--- /dev/null
+// AliAODDimuon: a class for AODs for the MUON Arm of the ALICE Experiment
+// Author: P. Cortese, Universita' del Piemonte Orientale in Alessandria and
+// INFN of Torino - Italy
+//
+// The class defines a dimuon pair object from two AliAODTrack objects.
+// AliAODDimuon objects are supposed to be added to the AliAODEvent structure
+// during analysis. They would then allow to calculate the dimuon-related
+// kinematic variables with a minimal disk occupancy.
+// The payload of the class has been reduced to two pointers to the two
+// tracks. An instance of this class has also to be added to the AliAODEvent
+// structure to provide additional information that is specific to MUON and
+// therefore has not been included into the AOD header.
+// Two transient data members are not stored on file as they can be recomputed
+// at runtime.
+//
+
+#include "AliAODDimuon.h"
+#include "TLorentzVector.h"
+#define AliAODDimuon_CXX
+
+ClassImp(AliAODDimuon)
+
+//______________________________________________________________________________
+AliAODDimuon::AliAODDimuon():AliVParticle(),fP(0),fMProton(0.93827231)
+{
+ // default constructor
+ fMu[0]=0;
+ fMu[1]=0;
+}
+
+//______________________________________________________________________________
+AliAODDimuon::AliAODDimuon(const AliAODDimuon& dimu):
+ AliVParticle(dimu),
+ fP(0),fMProton(0.93827231)
+{
+ // copy constructor
+ fMu[0]=dimu.Mu(0);
+ fMu[1]=dimu.Mu(1);
+}
+
+//______________________________________________________________________________
+AliAODDimuon &AliAODDimuon::operator=(const AliAODDimuon& dimu)
+{
+ // assignment operator
+ if(&dimu != this){
+ fP=0;
+ fMProton=0.93827231;
+ fMu[0]=dimu.Mu(0);
+ fMu[1]=dimu.Mu(1);
+ }
+ return *this;
+}
+
+//______________________________________________________________________________
+AliAODDimuon::AliAODDimuon(TObject *mu0, TObject *mu1):
+ fP(0),fMProton(0.93827231)
+{
+ // Creates a dimuon pair from two tracks
+
+ //printf("Creating dimuon from %p %p\n",mu0,mu1);
+ fMu[0]=mu0;
+ fMu[1]=mu1;
+}
+
+//______________________________________________________________________________
+AliAODDimuon::~AliAODDimuon()
+{
+ // destructor
+ if(fP)delete fP;
+ fP=0;
+}
+
+//______________________________________________________________________________
+void AliAODDimuon::BookP(){
+ // Fills the dimuon momentum if not filled yet
+ static UInt_t unID[2]={0,0};
+ if(!fP){
+ fP=new TLorentzVector(Px(),Py(),Pz(),E());
+ unID[0]=fMu[0].GetUniqueID();
+ unID[1]=fMu[1].GetUniqueID();
+ }
+ // For efficiency reasons
+ if((unID[0]!=fMu[0].GetUniqueID())||(unID[1]!=fMu[1].GetUniqueID())){
+ fP->SetPxPyPzE(Px(),Py(),Pz(),E());
+ unID[0]=fMu[0].GetUniqueID();
+ unID[1]=fMu[1].GetUniqueID();
+ }
+}
+
+//______________________________________________________________________________
+Double_t AliAODDimuon::Px() const {
+ // Px of the dimuon
+ if(this->CheckPointers())return -999999999;
+ return ((AliAODTrack*)fMu[0].GetObject())->Px()+
+ ((AliAODTrack*)fMu[1].GetObject())->Px();
+}
+
+//______________________________________________________________________________
+Double_t AliAODDimuon::Py() const {
+ // Py of the dimuon
+ if(this->CheckPointers())return -999999999;
+ return ((AliAODTrack*)fMu[0].GetObject())->Py()+
+ ((AliAODTrack*)fMu[1].GetObject())->Py();
+}
+
+//______________________________________________________________________________
+Double_t AliAODDimuon::Pz() const {
+ // Pz of the dimuon
+ if(this->CheckPointers())return -999999999;
+ return ((AliAODTrack*)fMu[0].GetObject())->Pz()+
+ ((AliAODTrack*)fMu[1].GetObject())->Pz();
+}
+
+//______________________________________________________________________________
+Double_t AliAODDimuon::Pt() const {
+ // Pt of the dimuon
+ if(this->CheckPointers())return -999999999;
+ Double_t px=Px();
+ Double_t py=Py();
+ return TMath::Sqrt(px*px+py*py);
+ return -999999999;
+}
+
+//______________________________________________________________________________
+Double_t AliAODDimuon::E() const {
+ // Dimuon energy
+ if(this->CheckPointers())return -999999999;
+ return ((AliAODTrack*)fMu[0].GetObject())->E()+
+ ((AliAODTrack*)fMu[1].GetObject())->E();
+}
+
+//______________________________________________________________________________
+Double_t AliAODDimuon::P() const {
+ // This is just to override the virtual function
+ printf("You should never call: Double_t AliAODDimuon::P() const\n");
+ return -999999999;
+}
+
+//______________________________________________________________________________
+Double_t AliAODDimuon::P() {
+ // Dimuon momentum
+ if(this->CheckPointers())return -999999999;
+ BookP();
+ return fP->P();
+}
+
+//______________________________________________________________________________
+Double_t AliAODDimuon::M() const {
+ // This is just to override the virtual function
+ printf("You should never call: Double_t AliAODDimuon::M() const\n");
+ return -999999999;
+}
+
+//______________________________________________________________________________
+Double_t AliAODDimuon::M() {
+ // Dimuon invariant mass
+ if(this->CheckPointers())return -999999999;
+ BookP();
+ return fP->M();
+}
+
+//______________________________________________________________________________
+Double_t AliAODDimuon::Mass() {
+ // Dimuon invariant mass
+ if(this->CheckPointers())return -999999999;
+ BookP();
+ return fP->M();
+}
+
+//______________________________________________________________________________
+Double_t AliAODDimuon::Eta() const {
+ // This is just to override the virtual function
+ printf("You should never call: Double_t AliAODDimuon::Eta() const\n");
+ return -999999999;
+}
+
+//______________________________________________________________________________
+Double_t AliAODDimuon::Eta() {
+ // Dimuon pseudorapidity
+ if(this->CheckPointers())return -999999999;
+ BookP();
+ return fP->Eta();
+}
+
+//______________________________________________________________________________
+Double_t AliAODDimuon::Phi() const {
+ // This is just to override the virtual function
+ printf("You should never call: Double_t AliAODDimuon::Phi() const\n");
+ return -999999999;
+}
+
+//______________________________________________________________________________
+Double_t AliAODDimuon::Phi() {
+ // Dimuon asimuthal angle
+ if(this->CheckPointers())return -999999999;
+ BookP();
+ return fP->Phi();
+}
+//______________________________________________________________________________
+Double_t AliAODDimuon::Theta() const {
+ // This is just to override the virtual function
+ printf("You should never call: Double_t AliAODDimuon::Theta() const\n");
+ return -999999999;
+}
+
+//______________________________________________________________________________
+Double_t AliAODDimuon::Theta() {
+ // Dimuon polar angle
+ if(this->CheckPointers())return -999999999;
+ BookP();
+ return fP->Theta();
+}
+
+//______________________________________________________________________________
+Double_t AliAODDimuon::Y() const {
+ // This is just to override the virtual function
+ printf("You should never call: Double_t AliAODDimuon::Y() const\n");
+ return -999999999;
+}
+
+//______________________________________________________________________________
+Double_t AliAODDimuon::Y() {
+ // Dimuon rapidity
+ if(this->CheckPointers())return -999999999;
+ BookP();
+ return fP->Rapidity();
+}
+
+//______________________________________________________________________________
+Short_t AliAODDimuon::Charge() const {
+ // Dimuon charge
+ if(this->CheckPointers())return -999;
+ return ((AliAODTrack*)fMu[0].GetObject())->Charge()+
+ ((AliAODTrack*)fMu[1].GetObject())->Charge();
+}
+
+//______________________________________________________________________________
+Int_t AliAODDimuon::CheckPointers() const{
+ // Checks if the track pointers have been initialized
+ if(fMu[0]==0||fMu[1]==0){
+ printf("Dimuon not initialized\n");
+ return -999;
+ }
+ if((fMu[0].GetObject())==0||(fMu[1].GetObject())==0){
+ printf("Can not get objects. Got: %p %p\n",fMu[0].GetObject(),fMu[1].GetObject());
+ return -999;
+ }
+ return 0;
+}
+
+//______________________________________________________________________________
+void AliAODDimuon::SetMu(Int_t imu, AliAODTrack *mu){
+ // Assign a track pointer
+ if (imu==0||imu==1){
+ fMu[imu]=mu;
+ }
+}
+
+//______________________________________________________________________________
+void AliAODDimuon::SetMuons(AliAODTrack *mu0, AliAODTrack *mu1){
+ // Assign the track pointers
+ fMu[0]=mu0;
+ fMu[1]=mu1;
+}
+
+//______________________________________________________________________________
+Double_t AliAODDimuon::XF() {
+ // Dimuon Feynman x
+ //Double_t ebeam=((AliAODEventInfo*)fEi.GetObject())->EBeam();
+ Double_t ebeam = 3500.; // temporary
+ if(ebeam<=0){
+ printf("AliAODDimuon::xf: can not compute xf with EBeam=%f\n",ebeam);
+ return -999999999;
+ }
+ if(this->CheckPointers())return -999999999;
+ BookP();
+ Double_t mDimu=M();
+ Double_t pMax=TMath::Sqrt(ebeam*ebeam-mDimu*mDimu);
+ return Pz()/pMax;
+}
+
+//______________________________________________________________________________
+// Calculation the Collins-Soper angle (adapted from code by R. Arnaldi)
+Double_t AliAODDimuon::CostCS(){
+ // Cosinus of the Collins-Soper polar decay angle
+ if(CheckPointers())return -999999999;
+ Double_t ebeam=3500.; //temporary
+ if(ebeam<=0){
+ printf("Can not compute costCS with EBeam=%f\n",ebeam);
+ return -999999999;
+ }
+ Double_t mp=fMProton;
+ Double_t pbeam=TMath::Sqrt(ebeam*ebeam-mp*mp);
+ Double_t pla10=((AliAODTrack*)fMu[0].GetObject())->Px();
+ Double_t pla11=((AliAODTrack*)fMu[0].GetObject())->Py();
+ Double_t pla12=((AliAODTrack*)fMu[0].GetObject())->Pz();
+ Double_t e1=((AliAODTrack*)fMu[0].GetObject())->E();
+ Double_t mu1Charge=((AliAODTrack*)fMu[0].GetObject())->Charge();
+ Double_t pla20=((AliAODTrack*)fMu[1].GetObject())->Px();
+ Double_t pla21=((AliAODTrack*)fMu[1].GetObject())->Py();
+ Double_t pla22=((AliAODTrack*)fMu[1].GetObject())->Pz();
+ Double_t e2=((AliAODTrack*)fMu[1].GetObject())->E();
+ Double_t mu2Charge=((AliAODTrack*)fMu[1].GetObject())->Charge();
+
+ // Fill the Lorentz vector for projectile and target
+ // For the moment we do not consider the crossing angle
+ // Projectile runs towards the MUON arm
+ TLorentzVector pProjLab(0.,0.,-pbeam,ebeam); // projectile
+ TLorentzVector pTargLab(0.,0., pbeam,ebeam); // target
+ //
+ // --- Get the muons parameters in the LAB frame
+ //
+ TLorentzVector pMu1Lab(pla10,pla11,pla12,e1);
+ TLorentzVector pMu2Lab(pla20,pla21,pla22,e2);
+ //
+ // --- Obtain the dimuon parameters in the LAB frame
+ //
+ TLorentzVector pDimuLab=pMu1Lab+pMu2Lab;
+ //
+ // --- Translate the dimuon parameters in the dimuon rest frame
+ //
+ TVector3 beta=(-1./pDimuLab.E())*pDimuLab.Vect();
+ TLorentzVector pMu1Dimu=pMu1Lab;
+ TLorentzVector pMu2Dimu=pMu2Lab;
+ TLorentzVector pProjDimu=pProjLab;
+ TLorentzVector pTargDimu=pTargLab;
+ pMu1Dimu.Boost(beta);
+ pMu2Dimu.Boost(beta);
+ pProjDimu.Boost(beta);
+ pTargDimu.Boost(beta);
+ //
+ // --- Determine the z axis for the CS angle
+ //
+ TVector3 zaxisCS=(((pProjDimu.Vect()).Unit())-((pTargDimu.Vect()).Unit())).Unit();
+ //
+ // --- Determine the CS angle (angle between mu+ and the z axis defined above)
+ //
+ Double_t cost;
+ if(mu1Charge > 0) {
+ cost = zaxisCS.Dot((pMu1Dimu.Vect()).Unit());
+ // Theta CS is not properly defined for Like-Sign muons
+ if(mu2Charge > 0 && cost<0) cost=-cost;
+ } else {
+ // Theta CS is not properly defined for Like-Sign muons
+ cost = zaxisCS.Dot((pMu2Dimu.Vect()).Unit());
+ if(mu2Charge < 0 && cost<0) cost=-cost;
+ }
+ return cost;
+}
+
+//______________________________________________________________________________
+// Calculation the Helicity polarization angle (adapted from code by R. Arnaldi)
+Double_t AliAODDimuon::CostHe(){
+ // Cosinus of the polar decay angle in the Helicity reference frame
+ if(CheckPointers())return -999999999;
+ Double_t ebeam=3500; //temporary
+ if(ebeam<=0){
+ printf("Can not compute costCS with EBeam=%f\n",ebeam);
+ return -999999999;
+ }
+ Double_t pbeam=TMath::Sqrt(ebeam*ebeam-fMProton*fMProton);
+ Double_t pla10=((AliAODTrack*)fMu[0].GetObject())->Px();
+ Double_t pla11=((AliAODTrack*)fMu[0].GetObject())->Py();
+ Double_t pla12=((AliAODTrack*)fMu[0].GetObject())->Pz();
+ Double_t e1=((AliAODTrack*)fMu[0].GetObject())->E();
+ Double_t mu1Charge=((AliAODTrack*)fMu[0].GetObject())->Charge();
+ Double_t pla20=((AliAODTrack*)fMu[1].GetObject())->Px();
+ Double_t pla21=((AliAODTrack*)fMu[1].GetObject())->Py();
+ Double_t pla22=((AliAODTrack*)fMu[1].GetObject())->Pz();
+ Double_t e2=((AliAODTrack*)fMu[1].GetObject())->E();
+ Double_t mu2Charge=((AliAODTrack*)fMu[1].GetObject())->Charge();
+
+ // Fill the Lorentz vector for projectile and target
+ // For the moment we consider no crossing angle
+ // Projectile runs towards the MUON arm
+ TLorentzVector pProjLab(0.,0.,-pbeam,ebeam); // projectile
+ TLorentzVector pTargLab(0.,0., pbeam,ebeam); // target
+ //
+ // --- Get the muons parameters in the LAB frame
+ //
+ TLorentzVector pMu1Lab(pla10,pla11,pla12,e1);
+ TLorentzVector pMu2Lab(pla20,pla21,pla22,e2);
+ //
+ // --- Obtain the dimuon parameters in the LAB frame
+ //
+ TLorentzVector pDimuLab=pMu1Lab+pMu2Lab;
+ //
+ // --- Translate the dimuon parameters in the dimuon rest frame
+ //
+ TVector3 beta=(-1./pDimuLab.E())*pDimuLab.Vect();
+ TLorentzVector pMu1Dimu=pMu1Lab;
+ TLorentzVector pMu2Dimu=pMu2Lab;
+ pMu1Dimu.Boost(beta);
+ pMu2Dimu.Boost(beta);
+ //
+ // --- Translate the dimuon parameters in the CM frame
+ //
+ TLorentzVector pDimuCM; //CM frame
+ TVector3 beta2;
+ beta2=(-1./(fMProton+pProjLab.E()))*pProjLab.Vect();
+ pDimuCM=pDimuLab;
+ pDimuCM.Boost(beta2);
+ //
+ // --- Determine the z axis for the calculation of the polarization angle
+ // (i.e. the direction of the dimuon in the CM system)
+ //
+ TVector3 zaxis;
+ zaxis=(pDimuCM.Vect()).Unit();
+ //
+ // --- Calculation of the polarization angle (Helicity)
+ // (angle between mu+ and the z axis defined above)
+ //
+ Double_t cost;
+ if(mu1Charge > 0) {
+ cost = zaxis.Dot((pMu1Dimu.Vect()).Unit());
+ // Theta Helicity is not properly defined for Like-Sign muons
+ if(mu2Charge > 0 && cost<0) cost=-cost;
+ } else {
+ cost = zaxis.Dot((pMu2Dimu.Vect()).Unit());
+ // Theta Helicity is not properly defined for Like-Sign muons
+ if(mu2Charge < 0 && cost<0) cost=-cost;
+ }
+ return cost;
+}
+
+//______________________________________________________________________________
+Int_t AliAODDimuon::AnyPt(){
+ // Test if the two muons match two trigger tracks
+ if(this->CheckPointers())return 0;
+ return (((AliAODTrack*)fMu[0].GetObject())->MatchTrigger())&&
+ (((AliAODTrack*)fMu[0].GetObject())->MatchTrigger());
+}
+
+//______________________________________________________________________________
+Int_t AliAODDimuon::LowPt(){
+ // Test if the two muons match two trigger tracks with a "Low Pt" cut
+ if(this->CheckPointers())return 0;
+ return (((AliAODTrack*)fMu[0].GetObject())->MatchTriggerLowPt())&&
+ (((AliAODTrack*)fMu[0].GetObject())->MatchTriggerLowPt());
+}
+
+//______________________________________________________________________________
+Int_t AliAODDimuon::HighPt(){
+ // Test if the two muons match two trigger tracks with a "High Pt" cut
+ if(this->CheckPointers())return 0;
+ return (((AliAODTrack*)fMu[0].GetObject())->MatchTriggerHighPt())&&
+ (((AliAODTrack*)fMu[0].GetObject())->MatchTriggerHighPt());
+}
+
+//______________________________________________________________________________
+Double_t AliAODDimuon::MaxChi2Match(){
+ // Maximum matching Chi2 between track and trigger track
+ if(this->CheckPointers())return -999999999;
+ return TMath::Max((((AliAODTrack*)fMu[0].GetObject())->GetChi2MatchTrigger()),
+ (((AliAODTrack*)fMu[0].GetObject())->GetChi2MatchTrigger()));
+}
git://git.uio.no / u / mrichter / AliRoot.git / blobdiff