Belle II Software light-2406-ragdoll
Helix.h
1/**************************************************************************
2 * basf2 (Belle II Analysis Software Framework) *
3 * Author: The Belle II Collaboration *
4 * *
5 * See git log for contributors and copyright holders. *
6 * This file is licensed under LGPL-3.0, see LICENSE.md. *
7 **************************************************************************/
8#pragma once
9
10#include <framework/datastore/RelationsObject.h>
11
12#include <Math/Vector3D.h>
13#include <TMatrixDfwd.h>
14
15#include <cmath>
16
17namespace Belle2 {
23 namespace HelixParameterIndex {
25 enum HelixParameterIndex {
26 iD0 = 0,
27 iPhi0 = 1,
28 iOmega = 2,
29 iZ0 = 3,
30 iTanLambda = 4,
34 iArcLength2D = 5,
35 };
36 }
37
59 class Helix : public RelationsObject {
60 public:
61
63 Helix();
64
75 Helix(const ROOT::Math::XYZVector& position,
76 const ROOT::Math::XYZVector& momentum,
77 const short int charge,
78 const double bZ);
79
90 Helix(const double& d0,
91 const double& phi0,
92 const double& omega,
93 const double& z0,
94 const double& tanLambda);
95
97 friend std::ostream& operator<<(std::ostream& output, const Helix& helix);
98
99
100 //---------------------------------------------------------------------------------------------------------------------------
103 //---------------------------------------------------------------------------------------------------------------------------
104 public:
106 double getPerigeeX() const;
107
109 double getPerigeeY() const;
110
112 double getPerigeeZ() const;
113
115 ROOT::Math::XYZVector getPerigee() const;
116
120 double getMomentumX(const double bZ) const;
121
125 double getMomentumY(const double bZ) const;
126
130 double getMomentumZ(const double bZ) const;
131
138 ROOT::Math::XYZVector getMomentum(const double bZ) const;
139
144 ROOT::Math::XYZVector getDirection() const;
145
150 double getTransverseMomentum(const double bZ) const;
151
153 double getKappa(const double bZ) const;
154
156 static double getAlpha(const double bZ);
157
159 short getChargeSign() const;
161
162
163 //---------------------------------------------------------------------------------------------------------------------------
166 //---------------------------------------------------------------------------------------------------------------------------
167 public:
181 double getArcLength2DAtCylindricalR(const double& cylindricalR) const;
182
194 double getArcLength2DAtXY(const double& x, const double& y) const;
195
206 double getArcLength2DAtNormalPlane(const double& x, const double& y,
207 const double& nX, const double& nY) const;
208
213 ROOT::Math::XYZVector getPositionAtArcLength2D(const double& arcLength2D) const;
214
225 ROOT::Math::XYZVector getTangentialAtArcLength2D(const double& arcLength2D) const;
226
231 ROOT::Math::XYZVector getUnitTangentialAtArcLength2D(const double& arcLength2D) const;
232
238 ROOT::Math::XYZVector getMomentumAtArcLength2D(const double& arcLength2D, const double& bz) const;
239
245 double passiveMoveBy(const ROOT::Math::XYZVector& by)
246 { return passiveMoveBy(by.X(), by.Y(), by.Z()); }
247
256 double passiveMoveBy(const double& byX,
257 const double& byY,
258 const double& byZ);
259
260
271 TMatrixD calcPassiveMoveByJacobian(const ROOT::Math::XYZVector& by, const double expandBelowChi = M_PI / 8) const;
272
273
274 protected:
275 public:
295 void calcPassiveMoveByJacobian(const double& byX,
296 const double& byY,
297 TMatrixD& jacobian,
298 const double expandBelowChi = M_PI / 8) const;
299
300 public:
308 void reverse();
309
315 static double reversePhi(const double& phi);
316
322 double calcArcLength2DFromSecantLength(const double& secantLength2D) const;
323
326 double calcSecantLengthToArcLength2DFactor(const double& secantLength2D) const;
328
329 protected:
331 static double calcASinXDividedByX(const double& x);
332
334 static double calcATanXDividedByX(const double& x);
335
337 static double calcDerivativeOfATanXDividedByX(const double& x);
338
348 void calcArcLength2DAndDrAtXY(const double& x, const double& y, double& arcLength2D, double& dr) const;
349
358 double calcArcLength2DAtDeltaCylindricalRAndDr(const double& deltaCylindricalR, const double& dr) const;
359
360
361 //---------------------------------------------------------------------------------------------------------------------------
364 //---------------------------------------------------------------------------------------------------------------------------
365 public:
372 double getD0() const { return m_d0; }
373
378 double getPhi0() const { return m_phi0; }
379
381 double getCosPhi0() const { return std::cos(getPhi0()); }
382
384 double getSinPhi0() const { return std::sin(getPhi0()); }
385
387 double getOmega() const { return m_omega; }
388
390 double getZ0() const { return m_z0; }
391
393 double getTanLambda() const { return m_tanLambda; }
394
396 double getCotTheta() const { return m_tanLambda; }
398
400 private:
401 //---------------------------------------------------------------------------------------------------------------------------
402 //--- Functions for internal conversions between cartesian and perigee helix parameters
403 //--- This can be placed in a seperate header which handles all the conversion stuff
404 //---------------------------------------------------------------------------------------------------------------------------
405
408 void setCartesian(const ROOT::Math::XYZVector& position,
409 const ROOT::Math::XYZVector& momentum,
410 const short int charge,
411 const double bZ);
412
414 Double32_t m_d0;
415
417 Double32_t m_phi0;
418
420 Double32_t m_omega;
421
423 Double32_t m_z0;
424
426 Double32_t m_tanLambda;
427
429 };
431}
432
This class represents an ideal helix in perigee parameterization.
Definition: Helix.h:59
Double32_t m_tanLambda
Memory for the slope of the track in the z coordinate over the two dimensional arc length (dz/ds)
Definition: Helix.h:426
double getPerigeeX() const
Calculates the x coordinate of the perigee point.
Definition: Helix.cc:54
double getSinPhi0() const
Getter for the cosine of the azimuth angle of travel direction at the perigee.
Definition: Helix.h:384
double getMomentumZ(const double bZ) const
Calculates the z momentum of the particle at the perigee point.
Definition: Helix.cc:84
Double32_t m_omega
Memory for the curvature of the signed curvature.
Definition: Helix.h:420
double getMomentumY(const double bZ) const
Calculates the y momentum of the particle at the perigee point.
Definition: Helix.cc:79
void reverse()
Reverses the direction of travel of the helix in place.
Definition: Helix.cc:119
double getCosPhi0() const
Getter for the cosine of the azimuth angle of travel direction at the perigee.
Definition: Helix.h:381
double getArcLength2DAtCylindricalR(const double &cylindricalR) const
Calculates the transverse travel distance at the point the helix first reaches the given cylindrical ...
Definition: Helix.cc:128
static double calcASinXDividedByX(const double &x)
Implementation of the function asin(x) / x which handles small x values smoothly.
Definition: Helix.cc:438
static double reversePhi(const double &phi)
Reverses an azimuthal angle to the opposite direction.
Definition: Helix.cc:421
short getChargeSign() const
Return track charge sign (1, 0 or -1).
Definition: Helix.cc:114
double getArcLength2DAtXY(const double &x, const double &y) const
Calculates the two dimensional arc length at which the circle in the xy projection is closest to the ...
Definition: Helix.cc:141
Double32_t m_z0
Memory for the z coordinate of the perigee.
Definition: Helix.h:423
static double getAlpha(const double bZ)
Calculates the alpha value for a given magnetic field in Tesla.
Definition: Helix.cc:109
double getCotTheta() const
Getter for cot theta, which is the z over two dimensional arc length slope of the track.
Definition: Helix.h:396
double getOmega() const
Getter for omega, which is a signed curvature measure of the track.
Definition: Helix.h:387
ROOT::Math::XYZVector getDirection() const
Getter for unit vector of momentum at the perigee position.
Definition: Helix.cc:94
friend std::ostream & operator<<(std::ostream &output, const Helix &helix)
Output operator for debugging and the generation of unittest error messages.
Definition: Helix.cc:631
ROOT::Math::XYZVector getTangentialAtArcLength2D(const double &arcLength2D) const
Calculates the tangential vector to the helix curve at the given two dimensional arc length.
Definition: Helix.cc:245
ROOT::Math::XYZVector getPositionAtArcLength2D(const double &arcLength2D) const
Calculates the position on the helix at the given two dimensional arc length.
Definition: Helix.cc:201
Double32_t m_d0
Memory for the signed distance to the perigee.
Definition: Helix.h:414
ROOT::Math::XYZVector getUnitTangentialAtArcLength2D(const double &arcLength2D) const
Calculates the unit tangential vector to the helix curve at the given two dimensional arc length.
Definition: Helix.cc:261
double getPerigeeZ() const
Calculates the z coordinate of the perigee point.
Definition: Helix.cc:64
void setCartesian(const ROOT::Math::XYZVector &position, const ROOT::Math::XYZVector &momentum, const short int charge, const double bZ)
Cartesian to Perigee conversion.
Definition: Helix.cc:588
double getD0() const
Getter for d0, which is the signed distance to the perigee in the r-phi plane.
Definition: Helix.h:372
ROOT::Math::XYZVector getMomentum(const double bZ) const
Getter for vector of momentum at the perigee position.
Definition: Helix.cc:89
void calcArcLength2DAndDrAtXY(const double &x, const double &y, double &arcLength2D, double &dr) const
Helper method to calculate the signed two dimensional arc length and the signed distance to the circl...
Definition: Helix.cc:545
double passiveMoveBy(const ROOT::Math::XYZVector &by)
Moves origin of the coordinate system (passive transformation) by the given vector.
Definition: Helix.h:245
double getArcLength2DAtNormalPlane(const double &x, const double &y, const double &nX, const double &nY) const
Calculates the arc length to reach a plane parallel to the z axes.
Definition: Helix.cc:149
double getMomentumX(const double bZ) const
Calculates the x momentum of the particle at the perigee point.
Definition: Helix.cc:74
double getTanLambda() const
Getter for tan lambda, which is the z over two dimensional arc length slope of the track.
Definition: Helix.h:393
TMatrixD calcPassiveMoveByJacobian(const ROOT::Math::XYZVector &by, const double expandBelowChi=M_PI/8) const
Calculate the 5x5 jacobian matrix for the transport of the helix parameters, when moving the origin o...
Definition: Helix.cc:301
double getPerigeeY() const
Calculates the y coordinate of the perigee point.
Definition: Helix.cc:59
double calcSecantLengthToArcLength2DFactor(const double &secantLength2D) const
Helper function to calculate the factor between the dimensional secant length and the two dimensional...
Definition: Helix.cc:432
Double32_t m_phi0
Memory for the azimuth angle between the transverse momentum and the x axis, which is in [-pi,...
Definition: Helix.h:417
double calcArcLength2DAtDeltaCylindricalRAndDr(const double &deltaCylindricalR, const double &dr) const
Helper method to calculate the two dimensional arc length from the perigee to a point at cylindrical ...
Definition: Helix.cc:581
double calcArcLength2DFromSecantLength(const double &secantLength2D) const
Helper function to calculate the two dimensional arc length from the length of a secant.
Definition: Helix.cc:426
double getZ0() const
Getter for z0, which is the z coordinate of the perigee.
Definition: Helix.h:390
double getKappa(const double bZ) const
Getter for kappa, which is charge / transverse momentum or equivalently omega * alpha.
Definition: Helix.cc:104
static double calcDerivativeOfATanXDividedByX(const double &x)
Implementation of the function d / dx (atan(x) / x) which handles small x values smoothly.
Definition: Helix.cc:509
Helix()
Constructor initializing all perigee parameters to zero.
Definition: Helix.cc:24
ClassDef(Helix, 2)
This class represents an ideal helix in perigee parameterization.
ROOT::Math::XYZVector getMomentumAtArcLength2D(const double &arcLength2D, const double &bz) const
Calculates the momentum vector at the given two dimensional arc length.
Definition: Helix.cc:270
ROOT::Math::XYZVector getPerigee() const
Getter for the perigee position.
Definition: Helix.cc:69
double getTransverseMomentum(const double bZ) const
Getter for the absolute value of the transverse momentum at the perigee.
Definition: Helix.cc:99
double getPhi0() const
Getter for phi0, which is the azimuth angle of the transverse momentum at the perigee.
Definition: Helix.h:378
static double calcATanXDividedByX(const double &x)
Implementation of the function atan(x) / x which handles small x values smoothly.
Definition: Helix.cc:477
Defines interface for accessing relations of objects in StoreArray.
Abstract base class for different kinds of events.
Definition: ClusterUtils.h:24