Bug fix. Removed delete statement
[u/mrichter/AliRoot.git] / STEER / AliCascadeVertexer.cxx
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c7bafca9 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. *
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8 * documentation strictly for non-commercial purposes is hereby granted *
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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 cascade vertexer class
18// Reads V0s and tracks, writes out cascade vertices
19// Fills the ESD with the cascades
20// Origin: Christian Kuhn, IReS, Strasbourg, christian.kuhn@ires.in2p3.fr
21//-------------------------------------------------------------------------
c028b974 22
23//modified by R. Vernet 30/6/2006 : daughter label
24//modified by R. Vernet 3/7/2006 : causality
5e4ff34d 25//modified by I. Belikov 24/11/2006 : static setter for the default cuts
c028b974 26
af885e0f 27#include "AliESDEvent.h"
c7bafca9 28#include "AliESDcascade.h"
29#include "AliCascadeVertexer.h"
30
31ClassImp(AliCascadeVertexer)
32
5e4ff34d 33//A set of loose cuts
34Double_t
e82eee7e 35 AliCascadeVertexer::fgChi2max=33.; //maximal allowed chi2
5e4ff34d 36Double_t
e82eee7e 37 AliCascadeVertexer::fgDV0min=0.05; //min V0 impact parameter
5e4ff34d 38Double_t
e82eee7e 39 AliCascadeVertexer::fgMassWin=0.01; //"window" around the Lambda mass
5e4ff34d 40Double_t
e82eee7e 41 AliCascadeVertexer::fgDBachMin=0.035; //min bachelor impact parameter
5e4ff34d 42Double_t
e82eee7e 43 AliCascadeVertexer::fgDCAmax=0.10; //max DCA between the V0 and the track
5e4ff34d 44Double_t
85f0f56e 45 AliCascadeVertexer::fgCPAmin=0.9985; //min cosine of the cascade pointing angle
5e4ff34d 46Double_t
e82eee7e 47 AliCascadeVertexer::fgRmin=0.2; //min radius of the fiducial volume
5e4ff34d 48Double_t
e82eee7e 49 AliCascadeVertexer::fgRmax=100.; //max radius of the fiducial volume
5e4ff34d 50
51
af885e0f 52Int_t AliCascadeVertexer::V0sTracks2CascadeVertices(AliESDEvent *event) {
c7bafca9 53 //--------------------------------------------------------------------
54 // This function reconstructs cascade vertices
55 // Adapted to the ESD by I.Belikov (Jouri.Belikov@cern.ch)
56 //--------------------------------------------------------------------
81f174b6 57 const AliESDVertex *vtxT3D=event->GetPrimaryVertex();
58
69c49ae1 59 Double_t xPrimaryVertex=vtxT3D->GetXv();
60 Double_t yPrimaryVertex=vtxT3D->GetYv();
61 Double_t zPrimaryVertex=vtxT3D->GetZv();
5e4ff34d 62
c7bafca9 63 Double_t b=event->GetMagneticField();
64 Int_t nV0=(Int_t)event->GetNumberOfV0s();
c028b974 65
66 //stores relevant V0s in an array
c7bafca9 67 TObjArray vtcs(nV0);
68 Int_t i;
69 for (i=0; i<nV0; i++) {
70 AliESDv0 *v=event->GetV0(i);
d6a49f20 71 if (v->GetOnFlyStatus()) continue;
81f174b6 72 if (v->GetD(xPrimaryVertex,yPrimaryVertex,zPrimaryVertex)<fDV0min) continue;
c7bafca9 73 vtcs.AddLast(v);
74 }
75 nV0=vtcs.GetEntriesFast();
76
c028b974 77 // stores relevant tracks in another array
c7bafca9 78 Int_t nentr=(Int_t)event->GetNumberOfTracks();
79 TArrayI trk(nentr); Int_t ntr=0;
80 for (i=0; i<nentr; i++) {
81 AliESDtrack *esdtr=event->GetTrack(i);
85f0f56e 82 ULong_t status=esdtr->GetStatus();
c7bafca9 83
84 if ((status&AliESDtrack::kITSrefit)==0)
85f0f56e 85 if ((status&AliESDtrack::kTPCrefit)==0) continue;
c7bafca9 86
81f174b6 87 if (TMath::Abs(esdtr->GetD(xPrimaryVertex,yPrimaryVertex,b))<fDBachMin) continue;
c7bafca9 88
89 trk[ntr++]=i;
90 }
91
92 Double_t massLambda=1.11568;
93 Int_t ncasc=0;
94
95 // Looking for the cascades...
c028b974 96
97 for (i=0; i<nV0; i++) { //loop on V0s
98
c7bafca9 99 AliESDv0 *v=(AliESDv0*)vtcs.UncheckedAt(i);
100 v->ChangeMassHypothesis(kLambda0); // the v0 must be Lambda
101 if (TMath::Abs(v->GetEffMass()-massLambda)>fMassWin) continue;
c028b974 102
103 for (Int_t j=0; j<ntr; j++) {//loop on tracks
c7bafca9 104 Int_t bidx=trk[j];
b75d63a7 105 //Bo: if (bidx==v->GetNindex()) continue; //bachelor and v0's negative tracks must be different
106 if (bidx==v->GetIndex(0)) continue; //Bo: consistency 0 for neg
c7bafca9 107 AliESDtrack *btrk=event->GetTrack(bidx);
c7bafca9 108 if (btrk->GetSign()>0) continue; // bachelor's charge
109
c028b974 110 AliESDv0 v0(*v), *pv0=&v0;
c7bafca9 111 AliExternalTrackParam bt(*btrk), *pbt=&bt;
112
113 Double_t dca=PropagateToDCA(pv0,pbt,b);
114 if (dca > fDCAmax) continue;
115
c028b974 116 AliESDcascade cascade(*pv0,*pbt,bidx);//constucts a cascade candidate
f776b387 117 //PH if (cascade.GetChi2Xi() > fChi2max) continue;
c7bafca9 118
85f0f56e 119 Double_t x,y,z; cascade.GetXYZcascade(x,y,z); // Bo: bug correction
c7bafca9 120 Double_t r2=x*x + y*y;
121 if (r2 > fRmax*fRmax) continue; // condition on fiducial zone
122 if (r2 < fRmin*fRmin) continue;
123
c028b974 124 Double_t pxV0,pyV0,pzV0;
125 pv0->GetPxPyPz(pxV0,pyV0,pzV0);
126 if (x*pxV0+y*pyV0+z*pzV0 < 0) continue; //causality
127
c7bafca9 128 Double_t x1,y1,z1; pv0->GetXYZ(x1,y1,z1);
129 if (r2 > (x1*x1+y1*y1)) continue;
c7bafca9 130
81f174b6 131 if (cascade.GetCascadeCosineOfPointingAngle(xPrimaryVertex,yPrimaryVertex,zPrimaryVertex) <fCPAmin) continue; //condition on the cascade pointing angle
c028b974 132
5c9c901e 133 cascade.SetDcaXiDaughters(dca);
c028b974 134 event->AddCascade(&cascade);
c7bafca9 135 ncasc++;
c028b974 136 } // end loop tracks
137 } // end loop V0s
c7bafca9 138
139 // Looking for the anti-cascades...
c028b974 140
141 for (i=0; i<nV0; i++) { //loop on V0s
c7bafca9 142 AliESDv0 *v=(AliESDv0*)vtcs.UncheckedAt(i);
143 v->ChangeMassHypothesis(kLambda0Bar); //the v0 must be anti-Lambda
144 if (TMath::Abs(v->GetEffMass()-massLambda)>fMassWin) continue;
c028b974 145
146 for (Int_t j=0; j<ntr; j++) {//loop on tracks
c7bafca9 147 Int_t bidx=trk[j];
b75d63a7 148 //Bo: if (bidx==v->GetPindex()) continue; //bachelor and v0's positive tracks must be different
149 if (bidx==v->GetIndex(1)) continue; //Bo: consistency 1 for pos
c7bafca9 150 AliESDtrack *btrk=event->GetTrack(bidx);
c7bafca9 151 if (btrk->GetSign()<0) continue; // bachelor's charge
152
153 AliESDv0 v0(*v), *pv0=&v0;
154 AliESDtrack bt(*btrk), *pbt=&bt;
155
156 Double_t dca=PropagateToDCA(pv0,pbt,b);
157 if (dca > fDCAmax) continue;
158
c028b974 159 AliESDcascade cascade(*pv0,*pbt,bidx); //constucts a cascade candidate
f776b387 160 //PH if (cascade.GetChi2Xi() > fChi2max) continue;
c7bafca9 161
85f0f56e 162 Double_t x,y,z; cascade.GetXYZcascade(x,y,z); // Bo: bug correction
c7bafca9 163 Double_t r2=x*x + y*y;
164 if (r2 > fRmax*fRmax) continue; // condition on fiducial zone
165 if (r2 < fRmin*fRmin) continue;
166
c028b974 167 Double_t pxV0,pyV0,pzV0;
168 pv0->GetPxPyPz(pxV0,pyV0,pzV0);
169 if (x*pxV0+y*pyV0+z*pzV0 < 0) continue; //causality
170
c7bafca9 171 Double_t x1,y1,z1; pv0->GetXYZ(x1,y1,z1);
172 if (r2 > (x1*x1+y1*y1)) continue;
c7bafca9 173
81f174b6 174 if (cascade.GetCascadeCosineOfPointingAngle(xPrimaryVertex,yPrimaryVertex,zPrimaryVertex) < fCPAmin) continue; //condition on the cascade pointing angle
5c9c901e 175
176 cascade.SetDcaXiDaughters(dca);
c028b974 177 event->AddCascade(&cascade);
c7bafca9 178 ncasc++;
179
c028b974 180 } // end loop tracks
181 } // end loop V0s
c7bafca9 182
183Info("V0sTracks2CascadeVertices","Number of reconstructed cascades: %d",ncasc);
184
185 return 0;
186}
187
188
97135b34 189Double_t AliCascadeVertexer::Det(Double_t a00, Double_t a01, Double_t a10, Double_t a11) const {
190 //--------------------------------------------------------------------
191 // This function calculates locally a 2x2 determinant
192 //--------------------------------------------------------------------
c7bafca9 193 return a00*a11 - a01*a10;
194}
195
97135b34 196Double_t AliCascadeVertexer::Det(Double_t a00,Double_t a01,Double_t a02,
197 Double_t a10,Double_t a11,Double_t a12,
198 Double_t a20,Double_t a21,Double_t a22) const {
199 //--------------------------------------------------------------------
200 // This function calculates locally a 3x3 determinant
201 //--------------------------------------------------------------------
202 return a00*Det(a11,a12,a21,a22)-a01*Det(a10,a12,a20,a22)+a02*Det(a10,a11,a20,a21);
c7bafca9 203}
204
205
206
207
97135b34 208Double_t AliCascadeVertexer::PropagateToDCA(AliESDv0 *v, AliExternalTrackParam *t, Double_t b) {
c7bafca9 209 //--------------------------------------------------------------------
210 // This function returns the DCA between the V0 and the track
211 //--------------------------------------------------------------------
212 Double_t alpha=t->GetAlpha(), cs1=TMath::Cos(alpha), sn1=TMath::Sin(alpha);
213 Double_t r[3]; t->GetXYZ(r);
214 Double_t x1=r[0], y1=r[1], z1=r[2];
215 Double_t p[3]; t->GetPxPyPz(p);
216 Double_t px1=p[0], py1=p[1], pz1=p[2];
217
218 Double_t x2,y2,z2; // position and momentum of V0
219 Double_t px2,py2,pz2;
220
221 v->GetXYZ(x2,y2,z2);
222 v->GetPxPyPz(px2,py2,pz2);
223
224// calculation dca
225
97135b34 226 Double_t dd= Det(x2-x1,y2-y1,z2-z1,px1,py1,pz1,px2,py2,pz2);
227 Double_t ax= Det(py1,pz1,py2,pz2);
228 Double_t ay=-Det(px1,pz1,px2,pz2);
229 Double_t az= Det(px1,py1,px2,py2);
c7bafca9 230
231 Double_t dca=TMath::Abs(dd)/TMath::Sqrt(ax*ax + ay*ay + az*az);
232
233//points of the DCA
97135b34 234 Double_t t1 = Det(x2-x1,y2-y1,z2-z1,px2,py2,pz2,ax,ay,az)/
235 Det(px1,py1,pz1,px2,py2,pz2,ax,ay,az);
c7bafca9 236
237 x1 += px1*t1; y1 += py1*t1; //z1 += pz1*t1;
238
239
240 //propagate track to the points of DCA
241
242 x1=x1*cs1 + y1*sn1;
243 if (!t->PropagateTo(x1,b)) {
244 Error("PropagateToDCA","Propagation failed !");
245 return 1.e+33;
246 }
247
248 return dca;
249}
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