// Fills the ESD with the cascades
// Origin: Christian Kuhn, IReS, Strasbourg, christian.kuhn@ires.in2p3.fr
//-------------------------------------------------------------------------
-#include <TObjArray.h>
-#include <TTree.h>
-#include "AliESD.h"
-#include "AliESDv0.h"
+//modified by R. Vernet 30/6/2006 : daughter label
+//modified by R. Vernet 3/7/2006 : causality
+//modified by I. Belikov 24/11/2006 : static setter for the default cuts
+
+#include "AliESDEvent.h"
#include "AliESDcascade.h"
#include "AliCascadeVertexer.h"
ClassImp(AliCascadeVertexer)
-Int_t AliCascadeVertexer::V0sTracks2CascadeVertices(AliESD *event) {
+//A set of loose cuts
+Double_t
+ AliCascadeVertexer::fgChi2max=33.; //maximal allowed chi2
+Double_t
+ AliCascadeVertexer::fgDV0min=0.01; //min V0 impact parameter
+Double_t
+ AliCascadeVertexer::fgMassWin=0.008; //"window" around the Lambda mass
+Double_t
+ AliCascadeVertexer::fgDBachMin=0.01; //min bachelor impact parameter
+Double_t
+ AliCascadeVertexer::fgDCAmax=2.0; //max DCA between the V0 and the track
+Double_t
+ AliCascadeVertexer::fgCPAmin=0.98; //min cosine of the cascade pointing angle
+Double_t
+ AliCascadeVertexer::fgRmin=0.2; //min radius of the fiducial volume
+Double_t
+ AliCascadeVertexer::fgRmax=100.; //max radius of the fiducial volume
+
+
+Int_t AliCascadeVertexer::V0sTracks2CascadeVertices(AliESDEvent *event) {
//--------------------------------------------------------------------
// This function reconstructs cascade vertices
// Adapted to the ESD by I.Belikov (Jouri.Belikov@cern.ch)
//--------------------------------------------------------------------
+ const AliESDVertex *vtxT3D=event->GetPrimaryVertex();
+
+ Double_t xPrimaryVertex=vtxT3D->GetXv();
+ Double_t yPrimaryVertex=vtxT3D->GetYv();
+ Double_t zPrimaryVertex=vtxT3D->GetZv();
+
Double_t b=event->GetMagneticField();
Int_t nV0=(Int_t)event->GetNumberOfV0s();
+
+ //stores relevant V0s in an array
TObjArray vtcs(nV0);
Int_t i;
for (i=0; i<nV0; i++) {
AliESDv0 *v=event->GetV0(i);
- if (v->GetD(fX,fY,fZ)<fDV0min) continue;
+ if (v->GetOnFlyStatus()) continue;
+ if (v->GetD(xPrimaryVertex,yPrimaryVertex,zPrimaryVertex)<fDV0min) continue;
vtcs.AddLast(v);
}
nV0=vtcs.GetEntriesFast();
+ // stores relevant tracks in another array
Int_t nentr=(Int_t)event->GetNumberOfTracks();
TArrayI trk(nentr); Int_t ntr=0;
for (i=0; i<nentr; i++) {
AliESDtrack *esdtr=event->GetTrack(i);
- UInt_t status=esdtr->GetStatus();
- UInt_t flags=AliESDtrack::kITSin|AliESDtrack::kTPCin|
- AliESDtrack::kTPCpid|AliESDtrack::kESDpid;
+ ULong_t status=esdtr->GetStatus();
if ((status&AliESDtrack::kITSrefit)==0)
- if (flags!=status) continue;
+ if ((status&AliESDtrack::kTPCrefit)==0) continue;
- if (TMath::Abs(esdtr->GetD(fX,fY,b))<fDBachMin) continue;
+ if (TMath::Abs(esdtr->GetD(xPrimaryVertex,yPrimaryVertex,b))<fDBachMin) continue;
trk[ntr++]=i;
}
Int_t ncasc=0;
// Looking for the cascades...
- for (i=0; i<nV0; i++) {
+
+ for (i=0; i<nV0; i++) { //loop on V0s
+
AliESDv0 *v=(AliESDv0*)vtcs.UncheckedAt(i);
- v->ChangeMassHypothesis(kLambda0); // the v0 must be Lambda
- if (TMath::Abs(v->GetEffMass()-massLambda)>fMassWin) continue;
- for (Int_t j=0; j<ntr; j++) {
+ AliESDv0 v0(*v);
+ v0.ChangeMassHypothesis(kLambda0); // the v0 must be Lambda
+ if (TMath::Abs(v0.GetEffMass()-massLambda)>fMassWin) continue;
+
+ for (Int_t j=0; j<ntr; j++) {//loop on tracks
Int_t bidx=trk[j];
+ //Bo: if (bidx==v->GetNindex()) continue; //bachelor and v0's negative tracks must be different
+ if (bidx==v0.GetIndex(0)) continue; //Bo: consistency 0 for neg
AliESDtrack *btrk=event->GetTrack(bidx);
-
if (btrk->GetSign()>0) continue; // bachelor's charge
- AliESDv0 v0(*v), *pv0=&v0;
+ AliESDv0 *pv0=&v0;
AliExternalTrackParam bt(*btrk), *pbt=&bt;
Double_t dca=PropagateToDCA(pv0,pbt,b);
if (dca > fDCAmax) continue;
- AliESDcascade cascade(*pv0,*pbt,bidx);
- if (cascade.GetChi2() > fChi2max) continue;
+ AliESDcascade cascade(*pv0,*pbt,bidx);//constucts a cascade candidate
+ //PH if (cascade.GetChi2Xi() > fChi2max) continue;
- Double_t x,y,z; cascade.GetXYZ(x,y,z);
+ Double_t x,y,z; cascade.GetXYZcascade(x,y,z); // Bo: bug correction
Double_t r2=x*x + y*y;
if (r2 > fRmax*fRmax) continue; // condition on fiducial zone
if (r2 < fRmin*fRmin) continue;
- {
+ Double_t pxV0,pyV0,pzV0;
+ pv0->GetPxPyPz(pxV0,pyV0,pzV0);
+ if (x*pxV0+y*pyV0+z*pzV0 < 0) continue; //causality
+
Double_t x1,y1,z1; pv0->GetXYZ(x1,y1,z1);
if (r2 > (x1*x1+y1*y1)) continue;
- //if ((z-fZ)*(z-fZ) > (z1-fZ)*(z1-fZ)) continue;
- }
-
- Double_t px,py,pz; cascade.GetPxPyPz(px,py,pz);
- Double_t p2=px*px+py*py+pz*pz;
- Double_t cost=((x-fX)*px + (y-fY)*py + (z-fZ)*pz)/
- TMath::Sqrt(p2*((x-fX)*(x-fX) + (y-fY)*(y-fY) + (z-fZ)*(z-fZ)));
- if (cost<fCPAmax) continue; //condition on the cascade pointing angle
- //cascade.ChangeMassHypothesis(); //default is Xi
-
- event->AddCascade(&cascade);
+ if (cascade.GetCascadeCosineOfPointingAngle(xPrimaryVertex,yPrimaryVertex,zPrimaryVertex) <fCPAmin) continue; //condition on the cascade pointing angle
+
+ cascade.SetDcaXiDaughters(dca);
+ event->AddCascade(&cascade);
ncasc++;
-
- }
- }
+ } // end loop tracks
+ } // end loop V0s
// Looking for the anti-cascades...
- for (i=0; i<nV0; i++) {
+
+ for (i=0; i<nV0; i++) { //loop on V0s
AliESDv0 *v=(AliESDv0*)vtcs.UncheckedAt(i);
- v->ChangeMassHypothesis(kLambda0Bar); //the v0 must be anti-Lambda
- if (TMath::Abs(v->GetEffMass()-massLambda)>fMassWin) continue;
- for (Int_t j=0; j<ntr; j++) {
+ AliESDv0 v0(*v);
+ v0.ChangeMassHypothesis(kLambda0Bar); //the v0 must be anti-Lambda
+ if (TMath::Abs(v0.GetEffMass()-massLambda)>fMassWin) continue;
+
+ for (Int_t j=0; j<ntr; j++) {//loop on tracks
Int_t bidx=trk[j];
+ //Bo: if (bidx==v->GetPindex()) continue; //bachelor and v0's positive tracks must be different
+ if (bidx==v0.GetIndex(1)) continue; //Bo: consistency 1 for pos
AliESDtrack *btrk=event->GetTrack(bidx);
-
if (btrk->GetSign()<0) continue; // bachelor's charge
- AliESDv0 v0(*v), *pv0=&v0;
+ AliESDv0 *pv0=&v0;
AliESDtrack bt(*btrk), *pbt=&bt;
Double_t dca=PropagateToDCA(pv0,pbt,b);
if (dca > fDCAmax) continue;
- AliESDcascade cascade(*pv0,*pbt,bidx);
- if (cascade.GetChi2() > fChi2max) continue;
+ AliESDcascade cascade(*pv0,*pbt,bidx); //constucts a cascade candidate
+ //PH if (cascade.GetChi2Xi() > fChi2max) continue;
- Double_t x,y,z; cascade.GetXYZ(x,y,z);
+ Double_t x,y,z; cascade.GetXYZcascade(x,y,z); // Bo: bug correction
Double_t r2=x*x + y*y;
if (r2 > fRmax*fRmax) continue; // condition on fiducial zone
if (r2 < fRmin*fRmin) continue;
- {
+ Double_t pxV0,pyV0,pzV0;
+ pv0->GetPxPyPz(pxV0,pyV0,pzV0);
+ if (x*pxV0+y*pyV0+z*pzV0 < 0) continue; //causality
+
Double_t x1,y1,z1; pv0->GetXYZ(x1,y1,z1);
if (r2 > (x1*x1+y1*y1)) continue;
- if (z*z > z1*z1) continue;
- }
- Double_t px,py,pz; cascade.GetPxPyPz(px,py,pz);
- Double_t p2=px*px+py*py+pz*pz;
- Double_t cost=((x-fX)*px + (y-fY)*py + (z-fZ)*pz)/
- TMath::Sqrt(p2*((x-fX)*(x-fX) + (y-fY)*(y-fY) + (z-fZ)*(z-fZ)));
-
- if (cost<fCPAmax) continue; //condition on the cascade pointing angle
- //cascade.ChangeMassHypothesis(); //default is Xi
-
- event->AddCascade(&cascade);
+ if (cascade.GetCascadeCosineOfPointingAngle(xPrimaryVertex,yPrimaryVertex,zPrimaryVertex) < fCPAmin) continue; //condition on the cascade pointing angle
+ cascade.SetDcaXiDaughters(dca);
+ event->AddCascade(&cascade);
ncasc++;
- }
- }
+ } // end loop tracks
+ } // end loop V0s
Info("V0sTracks2CascadeVertices","Number of reconstructed cascades: %d",ncasc);
}
-inline Double_t det(Double_t a00, Double_t a01, Double_t a10, Double_t a11){
- // determinant 2x2
+Double_t AliCascadeVertexer::Det(Double_t a00, Double_t a01, Double_t a10, Double_t a11) const {
+ //--------------------------------------------------------------------
+ // This function calculates locally a 2x2 determinant
+ //--------------------------------------------------------------------
return a00*a11 - a01*a10;
}
-inline Double_t det (Double_t a00,Double_t a01,Double_t a02,
- Double_t a10,Double_t a11,Double_t a12,
- Double_t a20,Double_t a21,Double_t a22) {
- // determinant 3x3
- return
- a00*det(a11,a12,a21,a22)-a01*det(a10,a12,a20,a22)+a02*det(a10,a11,a20,a21);
+Double_t AliCascadeVertexer::Det(Double_t a00,Double_t a01,Double_t a02,
+ Double_t a10,Double_t a11,Double_t a12,
+ Double_t a20,Double_t a21,Double_t a22) const {
+ //--------------------------------------------------------------------
+ // This function calculates locally a 3x3 determinant
+ //--------------------------------------------------------------------
+ return a00*Det(a11,a12,a21,a22)-a01*Det(a10,a12,a20,a22)+a02*Det(a10,a11,a20,a21);
}
-Double_t AliCascadeVertexer::
-PropagateToDCA(AliESDv0 *v, AliExternalTrackParam *t, Double_t b) {
+Double_t AliCascadeVertexer::PropagateToDCA(AliESDv0 *v, AliExternalTrackParam *t, Double_t b) {
//--------------------------------------------------------------------
// This function returns the DCA between the V0 and the track
//--------------------------------------------------------------------
// calculation dca
- Double_t dd= det(x2-x1,y2-y1,z2-z1,px1,py1,pz1,px2,py2,pz2);
- Double_t ax= det(py1,pz1,py2,pz2);
- Double_t ay=-det(px1,pz1,px2,pz2);
- Double_t az= det(px1,py1,px2,py2);
+ Double_t dd= Det(x2-x1,y2-y1,z2-z1,px1,py1,pz1,px2,py2,pz2);
+ Double_t ax= Det(py1,pz1,py2,pz2);
+ Double_t ay=-Det(px1,pz1,px2,pz2);
+ Double_t az= Det(px1,py1,px2,py2);
Double_t dca=TMath::Abs(dd)/TMath::Sqrt(ax*ax + ay*ay + az*az);
//points of the DCA
- Double_t t1 = det(x2-x1,y2-y1,z2-z1,px2,py2,pz2,ax,ay,az)/
- det(px1,py1,pz1,px2,py2,pz2,ax,ay,az);
+ Double_t t1 = Det(x2-x1,y2-y1,z2-z1,px2,py2,pz2,ax,ay,az)/
+ Det(px1,py1,pz1,px2,py2,pz2,ax,ay,az);
x1 += px1*t1; y1 += py1*t1; //z1 += pz1*t1;
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