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 //====================================================================================================================================================
18 // Description of an ALICE muon forward track pair, i.e. a pair of AliMuonForwardTrack objects
20 // Contact author: antonio.uras@cern.ch
22 //====================================================================================================================================================
25 #include "AliMUONTrackParam.h"
26 #include "TParticle.h"
27 #include "AliMuonForwardTrack.h"
28 #include "AliMUONTrackExtrap.h"
29 #include "TClonesArray.h"
30 #include "TDatabasePDG.h"
31 #include "TLorentzVector.h"
33 #include "AliMuonForwardTrackPair.h"
35 ClassImp(AliMuonForwardTrackPair)
37 //====================================================================================================================================================
39 AliMuonForwardTrackPair::AliMuonForwardTrackPair():
41 fMuonForwardTracks(0),
45 fXPointOfClosestApproach(9999),
46 fYPointOfClosestApproach(9999),
47 fZPointOfClosestApproach(9999)
50 // default constructor
52 fMuonForwardTracks = new TClonesArray("AliMuonForwardTrack", 2);
53 fMuonForwardTracks -> SetOwner(kTRUE);
57 //====================================================================================================================================================
59 AliMuonForwardTrackPair::AliMuonForwardTrackPair(AliMuonForwardTrack *track0, AliMuonForwardTrack *track1):
61 fMuonForwardTracks(0),
65 fXPointOfClosestApproach(9999),
66 fYPointOfClosestApproach(9999),
67 fZPointOfClosestApproach(9999)
70 fMuonForwardTracks = new TClonesArray("AliMuonForwardTrack", 2);
71 fMuonForwardTracks->SetOwner(kTRUE);
72 new ((*fMuonForwardTracks)[0]) AliMuonForwardTrack(*track0);
73 new ((*fMuonForwardTracks)[1]) AliMuonForwardTrack(*track1);
76 SetPointOfClosestApproach();
80 //====================================================================================================================================================
82 AliMuonForwardTrackPair::AliMuonForwardTrackPair(const AliMuonForwardTrackPair& trackPair):
84 fMuonForwardTracks(NULL),
85 fKinemMC(trackPair.fKinemMC),
86 fKinem(trackPair.fKinem),
87 fIsKinemSet(trackPair.fIsKinemSet),
88 fXPointOfClosestApproach(trackPair.fXPointOfClosestApproach),
89 fYPointOfClosestApproach(trackPair.fYPointOfClosestApproach),
90 fZPointOfClosestApproach(trackPair.fZPointOfClosestApproach)
94 fMuonForwardTracks = new TClonesArray(*(trackPair.fMuonForwardTracks));
95 fMuonForwardTracks -> SetOwner(kTRUE);
99 //====================================================================================================================================================
101 AliMuonForwardTrackPair& AliMuonForwardTrackPair::operator=(const AliMuonForwardTrackPair& trackPair) {
103 // Asignment operator
105 // check assignement to self
106 if (this == &trackPair) return *this;
108 // base class assignement
109 AliMuonForwardTrackPair::operator=(trackPair);
114 fMuonForwardTracks = new TClonesArray(*(trackPair.fMuonForwardTracks));
115 fMuonForwardTracks->SetOwner(kTRUE);
117 fKinemMC = trackPair.fKinemMC;
118 fKinem = trackPair.fKinem;
119 fIsKinemSet = trackPair.fIsKinemSet;
120 fXPointOfClosestApproach = trackPair.fXPointOfClosestApproach;
121 fYPointOfClosestApproach = trackPair.fYPointOfClosestApproach;
122 fZPointOfClosestApproach = trackPair.fZPointOfClosestApproach;
128 //====================================================================================================================================================
130 Double_t AliMuonForwardTrackPair::GetWeightedOffset(Double_t x, Double_t y, Double_t z) {
132 Double_t weightedOffset[2]={0};
134 weightedOffset[0] = GetTrack(0)->GetWeightedOffset(x, y, z);
135 weightedOffset[1] = GetTrack(1)->GetWeightedOffset(x, y, z);
137 Double_t weightedOffsetDimuon = TMath::Sqrt(0.5 * (weightedOffset[0]*weightedOffset[0] + weightedOffset[1]*weightedOffset[1]));
139 return weightedOffsetDimuon;
143 //====================================================================================================================================================
145 Double_t AliMuonForwardTrackPair::GetWeightedOffsetAtPCA() {
147 return GetWeightedOffset(fXPointOfClosestApproach, fYPointOfClosestApproach, fZPointOfClosestApproach);
151 //====================================================================================================================================================
153 Double_t AliMuonForwardTrackPair::GetPCAQuality() {
155 Double_t wOffset_1 = GetTrack(0)->GetWeightedOffset(fXPointOfClosestApproach, fYPointOfClosestApproach, fZPointOfClosestApproach);
156 Double_t wOffset_2 = GetTrack(1)->GetWeightedOffset(fXPointOfClosestApproach, fYPointOfClosestApproach, fZPointOfClosestApproach);
158 Double_t f1 = TMath::Exp(-0.5 * wOffset_1);
159 Double_t f2 = TMath::Exp(-0.5 * wOffset_2);
161 if (f1+f2 > 0.) return (2.*f1*f2)/(f1+f2);
166 //====================================================================================================================================================
168 Double_t AliMuonForwardTrackPair::GetMassWithoutMFT(Double_t x, Double_t y, Double_t z, Int_t nClusters) {
170 Int_t idCluster[2] = {0};
172 idCluster[0] = GetTrack(0)->GetNMUONClusters() - nClusters;
173 idCluster[1] = GetTrack(1)->GetNMUONClusters() - nClusters;
175 if (idCluster[0]<0) idCluster[0] = 0;
176 if (idCluster[1]<0) idCluster[1] = 0;
178 AliMUONTrackParam *param0 = GetTrack(0)->GetTrackParamAtMUONCluster(idCluster[0]);
179 AliMUONTrackParam *param1 = GetTrack(1)->GetTrackParamAtMUONCluster(idCluster[1]);
181 AliDebug(2, Form("MUON before extrap: 1st muon = (%f, %f, %f) 2nd muon = (%f, %f, %f)",
182 param0->Px(), param0->Py(), param0->Pz(), param1->Px(), param1->Py(), param1->Pz()));
184 AliDebug(2, Form("Extrapolating 1st muon from z = %f to z = %f", param0->GetZ(), z));
185 AliMUONTrackExtrap::ExtrapToVertex(param0, x, y, z, 0., 0.); // this should reproduce what is done in AliMUONESDInterface::MUONToESD(...)
186 AliDebug(2, Form("Extrapolating 2nd muon from z = %f to z = %f", param1->GetZ(), z));
187 AliMUONTrackExtrap::ExtrapToVertex(param1, x, y, z, 0., 0.); // this should reproduce what is done in AliMUONESDInterface::MUONToESD(...)
189 AliDebug(2, Form("MUON after extrap: 1st muon = (%f, %f, %f) 2nd muon = (%f, %f, %f)",
190 param0->Px(), param0->Py(), param0->Pz(), param1->Px(), param1->Py(), param1->Pz()));
192 Double_t momentum[2] = {0};
194 momentum[0] = param0->P();
195 momentum[1] = param1->P();
197 Double_t mMu = TDatabasePDG::Instance()->GetParticle("mu-")->Mass();
201 dimu.SetE(TMath::Sqrt(mMu*mMu + momentum[0]*momentum[0]) + TMath::Sqrt(mMu*mMu + momentum[1]*momentum[1]));
203 dimu.SetPx(param0->Px() + param1->Px());
204 dimu.SetPy(param0->Py() + param1->Py());
205 dimu.SetPz(param0->Pz() + param1->Pz());
211 //====================================================================================================================================================
213 void AliMuonForwardTrackPair::SetKinemMC() {
215 if ( !(GetTrack(0)->GetMCTrackRef()) || !(GetTrack(1)->GetMCTrackRef()) ) return;
217 AliDebug(2, Form("MC: 1st muon = (%f, %f, %f) 2nd muon = (%f, %f, %f)",
218 GetTrack(0)->GetMCTrackRef()->Px(), GetTrack(0)->GetMCTrackRef()->Py(), GetTrack(0)->GetMCTrackRef()->Pz(),
219 GetTrack(1)->GetMCTrackRef()->Px(), GetTrack(1)->GetMCTrackRef()->Py(), GetTrack(1)->GetMCTrackRef()->Pz()));
221 fKinemMC.SetE(GetTrack(0)->GetMCTrackRef()->Energy() + GetTrack(1)->GetMCTrackRef()->Energy());
223 fKinemMC.SetPx(GetTrack(0)->GetMCTrackRef()->Px() + GetTrack(1)->GetMCTrackRef()->Px());
224 fKinemMC.SetPy(GetTrack(0)->GetMCTrackRef()->Py() + GetTrack(1)->GetMCTrackRef()->Py());
225 fKinemMC.SetPz(GetTrack(0)->GetMCTrackRef()->Pz() + GetTrack(1)->GetMCTrackRef()->Pz());
229 //====================================================================================================================================================
231 void AliMuonForwardTrackPair::SetKinem(Double_t z, Int_t nClusters) {
233 // if (!fMuonForwardTracks) return kFALSE;
234 // if (!fMuonForwardTracks->At(0) || !fMuonForwardTracks->At(1)) return kFALSE;
236 Int_t idCluster[2] = {0};
238 idCluster[0] = GetTrack(0)->GetNMFTClusters() - nClusters;
239 idCluster[1] = GetTrack(1)->GetNMFTClusters() - nClusters;
241 if (idCluster[0]<0) idCluster[0] = 0;
242 if (idCluster[1]<0) idCluster[1] = 0;
244 Double_t momentum[2] = {0};
246 AliMUONTrackParam *param0 = GetTrack(0)->GetTrackParamAtMFTCluster(idCluster[0]);
247 AliMUONTrackParam *param1 = GetTrack(1)->GetTrackParamAtMFTCluster(idCluster[1]);
249 AliDebug(2, Form("MFT before extrap: 1st muon = (%f, %f, %f) 2nd muon = (%f, %f, %f)",
250 param0->Px(), param0->Py(), param0->Pz(), param1->Px(), param1->Py(), param1->Pz()));
252 if (TMath::Abs(z)<1e6) {
253 AliDebug(2, Form("Extrapolating 1st muon from z = %f to z = %f", param0->GetZ(), z));
254 AliMUONTrackExtrap::ExtrapToZCov(param0, z);
255 AliDebug(2, Form("Extrapolating 2nd muon from z = %f to z = %f", param1->GetZ(), z));
256 AliMUONTrackExtrap::ExtrapToZCov(param1, z);
259 AliDebug(2, Form("MFT after extrap: 1st muon = (%f, %f, %f) 2nd muon = (%f, %f, %f)",
260 param0->Px(), param0->Py(), param0->Pz(), param1->Px(), param1->Py(), param1->Pz()));
262 momentum[0] = (param0->P());
263 momentum[1] = (param1->P());
265 Double_t mMu = TDatabasePDG::Instance()->GetParticle("mu-")->Mass();
267 fKinem.SetE(TMath::Sqrt(mMu*mMu + momentum[0]*momentum[0]) + TMath::Sqrt(mMu*mMu + momentum[1]*momentum[1]));
268 fKinem.SetPx(param0->Px() + param1->Px());
269 fKinem.SetPy(param0->Py() + param1->Py());
270 fKinem.SetPz(param0->Pz() + param1->Pz());
276 //====================================================================================================================================================
278 void AliMuonForwardTrackPair::SetPointOfClosestApproach() {
280 AliMUONTrackParam *param0 = GetTrack(0)->GetTrackParamAtMFTCluster(0);
281 AliMUONTrackParam *param1 = GetTrack(1)->GetTrackParamAtMFTCluster(0);
283 Double_t step = 1.; // in cm
284 Double_t startPoint = 0.;
286 Double_t r[3]={0}, z[3]={startPoint, startPoint+step, startPoint+2*step};
288 for (Int_t i=0; i<3; i++) {
289 AliMUONTrackExtrap::ExtrapToZCov(param0, z[i]);
290 AliMUONTrackExtrap::ExtrapToZCov(param1, z[i]);
291 Double_t dX = param0->GetNonBendingCoor() - param1->GetNonBendingCoor();
292 Double_t dY = param0->GetBendingCoor() - param1->GetBendingCoor();
293 r[i] = TMath::Sqrt(dX*dX + dY*dY);
296 Double_t researchDirection=0.;
298 if (r[0]>r[1] && r[1]>r[2]) researchDirection = +1.; // towards z positive
299 else if (r[0]<r[1] && r[1]<r[2]) researchDirection = -1.; // towards z negative
300 else if (r[0]<r[1] && r[1]>r[2]) {
301 AliError("Point of closest approach cannot be found for dimuon (no minima)");
305 while (TMath::Abs(researchDirection)>0.5) {
306 if (researchDirection>0.) {
309 z[2] = z[1]+researchDirection*step;
314 z[0] = z[1]+researchDirection*step;
316 if (TMath::Abs(z[0])>900.) {
317 AliError("Point of closest approach cannot be found for dimuon (no minima)");
320 for (Int_t i=0; i<3; i++) {
321 AliMUONTrackExtrap::ExtrapToZCov(param0, z[i]);
322 AliMUONTrackExtrap::ExtrapToZCov(param1, z[i]);
323 Double_t dX = param0->GetNonBendingCoor() - param1->GetNonBendingCoor();
324 Double_t dY = param0->GetBendingCoor() - param1->GetBendingCoor();
325 r[i] = TMath::Sqrt(dX*dX + dY*dY);
327 researchDirection=0.;
328 if (r[0]>r[1] && r[1]>r[2]) researchDirection = +1.; // towards z positive
329 else if (r[0]<r[1] && r[1]<r[2]) researchDirection = -1.; // towards z negative
332 AliDebug(2,"Minimum region has been found");
335 while (step>AliMFTConstants::fPrecisionPointOfClosestApproach) {
338 for (Int_t i=0; i<3; i++) {
339 AliMUONTrackExtrap::ExtrapToZCov(param0, z[i]);
340 AliMUONTrackExtrap::ExtrapToZCov(param1, z[i]);
341 Double_t dX = param0->GetNonBendingCoor() - param1->GetNonBendingCoor();
342 Double_t dY = param0->GetBendingCoor() - param1->GetBendingCoor();
343 r[i] = TMath::Sqrt(dX*dX + dY*dY);
345 if (r[0]<r[1]) z[1] = z[0];
346 else if (r[2]<r[1]) z[1] = z[2];
350 fZPointOfClosestApproach = z[1];
351 AliMUONTrackExtrap::ExtrapToZCov(param0, fZPointOfClosestApproach);
352 AliMUONTrackExtrap::ExtrapToZCov(param1, fZPointOfClosestApproach);
353 fXPointOfClosestApproach = 0.5*(param0->GetNonBendingCoor() + param1->GetNonBendingCoor());
354 fYPointOfClosestApproach = 0.5*(param0->GetBendingCoor() + param1->GetBendingCoor());
356 AliDebug(2,Form("Point of Closest Approach: (%f, %f, %f)",fXPointOfClosestApproach,fYPointOfClosestApproach,fZPointOfClosestApproach));
360 //====================================================================================================================================================
362 Bool_t AliMuonForwardTrackPair::IsResonance() {
364 Bool_t result = kFALSE;
366 Int_t labelMC[2] = {0};
367 Int_t codePDG[2] = {0};
369 for (Int_t iTrack=0; iTrack<2; iTrack++) {
370 labelMC[iTrack] = GetTrack(iTrack)->GetParentMCLabel(0);
371 codePDG[iTrack] = GetTrack(iTrack)->GetParentPDGCode(0);
374 AliDebug(1, Form("Muons' mothers: (%d, %d)", labelMC[0], labelMC[1]));
376 if (labelMC[0]==labelMC[1] && codePDG[0]==codePDG[1] && (codePDG[0]== 113 ||
382 codePDG[0]==100443 ||
384 codePDG[0]==100553 ) ) result = kTRUE;
386 if (result) AliDebug(1, Form("Pair is a resonance %d", codePDG[0]));
392 //====================================================================================================================================================