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Common track parametrization in the barrel detectors (Yu.Belikov)
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15dd636f 1/**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
3 * *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
6 * *
7 * Permission to use, copy, modify and distribute this software and its *
8 * documentation strictly for non-commercial purposes is hereby granted *
9 * without fee, provided that the above copyright notice appears in all *
10 * copies and that both the copyright notice and this permission notice *
11 * appear in the supporting documentation. The authors make no claims *
12 * about the suitability of this software for any purpose. It is *
13 * provided "as is" without express or implied warranty. *
14 **************************************************************************/
15
16//-------------------------------------------------------------------------
17// Implementation of the ITS track class
18//
19// Origin: Marian Ivanov, CERN, Marian.Ivanov@cern.ch
20// dEdx analysis by: Boris Batyunya, JINR, Boris.Batiounia@cern.ch
21//-------------------------------------------------------------------------
22
23#include <TMatrixD.h>
24
25#include <TMath.h>
26
27#include "AliCluster.h"
28#include "AliESDtrack.h"
29#include "AliITStrackMI.h"
30
31ClassImp(AliITStrackMI)
32
33const Int_t kWARN=5;
34
35//____________________________________________________________________________
36AliITStrackMI::AliITStrackMI():AliITStrackV2(),
37 fNUsed(0),
38 fNSkipped(0),
39 fNDeadZone(0),
40 fDeadZoneProbability(0),
41 fReconstructed(kFALSE),
42 fConstrain(kFALSE)
43{
44 for(Int_t i=0; i<kMaxLayer; i++) fClIndex[i]=-1;
45 for(Int_t i=0; i<6; i++) { fNy[i]=0; fNz[i]=0; fNormQ[i]=0; fNormChi2[i]=1000;}
46 for(Int_t i=0; i<12; i++) {fDy[i]=0; fDz[i]=0; fSigmaY[i]=0; fSigmaZ[i]=0; fChi2MIP[i]=0;}
47 fD[0]=0; fD[1]=0;
48 fExpQ=40;
49 fdEdxMismatch=0;
50 fChi22=0;
628e7bb0 51 fGoldV0 = kFALSE;
15dd636f 52}
53
54//____________________________________________________________________________
55AliITStrackMI::AliITStrackMI(AliESDtrack& t,Bool_t c) throw (const Char_t *) :
56AliITStrackV2(t,c) {
57 //------------------------------------------------------------------
58 // Conversion ESD track -> ITS track.
59 // If c==kTRUE, create the ITS track out of the constrained params.
60 //------------------------------------------------------------------
61 fNUsed = 0;
62 fReconstructed = kFALSE;
63 fNSkipped =0;
64 fNDeadZone = 0;
65 fDeadZoneProbability = 0;
66 for(Int_t i=0; i<6; i++) {fClIndex[i]=-1; fNy[i]=0; fNz[i]=0; fNormQ[i]=0; fNormChi2[i]=1000;}
67 for(Int_t i=0; i<12; i++) {fDy[i]=0; fDz[i]=0; fSigmaY[i]=0; fSigmaZ[i]=0;fChi2MIP[i]=0;}
68 fD[0]=0; fD[1]=0;
69 fExpQ=40;
70 fConstrain = kFALSE;
71 fdEdxMismatch=0;
72 fChi22 =0;
628e7bb0 73 fGoldV0 = kFALSE;
15dd636f 74 //if (!Invariant()) throw "AliITStrackV2: conversion failed !\n";
75
76}
77
78void AliITStrackMI::UpdateESDtrack(ULong_t flags) {
79 fESDtrack->UpdateTrackParams(this,flags);
15e85efa 80 //if (flags == AliESDtrack::kITSin) fESDtrack->SetITSChi2MIP(fChi2MIP);
15dd636f 81}
82
83//____________________________________________________________________________
84AliITStrackMI::AliITStrackMI(const AliITStrackMI& t) : AliITStrackV2(t) {
85 //------------------------------------------------------------------
86 //Copy constructor
87 //------------------------------------------------------------------
88 fNUsed = t.fNUsed;
89 fReconstructed = t.fReconstructed;
90 fNSkipped = t.fNSkipped;
91 fNDeadZone = t.fNDeadZone;
92 fDeadZoneProbability = t.fDeadZoneProbability;
93 fLab = t.fLab;
94 fFakeRatio = t.fFakeRatio;
95 fdEdxMismatch = t.fdEdxMismatch;
96 fChi22 = t.fChi22;
628e7bb0 97 fGoldV0 = t.fGoldV0;;
15dd636f 98
99 fD[0]=t.fD[0]; fD[1]=t.fD[1];
628e7bb0 100 fDnorm[0] = t.fDnorm[0]; fDnorm[1]=t.fDnorm[1];
15dd636f 101 fExpQ= t.fExpQ;
102 for(Int_t i=0; i<6; i++) {
103 fClIndex[i]= t.fClIndex[i]; fNy[i]=t.fNy[i]; fNz[i]=t.fNz[i]; fNormQ[i]=t.fNormQ[i]; fNormChi2[i] = t.fNormChi2[i];
104 }
105 for(Int_t i=0; i<12; i++) {fDy[i]=t.fDy[i]; fDz[i]=t.fDz[i];
106 fSigmaY[i]=t.fSigmaY[i]; fSigmaZ[i]=t.fSigmaZ[i];fChi2MIP[i]=t.fChi2MIP[i];}
107 fConstrain = t.fConstrain;
108 //memcpy(fDy,t.fDy,6*sizeof(Float_t));
109 //memcpy(fDz,t.fDz,6*sizeof(Float_t));
110 //memcpy(fSigmaY,t.fSigmaY,6*sizeof(Float_t));
111 //memcpy(fSigmaZ,t.fSigmaZ,6*sizeof(Float_t));
112 //memcpy(fChi2MIP,t.fChi2MIP,12*sizeof(Float_t));
113}
114
115//_____________________________________________________________________________
116Int_t AliITStrackMI::Compare(const TObject *o) const {
117 //-----------------------------------------------------------------
118 // This function compares tracks according to the their curvature
119 //-----------------------------------------------------------------
120 AliITStrackMI *t=(AliITStrackMI*)o;
121 //Double_t co=TMath::Abs(t->Get1Pt());
122 //Double_t c =TMath::Abs(Get1Pt());
123 Double_t co=t->GetSigmaY2()*t->GetSigmaZ2()*(0.5+TMath::Sqrt(0.5*t->fD[0]*t->fD[0]+t->fD[1]*t->fD[1]));
124 Double_t c =GetSigmaY2()*GetSigmaZ2()*(0.5+TMath::Sqrt(0.5*fD[0]*fD[0]+fD[1]*fD[1]));
125 if (c>co) return 1;
126 else if (c<co) return -1;
127 return 0;
128}
129
130
131Double_t AliITStrackMI::GetPredictedChi2MI(Double_t cy, Double_t cz, Double_t cerry, Double_t cerrz) const
132{
133 //-----------------------------------------------------------------
134 // This function calculates a predicted chi2 increment.
135 //-----------------------------------------------------------------
6c94f330 136 Double_t p[2]={cy, cz};
137 Double_t cov[3]={cerry*cerry, 0., cerrz*cerrz};
138 return AliExternalTrackParam::GetPredictedChi2(p,cov);
15dd636f 139}
140
141//____________________________________________________________________________
142Int_t AliITStrackMI::CorrectForMaterial(Double_t d, Double_t x0) {
143 //------------------------------------------------------------------
144 //This function corrects the track parameters for crossed material
145 //------------------------------------------------------------------
6c94f330 146 //d=x0=0.;
147
148 Double_t p2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt());
15dd636f 149 Double_t et = p2 + GetMass()*GetMass();
150 Double_t beta2=p2/et;
151 et = sqrt(et);
6c94f330 152 d*=TMath::Sqrt((1.+ GetTgl()*GetTgl())/(1.- GetSnp()*GetSnp()));
15dd636f 153
154 //Multiple scattering******************
155 if (d!=0) {
156 Double_t theta2=14.1*14.1/(beta2*p2*1e6)*TMath::Abs(d);
157 //Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*TMath::Abs(d)*9.36*2.33;
6c94f330 158 Cov(5) += theta2*(1.- GetSnp()*GetSnp())*(1. + GetTgl()*GetTgl());
159 Cov(9) += theta2*(1. + GetTgl()*GetTgl())*(1. + GetTgl()*GetTgl());
160 Cov(13)+= theta2*GetTgl()*Get1Pt()*(1. + GetTgl()*GetTgl());
161 Cov(14)+= theta2*GetTgl()*Get1Pt()*GetTgl()*Get1Pt();
15dd636f 162 }
163
164 //Energy losses************************
165 if (x0!=0.) {
166 d*=x0;
167 // Double_t dE=0.153e-3/beta2*(log(5940*beta2/(1-beta2)) - beta2)*d;
168 //Double_t dE=0;
169 Double_t dE = 0.265*0.153e-3*(39.2-55.6*beta2+28.7*beta2*beta2+27.41/beta2)*d;
6c94f330 170 //if (beta2/(1-beta2)>3.5*3.5){
171 // dE=0.153e-3/beta2*(log(3.5*5940)+0.5*log(beta2/(1-beta2)) - beta2)*d;
172 //}
173 //else{
174 // dE=0.153e-3/beta2*(log(5940*beta2/(1-beta2)) - beta2)*d;
175 // dE+=0.06e-3/(beta2*beta2)*d;
176 //}
177
178 Par(4)*=(1.- et/p2*dE);
179 Double_t delta44 = (dE*Get1Pt()*et/p2);
15dd636f 180 delta44*=delta44;
6c94f330 181 Cov(14)+= delta44/400.;
15dd636f 182 }
183
184 if (!Invariant()) return 0;
185
186 return 1;
187}
188
189//____________________________________________________________________________
6c94f330 190Bool_t AliITStrackMI::UpdateMI(Double_t cy, Double_t cz, Double_t cerry, Double_t cerrz, Double_t chi2, Int_t index) {
15dd636f 191 //------------------------------------------------------------------
192 //This function updates track parameters
193 //------------------------------------------------------------------
6c94f330 194 Double_t dy=cy - GetY(), dz=cz - GetZ();
15dd636f 195 Int_t layer = (index & 0xf0000000) >> 28;
196 fDy[layer] = dy;
197 fDz[layer] = dz;
6c94f330 198 fSigmaY[layer] = TMath::Sqrt(cerry*cerry+GetSigmaY2());
199 fSigmaZ[layer] = TMath::Sqrt(cerrz*cerrz+GetSigmaZ2());
15dd636f 200
6c94f330 201 Double_t p[2]={cy, cz};
202 Double_t cov[3]={cerry*cerry, 0., cerrz*cerrz};
203 if (!AliExternalTrackParam::Update(p,cov)) return kFALSE;
15dd636f 204
205 if (!Invariant()) {
6c94f330 206 AliWarning("Wrong invariant !");
207 return kFALSE;
15dd636f 208 }
209
210 if (chi2<0) return 1;
211 Int_t n=GetNumberOfClusters();
212 fIndex[n]=index;
213 SetNumberOfClusters(n+1);
214 SetChi2(GetChi2()+chi2);
215
6c94f330 216 return kTRUE;
15dd636f 217}
218
219Int_t AliITStrackMI::GetProlongationFast(Double_t alp, Double_t xk,Double_t &y, Double_t &z)
220{
221 //-----------------------------------------------------------------------------
222 //get fast prolongation
223 //-----------------------------------------------------------------------------
6c94f330 224 Double_t ca=TMath::Cos(alp-GetAlpha()), sa=TMath::Sin(alp-GetAlpha());
225 Double_t cf=TMath::Sqrt(1.- GetSnp()*GetSnp());
15dd636f 226 // **** rotation **********************
6c94f330 227 y= -GetX()*sa + GetY()*ca;
15dd636f 228 // **** translation ******************
6c94f330 229 Double_t dx = xk- GetX()*ca - GetY()*sa;
230 Double_t f1=GetSnp()*ca - cf*sa, f2=f1 + GetC()*dx;
15dd636f 231 if (TMath::Abs(f2) >= 0.9999) {
232 return 0;
233 }
234 Double_t r1=TMath::Sqrt(1.- f1*f1), r2=TMath::Sqrt(1.- f2*f2);
235 y += dx*(f1+f2)/(r1+r2);
6c94f330 236 z = GetZ()+dx*(f1+f2)/(f1*r2 + f2*r1)*GetTgl();
15dd636f 237 return 1;
238}
239
628e7bb0 240
241Bool_t AliITStrackMI::IsGoldPrimary()
242{
243 //
244 // Indicates gold pimary track
245 //
246 Bool_t isGold=kTRUE;
247 if (!fConstrain) return kFALSE; //
248 if (fNDeadZone+fNDeadZone<5.5) isGold = kFALSE; // short track
249 //
250 if (fChi2/Float_t(fN)>2.){
251 if (fChi2MIP[0]+fNUsed>3.5) isGold = kFALSE;
252 }
253 if (fChi2MIP[2]>4.5) isGold = kFALSE; //back propagation chi2
254 //
255 if (fDnorm[0]>0&&fDnorm[1]>0){
256 const Float_t distcut2 =2.5*2.5; //normalize distance cut
257 Float_t dist2 = fD[0]*fD[0]/(fDnorm[0]*fDnorm[0])+fD[1]*fD[1]/(fDnorm[1]*fDnorm[1]); //normalize distance to the vertex (pools)
258 if (dist2>distcut2) isGold = kFALSE;
259 }
260 return isGold;
261}