]>
Commit | Line | Data |
---|---|---|
f826d409 | 1 | //--------------------------------------------------------------------------------- |
2 | // The AliKFParticleBase class | |
3 | // . | |
4 | // @author S.Gorbunov, I.Kisel | |
5 | // @version 1.0 | |
6 | // @since 13.05.07 | |
7 | // | |
8 | // Class to reconstruct and store the decayed particle parameters. | |
9 | // The method is described in CBM-SOFT note 2007-003, | |
10 | // ``Reconstruction of decayed particles based on the Kalman filter'', | |
11 | // http://www.gsi.de/documents/DOC-2007-May-14-1.pdf | |
12 | // | |
13 | // This class describes general mathematics which is used by AliKFParticle class | |
14 | // | |
15 | // -= Copyright © ALICE HLT Group =- | |
16 | //_________________________________________________________________________________ | |
17 | ||
18 | ||
19 | ||
20 | #ifndef ALIKFPARTICLEBASE_H | |
21 | #define ALIKFPARTICLEBASE_H | |
22 | ||
23 | #include "TObject.h" | |
24 | ||
25 | class AliKFParticleBase :public TObject { | |
26 | ||
27 | public: | |
28 | ||
29 | //* | |
30 | //* ABSTRACT METHODS HAVE TO BE DEFINED IN USER CLASS | |
31 | //* | |
32 | ||
33 | //* Virtual method to access the magnetic field | |
34 | ||
35 | virtual void GetFieldValue(const Double_t xyz[], Double_t B[]) const = 0; | |
36 | ||
37 | //* Virtual methods needed for particle transportation | |
38 | //* One can use particular implementations for collider (only Bz component) | |
39 | //* geometry and for fixed-target (CBM-like) geometry which are provided below | |
40 | //* in TRANSPORT section | |
41 | ||
42 | //* Get dS to xyz[] space point | |
43 | ||
44 | virtual Double_t GetDStoPoint( const Double_t xyz[] ) const = 0; | |
45 | ||
46 | //* Get dS to other particle p (dSp for particle p also returned) | |
47 | ||
48 | virtual void GetDStoParticle( const AliKFParticleBase &p, | |
49 | Double_t &DS, Double_t &DSp ) const = 0; | |
50 | ||
51 | //* Transport on dS value along trajectory, output to P,C | |
52 | ||
53 | virtual void Transport( Double_t dS, Double_t P[], Double_t C[] ) const = 0; | |
54 | ||
55 | ||
56 | ||
57 | //* | |
58 | //* INITIALIZATION | |
59 | //* | |
60 | ||
61 | //* Constructor | |
62 | ||
63 | AliKFParticleBase(); | |
64 | ||
65 | //* Destructor | |
66 | ||
e7b09c95 | 67 | virtual ~AliKFParticleBase() { ; } |
68 | ||
69 | //* Initialisation from "cartesian" coordinates ( X Y Z Px Py Pz ) | |
70 | //* Parameters, covariance matrix, charge, and mass hypothesis should be provided | |
71 | ||
72 | void Initialize( const Double_t Param[], const Double_t Cov[], Int_t Charge, Double_t Mass ); | |
f826d409 | 73 | |
74 | //* Initialise covariance matrix and set current parameters to 0.0 | |
75 | ||
76 | void Initialize(); | |
77 | ||
78 | //* Set decay vertex parameters for linearisation | |
79 | ||
80 | void SetVtxGuess( Double_t x, Double_t y, Double_t z ); | |
81 | ||
82 | //* | |
83 | //* ACCESSORS | |
84 | //* | |
85 | ||
86 | //* Simple accessors | |
87 | ||
88 | Double_t GetX () const { return fP[0]; } | |
89 | Double_t GetY () const { return fP[1]; } | |
90 | Double_t GetZ () const { return fP[2]; } | |
91 | Double_t GetPx () const { return fP[3]; } | |
92 | Double_t GetPy () const { return fP[4]; } | |
93 | Double_t GetPz () const { return fP[5]; } | |
94 | Double_t GetE () const { return fP[6]; } | |
95 | Double_t GetS () const { return fP[7]; } | |
96 | Int_t GetQ () const { return fQ; } | |
97 | Double_t GetChi2 () const { return fChi2; } | |
98 | Int_t GetNDF () const { return fNDF; } | |
99 | ||
100 | Double_t GetParameter ( Int_t i ) const { return fP[i]; } | |
101 | Double_t GetCovariance( Int_t i ) const { return fC[i]; } | |
102 | Double_t GetCovariance( Int_t i, Int_t j ) const { return fC[IJ(i,j)]; } | |
103 | ||
104 | //* Accessors with calculations( &value, &estimated sigma ) | |
105 | //* error flag returned (0 means no error during calculations) | |
106 | ||
706952f5 | 107 | Int_t GetMomentum ( Double_t &P, Double_t &SigmaP ) const ; |
108 | Int_t GetPt ( Double_t &Pt, Double_t &SigmaPt ) const ; | |
109 | Int_t GetEta ( Double_t &Eta, Double_t &SigmaEta ) const ; | |
110 | Int_t GetPhi ( Double_t &Phi, Double_t &SigmaPhi ) const ; | |
111 | Int_t GetMass ( Double_t &M, Double_t &SigmaM ) const ; | |
112 | Int_t GetDecayLength ( Double_t &L, Double_t &SigmaL ) const ; | |
446ce366 | 113 | Int_t GetDecayLengthXY ( Double_t &L, Double_t &SigmaL ) const ; |
706952f5 | 114 | Int_t GetLifeTime ( Double_t &T, Double_t &SigmaT ) const ; |
115 | Int_t GetR ( Double_t &R, Double_t &SigmaR ) const ; | |
f826d409 | 116 | |
117 | //* | |
118 | //* MODIFIERS | |
119 | //* | |
120 | ||
121 | Double_t & X () { return fP[0]; } | |
122 | Double_t & Y () { return fP[1]; } | |
123 | Double_t & Z () { return fP[2]; } | |
124 | Double_t & Px () { return fP[3]; } | |
125 | Double_t & Py () { return fP[4]; } | |
126 | Double_t & Pz () { return fP[5]; } | |
127 | Double_t & E () { return fP[6]; } | |
128 | Double_t & S () { return fP[7]; } | |
129 | Int_t & Q () { return fQ; } | |
130 | Double_t & Chi2 () { return fChi2; } | |
131 | Int_t & NDF () { return fNDF; } | |
132 | ||
133 | Double_t & Parameter ( Int_t i ) { return fP[i]; } | |
134 | Double_t & Covariance( Int_t i ) { return fC[i]; } | |
135 | Double_t & Covariance( Int_t i, Int_t j ) { return fC[IJ(i,j)]; } | |
136 | ||
137 | ||
138 | //* | |
139 | //* CONSTRUCTION OF THE PARTICLE BY ITS DAUGHTERS AND MOTHER | |
140 | //* USING THE KALMAN FILTER METHOD | |
141 | //* | |
142 | ||
143 | ||
144 | //* Simple way to add daughter ex. D0+= Pion; | |
145 | ||
146 | void operator +=( const AliKFParticleBase &Daughter ); | |
147 | ||
148 | //* Add daughter track to the particle | |
149 | ||
150 | void AddDaughter( const AliKFParticleBase &Daughter ); | |
151 | ||
152 | //* Set production vertex | |
153 | ||
154 | void SetProductionVertex( const AliKFParticleBase &Vtx ); | |
155 | ||
e7b09c95 | 156 | //* Set mass constraint |
f826d409 | 157 | |
e7b09c95 | 158 | void SetMassConstraint( Double_t Mass, Double_t SigmaMass = 0 ); |
f826d409 | 159 | |
e7b09c95 | 160 | //* Set no decay length for resonances |
161 | ||
162 | void SetNoDecayLength(); | |
163 | ||
164 | ||
f826d409 | 165 | //* Everything in one go |
166 | ||
167 | void Construct( const AliKFParticleBase *vDaughters[], Int_t NDaughters, | |
706952f5 | 168 | const AliKFParticleBase *ProdVtx=0, Double_t Mass=-1, Bool_t IsConstrained=0 ); |
f826d409 | 169 | |
170 | ||
171 | //* | |
172 | //* TRANSPORT | |
173 | //* | |
174 | //* ( main transportation parameter is S = SignedPath/Momentum ) | |
175 | //* ( parameters of decay & production vertices are stored locally ) | |
176 | //* | |
177 | ||
178 | ||
179 | //* Transport the particle to its decay vertex | |
180 | ||
181 | void TransportToDecayVertex(); | |
182 | ||
183 | //* Transport the particle to its production vertex | |
184 | ||
185 | void TransportToProductionVertex(); | |
186 | ||
187 | //* Transport the particle on dS parameter (SignedPath/Momentum) | |
188 | ||
189 | void TransportToDS( Double_t dS ); | |
190 | ||
191 | //* Particular extrapolators one can use | |
192 | ||
193 | Double_t GetDStoPointBz( Double_t Bz, const Double_t xyz[] ) const; | |
194 | ||
195 | void GetDStoParticleBz( Double_t Bz, const AliKFParticleBase &p, | |
196 | Double_t &dS, Double_t &dS1 ) const ; | |
197 | ||
198 | // Double_t GetDStoPointCBM( const Double_t xyz[] ) const; | |
199 | ||
200 | void TransportBz( Double_t Bz, Double_t dS, Double_t P[], Double_t C[] ) const; | |
201 | void TransportCBM( Double_t dS, Double_t P[], Double_t C[] ) const; | |
202 | ||
203 | ||
204 | //* | |
205 | //* OTHER UTILITIES | |
206 | //* | |
207 | ||
208 | //* Calculate distance from another object [cm] | |
209 | ||
210 | Double_t GetDistanceFromVertex( const Double_t vtx[] ) const; | |
211 | Double_t GetDistanceFromVertex( const AliKFParticleBase &Vtx ) const; | |
616ffc76 | 212 | Double_t GetDistanceFromParticle( const AliKFParticleBase &p ) const; |
f826d409 | 213 | |
214 | //* Calculate sqrt(Chi2/ndf) deviation from vertex | |
215 | //* v = [xyz], Cv=[Cxx,Cxy,Cyy,Cxz,Cyz,Czz]-covariance matrix | |
216 | ||
217 | Double_t GetDeviationFromVertex( const Double_t v[], | |
218 | const Double_t Cv[]=0 ) const; | |
219 | Double_t GetDeviationFromVertex( const AliKFParticleBase &Vtx ) const; | |
616ffc76 | 220 | Double_t GetDeviationFromParticle( const AliKFParticleBase &p ) const; |
f826d409 | 221 | |
222 | //* Subtract the particle from the vertex | |
223 | ||
de0d0ceb | 224 | void SubtractFromVertex( AliKFParticleBase &Vtx ) const; |
225 | ||
a65041d0 | 226 | //* Special method for creating gammas |
227 | ||
228 | void ConstructGammaBz( const AliKFParticleBase &daughter1, | |
229 | const AliKFParticleBase &daughter2, double Bz ); | |
230 | ||
f826d409 | 231 | protected: |
232 | ||
233 | static Int_t IJ( Int_t i, Int_t j ){ | |
234 | return ( j<=i ) ? i*(i+1)/2+j :j*(j+1)/2+i; | |
235 | } | |
236 | ||
237 | Double_t & Cij( Int_t i, Int_t j ){ return fC[IJ(i,j)]; } | |
238 | ||
239 | void Convert( bool ToProduction ); | |
240 | void TransportLine( Double_t S, Double_t P[], Double_t C[] ) const ; | |
241 | Double_t GetDStoPointLine( const Double_t xyz[] ) const; | |
242 | ||
a65041d0 | 243 | static Bool_t InvertSym3( const Double_t A[], Double_t Ainv[] ); |
244 | ||
f826d409 | 245 | static void MultQSQt( const Double_t Q[], const Double_t S[], |
246 | Double_t SOut[] ); | |
247 | ||
706952f5 | 248 | static Double_t GetSCorrection( const Double_t Part[], const Double_t XYZ[] ); |
249 | ||
616ffc76 | 250 | void GetMeasurement( const Double_t XYZ[], Double_t m[], Double_t V[] ) const ; |
f826d409 | 251 | |
252 | Double_t fP[8]; //* Main particle parameters {X,Y,Z,Px,Py,Pz,E,S[=DecayLength/P]} | |
253 | Double_t fC[36]; //* Low-triangle covariance matrix of fP | |
254 | Int_t fQ; //* Particle charge | |
255 | Int_t fNDF; //* Number of degrees of freedom | |
256 | Double_t fChi2; //* Chi^2 | |
257 | ||
258 | Double_t fSFromDecay; //* Distance from decay vertex to current position | |
259 | ||
260 | Bool_t fAtProductionVertex; //* Flag shows that the particle error along | |
261 | //* its trajectory is taken from production vertex | |
262 | ||
263 | Double_t fVtxGuess[3]; //* Guess for the position of the decay vertex | |
264 | //* ( used for linearisation of equations ) | |
265 | ||
266 | Bool_t fIsLinearized; //* Flag shows that the guess is present | |
267 | ||
268 | ClassDef( AliKFParticleBase, 1 ); | |
269 | }; | |
270 | ||
271 | #endif |