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 **************************************************************************/
17 * author: M.Kalisky@gsi.de
20 * Description: This class allows with purely kinematical cuts
21 * to select clean samples of electrons, pions and protons from the
22 * V0 online finder ESD V0 candidates for PID and dectector resonse
27 #include <TDatabasePDG.h>
30 #include "AliESDtrack.h"
31 #include "AliESDEvent.h"
32 #include "AliVEvent.h"
34 #include "AliKFParticle.h"
35 #include "AliVTrack.h"
36 #include "AliKFVertex.h"
38 #include "AliESDv0KineCuts.h"
40 ClassImp(AliESDv0KineCuts)
42 //____________________________________________________________________
43 AliESDv0KineCuts::AliESDv0KineCuts() :
59 // Default constructor
62 // default single track cuts
63 fTPCNcls = 1; // minimal number of the TPC clusters
64 fTPCrefit = kTRUE; // TPC refit
65 fTPCchi2perCls = 4.0; // chi2 per TPC cluster
66 fTPCclsRatio = 0.6; // minimal foun/findable TPC cluster ratio
67 fNoKinks = kTRUE; // kinks - no [kTRUE] or do not care [kFalse]
70 // default gamma cuts values
71 fGcutChi2NDF = 10; // Chi2NF cut value for the AliKFparticle gamma
72 fGcutCosPoint[0] = 0; // cos of the pointing angle [min, max]
73 fGcutCosPoint[1] = 0.02; // cos of the pointing angle [min, max]
74 fGcutDCA[0] = 0.; // DCA between the daughter tracks [min, max]
75 fGcutDCA[1] = 0.25; // DCA between the daughter tracks [min, max]
76 fGcutVertexR[0] = 3.; // radius of the conversion point [min, max]
77 fGcutVertexR[1] = 90.; // radius of the conversion point [min, max]
78 fGcutPsiPair[0] = 0.; // value of the psi pair cut [min, max]
79 fGcutPsiPair[1] = 0.05; // value of the psi pair cut [min, max]
80 fGcutInvMass = 0.05; // upper value on the gamma invariant mass
82 fK0cutChi2NDF = 10; // Chi2NF cut value for the AliKFparticle K0
83 fK0cutCosPoint[0] = 0.; // cos of the pointing angle [min, max]
84 fK0cutCosPoint[1] = 0.02; // cos of the pointing angle [min, max]
85 fK0cutDCA[0] = 0.; // DCA between the daughter tracks [min, max]
86 fK0cutDCA[1] = 0.2; // DCA between the daughter tracks [min, max]
87 fK0cutVertexR[0] = 2.0; // radius of the decay point [min, max]
88 fK0cutVertexR[1] = 30.0; // radius of the decay point [min, max]
89 fK0cutInvMass[0] = 0.486; // invariant mass window
90 fK0cutInvMass[1] = 0.508; // invariant mass window
91 // Lambda & anti-Lambda cut values
92 fLcutChi2NDF = 10; // Chi2NF cut value for the AliKFparticle K0
93 fLcutCosPoint[0] = 0.; // cos of the pointing angle [min, max]
94 fLcutCosPoint[1] = 0.02; // cos of the pointing angle [min, max]
95 fLcutDCA[0] = 0.; // DCA between the daughter tracks [min, max]
96 fLcutDCA[1] = 0.2; // DCA between the daughter tracks [min, max]
97 fLcutVertexR[0] = 2.0; // radius of the decay point [min, max]
98 fLcutVertexR[1] = 40.0; // radius of the decay point [min, max]
99 fLcutInvMass[0] = 1.11; // invariant mass window
100 fLcutInvMass[1] = 1.12; // invariant mass window
103 //____________________________________________________________________
104 AliESDv0KineCuts::~AliESDv0KineCuts(){
111 //____________________________________________________________________
112 AliESDv0KineCuts::AliESDv0KineCuts(const AliESDv0KineCuts &ref):
115 , fPrimaryVertex(0x0)
120 , fTPCchi2perCls(4.0)
134 //____________________________________________________________________
135 AliESDv0KineCuts &AliESDv0KineCuts::operator=(const AliESDv0KineCuts &ref){
137 // assignment operator
143 //____________________________________________________________________
144 void AliESDv0KineCuts::Copy(TObject &ref) const {
146 // Performs the copying of the object
151 AliESDv0KineCuts &target = dynamic_cast<AliESDv0KineCuts &>(ref);
153 // default single track cuts
154 target.fTPCNcls = fTPCNcls;
155 target.fTPCrefit = fTPCrefit;
156 target.fTPCchi2perCls = fTPCchi2perCls;
157 target.fTPCclsRatio = fTPCclsRatio;
158 target.fNoKinks = fNoKinks;
161 // default gamma cuts values
162 target.fGcutChi2NDF = fGcutChi2NDF;
163 memcpy(target.fGcutCosPoint, fGcutCosPoint, sizeof(Float_t) * 2);
164 memcpy(target.fGcutDCA, fGcutDCA, sizeof(Float_t) * 2);
165 memcpy(target.fGcutVertexR, fGcutVertexR, sizeof(Float_t) * 2);
166 memcpy(target.fGcutPsiPair, fGcutPsiPair, sizeof(Float_t) * 2);
167 target.fGcutInvMass = fGcutInvMass;
169 target.fK0cutChi2NDF = fK0cutChi2NDF;
170 memcpy(target.fK0cutCosPoint, fK0cutCosPoint, sizeof(Float_t) * 2);
171 memcpy(target.fK0cutDCA, fK0cutDCA, sizeof(Float_t) * 2);
172 memcpy(target.fK0cutVertexR, fK0cutVertexR, sizeof(Float_t) * 2);
173 memcpy(target.fK0cutInvMass, fK0cutInvMass, sizeof(Float_t) * 2);
174 // Lambda & anti-Lambda cut values
175 target.fLcutChi2NDF = fLcutChi2NDF;
176 memcpy(target.fLcutCosPoint, fLcutCosPoint, sizeof(Float_t) * 2);
177 memcpy(target.fLcutDCA, fLcutDCA, sizeof(Float_t) * 2);
178 memcpy(target.fLcutVertexR, fLcutVertexR, sizeof(Float_t) * 2);
179 memcpy(target.fLcutInvMass, fLcutInvMass, sizeof(Float_t) * 2);
182 //____________________________________________________________________
183 Bool_t AliESDv0KineCuts::ProcessV0(AliESDv0* const v0, Int_t &pdgV0, Int_t &pdgP, Int_t &pdgN){
185 // main user function
188 if(!v0) return kFALSE;
190 AliErrorClass("No valid Event pointer available, provide it first");
194 if(!V0CutsCommon(v0)) return kFALSE;
196 const Int_t id = PreselectV0(v0);
198 if(!SingleTrackCuts(v0)) return kFALSE;
204 return CaseGamma(v0, pdgV0, pdgP, pdgN);
206 return CaseK0(v0, pdgV0, pdgP, pdgN);
208 return CaseLambda(v0, pdgV0, pdgP, pdgN, 0);
210 return CaseLambda(v0, pdgV0, pdgP, pdgN, 1);
217 //____________________________________________________________________
218 Bool_t AliESDv0KineCuts::ProcessV0(AliESDv0* const v0, Int_t &pdgP, Int_t &pdgN){
220 // main user function, simplified if the V0 identity is not necessary
223 if(!v0) return kFALSE;
225 AliErrorClass("No valid Event pointer available, provide it first");
230 return ProcessV0(v0, idV0, pdgP, pdgN);
233 //____________________________________________________________________
234 Int_t AliESDv0KineCuts::PreselectV0(AliESDv0* const v0){
236 // Make a preselection (exclusive) of the V0 cadidates based on
238 // the armenteros cut values are currently fixed and user is not able to set them via
239 // set funcions. The reason is that these cuts are optimized and furneter changes should
240 // not be necessary. To prove otherwise please study in detail before changing the values
243 Float_t ap[2] = {-1., -1.};
246 const Float_t alpha = ap[0];
247 const Float_t qt = ap[1];
250 // - the reagions for different candidates must not overlap
253 const Double_t cutAlphaG = 0.35;
254 const Double_t cutQTG = 0.05;
255 const Double_t cutAlphaG2[2] = {0.6, 0.8};
256 const Double_t cutQTG2 = 0.04;
259 const Float_t cutQTK0[2] = {0.1075, 0.215};
260 const Float_t cutAPK0[2] = {0.199, 0.8}; // parameters for curved QT cut
262 // Lambda & A-Lambda cuts
263 const Float_t cutQTL = 0.03;
264 const Float_t cutAlphaL[2] = {0.35, 0.7};
265 const Float_t cutAlphaAL[2] = {-0.7, -0.35};
266 const Float_t cutAPL[3] = {0.107, -0.69, 0.5}; // parameters fir curved QT cut
269 if(kPurity == fMode){
270 // Check for Gamma candidates
272 if( (TMath::Abs(alpha) < cutAlphaG) ) return kGamma;
274 // additional region - should help high pT gammas
276 if( (TMath::Abs(alpha) > cutAlphaG2[0]) && (TMath::Abs(alpha) < cutAlphaG2[1]) ) return kGamma;
279 if(kEffGamma == fMode){
280 if(qt < cutQTG) return kGamma;
284 // Check for K0 candidates
285 Float_t q = cutAPK0[0] * TMath::Sqrt(TMath::Abs(1 - alpha*alpha/(cutAPK0[1]*cutAPK0[1])));
286 if( (qt > cutQTK0[0]) && (qt < cutQTK0[1]) && (qt > q) ){
290 // Check for Lambda candidates
291 q = cutAPL[0] * TMath::Sqrt(TMath::Abs(1 - ( (alpha + cutAPL[1]) * (alpha + cutAPL[1]) ) / (cutAPL[2]*cutAPL[2]) ));
292 if( (alpha > cutAlphaL[0]) && (alpha < cutAlphaL[1]) && (qt > cutQTL) && (qt < q) ){
296 // Check for A-Lambda candidates
297 q = cutAPL[0] * TMath::Sqrt(TMath::Abs(1 - ( (alpha - cutAPL[1]) * (alpha - cutAPL[1]) ) / (cutAPL[2]*cutAPL[2]) ));
298 if( (alpha > cutAlphaAL[0]) && (alpha < cutAlphaAL[1]) && (qt > cutQTL) && (qt < q) ){
304 //____________________________________________________________________
305 Bool_t AliESDv0KineCuts::SingleTrackCuts(AliESDv0 * const v0){
307 // apply single track cuts
308 // correct sign not relevat here
311 if(!v0) return kFALSE;
313 Int_t pIndex = 0, nIndex = 0;
314 pIndex = v0->GetPindex();
315 nIndex = v0->GetNindex();
317 d[0] = dynamic_cast<AliESDtrack*>(fEvent->GetTrack(pIndex));
318 d[1] = dynamic_cast<AliESDtrack*>(fEvent->GetTrack(nIndex));
320 for(Int_t i=0; i<2; ++i){
321 if(!d[i]) return kFALSE;
324 ULong_t status = d[i]->GetStatus();
326 // No. of TPC clusters leave to the users
327 if(d[i]->GetTPCNcls() < 1) return kFALSE;
330 if(!(status & AliESDtrack::kTPCrefit)) return kFALSE;
332 // Chi2 per TPC cluster
333 Int_t nTPCclusters = d[i]->GetTPCNcls();
334 Float_t chi2perTPCcluster = d[i]->GetTPCchi2()/Float_t(nTPCclusters);
335 if(chi2perTPCcluster > 4) return kFALSE;
338 Float_t cRatioTPC = d[i]->GetTPCNclsF() > 0. ? static_cast<Float_t>(d[i]->GetTPCNcls())/static_cast<Float_t> (d[i]->GetTPCNclsF()) : 1.;
339 if(cRatioTPC < 0.6) return kFALSE;
342 if(d[i]->GetKinkIndex(0) != 0) return kFALSE;
348 //____________________________________________________________________
349 Bool_t AliESDv0KineCuts::CaseGamma(AliESDv0* const v0, Int_t &pdgV0, Int_t &pdgP, Int_t &pdgN){
351 // process the gamma conversion candidate
354 if(!v0) return kFALSE;
356 AliVTrack* daughter[2];
357 Int_t pIndex = 0, nIndex = 0;
359 Bool_t sign = CheckSigns(v0);
361 pIndex = v0->GetPindex();
362 nIndex = v0->GetNindex();
365 pIndex = v0->GetNindex();
366 nIndex = v0->GetPindex();
368 daughter[0] = dynamic_cast<AliVTrack *>(fEvent->GetTrack(pIndex));
369 daughter[1] = dynamic_cast<AliVTrack *>(fEvent->GetTrack(nIndex));
370 if(!daughter[0] || !daughter[1]) return kFALSE;
372 AliKFParticle *kfMother = CreateMotherParticle(daughter[0], daughter[1], TMath::Abs(kElectron), TMath::Abs(kElectron));
373 if(!kfMother) return kFALSE;
376 d[0] = dynamic_cast<AliESDtrack*>(fEvent->GetTrack(pIndex));
377 d[1] = dynamic_cast<AliESDtrack*>(fEvent->GetTrack(nIndex));
379 Float_t iMass = v0->GetEffMass(0, 0);
381 // cos pointing angle
382 Double_t cosPoint = v0->GetV0CosineOfPointingAngle();
383 cosPoint = TMath::ACos(cosPoint);
385 // DCA between daughters
386 Double_t dca = v0->GetDcaV0Daughters();
391 Double_t r = TMath::Sqrt(x*x + y*y);
395 if ( GetConvPosXY(d[0], d[1], xy) ){
396 r2 = TMath::Sqrt(xy[0]*xy[0] + xy[1]*xy[1]);
400 Double_t psiPair = PsiPair(v0);
403 Double_t chi2ndf = kfMother->GetChi2()/kfMother->GetNDF();
405 if(kfMother) delete kfMother;
409 if(iMass > fGcutInvMass) return kFALSE;
411 if(chi2ndf > fGcutChi2NDF) return kFALSE;
413 if(cosPoint < fGcutCosPoint[0] || cosPoint > fGcutCosPoint[1]) return kFALSE;
415 if(dca < fGcutDCA[0] || dca > fGcutDCA[1]) return kFALSE;
417 if(r < fGcutVertexR[0] || r > fGcutVertexR[1]) return kFALSE;
419 if(psiPair < fGcutPsiPair[0] || psiPair > fGcutPsiPair[1]) return kFALSE;
435 //____________________________________________________________________
436 Bool_t AliESDv0KineCuts::CaseK0(AliESDv0* const v0, Int_t &pdgV0, Int_t &pdgP, Int_t &pdgN){
438 // process the K0 candidate
441 if(!v0) return kFALSE;
443 AliVTrack* daughter[2];
444 Int_t pIndex = 0, nIndex = 0;
445 Bool_t sign = CheckSigns(v0);
447 pIndex = v0->GetPindex();
448 nIndex = v0->GetNindex();
451 pIndex = v0->GetNindex();
452 nIndex = v0->GetPindex();
455 daughter[0] = dynamic_cast<AliVTrack *>(fEvent->GetTrack(pIndex));
456 daughter[1] = dynamic_cast<AliVTrack *>(fEvent->GetTrack(nIndex));
457 if(!daughter[0] || !daughter[1]) return kFALSE;
459 AliKFParticle *kfMother = CreateMotherParticle(daughter[0], daughter[1], TMath::Abs(kPiPlus), TMath::Abs(kPiPlus));
460 if(!kfMother) return kFALSE;
463 d[0] = dynamic_cast<AliESDtrack*>(fEvent->GetTrack(pIndex));
464 d[1] = dynamic_cast<AliESDtrack*>(fEvent->GetTrack(nIndex));
466 Float_t iMass = v0->GetEffMass(2, 2);
468 // cos pointing angle
469 Double_t cosPoint = v0->GetV0CosineOfPointingAngle();
470 cosPoint = TMath::ACos(cosPoint);
472 // DCA between daughters
473 Double_t dca = v0->GetDcaV0Daughters();
479 Double_t r = TMath::Sqrt(x*x + y*y);
482 Double_t chi2ndf = kfMother->GetChi2()/kfMother->GetNDF();
484 if(kfMother) delete kfMother;
489 if(iMass < fK0cutInvMass[0] || iMass > fK0cutInvMass[1]) return kFALSE;
491 if(chi2ndf > fK0cutChi2NDF) return kFALSE;
493 if(cosPoint < fK0cutCosPoint[0] || cosPoint > fK0cutCosPoint[1]) return kFALSE;
495 if(dca < fK0cutDCA[0] || dca > fK0cutDCA[1]) return kFALSE;
497 if(r < fK0cutVertexR[0] || r > fK0cutVertexR[1]) return kFALSE;
512 //____________________________________________________________________
513 Bool_t AliESDv0KineCuts::CaseLambda(AliESDv0* const v0, Int_t &pdgV0, Int_t &pdgP, Int_t &pdgN, Int_t id){
515 // process teh Lambda and Anti-Lambda candidate
518 if(!v0) return kFALSE;
520 const Double_t cL0mass=TDatabasePDG::Instance()->GetParticle(kLambda0)->Mass(); // PDG lambda mass
522 AliVTrack* daughter[2];
523 Int_t pIndex = 0, nIndex = 0;
524 Float_t mMass[2] = {-1., -1.};
525 Bool_t sign = CheckSigns(v0);
527 pIndex = v0->GetPindex();
528 nIndex = v0->GetNindex();
529 mMass[0] = v0->GetEffMass(4, 2);
530 mMass[1] = v0->GetEffMass(2, 4);
533 pIndex = v0->GetNindex();
534 nIndex = v0->GetPindex();
535 mMass[0] = v0->GetEffMass(2, 4);
536 mMass[1] = v0->GetEffMass(4, 2);
539 daughter[0] = dynamic_cast<AliVTrack *>(fEvent->GetTrack(pIndex));
540 daughter[1] = dynamic_cast<AliVTrack *>(fEvent->GetTrack(nIndex));
541 if(!daughter[0] || !daughter[1]) return kFALSE;
543 AliKFParticle *kfMother[2] = {0x0, 0x0};
545 kfMother[0] = CreateMotherParticle(daughter[0], daughter[1], TMath::Abs(kProton), TMath::Abs(kPiPlus));
546 if(!kfMother[0]) return kFALSE;
549 kfMother[1] = CreateMotherParticle(daughter[0], daughter[1], TMath::Abs(kPiPlus), TMath::Abs(kProton));
550 if(!kfMother[1]) return kFALSE;
552 Float_t dMass[2] = {TMath::Abs(mMass[0] - cL0mass), TMath::Abs(mMass[1] - cL0mass)};
555 d[0] = dynamic_cast<AliESDtrack*>(fEvent->GetTrack(pIndex));
556 d[1] = dynamic_cast<AliESDtrack*>(fEvent->GetTrack(nIndex));
557 if(!d[0] || !d[1]) return kFALSE;
559 Float_t p[2] = {d[0]->GetP(), d[1]->GetP()};
561 // check the 3 lambda - antilambda variables
562 Int_t check[2] = {-1, -1}; // 0 : lambda, 1 : antilambda
563 // 1) momentum of the daughter particles - proton is expected to have higher momentum than pion
564 check[0] = (p[0] > p[1]) ? 0 : 1;
565 // 2) mass of the mother particle
566 check[1] = (dMass[0] < dMass[1]) ? 0 : 1;
568 // require positive correlation of (1) and (2)
569 if(check[0] != check[1]){
570 if(kfMother[0]) delete kfMother[0];
571 if(kfMother[1]) delete kfMother[1];
575 // now that the check[0] == check[1]
576 const Int_t type = check[0];
578 // require that the input armenteros preselection agree:
579 if(type != id) return kFALSE;
583 iMass = (type == 0) ? v0->GetEffMass(4, 2) : v0->GetEffMass(2, 4);
586 iMass = (type == 0) ? v0->GetEffMass(2, 4) : v0->GetEffMass(4, 2);
589 // cos pointing angle
590 Double_t cosPoint = v0->GetV0CosineOfPointingAngle();
591 cosPoint = TMath::ACos(cosPoint);
593 // DCA between daughters
594 Double_t dca = v0->GetDcaV0Daughters();
599 Double_t r = TMath::Sqrt(x*x + y*y);
601 // proton - pion indices
602 Int_t ix[2] = {0, 1};
609 Double_t chi2ndf = kfMother[type]->GetChi2()/kfMother[type]->GetNDF();
611 if(kfMother[0]) delete kfMother[0];
612 if(kfMother[1]) delete kfMother[1];
618 if(iMass < fLcutInvMass[0] || iMass > fLcutInvMass[1]) return kFALSE;
620 if(chi2ndf > fLcutChi2NDF) return kFALSE;
622 if(cosPoint < fLcutCosPoint[0] || cosPoint > fLcutCosPoint[1]) return kFALSE;
624 if(dca < fLcutDCA[0] || dca > fLcutDCA[1]) return kFALSE;
626 if(r < fLcutVertexR[0] || r > fLcutVertexR[1]) return kFALSE;
655 //____________________________________________________________________
656 Bool_t AliESDv0KineCuts::V0CutsCommon(const AliESDv0 * const v0){
658 // V0 cuts common to all V0s
661 AliESDtrack* dN, *dP;
663 dP = dynamic_cast<AliESDtrack *>(fEvent->GetTrack(v0->GetPindex()));
664 dN = dynamic_cast<AliESDtrack *>(fEvent->GetTrack(v0->GetNindex()));
666 if(!dN || !dP) return kFALSE;
668 Int_t qP = dP->Charge();
669 Int_t qN = dN->Charge();
671 if((qP*qN) != -1) return kFALSE;
675 //____________________________________________________________________
676 void AliESDv0KineCuts::Armenteros(AliESDv0* const v0, Float_t val[2]){
678 // computes the Armenteros variables for given V0
679 // fills the histogram
680 // returns the values via "val"
683 Double_t mn[3] = {0,0,0};
684 Double_t mp[3] = {0,0,0};
685 Double_t mm[3] = {0,0,0};
688 v0->GetNPxPyPz(mn[0],mn[1],mn[2]); //reconstructed cartesian momentum components of negative daughter
689 v0->GetPPxPyPz(mp[0],mp[1],mp[2]); //reconstructed cartesian momentum components of positive daughter
692 v0->GetPPxPyPz(mn[0],mn[1],mn[2]); //reconstructed cartesian momentum components of negative daughter
693 v0->GetNPxPyPz(mp[0],mp[1],mp[2]); //reconstructed cartesian momentum components of positive daughter
695 v0->GetPxPyPz(mm[0],mm[1],mm[2]); //reconstructed cartesian momentum components of mother
697 TVector3 vecN(mn[0],mn[1],mn[2]);
698 TVector3 vecP(mp[0],mp[1],mp[2]);
699 TVector3 vecM(mm[0],mm[1],mm[2]);
701 Double_t thetaP = acos((vecP * vecM)/(vecP.Mag() * vecM.Mag()));
702 Double_t thetaN = acos((vecN * vecM)/(vecN.Mag() * vecM.Mag()));
704 Double_t alfa = ((vecP.Mag())*cos(thetaP)-(vecN.Mag())*cos(thetaN))/
705 ((vecP.Mag())*cos(thetaP)+(vecN.Mag())*cos(thetaN)) ;
706 Double_t qt = vecP.Mag()*sin(thetaP);
711 //____________________________________________________________________
712 Bool_t AliESDv0KineCuts::CheckSigns(AliESDv0* const v0){
714 // check wheter the sign was correctly applied to
715 // V0 daughter tracks
718 Bool_t correct = kFALSE;
720 Int_t pIndex = 0, nIndex = 0;
721 pIndex = v0->GetPindex();
722 nIndex = v0->GetNindex();
725 d[0] = dynamic_cast<AliESDtrack*>(fEvent->GetTrack(pIndex));
726 d[1] = dynamic_cast<AliESDtrack*>(fEvent->GetTrack(nIndex));
729 sign[0] = (int)d[0]->GetSign();
730 sign[1] = (int)d[1]->GetSign();
732 if(-1 == sign[0] && 1 == sign[1]){
741 //________________________________________________________________
742 Double_t AliESDv0KineCuts::PsiPair(AliESDv0* const v0) {
744 // Angle between daughter momentum plane and plane
747 if(!fEvent) return -1.;
749 Float_t magField = fEvent->GetMagneticField();
754 pIndex = v0->GetPindex();
755 nIndex = v0->GetNindex();
758 pIndex = v0->GetNindex();
759 nIndex = v0->GetPindex();
763 AliESDtrack* daughter[2];
765 daughter[0] = dynamic_cast<AliESDtrack *>(fEvent->GetTrack(pIndex));
766 daughter[1] = dynamic_cast<AliESDtrack *>(fEvent->GetTrack(nIndex));
769 v0->GetXYZ(x,y,z);//Reconstructed coordinates of V0; to be replaced by Markus Rammler's method in case of conversions!
771 Double_t mn[3] = {0,0,0};
772 Double_t mp[3] = {0,0,0};
775 v0->GetNPxPyPz(mn[0],mn[1],mn[2]);//reconstructed cartesian momentum components of negative daughter;
776 v0->GetPPxPyPz(mp[0],mp[1],mp[2]);//reconstructed cartesian momentum components of positive daughter;
779 Double_t deltat = 1.;
780 deltat = TMath::ATan(mp[2]/(TMath::Sqrt(mp[0]*mp[0] + mp[1]*mp[1])+1.e-13)) - TMath::ATan(mn[2]/(TMath::Sqrt(mn[0]*mn[0] + mn[1]*mn[1])+1.e-13));//difference of angles of the two daughter tracks with z-axis
782 Double_t radiussum = TMath::Sqrt(x*x + y*y) + 50;//radius to which tracks shall be propagated
784 Double_t momPosProp[3];
785 Double_t momNegProp[3];
787 AliExternalTrackParam pt(*daughter[0]), nt(*daughter[1]);
789 Double_t psiPair = 4.;
791 if(nt.PropagateTo(radiussum,magField) == 0)//propagate tracks to the outside
793 if(pt.PropagateTo(radiussum,magField) == 0)
795 pt.GetPxPyPz(momPosProp);//Get momentum vectors of tracks after propagation
796 nt.GetPxPyPz(momNegProp);
799 TMath::Sqrt(momNegProp[0]*momNegProp[0]+momNegProp[1]*momNegProp[1]+momNegProp[2]*momNegProp[2]);//absolute momentum value of negative daughter
801 TMath::Sqrt(momPosProp[0]*momPosProp[0]+momPosProp[1]*momPosProp[1]+momPosProp[2]*momPosProp[2]);//absolute momentum value of positive daughter
803 Double_t scalarproduct =
804 momPosProp[0]*momNegProp[0]+momPosProp[1]*momNegProp[1]+momPosProp[2]*momNegProp[2];//scalar product of propagated positive and negative daughters' momenta
806 Double_t chipair = TMath::ACos(scalarproduct/(pEle*pPos));//Angle between propagated daughter tracks
808 psiPair = TMath::Abs(TMath::ASin(deltat/chipair));
812 //___________________________________________________________________
813 Bool_t AliESDv0KineCuts::GetConvPosXY(AliESDtrack * const ptrack, AliESDtrack * const ntrack, Double_t convpos[2]){
815 // recalculate the gamma conversion XY postition
818 const Double_t b = fEvent->GetMagneticField();
820 Double_t helixcenterpos[2];
821 GetHelixCenter(ptrack,b,ptrack->Charge(),helixcenterpos);
823 Double_t helixcenterneg[2];
824 GetHelixCenter(ntrack,b,ntrack->Charge(),helixcenterneg);
826 Double_t poshelix[6];
827 ptrack->GetHelixParameters(poshelix,b);
828 Double_t posradius = TMath::Abs(1./poshelix[4]);
830 Double_t neghelix[6];
831 ntrack->GetHelixParameters(neghelix,b);
832 Double_t negradius = TMath::Abs(1./neghelix[4]);
834 Double_t xpos = helixcenterpos[0];
835 Double_t ypos = helixcenterpos[1];
836 Double_t xneg = helixcenterneg[0];
837 Double_t yneg = helixcenterneg[1];
839 convpos[0] = (xpos*negradius + xneg*posradius)/(negradius+posradius);
840 convpos[1] = (ypos*negradius+ yneg*posradius)/(negradius+posradius);
844 //___________________________________________________________________
845 Bool_t AliESDv0KineCuts::GetHelixCenter(AliESDtrack * const track, Double_t b,Int_t charge, Double_t center[2]){
847 // computes the center of the track helix
850 Double_t pi = TMath::Pi();
853 track->GetHelixParameters(helix,b);
855 Double_t xpos = helix[5];
856 Double_t ypos = helix[0];
857 Double_t radius = TMath::Abs(1./helix[4]);
858 Double_t phi = helix[2];
865 Double_t xpoint = radius * TMath::Cos(phi);
866 Double_t ypoint = radius * TMath::Sin(phi);
890 center[0] = xpos + xpoint;
891 center[1] = ypos + ypoint;
895 //___________________________________________________________________
896 AliKFParticle *AliESDv0KineCuts::CreateMotherParticle(const AliVTrack* const pdaughter, const AliVTrack* const ndaughter, Int_t pspec, Int_t nspec){
898 // Creates a mother particle
900 AliKFParticle pkfdaughter(*pdaughter, pspec);
901 AliKFParticle nkfdaughter(*ndaughter, nspec);
904 // Create the mother particle
905 AliKFParticle *m = new AliKFParticle(pkfdaughter, nkfdaughter);
907 if(TMath::Abs(kElectron) == pspec && TMath::Abs(kElectron) == nspec) m->SetMassConstraint(0, 0.001);
908 else if(TMath::Abs(kPiPlus) == pspec && TMath::Abs(kPiPlus) == nspec) m->SetMassConstraint(TDatabasePDG::Instance()->GetParticle(kK0Short)->Mass(), 0.);
909 else if(TMath::Abs(kProton) == pspec && TMath::Abs(kPiPlus) == nspec) m->SetMassConstraint(TDatabasePDG::Instance()->GetParticle(kLambda0)->Mass(), 0.);
910 else if(TMath::Abs(kPiPlus) == pspec && TMath::Abs(kProton) == nspec) m->SetMassConstraint(TDatabasePDG::Instance()->GetParticle(kLambda0)->Mass(), 0.);
912 AliErrorClass("Wrong daughter ID - mass constraint can not be set");
915 AliKFVertex improvedVertex = *fPrimaryVertex;
916 improvedVertex += *m;
917 m->SetProductionVertex(improvedVertex);
920 // mother particle will not be added to primary vertex but only to its copy
921 // as this confilcts with calling
922 // m->SetPrimaryVertex() function and
923 // subsequently removing the mother particle afterwards
924 // Source: Sergey Gorbunov
928 //____________________________________________________________________
929 void AliESDv0KineCuts::SetEvent(AliESDEvent* const event){
931 // direct setter of ESD event
935 AliErrorClass("Invalid input event pointer");
940 //____________________________________________________________________
941 void AliESDv0KineCuts::SetEvent(AliVEvent* const event){
943 // direct setter of ESD event
946 fEvent = static_cast<AliESDEvent*>(event);
948 AliErrorClass("Invalid input event pointer");
953 //________________________________________________________________
954 void AliESDv0KineCuts::SetPrimaryVertex(AliKFVertex* const v){
956 // set the primary vertex of the event
960 AliErrorClass("Failed to initialize the primary vertex");
964 //___________________________________________________________________
965 void AliESDv0KineCuts::SetMode(Int_t mode, Int_t type){
967 // this function allows the user to select (prior running the 'ProcessV0' function)
968 // to select different approaches to V0 selection - the 'mode'
970 // different systems (pp, PbPb) - 'type'
972 // To see the cut values for different modes please refer to the
973 // function SetCuts()
975 // Important notice: based on the parameters particular sets of cuts will
976 // be activated for teh V0 selection. If some additional changes to single
977 // cuts are needed please us the SetXXXcut function (see the header file)
982 fMode = kPurity; // used to obtain highest purity possible - the efficiency may be low
984 fMode = kEffGamma; // used to obtain highes efficiency possible - the purity may be worse
986 AliError("V0 selection mode not recognozed, setting 'kPurity'");
992 fType = kPP; // cuts optimized for low multiplicity
994 fType = kPbPb; // cuts optimized for high multiplicity
997 // setup the cut values for selected mode & type
1001 //___________________________________________________________________
1002 void AliESDv0KineCuts::SetMode(Int_t mode, const char* type){
1004 // overloaded function - please see above
1009 if(!strcmp("pp", type)) t = kPP;
1010 else if(!(strcmp("PbPb", type))) t = kPbPb;
1012 AliError("data type not recognized, setting 'pp'");
1019 //___________________________________________________________________
1020 void AliESDv0KineCuts::SetCuts(){
1022 // this funciton sets the default cut values based on the selected
1024 // please note that only the cuts that have different values than the default
1025 // cuts are updated here
1028 // last update: 14/02/2011
1029 // as a very preliminary - the only change to default cuts is to apply
1030 // less restricting gamma conversion selection in PreselectV0() function