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c04e3238 1#ifndef ALIMUONTRACKEXTRAP_H
2#define ALIMUONTRACKEXTRAP_H
3/* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * See cxx source for full Copyright notice */
5
6/*$Id$*/
7// Revision of includes 07/05/2004
8
9/// \ingroup rec
10/// \class AliMUONTrackExtrap
11/// \brief Track parameters in ALICE dimuon spectrometer
12///
13//////////////////////////////////////////////////////////////
14/// Tools for track extrapolation in ALICE dimuon spectrometer
15//////////////////////////////////////////////////////////////
16
17#include <TObject.h>
690d2205 18#include <TMatrixD.h>
c04e3238 19
20class AliMagF;
21class AliMUONTrackParam;
22
23class AliMUONTrackExtrap : public TObject
24{
25 public:
26 /// Constructor
27 AliMUONTrackExtrap() : TObject(){};
28 /// Destructor
29 virtual ~AliMUONTrackExtrap(){};
30
9f093251 31 static void SetField(const AliMagF* magField);
32
33 /// return kTRUE if the field is switched ON
34 static Bool_t IsFieldON() {return fgFieldON;}
c04e3238 35
208f139e 36 static Double_t GetImpactParamFromBendingMomentum(Double_t bendingMomentum);
37 static Double_t GetBendingMomentumFromImpactParam(Double_t impactParam);
38
690d2205 39 // Linearly extrapolate track parameters and covariances
9f093251 40 static void LinearExtrapToZ(AliMUONTrackParam* trackParam, Double_t zEnd, Bool_t updatePropagator = kFALSE);
690d2205 41
42 // Extrapolate track parameters in magnetic field
019df241 43 static void ExtrapToZ(AliMUONTrackParam *trackParam, Double_t zEnd);
690d2205 44
45 // Extrapolate track parameters and covariances in magnetic field
ea94c18b 46 static void ExtrapToZCov(AliMUONTrackParam* trackParam, Double_t zEnd, Bool_t updatePropagator = kFALSE);
690d2205 47
48 // Extrapolate track parameters to vertex, corrected for multiple scattering and energy loss effects
49 // Add branson correction resolution and energy loss fluctuation to parameter covariances
50 static void ExtrapToVertex(AliMUONTrackParam* trackParam,
51 Double_t xVtx, Double_t yVtx, Double_t zVtx,
52 Double_t errXVtx, Double_t errYVtx);
53
54 // Extrapolate track parameters to vertex, corrected for multiple scattering effects only
55 // Add branson correction resolution to parameter covariances
56 static void ExtrapToVertexWithoutELoss(AliMUONTrackParam* trackParam,
57 Double_t xVtx, Double_t yVtx, Double_t zVtx,
58 Double_t errXVtx, Double_t errYVtx);
59
60 // Extrapolate track parameters to vertex, corrected for energy loss effects only
61 // Add dispersion due to multiple scattering and energy loss fluctuation to parameter covariances
62 static void ExtrapToVertexWithoutBranson(AliMUONTrackParam* trackParam, Double_t zVtx);
63
64 // Extrapolate track parameters to vertex without multiple scattering and energy loss corrections
65 // Add dispersion due to multiple scattering to parameter covariances
208f139e 66 static void ExtrapToVertexUncorrected(AliMUONTrackParam* trackParam, Double_t zVtx);
fac70e25 67
68 static Double_t TotalMomentumEnergyLoss(AliMUONTrackParam* trackParam, Double_t xVtx, Double_t yVtx, Double_t zVtx);
c04e3238 69
ea94c18b 70 static Double_t GetMCSAngle2(const AliMUONTrackParam& param, Double_t dZ, Double_t x0);
71 static void AddMCSEffect(AliMUONTrackParam *param, Double_t dZ, Double_t x0);
208f139e 72
c04e3238 73 static void ExtrapOneStepRungekutta(Double_t charge, Double_t step, Double_t* vect, Double_t* vout);
74
75
76 private:
4284483e 77 static const AliMagF* fgkField; //!< field map
9f093251 78 static const Double_t fgkSimpleBPosition; //!< position of the dipole
79 static const Double_t fgkSimpleBLength; //!< length of the dipole
80 static Double_t fgSimpleBValue; //!< magnetic field value at the centre
81 static Bool_t fgFieldON; //!< kTRUE if the field is switched ON
4284483e 82 static const Bool_t fgkUseHelix; //!< Tell whether to use Helix or not (default is Runge-Kutta)
83 static const Int_t fgkMaxStepNumber; //!< Maximum number of steps for track extrapolation
84 static const Double_t fgkHelixStepLength; //!< Step lenght for track extrapolation (used in Helix)
85 static const Double_t fgkRungeKuttaMaxResidue;//!< Maximal distance (in Z) to destination to stop the track extrapolation (used in Runge-Kutta)
86
c04e3238 87 // Functions
71a2d3aa 88
89 /// Not implemented
c04e3238 90 AliMUONTrackExtrap(const AliMUONTrackExtrap& trackExtrap);
71a2d3aa 91 /// Not implemented
c04e3238 92 AliMUONTrackExtrap& operator=(const AliMUONTrackExtrap& trackExtrap);
93
4284483e 94 static void ExtrapToZHelix(AliMUONTrackParam *trackParam, Double_t Z);
95 static void ExtrapToZRungekutta(AliMUONTrackParam *trackParam, Double_t Z);
96
97 static void ConvertTrackParamForExtrap(AliMUONTrackParam* trackParam, Double_t forwardBackward, Double_t *v3);
eb3178e9 98 static void RecoverTrackParam(Double_t *v3, Double_t Charge, AliMUONTrackParam* trackParam);
c04e3238 99
690d2205 100 static void ExtrapToVertex(AliMUONTrackParam* trackParam,
101 Double_t xVtx, Double_t yVtx, Double_t zVtx,
102 Double_t errXVtx, Double_t errYVtx,
103 Bool_t correctForMCS, Bool_t correctForEnergyLoss);
104
8cde4af5 105 static void AddMCSEffectInAbsorber(AliMUONTrackParam* trackParam, Double_t pathLength, Double_t f0, Double_t f1, Double_t f2);
690d2205 106 static void CorrectMCSEffectInAbsorber(AliMUONTrackParam* param,
107 Double_t xVtx, Double_t yVtx, Double_t zVtx,
108 Double_t errXVtx, Double_t errYVtx,
109 Double_t absZBeg, Double_t pathLength, Double_t f0, Double_t f1, Double_t f2);
110 static void CorrectELossEffectInAbsorber(AliMUONTrackParam* param, Double_t eLoss, Double_t sigmaELoss2);
18abc511 111 static Bool_t GetAbsorberCorrectionParam(Double_t trackXYZIn[3], Double_t trackXYZOut[3], Double_t pTotal,
112 Double_t &pathLength, Double_t &f0, Double_t &f1, Double_t &f2,
113 Double_t &meanRho, Double_t &totalELoss, Double_t &sigmaELoss2);
8cde4af5 114
84f061ef 115 static Double_t BetheBloch(Double_t pTotal, Double_t pathLength, Double_t rho, Double_t atomicA, Double_t atomicZ);
690d2205 116 static Double_t EnergyLossFluctuation2(Double_t pTotal, Double_t pathLength, Double_t rho, Double_t atomicA, Double_t atomicZ);
117
118 static void Cov2CovP(const TMatrixD &param, TMatrixD &cov);
119 static void CovP2Cov(const TMatrixD &param, TMatrixD &cov);
c04e3238 120
121 static void ExtrapOneStepHelix(Double_t charge, Double_t step, Double_t *vect, Double_t *vout);
122 static void ExtrapOneStepHelix3(Double_t field, Double_t step, Double_t *vect, Double_t *vout);
123
124 static void GetField(Double_t *Position, Double_t *Field);
125
126 ClassDef(AliMUONTrackExtrap, 0) // Tools for track extrapolation in ALICE dimuon spectrometer
127};
128
129#endif