1 #ifndef ALIEXTERNALTRACKPARAM_H
2 #define ALIEXTERNALTRACKPARAM_H
3 /* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * See cxx source for full Copyright notice */
8 /*****************************************************************************
9 * "External" track parametrisation class *
11 * external param0: local Y-coordinate of a track (cm) *
12 * external param1: local Z-coordinate of a track (cm) *
13 * external param2: local sine of the track momentum azimuthal angle *
14 * external param3: tangent of the track momentum dip angle *
15 * external param4: 1/pt (1/(GeV/c)) *
17 * The parameters are estimated at an exact position x in a local coord. *
18 * system rotated by angle alpha with respect to the global coord.system. *
19 * Origin: I.Belikov, CERN, Jouri.Belikov@cern.ch *
20 *****************************************************************************/
23 #include "AliVTrack.h"
25 const Double_t kVeryBig=1./kAlmost0;
26 const Double_t kMostProbablePt=0.35;
31 class AliExternalTrackParam: public AliVTrack {
33 AliExternalTrackParam();
34 AliExternalTrackParam(const AliExternalTrackParam &);
35 AliExternalTrackParam& operator=(const AliExternalTrackParam & trkPar);
36 AliExternalTrackParam(Double_t x, Double_t alpha,
37 const Double_t param[5], const Double_t covar[15]);
38 AliExternalTrackParam(const AliVTrack *vTrack);
39 AliExternalTrackParam(Double_t xyz[3],Double_t pxpypz[3],
40 Double_t cv[21],Short_t sign);
41 virtual ~AliExternalTrackParam(){}
44 void Set(T x, T alpha, const T param[5], const T covar[15]) {
45 // Sets the parameters
47 for (Int_t i = 0; i < 5; i++) fP[i] = param[i];
48 for (Int_t i = 0; i < 15; i++) fC[i] = covar[i];
51 void Set(Double_t xyz[3],Double_t pxpypz[3],Double_t cv[21],Short_t sign);
53 static void SetMostProbablePt(Double_t pt) { fgMostProbablePt=pt; }
54 static Double_t GetMostProbablePt() { return fgMostProbablePt; }
57 void ResetCovariance(Double_t s2);
58 void AddCovariance(const Double_t cov[15]);
60 const Double_t *GetParameter() const {return fP;}
61 const Double_t *GetCovariance() const {return fC;}
63 Double_t GetAlpha() const {return fAlpha;}
64 Double_t GetX() const {return fX;}
65 Double_t GetY() const {return fP[0];}
66 Double_t GetZ() const {return fP[1];}
67 Double_t GetSnp() const {return fP[2];}
68 Double_t GetTgl() const {return fP[3];}
69 Double_t GetSigned1Pt() const {return fP[4];}
71 Double_t GetSigmaY2() const {return fC[0];}
72 Double_t GetSigmaZY() const {return fC[1];}
73 Double_t GetSigmaZ2() const {return fC[2];}
74 Double_t GetSigmaSnpY() const {return fC[3];}
75 Double_t GetSigmaSnpZ() const {return fC[4];}
76 Double_t GetSigmaSnp2() const {return fC[5];}
77 Double_t GetSigmaTglY() const {return fC[6];}
78 Double_t GetSigmaTglZ() const {return fC[7];}
79 Double_t GetSigmaTglSnp() const {return fC[8];}
80 Double_t GetSigmaTgl2() const {return fC[9];}
81 Double_t GetSigma1PtY() const {return fC[10];}
82 Double_t GetSigma1PtZ() const {return fC[11];}
83 Double_t GetSigma1PtSnp() const {return fC[12];}
84 Double_t GetSigma1PtTgl() const {return fC[13];}
85 Double_t GetSigma1Pt2() const {return fC[14];}
87 // additional functions for AliVParticle
91 Double_t Pt() const { return TMath::Abs(GetSignedPt()); }
92 Double_t P() const { return GetP(); }
93 Bool_t PxPyPz(Double_t p[3]) const { return GetPxPyPz(p); }
98 Bool_t XvYvZv(Double_t x[3]) const { return GetXYZ(x); }
100 Double_t OneOverPt() const { return 1./Pt(); }
101 Double_t Phi() const;
102 Double_t Theta() const;
103 virtual Double_t E() const;
104 virtual Double_t M() const;
105 Double_t Eta() const;
106 virtual Double_t Y() const;
107 virtual Short_t Charge() const { return (Short_t)GetSign(); }
108 virtual const Double_t *PID() const { return 0x0; }
110 // additional functions from AliVTrack
111 virtual Int_t GetID() const { return -999; }
112 virtual UChar_t GetITSClusterMap() const {return 0; }
113 virtual ULong_t GetStatus() const { return 0; }
115 Double_t GetSign() const {return (fP[4]>0) ? 1 : -1;}
116 Double_t GetP() const;
117 Double_t GetSignedPt() const {
118 return (TMath::Abs(fP[4])>kAlmost0) ? 1./fP[4]:TMath::Sign(kVeryBig,fP[4]);
120 Double_t Get1P() const;
121 virtual Double_t GetC(Double_t b) const {return fP[4]*b*kB2C;}
122 void GetDZ(Double_t x,Double_t y,Double_t z,Double_t b,Float_t dz[2]) const;
123 Double_t GetD(Double_t xv, Double_t yv, Double_t b) const;
124 Double_t GetLinearD(Double_t xv, Double_t yv) const;
125 Bool_t CorrectForMeanMaterial(Double_t xOverX0, Double_t xTimesRho,
126 Double_t mass, Bool_t anglecorr=kFALSE,
127 Double_t (*f)(Double_t)=AliExternalTrackParam::BetheBlochSolid);
130 // Bethe-Bloch formula parameterizations
132 static Double_t BetheBlochAleph(Double_t bg,
133 Double_t kp1=0.76176e-1,
135 Double_t kp3=0.13279e-4,
139 static Double_t BetheBlochGeant(Double_t bg,
147 static Double_t BetheBlochSolid(Double_t bg);
148 static Double_t BetheBlochGas(Double_t bg);
150 Double_t GetPredictedChi2(Double_t p[2],Double_t cov[3]) const;
153 GetPredictedChi2(Double_t p[3],Double_t covyz[3],Double_t covxyz[3]) const;
155 PropagateTo(Double_t p[3],Double_t covyz[3],Double_t covxyz[3],Double_t b);
157 Double_t *GetResiduals(Double_t *p,Double_t *cov,Bool_t updated=kTRUE) const;
158 Bool_t Update(Double_t p[2],Double_t cov[3]);
159 Bool_t Rotate(Double_t alpha);
160 Bool_t PropagateTo(Double_t x, Double_t b);
161 Bool_t Propagate(Double_t alpha, Double_t x, Double_t b);
162 void Propagate(Double_t len,Double_t x[3],Double_t p[3],Double_t bz) const;
163 Bool_t Intersect(Double_t pnt[3], Double_t norm[3], Double_t bz) const;
165 void GetHelixParameters(Double_t h[6], Double_t b) const;
166 Double_t GetDCA(const AliExternalTrackParam *p, Double_t b,
167 Double_t &xthis,Double_t &xp) const;
168 Double_t PropagateToDCA(AliExternalTrackParam *p, Double_t b);
169 Bool_t PropagateToDCA(const AliVVertex *vtx, Double_t b, Double_t maxd,
170 Double_t dz[2]=0, Double_t cov[3]=0);
172 void GetDirection(Double_t d[3]) const;
173 Bool_t GetPxPyPz(Double_t *p) const;
174 Bool_t GetXYZ(Double_t *p) const;
175 Bool_t GetCovarianceXYZPxPyPz(Double_t cv[21]) const;
176 Bool_t GetPxPyPzAt(Double_t x, Double_t b, Double_t p[3]) const;
177 Bool_t GetXYZAt(Double_t x, Double_t b, Double_t r[3]) const;
178 Bool_t GetYAt(Double_t x, Double_t b, Double_t &y) const;
179 Bool_t GetZAt(Double_t x, Double_t b, Double_t &z) const;
180 void Print(Option_t* option = "") const;
181 Double_t GetSnpAt(Double_t x,Double_t b) const;
184 Bool_t CorrectForMaterial(Double_t d, Double_t x0, Double_t mass,
185 Double_t (*f)(Double_t)=AliExternalTrackParam::BetheBlochSolid);
187 Bool_t GetDistance(AliExternalTrackParam *param2, Double_t x, Double_t dist[3], Double_t b);
188 Int_t GetIndex(Int_t i, Int_t j) const;
189 Int_t GetLabel() const {return -1;}
191 // visualization (M. Ivanov)
193 virtual void FillPolymarker(TPolyMarker3D *pol, Float_t magf, Float_t minR, Float_t maxR, Float_t stepR);
194 virtual void DrawTrack(Float_t magF, Float_t minR, Float_t maxR, Float_t stepR);
196 Double_t &Par(Int_t i) {return fP[i];}
197 Double_t &Cov(Int_t i) {return fC[i];}
200 Double32_t fX; // X coordinate for the point of parametrisation
201 Double32_t fAlpha; // Local <-->global coor.system rotation angle
202 Double32_t fP[5]; // The track parameters
203 Double32_t fC[15]; // The track parameter covariance matrix
205 static Double32_t fgMostProbablePt; // "Most probable" pt
206 // (to be used if Bz=0)
207 ClassDef(AliExternalTrackParam, 8)
210 inline void AliExternalTrackParam::ResetCovariance(Double_t s2) {
212 // Reset the covarince matrix to "something big"
215 fC[1] = 0.; fC[2]*= s2;
216 fC[3] = 0.; fC[4] = 0.; fC[5]*= s2;
217 fC[6] = 0.; fC[7] = 0.; fC[8] = 0.; fC[9]*= s2;
218 fC[10]= 0.; fC[11]= 0.; fC[12]= 0.; fC[13]= 0.; fC[14]*=s2;