1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
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 **************************************************************************/
16 //-------------------------------------------------------------------------
17 // Implementation of the ITS track class
19 // Origin: Marian Ivanov, CERN, Marian.Ivanov@cern.ch
20 // dEdx analysis by: Boris Batyunya, JINR, Boris.Batiounia@cern.ch
21 //-------------------------------------------------------------------------
29 #include "AliCluster.h"
30 #include "AliESDtrack.h"
31 #include "AliITSgeomTGeo.h"
32 #include "AliITStrackMI.h"
34 ClassImp(AliITStrackMI)
38 //____________________________________________________________________________
39 AliITStrackMI::AliITStrackMI():AliITStrackV2(),
43 fDeadZoneProbability(0),
44 fReconstructed(kFALSE),
52 for(Int_t i=0; i<AliITSgeomTGeo::GetNLayers(); i++) fClIndex[i]=-1;
53 for(Int_t i=0; i<6; i++) { fNy[i]=0; fNz[i]=0; fNormQ[i]=0; fNormChi2[i]=1000;}
54 for(Int_t i=0; i<12; i++) {fDy[i]=0; fDz[i]=0; fSigmaY[i]=0; fSigmaZ[i]=0; fChi2MIP[i]=0;}
56 fDnorm[0]=0; fDnorm[1]=0;
59 //____________________________________________________________________________
60 AliITStrackMI::AliITStrackMI(AliESDtrack& t,Bool_t c) throw (const Char_t *) :
65 fDeadZoneProbability(0),
66 fReconstructed(kFALSE),
72 //------------------------------------------------------------------
73 // Conversion ESD track -> ITS track.
74 // If c==kTRUE, create the ITS track out of the constrained params.
75 //------------------------------------------------------------------
76 for(Int_t i=0; i<6; i++) {fClIndex[i]=-1; fNy[i]=0; fNz[i]=0; fNormQ[i]=0; fNormChi2[i]=1000;}
77 for(Int_t i=0; i<12; i++) {fDy[i]=0; fDz[i]=0; fSigmaY[i]=0; fSigmaZ[i]=0;fChi2MIP[i]=0;}
79 fDnorm[0]=0; fDnorm[1]=0;
80 //if (!Invariant()) throw "AliITStrackV2: conversion failed !\n";
84 //____________________________________________________________________________
85 AliITStrackMI::AliITStrackMI(const AliITStrackMI& t) : AliITStrackV2(t),
87 fNSkipped(t.fNSkipped),
88 fNDeadZone(t.fNDeadZone),
89 fDeadZoneProbability(t.fDeadZoneProbability),
90 fReconstructed(t.fReconstructed),
93 fdEdxMismatch(t.fdEdxMismatch),
94 fConstrain(t.fConstrain),
96 //------------------------------------------------------------------
98 //------------------------------------------------------------------
100 fFakeRatio = t.fFakeRatio;
102 fD[0]=t.fD[0]; fD[1]=t.fD[1];
103 fDnorm[0] = t.fDnorm[0]; fDnorm[1]=t.fDnorm[1];
104 for(Int_t i=0; i<6; i++) {
105 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];
107 for(Int_t i=0; i<12; i++) {fDy[i]=t.fDy[i]; fDz[i]=t.fDz[i];
108 fSigmaY[i]=t.fSigmaY[i]; fSigmaZ[i]=t.fSigmaZ[i];fChi2MIP[i]=t.fChi2MIP[i];}
109 //memcpy(fDy,t.fDy,6*sizeof(Float_t));
110 //memcpy(fDz,t.fDz,6*sizeof(Float_t));
111 //memcpy(fSigmaY,t.fSigmaY,6*sizeof(Float_t));
112 //memcpy(fSigmaZ,t.fSigmaZ,6*sizeof(Float_t));
113 //memcpy(fChi2MIP,t.fChi2MIP,12*sizeof(Float_t));
116 //_____________________________________________________________________________
117 Int_t AliITStrackMI::Compare(const TObject *o) const {
118 //-----------------------------------------------------------------
119 // This function compares tracks according to the their curvature
120 //-----------------------------------------------------------------
121 AliITStrackMI *t=(AliITStrackMI*)o;
122 //Double_t co=TMath::Abs(t->Get1Pt());
123 //Double_t c =TMath::Abs(Get1Pt());
124 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]));
125 Double_t c =GetSigmaY2()*GetSigmaZ2()*(0.5+TMath::Sqrt(0.5*fD[0]*fD[0]+fD[1]*fD[1]));
127 else if (c<co) return -1;
132 Double_t AliITStrackMI::GetPredictedChi2MI(Double_t cy, Double_t cz, Double_t cerry, Double_t cerrz) const
134 //-----------------------------------------------------------------
135 // This function calculates a predicted chi2 increment.
136 //-----------------------------------------------------------------
137 Double_t p[2]={cy, cz};
138 Double_t cov[3]={cerry*cerry, 0., cerrz*cerrz};
139 return AliExternalTrackParam::GetPredictedChi2(p,cov);
142 //____________________________________________________________________________
143 Int_t AliITStrackMI::CorrectForMaterial(Double_t d, Double_t x0) {
144 //------------------------------------------------------------------
145 //This function corrects the track parameters for crossed material
146 //------------------------------------------------------------------
149 Double_t p2=(1.+ GetTgl()*GetTgl())/(GetSigned1Pt()*GetSigned1Pt());
150 Double_t et = p2 + GetMass()*GetMass();
151 Double_t beta2=p2/et;
153 d*=TMath::Sqrt((1.+ GetTgl()*GetTgl())/(1.- GetSnp()*GetSnp()));
155 //Multiple scattering******************
157 Double_t theta2=14.1*14.1/(beta2*p2*1e6)*TMath::Abs(d);
158 //Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*TMath::Abs(d)*9.36*2.33;
159 Cov(5) += theta2*(1.- GetSnp()*GetSnp())*(1. + GetTgl()*GetTgl());
160 Cov(9) += theta2*(1. + GetTgl()*GetTgl())*(1. + GetTgl()*GetTgl());
161 Cov(13)+= theta2*GetTgl()*GetSigned1Pt()*(1. + GetTgl()*GetTgl());
162 Cov(14)+= theta2*GetTgl()*GetSigned1Pt()*GetTgl()*GetSigned1Pt();
165 //Energy losses************************
168 // Double_t dE=0.153e-3/beta2*(log(5940*beta2/(1-beta2)) - beta2)*d;
170 Double_t dE = 0.265*0.153e-3*(39.2-55.6*beta2+28.7*beta2*beta2+27.41/beta2)*d;
171 //if (beta2/(1-beta2)>3.5*3.5){
172 // dE=0.153e-3/beta2*(log(3.5*5940)+0.5*log(beta2/(1-beta2)) - beta2)*d;
175 // dE=0.153e-3/beta2*(log(5940*beta2/(1-beta2)) - beta2)*d;
176 // dE+=0.06e-3/(beta2*beta2)*d;
179 Par(4)*=(1.- et/p2*dE);
180 Double_t delta44 = (dE*GetSigned1Pt()*et/p2);
182 Cov(14)+= delta44/400.;
185 if (!Invariant()) return 0;
190 //____________________________________________________________________________
191 Bool_t AliITStrackMI::UpdateMI(const AliCluster *c, Double_t chi2, Int_t index) {
192 //------------------------------------------------------------------
193 //This function updates track parameters
194 //------------------------------------------------------------------
195 Double_t dy=c->GetY() - GetY(), dz=c->GetZ() - GetZ();
196 Int_t layer = (index & 0xf0000000) >> 28;
199 fSigmaY[layer] = TMath::Sqrt(c->GetSigmaY2()+GetSigmaY2());
200 fSigmaZ[layer] = TMath::Sqrt(c->GetSigmaZ2()+GetSigmaZ2());
202 return Update(c,chi2,index);
205 Int_t AliITStrackMI::GetProlongationFast(Double_t alp, Double_t xk,Double_t &y, Double_t &z)
207 //-----------------------------------------------------------------------------
208 //get fast prolongation
209 //-----------------------------------------------------------------------------
210 Double_t ca=TMath::Cos(alp-GetAlpha()), sa=TMath::Sin(alp-GetAlpha());
211 Double_t cf=TMath::Sqrt(1.- GetSnp()*GetSnp());
212 // **** rotation **********************
213 y= -GetX()*sa + GetY()*ca;
214 // **** translation ******************
215 Double_t dx = xk- GetX()*ca - GetY()*sa;
216 Double_t f1=GetSnp()*ca - cf*sa, f2=f1 + GetC()*dx;
217 if (TMath::Abs(f2) >= 0.9999) {
220 Double_t r1=TMath::Sqrt(1.- f1*f1), r2=TMath::Sqrt(1.- f2*f2);
221 y += dx*(f1+f2)/(r1+r2);
222 z = GetZ()+dx*(f1+f2)/(f1*r2 + f2*r1)*GetTgl();
227 Bool_t AliITStrackMI::IsGoldPrimary()
230 // Indicates gold pimary track
233 if (!fConstrain) return kFALSE; //
234 if (fNDeadZone+fNDeadZone<5.5) isGold = kFALSE; // short track
236 if (fChi2/Float_t(fN)>2.){
237 if (fChi2MIP[0]+fNUsed>3.5) isGold = kFALSE;
239 if (fChi2MIP[2]>4.5) isGold = kFALSE; //back propagation chi2
241 if (fDnorm[0]>0&&fDnorm[1]>0){
242 const Float_t distcut2 =2.5*2.5; //normalize distance cut
243 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)
244 if (dist2>distcut2) isGold = kFALSE;