Possibility to calculate the DCA between two ESD track. The V0 and cascade vertexes...
[u/mrichter/AliRoot.git] / STEER / AliExternalTrackParam.h
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51ad6848 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 */
5
6/* $Id$ */
7
49d13e89 8/*****************************************************************************
9 * "External" track parametrisation class *
10 * *
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)) *
16 * *
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 *****************************************************************************/
a5e407e9 21#include "TObject.h"
a5e407e9 22
49d13e89 23const Double_t kB2C=0.299792458e-3;
24const Double_t kAlmost1=0.999;
25const Double_t kAlmost0=1e-33;
26const Double_t kVeryBig=1./kAlmost0;
27
51ad6848 28class AliKalmanTrack;
29
a5e407e9 30class AliExternalTrackParam: public TObject {
51ad6848 31 public:
32 AliExternalTrackParam();
33 AliExternalTrackParam(Double_t x, Double_t alpha,
34 const Double_t param[5], const Double_t covar[15]);
35 AliExternalTrackParam(const AliKalmanTrack& track);
ac3eaff4 36
c9ec41e8 37 void Reset();
38 void Set(const AliKalmanTrack& track);
39
49d13e89 40 const Double_t *GetParameter() const {return fP;}
41 const Double_t *GetCovariance() const {return fC;}
c7bafca9 42 Double_t GetSigmaY2() const {return fC[0];}
43 Double_t GetSigmaZ2() const {return fC[2];}
44 Double_t GetX() const {return fX;}
45 Double_t GetAlpha() const {return fAlpha;}
c9ec41e8 46 Double_t GetSign() const {return (fP[4]>0) ? 1 : -1;}
47 Double_t GetP() const;
c7bafca9 48 Double_t GetD(Double_t xv, Double_t yv, Double_t b) const;
49d13e89 49 Double_t GetLinearD(Double_t xv, Double_t yv) const;
c7bafca9 50 Bool_t CorrectForMaterial(Double_t d, Double_t x0, Double_t mass);
49d13e89 51 Double_t GetPredictedChi2(Double_t p[2],Double_t cov[3]) const;
52 Bool_t Update(Double_t p[2],Double_t cov[3]);
53 Bool_t Rotate(Double_t alpha);
54 Bool_t PropagateTo(Double_t x, Double_t b);
55 Bool_t Propagate(Double_t alpha, Double_t x, Double_t b) {
56 if (Rotate(alpha))
57 if (PropagateTo(x,b)) return kTRUE;
58 return kFALSE;
59 }
60
c7bafca9 61 void GetHelixParameters(Double_t h[6], Double_t b) const;
62 Double_t GetDCA(const AliExternalTrackParam *p, Double_t b,
63 Double_t &xthis,Double_t &xp) const;
64 Double_t PropagateToDCA(AliExternalTrackParam *p, Double_t b);
65
c9ec41e8 66 Bool_t GetPxPyPz(Double_t *p) const;
67 Bool_t GetXYZ(Double_t *p) const;
68 Bool_t GetCovarianceXYZPxPyPz(Double_t cv[21]) const;
69 Bool_t GetPxPyPzAt(Double_t x, Double_t b, Double_t p[3]) const;
70 Bool_t GetXYZAt(Double_t x, Double_t b, Double_t r[3]) const;
c9ec41e8 71 void Print(Option_t* option = "") const;
5b77d93c 72 // MI
73 virtual Bool_t CorrectForMaterial(Double_t d, Double_t x0, Double_t rho, Double_t mass);
74 virtual Bool_t PropagateTo(Double_t x, Double_t mass, Double_t maxStep, Bool_t rotateTo=kTRUE);
c9ec41e8 75
76private:
49d13e89 77 Double_t fX; // X coordinate for the point of parametrisation
78 Double_t fAlpha; // Local <-->global coor.system rotation angle
79 Double_t fP[5]; // The track parameters
80 Double_t fC[15]; // The track parameter covariance matrix
c9ec41e8 81
82 ClassDef(AliExternalTrackParam, 4)
51ad6848 83};
84
85#endif