &pivot, const HepVector &a, const HepSymMatrix &Ea)
	Constructor with pivot, helix parameter a, and its error matrix.
	VFHelix (const HepPoint3D &pivot, const HepVector &a)
	Constructor without error matrix.
	VFHelix (const HepPoint3D &position, const Hep3Vector &momentum, double charge)
	Constructor with position, momentum, and charge.
virtual	~VFHelix ()
	Destructor.
const HepPoint3D &	center (void) const
	returns position of helix center(z = 0.);
const HepPoint3D &	pivot (void) const
	returns pivot position.
double	radius (void) const
	returns radious of helix.
HepPoint3D	x (double dPhi=0.) const
	returns position after rotating angle dPhi in phi direction.
double *	x (double dPhi, double p[3]) const
HepPoint3D	x (double dPhi, HepSymMatrix &Ex) const
	returns position and convariance matrix(Ex) after rotation.
Hep3Vector	direction (double dPhi=0.) const
	returns direction vector after rotating angle dPhi in phi direction.
Hep3Vector	momentum (double dPhi=0.) const
	returns momentum vector after rotating angle dPhi in phi direction.
Hep3Vector	momentum (double dPhi, HepSymMatrix &Em) const
	returns momentum vector after rotating angle dPhi in phi direction.
HepLorentzVector	momentum (double dPhi, double mass) const
	returns 4momentum vector after rotating angle dPhi in phi direction.
HepLorentzVector	momentum (double dPhi, double mass, HepSymMatrix &Em) const
	returns 4momentum vector after rotating angle dPhi in phi direction.
HepLorentzVector	momentum (double dPhi, double mass, HepPoint3D &x, HepSymMatrix &Emx) const
	returns 4momentum vector after rotating angle dPhi in phi direction.
double	dr (void) const
	returns an element of parameters.
double	phi0 (void) const
double	kappa (void) const
double	dz (void) const
double	tanl (void) const
double	curv (void) const
double	sinPhi0 (void) const
double	cosPhi0 (void) const
const HepVector &	a (void) const
	returns helix parameters.
const HepSymMatrix &	Ea (void) const
	returns error matrix.
const HepVector &	a (const HepVector &newA)
	sets helix parameters.
const HepSymMatrix &	Ea (const HepSymMatrix &newdA)
	sets helix paramters and error matrix.
const HepPoint3D &	pivot (const HepPoint3D &newPivot)
	sets pivot position.
void	set (const HepPoint3D &pivot, const HepVector &a, const HepSymMatrix &Ea)
	sets helix pivot position, parameters, and error matrix.
void	ignoreErrorMatrix (void)
	unsets error matrix. Error calculations will be ignored after this function call until an error matrix be set again. 0 matrix will be return as a return value for error matrix when you call functions which returns an error matrix.
double	bFieldZ (double)
	sets/returns z componet of the magnetic field.
double	bFieldZ (void) const
VFHelix &	operator= (const VFHelix &)
	Copy operator.
HepMatrix	delApDelA (const HepVector &ap) const
HepMatrix	delXDelA (double phi) const
HepMatrix	delMDelA (double phi) const
HepMatrix	del4MDelA (double phi, double mass) const
HepMatrix	del4MXDelA (double phi, double mass) const
Static Public Attributes
static const double	ConstantAlpha = 333.564095
	Constant alpha for uniform field.
Private Member Functions
void	updateCache (void)
Private Attributes
double	m_bField
double	m_alpha
HepPoint3D	m_pivot
HepVector	m_a
HepSymMatrix	m_Ea
bool	m_matrixValid
HepPoint3D	m_center
double	m_cp
double	m_sp
double	m_pt
double	m_r
double	m_ac [5]

---

Detailed Description

VFHelix parameter class.

Definition at line 38 of file Helix.h.

---

Constructor & Destructor Documentation

VFHelix::VFHelix	(	const HepPoint3D &	pivot,
		const HepVector &	a,
		const HepSymMatrix &	Ea
	)

Constructor with pivot, helix parameter a, and its error matrix.

Definition at line 37 of file Helix.cxx.

References VertexFitBField::getBFieldZRef(), VertexFitBField::instance(), m_alpha, m_bField, and updateCache().

: m_bField(10.0),
  m_alpha(333.564095),
  m_pivot(pivot),
  m_a(a),
  m_Ea(Ea),
  m_matrixValid(true)
{
    // m_alpha = 10000. / 2.99792458 / m_bField;
    // m_alpha = 333.564095;
    m_bField = 10 * VertexFitBField::instance()->getBFieldZRef();
    m_alpha = 10000. / 2.99792458 / m_bField; 
    //std::cout << "m_bField =  " << m_bField << "   m_alpha = " << m_alpha << std::endl;
    updateCache();
}

VFHelix::VFHelix	(	const HepPoint3D &	pivot,
		const HepVector &	a
	)

Constructor without error matrix.

Definition at line 55 of file Helix.cxx.

References VertexFitBField::getBFieldZRef(), VertexFitBField::instance(), m_alpha, m_bField, and updateCache().

: m_bField(10.0),
  m_alpha(333.564095),
  m_pivot(pivot),
  m_a(a),
  m_Ea(HepSymMatrix(5,0)),
  m_matrixValid(false)
{
    // m_alpha = 333.564095;
    m_bField = 10 * VertexFitBField::instance()->getBFieldZRef();
    m_alpha = 10000. / 2.99792458 / m_bField;

    updateCache();
}

VFHelix::VFHelix	(	const HepPoint3D &	position,
		const Hep3Vector &	momentum,
		double	charge
	)

Constructor with position, momentum, and charge.

Definition at line 71 of file Helix.cxx.

References DBL_MAX, VertexFitBField::getBFieldZRef(), VertexFitBField::instance(), m_a, m_alpha, m_bField, M_PI2, M_PI4, and updateCache().

: m_bField(10.0),
  m_alpha(333.564095),
  m_pivot(position),
  m_a(HepVector(5,0)),
  m_Ea(HepSymMatrix(5,0)),
  m_matrixValid(false)
{

    m_bField = 10 * VertexFitBField::instance()->getBFieldZRef();
    m_alpha = 10000. / 2.99792458 / m_bField;
   
    m_a[0] = 0.;
    m_a[1] = fmod(atan2(- momentum.x(), momentum.y())
                  + M_PI4, M_PI2);
    m_a[3] = 0.;
    double perp(momentum.perp());
    if (perp != 0.0) {
        m_a[2] = charge / perp;
        m_a[4] = momentum.z() / perp; 
    }
    else {
        m_a[2] = charge * (DBL_MAX);
        if (momentum.z() >= 0) {
            m_a[4] = (DBL_MAX);
        } else {
            m_a[4] = -(DBL_MAX);
        }
    }
    // m_alpha = 333.564095;
    updateCache();
}

VFHelix::~VFHelix

(

)

[virtual]

Destructor.

Definition at line 106 of file Helix.cxx.

                  {
}

---

Member Function Documentation

const HepVector & VFHelix::a

(

const HepVector &

newA

)

[inline]

sets helix parameters.

Definition at line 252 of file Helix.h.

References m_a, and updateCache().

                              {
    m_a = i;
    updateCache();
    return m_a;
}

const HepVector & VFHelix::a

(

void

)

const [inline]

returns helix parameters.

Definition at line 240 of file Helix.h.

References m_a.

Referenced by SD0Tag::execute(), CalibEventSelect::execute(), DQASelHadron::execute(), DQAKsKpi::execute(), Rhopi::execute(), Gam4pikp::execute(), DQADtag::fillTrackItem(), BestDTagSvc::isGoodTrack(), DSemilepAlg::isGoodTrack(), DTagTool::isGoodTrack(), Pipipi0::MTotal(), Pipi::MTotal(), Kpipi0pi0::MTotal(), Kpipi0::MTotal(), Kpi::MTotal(), Kkpipi::MTotal(), Kkpi0::MTotal(), Kk::MTotal(), K3pipi0::MTotal(), K3pi::MTotal(), K0pipipi0::MTotal(), K0pipi::MTotal(), K0pi0::MTotal(), K0kpi::MTotal(), K0kk::MTotal(), LocalPionSelector::operator()(), and LocalKaonSelector::operator()().

                     {
    return m_a;
}

double VFHelix::bFieldZ

(

void

)

const [inline]

Definition at line 275 of file Helix.h.

References m_bField.

                           {
    return m_bField;
}

double VFHelix::bFieldZ

(

double

)

[inline]

sets/returns z componet of the magnetic field.

Definition at line 266 of file Helix.h.

References m_alpha, m_bField, and updateCache().

                         {
    m_bField = a;
    m_alpha = 10000. / 2.99792458 / m_bField;
    updateCache();
    return m_bField;
}

const HepPoint3D & VFHelix::center

(

void

)

const [inline]

returns position of helix center(z = 0.);

Definition at line 180 of file Helix.h.

References m_center.

                          {
    return m_center;
}

double VFHelix::cosPhi0

(

void

)

const [inline]

Definition at line 287 of file Helix.h.

References m_cp.

                           {
    return m_cp;
}

double VFHelix::curv

(

void

)

const [inline]

Definition at line 234 of file Helix.h.

References m_r.

                        {
    return m_r;
}

HepMatrix VFHelix::del4MDelA	(	double	phi,
		double	mass
	)			const

Definition at line 578 of file Helix.cxx.

References cos(), DBL_MAX, m_ac, phi0(), and sin().

Referenced by momentum().

                                                {
    //
    //   Calculate Jacobian (@4m/@a)
    //   Vector a  is helix parameters and phi is internal parameter.
    //   Vector 4m is 4 momentum.
    //

    HepMatrix d4MDA(4,5,0);

    double phi0 = m_ac[1];
    double cpa  = m_ac[2];
    double tnl  = m_ac[4];

    double cosf0phi = cos(phi0+phi);
    double sinf0phi = sin(phi0+phi);

    double rho;
    if(cpa != 0.)rho = 1./cpa;
    else rho = (DBL_MAX);

    double charge = 1.;
    if(cpa < 0.)charge = -1.;

    double E = sqrt(rho*rho*(1.+tnl*tnl)+mass*mass);

    d4MDA[0][1] = -fabs(rho)*cosf0phi;
    d4MDA[0][2] = charge*rho*rho*sinf0phi;
 
    d4MDA[1][1] = -fabs(rho)*sinf0phi;
    d4MDA[1][2] = -charge*rho*rho*cosf0phi;

    d4MDA[2][2] = -charge*rho*rho*tnl;
    d4MDA[2][4] = fabs(rho);

    if (cpa != 0.0 && E != 0.0) {
      d4MDA[3][2] = (-1.-tnl*tnl)/(cpa*cpa*cpa*E);
      d4MDA[3][4] = tnl/(cpa*cpa*E);
    } else {
      d4MDA[3][2] = (DBL_MAX);
      d4MDA[3][4] = (DBL_MAX);
    }
    return d4MDA;
}

HepMatrix VFHelix::del4MXDelA	(	double	phi,
		double	mass
	)			const

Definition at line 624 of file Helix.cxx.

References cos(), DBL_MAX, dr(), dz(), m_ac, m_cp, m_r, m_sp, phi0(), and sin().

Referenced by momentum().

                                                 {
    //
    //   Calculate Jacobian (@4mx/@a)
    //   Vector a  is helix parameters and phi is internal parameter.
    //   Vector 4xm is 4 momentum and position.
    //

    HepMatrix d4MXDA(7,5,0);

    const double & dr      = m_ac[0];
    const double & phi0    = m_ac[1];
    const double & cpa     = m_ac[2];
    const double & dz      = m_ac[3];
    const double & tnl     = m_ac[4];

    double cosf0phi = cos(phi0+phi);
    double sinf0phi = sin(phi0+phi);

    double rho;
    if(cpa != 0.)rho = 1./cpa;
    else rho = (DBL_MAX);

    double charge = 1.;
    if(cpa < 0.)charge = -1.;

    double E = sqrt(rho * rho * (1. + tnl * tnl) + mass * mass);

    d4MXDA[0][1] = - fabs(rho) * cosf0phi;
    d4MXDA[0][2] = charge * rho * rho * sinf0phi;
 
    d4MXDA[1][1] = - fabs(rho) * sinf0phi;
    d4MXDA[1][2] = - charge * rho * rho * cosf0phi;

    d4MXDA[2][2] = - charge * rho * rho * tnl;
    d4MXDA[2][4] = fabs(rho);

    if (cpa != 0.0 && E != 0.0) {
      d4MXDA[3][2] = (- 1. - tnl * tnl) / (cpa * cpa * cpa * E);
      d4MXDA[3][4] = tnl / (cpa * cpa * E);
    } else {
      d4MXDA[3][2] = (DBL_MAX);
      d4MXDA[3][4] = (DBL_MAX);
    }
    
    d4MXDA[4][0] = m_cp;
    d4MXDA[4][1] = - dr * m_sp + m_r * (- m_sp + sinf0phi);
    if (cpa != 0.0) {
      d4MXDA[4][2] = - (m_r / cpa) * (m_cp - cosf0phi);
    } else {
      d4MXDA[4][2] = (DBL_MAX);
    }
     
    d4MXDA[5][0] = m_sp;
    d4MXDA[5][1] = dr * m_cp + m_r * (m_cp - cosf0phi);
    if (cpa != 0.0) {
      d4MXDA[5][2] = - (m_r / cpa) * (m_sp - sinf0phi);

      d4MXDA[6][2] = (m_r / cpa) * tnl * phi;
    } else {
      d4MXDA[5][2] = (DBL_MAX);

      d4MXDA[6][2] = (DBL_MAX);
    }

    d4MXDA[6][3] = 1.;
    d4MXDA[6][4] = - m_r * phi;

    return d4MXDA;
}

HepMatrix VFHelix::delApDelA

(

const HepVector &

ap

)

const

Definition at line 419 of file Helix.cxx.

References cos(), DBL_MAX, dr(), dz(), m_ac, M_PI, M_PI2, M_PI8, m_r, phi0(), and sin().

Referenced by pivot().

                                             {
    //
    //   Calculate Jacobian (@ap/@a)
    //   Vector ap is new helix parameters and a is old helix parameters. 
    //

    HepMatrix dApDA(5,5,0);

    const double & dr    = m_ac[0];
    const double & phi0  = m_ac[1];
    const double & cpa   = m_ac[2];
    const double & dz    = m_ac[3];
    const double & tnl   = m_ac[4];

    double drp   = ap[0];
    double phi0p = ap[1];
    double cpap  = ap[2];
    double dzp   = ap[3];
    double tnlp  = ap[4];

    double rdr   = m_r + dr;
    double rdrpr;
    if ((m_r + drp) != 0.0) {
      rdrpr = 1. / (m_r + drp);
    } else {
      rdrpr = (DBL_MAX);
    }
    // double csfd  = cos(phi0)*cos(phi0p) + sin(phi0)*sin(phi0p); 
    // double snfd  = cos(phi0)*sin(phi0p) - sin(phi0)*cos(phi0p); 
    double csfd  = cos(phi0p - phi0);
    double snfd  = sin(phi0p - phi0);
    double phid  = fmod(phi0p - phi0 + M_PI8, M_PI2);
    if (phid > M_PI) phid = phid - M_PI2;

    dApDA[0][0]  =  csfd;
    dApDA[0][1]  =  rdr*snfd;
    if(cpa!=0.0) {
      dApDA[0][2]  =  (m_r/cpa)*( 1.0 - csfd );
    } else {
      dApDA[0][2]  = (DBL_MAX);
    }

    dApDA[1][0]  = - rdrpr*snfd;
    dApDA[1][1]  = rdr*rdrpr*csfd;
    if(cpa!=0.0) {
      dApDA[1][2]  = (m_r/cpa)*rdrpr*snfd;
    } else {
      dApDA[1][2]  = (DBL_MAX);
    }
    
    dApDA[2][2]  = 1.0;

    dApDA[3][0]  = m_r*rdrpr*tnl*snfd;
    dApDA[3][1]  = m_r*tnl*(1.0 - rdr*rdrpr*csfd);
    if(cpa!=0.0) {
      dApDA[3][2]  = (m_r/cpa)*tnl*(phid - m_r*rdrpr*snfd);
    } else {
      dApDA[3][2]  = (DBL_MAX);
    }
    dApDA[3][3]  = 1.0;
    dApDA[3][4]  = - m_r*phid;

    dApDA[4][4] = 1.0;
 
    return dApDA;
}

HepMatrix VFHelix::delMDelA

(

double

phi

)

const

Definition at line 541 of file Helix.cxx.

References cos(), DBL_MAX, m_ac, phi0(), and sin().

Referenced by momentum().

                                  {
    //
    //   Calculate Jacobian (@m/@a)
    //   Vector a is helix parameters and phi is internal parameter.
    //   Vector m is momentum.
    //

    HepMatrix dMDA(3,5,0);

    const double & phi0 = m_ac[1];
    const double & cpa  = m_ac[2];
    const double & tnl  = m_ac[4];

    double cosf0phi = cos(phi0+phi);
    double sinf0phi = sin(phi0+phi);

    double rho;
    if(cpa != 0.)rho = 1./cpa;
    else rho = (DBL_MAX);

    double charge = 1.;
    if(cpa < 0.)charge = -1.;

    dMDA[0][1] = -fabs(rho)*cosf0phi;
    dMDA[0][2] = charge*rho*rho*sinf0phi;
 
    dMDA[1][1] = -fabs(rho)*sinf0phi;
    dMDA[1][2] = -charge*rho*rho*cosf0phi;

    dMDA[2][2] = -charge*rho*rho*tnl;
    dMDA[2][4] = fabs(rho);

    return dMDA;
}

HepMatrix VFHelix::delXDelA

(

double

phi

)

const

Definition at line 487 of file Helix.cxx.

References cos(), DBL_MAX, dr(), dz(), m_ac, m_cp, m_r, m_sp, phi0(), and sin().

Referenced by x().

                                  {
    //
    //   Calculate Jacobian (@x/@a)
    //   Vector a is helix parameters and phi is internal parameter
    //   which specifys the point to be calculated for Ex(phi).
    //

    HepMatrix dXDA(3,5,0);

    const double & dr      = m_ac[0];
    const double & phi0    = m_ac[1];
    const double & cpa     = m_ac[2];
    const double & dz      = m_ac[3];
    const double & tnl     = m_ac[4];

    double cosf0phi = cos(phi0 + phi);
    double sinf0phi = sin(phi0 + phi);

    dXDA[0][0]     = m_cp;
    dXDA[0][1]     = - dr * m_sp + m_r * (- m_sp + sinf0phi); 
    if(cpa!=0.0) {
      dXDA[0][2]     = - (m_r / cpa) * (m_cp - cosf0phi);
    } else {
      dXDA[0][2] = (DBL_MAX);
    }
    // dXDA[0][3]     = 0.0;
    // dXDA[0][4]     = 0.0;
 
    dXDA[1][0]     = m_sp;
    dXDA[1][1]     = dr * m_cp + m_r * (m_cp - cosf0phi);
    if(cpa!=0.0) {
      dXDA[1][2]     = - (m_r / cpa) * (m_sp - sinf0phi);
    } else {
      dXDA[1][2] = (DBL_MAX);
    }
    // dXDA[1][3]     = 0.0;
    // dXDA[1][4]     = 0.0;

    // dXDA[2][0]     = 0.0;
    // dXDA[2][1]     = 0.0;
    if(cpa!=0.0) {
      dXDA[2][2]     = (m_r / cpa) * tnl * phi;
    } else {
      dXDA[2][2] = (DBL_MAX);
    }
    dXDA[2][3]     = 1.0;
    dXDA[2][4]     = - m_r * phi;

    return dXDA;
}

Hep3Vector VFHelix::direction

(

double

dPhi = 0.

)

const [inline]

returns direction vector after rotating angle dPhi in phi direction.

Definition at line 198 of file Helix.h.

References momentum().

                                   {
    return momentum(phi).unit();
}

double VFHelix::dr

(

void

)

const [inline]

returns an element of parameters.

Definition at line 204 of file Helix.h.

References m_ac.

Referenced by del4MXDelA(), delApDelA(), delXDelA(), and pivot().

                      {
    return m_ac[0];
}

double VFHelix::dz

(

void

)

const [inline]

Definition at line 222 of file Helix.h.

References m_ac.

Referenced by del4MXDelA(), delApDelA(), delXDelA(), and pivot().

                      {
    return m_ac[3];
}

const HepSymMatrix & VFHelix::Ea

(

const HepSymMatrix &

newdA

)

[inline]

sets helix paramters and error matrix.

Definition at line 260 of file Helix.h.

References m_Ea.

                                  {
    return m_Ea = i;
}

const HepSymMatrix & VFHelix::Ea

(

void

)

const [inline]

returns error matrix.

Definition at line 246 of file Helix.h.

References m_Ea.

                      {
    return m_Ea;
}

void VFHelix::ignoreErrorMatrix

(

void

)

unsets error matrix. Error calculations will be ignored after this function call until an error matrix be set again. 0 matrix will be return as a return value for error matrix when you call functions which returns an error matrix.

Definition at line 695 of file Helix.cxx.

References m_Ea, and m_matrixValid.

                               {
    m_matrixValid = false;
    m_Ea *= 0.;
}

double VFHelix::kappa

(

void

)

const [inline]

Definition at line 216 of file Helix.h.

References m_ac.

Referenced by pivot().

                         {
    return m_ac[2];
}

HepLorentzVector VFHelix::momentum	(	double	dPhi,
		double	mass,
		HepPoint3D &	x,
		HepSymMatrix &	Emx
	)			const

returns 4momentum vector after rotating angle dPhi in phi direction.

Definition at line 256 of file Helix.cxx.

References cos(), del4MXDelA(), m_ac, m_cp, m_Ea, m_matrixValid, m_pivot, m_pt, m_r, m_sp, and sin().

                                          {
  // 
  // Calculate momentum.
  //
  // Pt = | 1/kappa | (GeV/c)
  //
  // Px = -Pt * sin(phi0 + phi) 
  // Py =  Pt * cos(phi0 + phi)
  // Pz =  Pt * tan(lambda)
  //
  // E  = sqrt( 1/kappa/kappa * (1+tan(lambda)*tan(lambda)) + mass*mass )
  
  double pt = fabs(m_pt);
  double px = - pt * sin(m_ac[1] + phi);
  double py =   pt * cos(m_ac[1] + phi);
  double pz =   pt * m_ac[4];
  double E  = sqrt(pt * pt * (1. + m_ac[4] * m_ac[4]) + mass * mass);

  x.setX(m_pivot.x() + m_ac[0] * m_cp + m_r * (m_cp - cos(m_ac[1] + phi)));
  x.setY(m_pivot.y() + m_ac[0] * m_sp + m_r * (m_sp - sin(m_ac[1] + phi)));
  x.setZ(m_pivot.z() + m_ac[3] - m_r * m_ac[4] * phi);

  if (m_matrixValid) Emx = m_Ea.similarity(del4MXDelA(phi,mass));
  else               Emx = m_Ea;
  
  return HepLorentzVector(px, py, pz, E);
}

HepLorentzVector VFHelix::momentum	(	double	dPhi,
		double	mass,
		HepSymMatrix &	Em
	)			const

returns 4momentum vector after rotating angle dPhi in phi direction.

Definition at line 231 of file Helix.cxx.

References cos(), del4MDelA(), m_ac, m_Ea, m_matrixValid, m_pt, and sin().

                                                                  {
    // 
    // Calculate momentum.
    //
    // Pt = | 1/kappa | (GeV/c)
    //
    // Px = -Pt * sin(phi0 + phi) 
    // Py =  Pt * cos(phi0 + phi)
    // Pz =  Pt * tan(lambda)
    //
    // E  = sqrt( 1/kappa/kappa * (1+tan(lambda)*tan(lambda)) + mass*mass )

    double pt = fabs(m_pt);
    double px = - pt * sin(m_ac[1] + phi);
    double py =   pt * cos(m_ac[1] + phi);
    double pz =   pt * m_ac[4];
    double E  =   sqrt(pt*pt*(1.+m_ac[4]*m_ac[4])+mass*mass);

    if (m_matrixValid) Em = m_Ea.similarity(del4MDelA(phi,mass));
    else               Em = m_Ea;

    return HepLorentzVector(px, py, pz, E);
}

HepLorentzVector VFHelix::momentum	(	double	dPhi,
		double	mass
	)			const

returns 4momentum vector after rotating angle dPhi in phi direction.

Definition at line 208 of file Helix.cxx.

References cos(), m_ac, m_pt, and sin().

                                               {
    // 
    // Calculate momentum.
    //
    // Pt = | 1/kappa | (GeV/c)
    //
    // Px = -Pt * sin(phi0 + phi) 
    // Py =  Pt * cos(phi0 + phi)
    // Pz =  Pt * tan(lambda)
    //
    // E  = sqrt( 1/kappa/kappa * (1+tan(lambda)*tan(lambda)) + mass*mass )

    double pt = fabs(m_pt);
    double px = - pt * sin(m_ac[1] + phi);
    double py =   pt * cos(m_ac[1] + phi);
    double pz =   pt * m_ac[4];
    double E  =   sqrt(pt*pt*(1.+m_ac[4]*m_ac[4])+mass*mass);

    return HepLorentzVector(px, py, pz, E);
}

Hep3Vector VFHelix::momentum	(	double	dPhi,
		HepSymMatrix &	Em
	)			const

returns momentum vector after rotating angle dPhi in phi direction.

Definition at line 185 of file Helix.cxx.

References cos(), delMDelA(), m_ac, m_Ea, m_matrixValid, m_pt, and sin().

                                                     {
    // 
    // Calculate momentum.
    //
    // Pt = | 1/kappa | (GeV/c)
    //
    // Px = -Pt * sin(phi0 + phi) 
    // Py =  Pt * cos(phi0 + phi)
    // Pz =  Pt * tan(lambda)
    //

    double pt = fabs(m_pt);
    double px = - pt * sin(m_ac[1] + phi);
    double py =   pt * cos(m_ac[1] + phi);
    double pz =   pt * m_ac[4];

    if (m_matrixValid) Em = m_Ea.similarity(delMDelA(phi));
    else               Em = m_Ea;

    return Hep3Vector(px, py, pz);
}

Hep3Vector VFHelix::momentum

(

double

dPhi = 0.

)

const

returns momentum vector after rotating angle dPhi in phi direction.

Definition at line 165 of file Helix.cxx.

References cos(), m_ac, m_pt, and sin().

Referenced by direction().

                                  {
    // 
    // Calculate momentum.
    //
    // Pt = | 1/kappa | (GeV/c)
    //
    // Px = -Pt * sin(phi0 + phi) 
    // Py =  Pt * cos(phi0 + phi)
    // Pz =  Pt * tan(lambda)
    //

    double pt = fabs(m_pt);
    double px = - pt * sin(m_ac[1] + phi);
    double py =   pt * cos(m_ac[1] + phi);
    double pz =   pt * m_ac[4];

    return Hep3Vector(px, py, pz);
}

VFHelix & VFHelix::operator=

(

const VFHelix &

)

Copy operator.

Definition at line 361 of file Helix.cxx.

References genRecEmupikp::i, m_a, m_ac, m_alpha, m_bField, m_center, m_cp, m_Ea, m_matrixValid, m_pivot, m_pt, m_r, and m_sp.

                                      {
    if (this == & i) return * this;

    m_bField = i.m_bField;
    m_alpha = i.m_alpha;
    m_pivot = i.m_pivot;
    m_a = i.m_a;
    m_Ea = i.m_Ea;
    m_matrixValid = i.m_matrixValid;

    m_center = i.m_center;
    m_cp = i.m_cp;
    m_sp = i.m_sp;
    m_pt = i.m_pt;
    m_r  = i.m_r;
    m_ac[0] = i.m_ac[0];
    m_ac[1] = i.m_ac[1];
    m_ac[2] = i.m_ac[2];
    m_ac[3] = i.m_ac[3];
    m_ac[4] = i.m_ac[4];

    return * this;
}

double VFHelix::phi0

(

void

)

const [inline]

Definition at line 210 of file Helix.h.

References m_ac.

Referenced by del4MDelA(), del4MXDelA(), delApDelA(), delMDelA(), delXDelA(), and pivot().

                        {
    return m_ac[1];
}

const HepPoint3D & VFHelix::pivot

(

const HepPoint3D &

newPivot

)

sets pivot position.

Definition at line 289 of file Helix.cxx.

References cos(), delApDelA(), dr(), dz(), kappa(), m_a, m_ac, m_Ea, m_matrixValid, M_PI, M_PI2, M_PI4, M_PI8, m_pivot, m_r, phi0(), tanl(), and updateCache().

                                          {
    const double & dr    = m_ac[0];
    const double & phi0  = m_ac[1];
    const double & kappa = m_ac[2];
    const double & dz    = m_ac[3];
    const double & tanl  = m_ac[4];

    double rdr = dr + m_r;
    double phi = fmod(phi0 + M_PI4, M_PI2);
    double csf0 = cos(phi);
    double snf0 = (1. - csf0) * (1. + csf0);
    snf0 = sqrt((snf0 > 0.) ? snf0 : 0.);
    if(phi > M_PI) snf0 = - snf0;

    double xc = m_pivot.x() + rdr * csf0;
    double yc = m_pivot.y() + rdr * snf0;
    double csf, snf;
    if(m_r != 0.0) {
      csf = (xc - newPivot.x()) / m_r;
      snf = (yc - newPivot.y()) / m_r;
      double anrm = sqrt(csf * csf + snf * snf);
      if(anrm != 0.0) {
        csf /= anrm;
        snf /= anrm;
        phi = atan2(snf, csf);
      } else {
        csf = 1.0;
        snf = 0.0;
        phi = 0.0;
      }
    } else {
      csf = 1.0;
      snf = 0.0;
      phi = 0.0;
    }
    double phid = fmod(phi - phi0 + M_PI8, M_PI2);
    if(phid > M_PI) phid = phid - M_PI2;
    double drp = (m_pivot.x() + dr * csf0 + m_r * (csf0 - csf) - newPivot.x())
        * csf
        + (m_pivot.y() + dr * snf0 + m_r * (snf0 - snf) - newPivot.y()) * snf;
    double dzp = m_pivot.z() + dz - m_r * tanl * phid - newPivot.z();

    HepVector ap(5);
    ap[0] = drp;
    ap[1] = fmod(phi + M_PI4, M_PI2);
    ap[2] = kappa;
    ap[3] = dzp;
    ap[4] = tanl;

    //    if (m_matrixValid) m_Ea.assign(delApDelA(ap) * m_Ea * delApDelA(ap).T());
    if (m_matrixValid) m_Ea = m_Ea.similarity(delApDelA(ap));

    m_a = ap;
    m_pivot = newPivot;

    //...Are these needed?...iw...
    updateCache();
    return m_pivot;
}

const HepPoint3D & VFHelix::pivot

(

void

)

const [inline]

returns pivot position.

Definition at line 186 of file Helix.h.

References m_pivot.

Referenced by SD0Tag::execute(), CalibEventSelect::execute(), DQASelHadron::execute(), DQAKsKpi::execute(), Rhopi::execute(), Gam4pikp::execute(), DQADtag::fillTrackItem(), BestDTagSvc::isGoodTrack(), DSemilepAlg::isGoodTrack(), DTagTool::isGoodTrack(), Pipipi0::MTotal(), Pipi::MTotal(), Kpipi0pi0::MTotal(), Kpipi0::MTotal(), Kpi::MTotal(), Kkpipi::MTotal(), Kkpi0::MTotal(), Kk::MTotal(), K3pipi0::MTotal(), K3pi::MTotal(), K0pipipi0::MTotal(), K0pipi::MTotal(), K0pi0::MTotal(), K0kpi::MTotal(), K0kk::MTotal(), LocalPionSelector::operator()(), and LocalKaonSelector::operator()().

                         {
    return m_pivot;
}

double VFHelix::radius

(

void

)

const [inline]

returns radious of helix.

Definition at line 192 of file Helix.h.

References m_r.

                          {
    return m_r;
}

void VFHelix::set	(	const HepPoint3D &	pivot,
		const HepVector &	a,
		const HepSymMatrix &	Ea
	)

sets helix pivot position, parameters, and error matrix.

Definition at line 350 of file Helix.cxx.

References m_a, m_Ea, m_matrixValid, m_pivot, and updateCache().

                                    {
    m_pivot = pivot;
    m_a = a;
    m_Ea = Ea;
    m_matrixValid = true;
    updateCache();
}

double VFHelix::sinPhi0

(

void

)

const [inline]

Definition at line 281 of file Helix.h.

References m_sp.

                           {
    return m_sp;
}

double VFHelix::tanl

(

void

)

const [inline]

Definition at line 228 of file Helix.h.

References m_ac.

Referenced by pivot().

                        {
    return m_ac[4];
}

void VFHelix::updateCache

(

void

)

[private]

Definition at line 386 of file Helix.cxx.

References cos(), DBL_MAX, m_a, m_ac, m_alpha, m_center, m_cp, m_pivot, m_pt, m_r, m_sp, sin(), and x().

Referenced by a(), bFieldZ(), pivot(), set(), and VFHelix().

                         {
    //
    //   Calculate VFHelix center( xc, yc ).
    //   
    //   xc = x0 + (dr + (alpha / kappa)) * cos(phi0)  (cm)
    //   yc = y0 + (dr + (alpha / kappa)) * sin(phi0)  (cm)
    //

    m_ac[0] = m_a[0];
    m_ac[1] = m_a[1];
    m_ac[2] = m_a[2];
    m_ac[3] = m_a[3];
    m_ac[4] = m_a[4];

    m_cp = cos(m_ac[1]);
    m_sp = sin(m_ac[1]);
    if (m_ac[2] != 0.0) {
        m_pt = 1. / m_ac[2];
        m_r = m_alpha / m_ac[2];
    }
    else {
        m_pt = (DBL_MAX);
        m_r = (DBL_MAX);
    }

    double x = m_pivot.x() + (m_ac[0] + m_r) * m_cp;
    double y = m_pivot.y() + (m_ac[0] + m_r) * m_sp;
    m_center.setX(x);
    m_center.setY(y);
    m_center.setZ(0.);
}

HepPoint3D VFHelix::x	(	double	dPhi,
		HepSymMatrix &	Ex
	)			const

returns position and convariance matrix(Ex) after rotation.

Definition at line 144 of file Helix.cxx.

References cos(), delXDelA(), m_ac, m_cp, m_Ea, m_matrixValid, m_pivot, m_r, m_sp, sin(), and x().

                                              {
    double x = m_pivot.x() + m_ac[0] * m_cp + m_r * (m_cp - cos(m_ac[1] +phi));
    double y = m_pivot.y() + m_ac[0] * m_sp + m_r * (m_sp - sin(m_ac[1] +phi));
    double z = m_pivot.z() + m_ac[3] - m_r * m_ac[4] * phi;

    //
    //   Calculate position error matrix.
    //   Ex(phi) = (@x/@a)(Ea)(@x/@a)^T, phi is deflection angle to specify the
    //   point to be calcualted.
    //
    // HepMatrix dXDA(3, 5, 0);
    // dXDA = delXDelA(phi);
    // Ex.assign(dXDA * m_Ea * dXDA.T());

    if (m_matrixValid) Ex = m_Ea.similarity(delXDelA(phi));
    else               Ex = m_Ea;

    return HepPoint3D(x, y, z);
}

double * VFHelix::x	(	double	dPhi,
		double	p[3]
	)			const

Definition at line 127 of file Helix.cxx.

References cos(), m_ac, m_cp, m_pivot, m_r, m_sp, and sin().

                                        {
    //
    // Calculate position (x,y,z) along helix.
    //   
    // x = x0 + dr * cos(phi0) + (alpha / kappa) * (cos(phi0) - cos(phi0+phi))
    // y = y0 + dr * sin(phi0) + (alpha / kappa) * (sin(phi0) - sin(phi0+phi))
    // z = z0 + dz             - (alpha / kappa) * tan(lambda) * phi
    //

    p[0] = m_pivot.x() + m_ac[0] * m_cp + m_r * (m_cp - cos(m_ac[1] + phi));
    p[1] = m_pivot.y() + m_ac[0] * m_sp + m_r * (m_sp - sin(m_ac[1] + phi));
    p[2] = m_pivot.z() + m_ac[3] - m_r * m_ac[4] * phi;

    return p;
}

HepPoint3D VFHelix::x

(

double

dPhi = 0.

)

const

returns position after rotating angle dPhi in phi direction.

Definition at line 110 of file Helix.cxx.

References cos(), m_ac, m_cp, m_pivot, m_r, m_sp, and sin().

Referenced by updateCache(), and x().

                           {
    //
    // Calculate position (x,y,z) along helix.
    //   
    // x = x0 + dr * cos(phi0) + (alpha / kappa) * (cos(phi0) - cos(phi0+phi))
    // y = y0 + dr * sin(phi0) + (alpha / kappa) * (sin(phi0) - sin(phi0+phi))
    // z = z0 + dz             - (alpha / kappa) * tan(lambda) * phi
    //

    double x = m_pivot.x() + m_ac[0] * m_cp + m_r * (m_cp - cos(m_ac[1] +phi));
    double y = m_pivot.y() + m_ac[0] * m_sp + m_r * (m_sp - sin(m_ac[1] +phi));
    double z = m_pivot.z() + m_ac[3] - m_r * m_ac[4] * phi;

    return HepPoint3D(x, y, z);
}

---

Member Data Documentation

const double VFHelix::ConstantAlpha = 333.564095 [static]

Constant alpha for uniform field.

Definition at line 148 of file Helix.h.

HepVector VFHelix::m_a [private]

Definition at line 154 of file Helix.h.

Referenced by a(), operator=(), pivot(), set(), updateCache(), and VFHelix().

double VFHelix::m_ac[5] [private]

Definition at line 164 of file Helix.h.

Referenced by del4MDelA(), del4MXDelA(), delApDelA(), delMDelA(), delXDelA(), dr(), dz(), kappa(), momentum(), operator=(), phi0(), pivot(), tanl(), updateCache(), and x().

double VFHelix::m_alpha [private]

Definition at line 152 of file Helix.h.

Referenced by bFieldZ(), operator=(), updateCache(), and VFHelix().

double VFHelix::m_bField [private]

Definition at line 151 of file Helix.h.

Referenced by bFieldZ(), operator=(), and VFHelix().

HepPoint3D VFHelix::m_center [private]

Definition at line 159 of file Helix.h.

Referenced by center(), operator=(), and updateCache().

double VFHelix::m_cp [private]

Definition at line 160 of file Helix.h.

Referenced by cosPhi0(), del4MXDelA(), delXDelA(), momentum(), operator=(), updateCache(), and x().

HepSymMatrix VFHelix::m_Ea [private]

Definition at line 155 of file Helix.h.

Referenced by Ea(), ignoreErrorMatrix(), momentum(), operator=(), pivot(), set(), and x().

bool VFHelix::m_matrixValid [private]

Definition at line 156 of file Helix.h.

Referenced by ignoreErrorMatrix(), momentum(), operator=(), pivot(), set(), and x().

HepPoint3D VFHelix::m_pivot [private]

Definition at line 153 of file Helix.h.

Referenced by momentum(), operator=(), pivot(), set(), updateCache(), and x().

double VFHelix::m_pt [private]

Definition at line 162 of file Helix.h.

Referenced by momentum(), operator=(), and updateCache().

double VFHelix::m_r [private]

Definition at line 163 of file Helix.h.

Referenced by curv(), del4MXDelA(), delApDelA(), delXDelA(), momentum(), operator=(), pivot(), radius(), updateCache(), and x().

double VFHelix::m_sp [private]

Definition at line 161 of file Helix.h.

Referenced by del4MXDelA(), delXDelA(), momentum(), operator=(), sinPhi0(), updateCache(), and x().

---