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 **************************************************************************/
18 //-------------------------------------------------------------------------
19 // Implementation of the ESD V0 vertex class
20 // This class is part of the Event Data Summary
21 // set of classes and contains information about
22 // V0 kind vertexes generated by a neutral particle
23 // Origin: Iouri Belikov, IReS, Strasbourg, Jouri.Belikov@cern.ch
24 // Modified by: Marian Ivanov, CERN, Marian.Ivanov@cern.ch
25 // and Boris Hippolyte,IPHC, hippolyt@in2p3.fr
26 //-------------------------------------------------------------------------
28 #include <Riostream.h>
30 #include <TDatabasePDG.h>
32 #include <TParticlePDG.h>
36 #include "AliExternalTrackParam.h"
40 AliESDV0Params AliESDv0::fgkParams;
42 AliESDv0::AliESDv0() :
46 fEffMass(TDatabasePDG::Instance()->GetParticle(kK0Short)->Mass()),
64 //--------------------------------------------------------------------
65 // Default constructor (K0s)
66 //--------------------------------------------------------------------
68 for (Int_t i=0; i<3; i++) {
74 for (Int_t i=0; i<6; i++) {
78 for (Int_t i=0;i<6;i++){fClusters[0][i]=0; fClusters[1][i]=0;}
79 fNormDCAPrim[0]=fNormDCAPrim[1]=0;
80 for (Int_t i=0;i<3;i++){fAngle[i]=0;}
81 for (Int_t i=0;i<4;i++){fCausality[i]=0;}
84 AliESDv0::AliESDv0(const AliESDv0& v0) :
86 fOnFlyStatus(v0.fOnFlyStatus),
87 fPdgCode(v0.fPdgCode),
88 fEffMass(v0.fEffMass),
89 fDcaV0Daughters(v0.fDcaV0Daughters),
90 fPointAngle(v0.fPointAngle),
98 fDistSigma(v0.fDistSigma),
99 fChi2Before(v0.fChi2Before),
100 fNBefore(v0.fNBefore),
101 fChi2After(v0.fChi2After),
103 fPointAngleFi(v0.fPointAngleFi),
104 fPointAngleTh(v0.fPointAngleTh)
106 //--------------------------------------------------------------------
107 // The copy constructor
108 //--------------------------------------------------------------------
110 for (int i=0; i<3; i++) {
111 fPos[i] = v0.fPos[i];
112 fNmom[i] = v0.fNmom[i];
113 fPmom[i] = v0.fPmom[i];
115 for (int i=0; i<6; i++) {
116 fPosCov[i] = v0.fPosCov[i];
119 for (Int_t i=0; i<2; i++) {
120 fNormDCAPrim[i]=v0.fNormDCAPrim[i];
122 for (Int_t i=0;i<6;i++){
123 fClusters[0][i]=v0.fClusters[0][i];
124 fClusters[1][i]=v0.fClusters[1][i];
126 for (Int_t i=0;i<3;i++){
127 fAngle[i]=v0.fAngle[i];
129 for (Int_t i=0;i<4;i++){fCausality[i]=v0.fCausality[i];}
132 AliESDv0::AliESDv0(const AliExternalTrackParam &t1, Int_t i1,
133 const AliExternalTrackParam &t2, Int_t i2) :
135 fOnFlyStatus(kFALSE),
137 fEffMass(TDatabasePDG::Instance()->GetParticle(kK0Short)->Mass()),
155 //--------------------------------------------------------------------
156 // Main constructor (K0s)
157 //--------------------------------------------------------------------
159 for (Int_t i=0; i<6; i++) {
163 //Trivial estimation of the vertex parameters
164 Double_t alpha=t1.GetAlpha(), cs=TMath::Cos(alpha), sn=TMath::Sin(alpha);
167 Double_t px1=tmp[0], py1=tmp[1], pz1=tmp[2];
169 Double_t x1=tmp[0], y1=tmp[1], z1=tmp[2];
170 const Double_t ss=0.0005*0.0005;//a kind of a residual misalignment precision
171 Double_t sx1=sn*sn*t1.GetSigmaY2()+ss, sy1=cs*cs*t1.GetSigmaY2()+ss;
174 alpha=t2.GetAlpha(); cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
176 Double_t px2=tmp[0], py2=tmp[1], pz2=tmp[2];
178 Double_t x2=tmp[0], y2=tmp[1], z2=tmp[2];
179 Double_t sx2=sn*sn*t2.GetSigmaY2()+ss, sy2=cs*cs*t2.GetSigmaY2()+ss;
181 Double_t sz1=t1.GetSigmaZ2(), sz2=t2.GetSigmaZ2();
182 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
183 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
184 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
185 fPos[0]=wx1*x1 + wx2*x2; fPos[1]=wy1*y1 + wy2*y2; fPos[2]=wz1*z1 + wz2*z2;
187 //fPos[0]=0.5*(x1+x2); fPos[1]=0.5*(y1+y2); fPos[2]=0.5*(z1+z2);
188 fNmom[0]=px1; fNmom[1]=py1; fNmom[2]=pz1;
189 fPmom[0]=px2; fPmom[1]=py2; fPmom[2]=pz2;
191 for (Int_t i=0;i<6;i++){fClusters[0][i]=0; fClusters[1][i]=0;}
192 fNormDCAPrim[0]=fNormDCAPrim[1]=0;
193 for (Int_t i=0;i<3;i++){fAngle[i]=0;}
194 for (Int_t i=0;i<4;i++){fCausality[i]=0;}
197 AliESDv0::~AliESDv0(){
198 //--------------------------------------------------------------------
200 //--------------------------------------------------------------------
205 Double_t AliESDv0::ChangeMassHypothesis(Int_t code) {
206 //--------------------------------------------------------------------
207 // This function changes the mass hypothesis for this V0
208 // and returns the "kinematical quality" of this hypothesis
209 //--------------------------------------------------------------------
211 Double_t piMass=TDatabasePDG::Instance()->GetParticle(kPiPlus)->Mass();
213 Double_t prMass=TDatabasePDG::Instance()->GetParticle(kProton)->Mass();
215 Double_t k0Mass=TDatabasePDG::Instance()->GetParticle(kK0Short)->Mass();
217 Double_t l0Mass=TDatabasePDG::Instance()->GetParticle(kLambda0)->Mass();
219 Double_t nmass=piMass, pmass=piMass, mass=k0Mass, ps=0.206;
225 nmass=piMass; pmass=prMass; mass=l0Mass; ps=0.101; break;
227 pmass=piMass; nmass=prMass; mass=l0Mass; ps=0.101; break;
231 AliError("invalide PDG code ! Assuming K0s...");
236 Double_t pxn=fNmom[0], pyn=fNmom[1], pzn=fNmom[2];
237 Double_t pxp=fPmom[0], pyp=fPmom[1], pzp=fPmom[2];
239 Double_t en=TMath::Sqrt(nmass*nmass + pxn*pxn + pyn*pyn + pzn*pzn);
240 Double_t ep=TMath::Sqrt(pmass*pmass + pxp*pxp + pyp*pyp + pzp*pzp);
241 Double_t pxl=pxn+pxp, pyl=pyn+pyp, pzl=pzn+pzp;
242 Double_t pl=TMath::Sqrt(pxl*pxl + pyl*pyl + pzl*pzl);
244 fEffMass=TMath::Sqrt((en+ep)*(en+ep)-pl*pl);
246 Double_t beta=pl/(en+ep);
247 Double_t pln=(pxn*pxl + pyn*pyl + pzn*pzl)/pl;
248 Double_t plp=(pxp*pxl + pyp*pyl + pzp*pzl)/pl;
250 Double_t pt2=pxp*pxp + pyp*pyp + pzp*pzp - plp*plp;
252 Double_t a=(plp-pln)/(plp+pln);
253 a -= (pmass*pmass-nmass*nmass)/(mass*mass);
254 a = 0.25*beta*beta*mass*mass*a*a + pt2;
260 void AliESDv0::GetPxPyPz(Double_t &px, Double_t &py, Double_t &pz) const {
261 //--------------------------------------------------------------------
262 // This function returns V0's momentum (global)
263 //--------------------------------------------------------------------
264 px=fNmom[0]+fPmom[0];
265 py=fNmom[1]+fPmom[1];
266 pz=fNmom[2]+fPmom[2];
269 void AliESDv0::GetXYZ(Double_t &x, Double_t &y, Double_t &z) const {
270 //--------------------------------------------------------------------
271 // This function returns V0's position (global)
272 //--------------------------------------------------------------------
278 Float_t AliESDv0::GetD(Double_t x0, Double_t y0, Double_t z0) const {
279 //--------------------------------------------------------------------
280 // This function returns V0's impact parameter
281 //--------------------------------------------------------------------
282 Double_t x=fPos[0],y=fPos[1],z=fPos[2];
283 Double_t px=fNmom[0]+fPmom[0];
284 Double_t py=fNmom[1]+fPmom[1];
285 Double_t pz=fNmom[2]+fPmom[2];
287 Double_t dx=(y0-y)*pz - (z0-z)*py;
288 Double_t dy=(x0-x)*pz - (z0-z)*px;
289 Double_t dz=(x0-x)*py - (y0-y)*px;
290 Double_t d=TMath::Sqrt((dx*dx+dy*dy+dz*dz)/(px*px+py*py+pz*pz));
295 Float_t AliESDv0::GetV0CosineOfPointingAngle(Double_t& refPointX, Double_t& refPointY, Double_t& refPointZ) const {
296 // calculates the pointing angle of the V0 wrt a reference point
298 Double_t momV0[3]; //momentum of the V0
299 GetPxPyPz(momV0[0],momV0[1],momV0[2]);
301 Double_t deltaPos[3]; //vector between the reference point and the V0 vertex
302 deltaPos[0] = fPos[0] - refPointX;
303 deltaPos[1] = fPos[1] - refPointY;
304 deltaPos[2] = fPos[2] - refPointZ;
306 Double_t momV02 = momV0[0]*momV0[0] + momV0[1]*momV0[1] + momV0[2]*momV0[2];
307 Double_t deltaPos2 = deltaPos[0]*deltaPos[0] + deltaPos[1]*deltaPos[1] + deltaPos[2]*deltaPos[2];
309 Double_t cosinePointingAngle = (deltaPos[0]*momV0[0] +
310 deltaPos[1]*momV0[1] +
311 deltaPos[2]*momV0[2] ) /
312 TMath::Sqrt(momV02 * deltaPos2);
314 return cosinePointingAngle;
318 // **** The following functions need to be revised
320 void AliESDv0::GetPosCov(Double_t cov[6]) const {
322 for (Int_t i=0; i<6; ++i) cov[i] = fPosCov[i];
326 Double_t AliESDv0::GetSigmaY(){
328 // return sigmay in y at vertex position using covariance matrix
330 const Double_t * cp = fParamP.GetCovariance();
331 const Double_t * cm = fParamN.GetCovariance();
332 Double_t sigmay = cp[0]+cm[0]+ cp[5]*(fParamP.GetX()-fRr)*(fParamP.GetX()-fRr)+ cm[5]*(fParamN.GetX()-fRr)*(fParamN.GetX()-fRr);
333 return (sigmay>0) ? TMath::Sqrt(sigmay):100;
336 Double_t AliESDv0::GetSigmaZ(){
338 // return sigmay in y at vertex position using covariance matrix
340 const Double_t * cp = fParamP.GetCovariance();
341 const Double_t * cm = fParamN.GetCovariance();
342 Double_t sigmaz = cp[2]+cm[2]+ cp[9]*(fParamP.GetX()-fRr)*(fParamP.GetX()-fRr)+ cm[9]*(fParamN.GetX()-fRr)*(fParamN.GetX()-fRr);
343 return (sigmaz>0) ? TMath::Sqrt(sigmaz):100;
346 Double_t AliESDv0::GetSigmaD0(){
348 // Sigma parameterization using covariance matrix
350 // sigma of distance between two tracks in vertex position
351 // sigma of DCA is proportianal to sigmaD0
352 // factor 2 difference is explained by the fact that the DCA is calculated at the position
353 // where the tracks as closest together ( not exact position of the vertex)
355 const Double_t * cp = fParamP.GetCovariance();
356 const Double_t * cm = fParamN.GetCovariance();
357 Double_t sigmaD0 = cp[0]+cm[0]+cp[2]+cm[2]+fgkParams.fPSigmaOffsetD0*fgkParams.fPSigmaOffsetD0;
358 sigmaD0 += ((fParamP.GetX()-fRr)*(fParamP.GetX()-fRr))*(cp[5]+cp[9]);
359 sigmaD0 += ((fParamN.GetX()-fRr)*(fParamN.GetX()-fRr))*(cm[5]+cm[9]);
360 return (sigmaD0>0)? TMath::Sqrt(sigmaD0):100;
364 Double_t AliESDv0::GetSigmaAP0(){
366 //Sigma parameterization using covariance matrices
368 Double_t prec = TMath::Sqrt((fNmom[0]+fPmom[0])*(fNmom[0]+fPmom[0])
369 +(fNmom[1]+fPmom[1])*(fNmom[1]+fPmom[1])
370 +(fNmom[2]+fPmom[2])*(fNmom[2]+fPmom[2]));
371 Double_t normp = TMath::Sqrt(fPmom[0]*fPmom[0]+fPmom[1]*fPmom[1]+fPmom[2]*fPmom[2])/prec; // fraction of the momenta
372 Double_t normm = TMath::Sqrt(fNmom[0]*fNmom[0]+fNmom[1]*fNmom[1]+fNmom[2]*fNmom[2])/prec;
373 const Double_t * cp = fParamP.GetCovariance();
374 const Double_t * cm = fParamN.GetCovariance();
375 Double_t sigmaAP0 = fgkParams.fPSigmaOffsetAP0*fgkParams.fPSigmaOffsetAP0; // minimal part
376 sigmaAP0 += (cp[5]+cp[9])*(normp*normp)+(cm[5]+cm[9])*(normm*normm); // angular resolution part
377 Double_t sigmaAP1 = GetSigmaD0()/(TMath::Abs(fRr)+0.01); // vertex position part
378 sigmaAP0 += 0.5*sigmaAP1*sigmaAP1;
379 return (sigmaAP0>0)? TMath::Sqrt(sigmaAP0):100;
382 Double_t AliESDv0::GetEffectiveSigmaD0(){
384 // minimax - effective Sigma parameterization
385 // p12 effective curvature and v0 radius postion used as parameters
387 Double_t p12 = TMath::Sqrt(fParamP.GetParameter()[4]*fParamP.GetParameter()[4]+
388 fParamN.GetParameter()[4]*fParamN.GetParameter()[4]);
389 Double_t sigmaED0= TMath::Max(TMath::Sqrt(fRr)-fgkParams.fPSigmaRminDE,0.0)*fgkParams.fPSigmaCoefDE*p12*p12;
392 sigmaED0 = TMath::Sqrt(sigmaED0+fgkParams.fPSigmaOffsetDE*fgkParams.fPSigmaOffsetDE);
393 return (sigmaED0<fgkParams.fPSigmaMaxDE) ? sigmaED0: fgkParams.fPSigmaMaxDE;
397 Double_t AliESDv0::GetEffectiveSigmaAP0(){
399 // effective Sigma parameterization of point angle resolution
401 Double_t p12 = TMath::Sqrt(fParamP.GetParameter()[4]*fParamP.GetParameter()[4]+
402 fParamN.GetParameter()[4]*fParamN.GetParameter()[4]);
403 Double_t sigmaAPE= fgkParams.fPSigmaBase0APE;
404 sigmaAPE+= fgkParams.fPSigmaR0APE/(fgkParams.fPSigmaR1APE+fRr);
405 sigmaAPE*= (fgkParams.fPSigmaP0APE+fgkParams.fPSigmaP1APE*p12);
406 sigmaAPE = TMath::Min(sigmaAPE,fgkParams.fPSigmaMaxAPE);
411 Double_t AliESDv0::GetMinimaxSigmaAP0(){
413 // calculate mini-max effective sigma of point angle resolution
415 //compv0->fTree->SetAlias("SigmaAP2","max(min((SigmaAP0+SigmaAPE0)*0.5,1.5*SigmaAPE0),0.5*SigmaAPE0+0.003)");
416 Double_t effectiveSigma = GetEffectiveSigmaAP0();
417 Double_t sigmaMMAP = 0.5*(GetSigmaAP0()+effectiveSigma);
418 sigmaMMAP = TMath::Min(sigmaMMAP, fgkParams.fPMaxFractionAP0*effectiveSigma);
419 sigmaMMAP = TMath::Max(sigmaMMAP, fgkParams.fPMinFractionAP0*effectiveSigma+fgkParams.fPMinAP0);
422 Double_t AliESDv0::GetMinimaxSigmaD0(){
424 // calculate mini-max sigma of dca resolution
426 //compv0->fTree->SetAlias("SigmaD2","max(min((SigmaD0+SigmaDE0)*0.5,1.5*SigmaDE0),0.5*SigmaDE0)");
427 Double_t effectiveSigma = GetEffectiveSigmaD0();
428 Double_t sigmaMMD0 = 0.5*(GetSigmaD0()+effectiveSigma);
429 sigmaMMD0 = TMath::Min(sigmaMMD0, fgkParams.fPMaxFractionD0*effectiveSigma);
430 sigmaMMD0 = TMath::Max(sigmaMMD0, fgkParams.fPMinFractionD0*effectiveSigma+fgkParams.fPMinD0);
435 Double_t AliESDv0::GetLikelihoodAP(Int_t mode0, Int_t mode1){
437 // get likelihood for point angle
439 Double_t sigmaAP = 0.007; //default sigma
442 sigmaAP = GetSigmaAP0(); // mode 0 - covariance matrix estimates used
445 sigmaAP = GetEffectiveSigmaAP0(); // mode 1 - effective sigma used
448 sigmaAP = GetMinimaxSigmaAP0(); // mode 2 - minimax sigma
451 Double_t apNorm = TMath::Min(TMath::ACos(fPointAngle)/sigmaAP,50.);
452 //normalized point angle, restricted - because of overflow problems in Exp
453 Double_t likelihood = 0;
456 likelihood = TMath::Exp(-0.5*apNorm*apNorm);
460 likelihood = (TMath::Exp(-0.5*apNorm*apNorm)+0.5* TMath::Exp(-0.25*apNorm*apNorm))/1.5;
464 likelihood = (TMath::Exp(-0.5*apNorm*apNorm)+0.5* TMath::Exp(-0.25*apNorm*apNorm)+0.25*TMath::Exp(-0.125*apNorm*apNorm))/1.75;
471 Double_t AliESDv0::GetLikelihoodD(Int_t mode0, Int_t mode1){
473 // get likelihood for DCA
475 Double_t sigmaD = 0.03; //default sigma
478 sigmaD = GetSigmaD0(); // mode 0 - covariance matrix estimates used
481 sigmaD = GetEffectiveSigmaD0(); // mode 1 - effective sigma used
484 sigmaD = GetMinimaxSigmaD0(); // mode 2 - minimax sigma
488 //Bo: Double_t dNorm = TMath::Min(fDist2/sigmaD,50.);
489 Double_t dNorm = TMath::Min(fDcaV0Daughters/sigmaD,50.);//Bo:
490 //normalized point angle, restricted - because of overflow problems in Exp
491 Double_t likelihood = 0;
494 likelihood = TMath::Exp(-2.*dNorm);
498 likelihood = (TMath::Exp(-2.*dNorm)+0.5* TMath::Exp(-dNorm))/1.5;
502 likelihood = (TMath::Exp(-2.*dNorm)+0.5* TMath::Exp(-dNorm)+0.25*TMath::Exp(-0.5*dNorm))/1.75;
510 Double_t AliESDv0::GetLikelihoodC(Int_t mode0, Int_t /*mode1*/){
512 // get likelihood for Causality
513 // !!! Causality variables defined in AliITStrackerMI !!!
514 // when more information was available
516 Double_t likelihood = 0.5;
517 Double_t minCausal = TMath::Min(fCausality[0],fCausality[1]);
518 Double_t maxCausal = TMath::Max(fCausality[0],fCausality[1]);
519 // minCausal = TMath::Max(minCausal,0.5*maxCausal);
520 //compv0->fTree->SetAlias("LCausal","(1.05-(2*(0.8-exp(-max(RC.fV0rec.fCausality[0],RC.fV0rec.fCausality[1])))+2*(0.8-exp(-min(RC.fV0rec.fCausality[0],RC.fV0rec.fCausality[1]))))/2)**4");
525 likelihood = TMath::Power((1.05-2*(0.8-TMath::Exp(-maxCausal))),4.);
528 likelihood = TMath::Power(1.05-(2*(0.8-TMath::Exp(-maxCausal))+(2*(0.8-TMath::Exp(-minCausal))))*0.5,4.);
535 void AliESDv0::SetCausality(Float_t pb0, Float_t pb1, Float_t pa0, Float_t pa1)
540 fCausality[0] = pb0; // probability - track 0 exist before vertex
541 fCausality[1] = pb1; // probability - track 1 exist before vertex
542 fCausality[2] = pa0; // probability - track 0 exist close after vertex
543 fCausality[3] = pa1; // probability - track 1 exist close after vertex
545 void AliESDv0::SetClusters(Int_t *clp, Int_t *clm)
548 // Set its clusters indexes
550 for (Int_t i=0;i<6;i++) fClusters[0][i] = clp[i];
551 for (Int_t i=0;i<6;i++) fClusters[1][i] = clm[i];