3 /* Copyright(c) 1998-2003, ALICE Experiment at CERN, All rights reserved. *
4 * See cxx source for full Copyright notice */
7 //-------------------------------------------------------
8 // Primary Vertex Class
10 // Origin: A.Dainese, Padova, andrea.dainese@pd.infn.it
11 //-------------------------------------------------------
13 /*****************************************************************************
15 * This class deals with primary vertex. *
16 * AliITSVertex objects are created by the class AliITSVertexer and its *
18 * Different constructors are provided: *
19 * - for primary vertex determined with pixels in pp (only Z) *
20 * - for primary vertex determined with pixels in ion-ion (X,Y,Z) *
21 * - for primary vertex determined with ITS tracks in pp (X,Y,Z) *
22 * This class replaces the previous version of AliITSVertex, designed *
23 * originally only for A-A collisions. The functionalities of the old class *
24 * are maintained in the AliITSVertexerIons class *
26 *****************************************************************************/
28 //---- Root headers -----
31 class AliITSVertex : public TNamed {
36 AliITSVertex(Double_t positionZ,Double_t sigmaZ,Int_t nContributors,
37 Char_t *vtxName="Vertex");
38 AliITSVertex(Double_t phi,Double_t position[3],Double_t covmatrix[6],
39 Double_t chi2,Int_t nContributors,
40 Char_t *vtxName="Vertex");
41 AliITSVertex(Double_t position[3],Double_t sigma[3],
42 Char_t *vtxName="Vertex");
43 AliITSVertex(Double_t position[3],Double_t sigma[3],Double_t snr[3],
44 Char_t *vtxName="Vertex");
46 virtual ~AliITSVertex();
49 void GetXYZ(Double_t position[3]) const;
50 void GetSigmaXYZ(Double_t sigma[3]) const;
51 void GetCovMatrix(Double_t covmatrix[6]) const;
52 void GetSNR(Double_t snr[3]) const;
54 void GetXYZ_ThrustFrame(Double_t position[3]) const;
55 void GetSigmaXYZ_ThrustFrame(Double_t sigma[3]) const;
56 void GetCovMatrix_ThrustFrame(Double_t covmatrix[6]) const;
58 Double_t GetXv() const;
59 Double_t GetYv() const;
60 Double_t GetZv() const;
61 Double_t GetXRes() const;
62 Double_t GetYRes() const;
63 Double_t GetZRes() const;
64 Double_t GetXSNR() const { return fSNR[0]; }
65 Double_t GetYSNR() const { return fSNR[1]; }
66 Double_t GetZSNR() const { return fSNR[2]; }
68 Double_t GetPhi() const { return fPhi; }
69 Double_t GetChi2() const { return fChi2; }
70 Double_t GetChi2toNDF() const
71 { return fChi2/(2.*(Double_t)fNContributors-3.); }
72 Int_t GetNContributors() const { return fNContributors; }
74 void PrintStatus() const;
75 void SetDebug(Int_t dbg = 0) { fDebug = dbg; return; }
76 void SetTruePos(Double_t *tp){for(Int_t i=0;i<3;i++)fTruePos[i]=tp[i];}
77 void GetTruePos(Double_t &x,Double_t &y,Double_t &z) const
78 {x=fTruePos[0]; y=fTruePos[1]; z=fTruePos[2];}
86 Double_t fPosition[3]; // vertex position
87 Double_t fCovXX,fCovXY,fCovYY,fCovXZ,fCovYZ,fCovZZ; // vertex covariance matrix
88 Double_t fSNR[3]; // S/N ratio
89 Double_t fPhi; // position is given in a frame rotated of an angle fPhi around z axis: but in most cases fPhi = 0 !
90 Double_t fChi2; // chi2 of vertex fit
91 Int_t fNContributors; // # of tracklets/tracks used for the estimate
92 Int_t fDebug; //! for debugging
93 Double_t fTruePos[3]; //true vertex position (for comparison purposes)
94 ClassDef(AliITSVertex,3) // Class for Primary Vertex