+/**************************************************************************
+ * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
+ * *
+ * Author: The ALICE Off-line Project. *
+ * Contributors are mentioned in the code where appropriate. *
+ * *
+ * Permission to use, copy, modify and distribute this software and its *
+ * documentation strictly for non-commercial purposes is hereby granted *
+ * without fee, provided that the above copyright notice appears in all *
+ * copies and that both the copyright notice and this permission notice *
+ * appear in the supporting documentation. The authors make no claims *
+ * about the suitability of this software for any purpose. It is *
+ * provided "as is" without express or implied warranty. *
+ **************************************************************************/
+
+////////////////////////////////////////////////////////////////////////////////
//
-// Class AliRsnMother
-//
-// Implementation of a pair of tracks, for several purposes
-// - computing the total 4-momentum & inv. mass for output histos filling
-// - evaluating cut checks on the pair of particles
-// - evaluating any kind of kinematic value over their sum
+// This class implements a candidate resonance. It has two pointers to its
+// two candidate daughters, whose 4-momenta are combined to obtain the mother
+// invariant mass and other kinematical quantities.
+// This class contains also some methods used to compute kinematical relations
+// between the candidate resonance and other particles.
//
-// authors: Martin Vala (martin.vala@cern.ch)
-// Alberto Pulvirenti (alberto.pulvirenti@ct.infn.it)
+// authors: A. Pulvirenti (alberto.pulvirenti@ct.infn.it)
+// M. Vala (martin.vala@cern.ch)
//
+////////////////////////////////////////////////////////////////////////////////
+
#include <Riostream.h>
#include <TVector3.h>
-#include "AliRsnDaughter.h"
-#include "AliRsnPairDef.h"
-#include "AliRsnMother.h"
-ClassImp(AliRsnMother)
+#include "AliAODMCParticle.h"
+#include "AliMCParticle.h"
+#include "AliRsnEvent.h"
-//_____________________________________________________________________________
-AliRsnMother::AliRsnMother() :
- fUseMC(kFALSE),
- fDefaultMass(0.0),
- fSum(),
- fSumMC(),
- fRef(),
- fRefMC()
-{
-//
-// Constructor.
-// Initializes all variables to meaningless values.
-//
+#include "AliRsnMother.h"
- Int_t i;
- for (i = 0; i < 2; i++) fDaughter[i] = 0x0;
-}
+ClassImp(AliRsnMother)
-//_____________________________________________________________________________
-AliRsnMother::AliRsnMother(const AliRsnMother &obj) :
- TObject(obj),
- fUseMC(obj.fUseMC),
- fDefaultMass(obj.fDefaultMass),
- fSum(obj.fSum),
- fSumMC(obj.fSumMC),
- fRef(obj.fRef),
- fRefMC(obj.fRefMC)
+//__________________________________________________________________________________________________
+AliRsnMother::AliRsnMother(const AliRsnMother &obj) :
+ TObject(obj),
+ fRefEvent(obj.fRefEvent),
+ fSum(obj.fSum),
+ fSumMC(obj.fSumMC),
+ fRef(obj.fRef),
+ fRefMC(obj.fRefMC)
{
//
// Copy constructor.
-// Initializes all variables to copy values.
// Does not duplicate pointers.
//
- Int_t i;
- for (i = 0; i < 2; i++) fDaughter[i] = obj.fDaughter[i];
+ Int_t i;
+ for (i = 0; i < 2; i++) fDaughter[i] = obj.fDaughter[i];
}
-//_____________________________________________________________________________
+//__________________________________________________________________________________________________
AliRsnMother& AliRsnMother::operator=(const AliRsnMother &obj)
{
//
// Assignment operator.
-// Initializes all variables to copy values.
// Does not duplicate pointers.
//
- Int_t i;
-
- fDefaultMass = obj.fDefaultMass;
- fSum = obj.fSum;
- fRef = obj.fRef;
- fSumMC = obj.fSumMC;
- fRefMC = obj.fRefMC;
-
- for (i = 0; i < 2; i++) fDaughter[i] = obj.fDaughter[i];
-
- return (*this);
+ fSum = obj.fSum;
+ fRef = obj.fRef;
+ fSumMC = obj.fSumMC;
+ fRefMC = obj.fRefMC;
+ fRefEvent = obj.fRefEvent;
+ fDaughter[0] = obj.fDaughter[0];
+ fDaughter[1] = obj.fDaughter[1];
+
+ return (*this);
}
-//_____________________________________________________________________________
+//__________________________________________________________________________________________________
AliRsnMother::~AliRsnMother()
{
//
//
}
-//_____________________________________________________________________________
-Int_t AliRsnMother::CommonMother() const
+//_______________________________________________________________________________________________________________________
+void AliRsnMother::Reset()
{
//
-// Checks if the two tracks in the pair have the same mother.
-// This can be known if MC info is present.
-// If the mother label is the same, rhe PDG code of the mother is returned,
-// otherwise the method returns 0.
+// Resets the mother, zeroing all data members.
//
- // if MC info is not available, the pairs is not true by default
- if (!fDaughter[0]->GetRefMC() || !fDaughter[1]->GetRefMC())
- {
- AliInfo("Cannot know if the pairs is true or not because MC Info is not present");
- return 0;
- }
+ Int_t i;
+ for (i = 0; i < 2; i++) fDaughter[i] = 0x0;
+ fRefEvent = 0x0;
+ fSum.SetXYZM(0.0, 0.0, 0.0, 0.0);
+ fRef.SetXYZM(0.0, 0.0, 0.0, 0.0);
+}
- // check that labels are the same
- if (fDaughter[0]->GetParticle()->GetFirstMother() != fDaughter[1]->GetParticle()->GetFirstMother())
- return 0;
+//__________________________________________________________________________________________________
+Int_t AliRsnMother::CommonMother() const
+{
+//
+// If MC info is available, checks if the two tracks in the pair have the same mother.
+// If the mother label is the same, the function returns the PDG code of mother,
+// otherwise it returns 0.
+// The two arguments passed by reference contain the GEANT labels of the mother
+// of the two particles to which the two daughters point. This is for being able
+// to check if they are really coming from a resonance (indexes >= 0) or not.
+//
- // if we reach this point, the two tracks have the same mother
- // let's check now the PDG code of this common mother
- return TMath::Abs(fDaughter[0]->GetMotherPDG());
+ Int_t m1 = fDaughter[0]->GetMother();
+ Int_t m2 = fDaughter[1]->GetMother();
+ Int_t out = 0;
+
+ // a true mother makes sense only if both mothers
+ // are not-negative and equal
+ if (m1 >= 0 && m2 >= 0 && m1 == m2) {
+ out = TMath::Abs(fDaughter[0]->GetMotherPDG());
+ AliDebugClass(1, Form("Mothers are: %d %d --> EQUAL (PDG = %d)", m1, m2, out));
+ }
+
+ return out;
}
-//_____________________________________________________________________________
-void AliRsnMother::SetDaughters
-(AliRsnDaughter *d0, Double_t mass0, AliRsnDaughter *d1, Double_t mass1)
+//__________________________________________________________________________________________________
+Double_t AliRsnMother::AngleToLeading(Bool_t &success)
{
//
-// Sets the pair defined in this usind tso passed daughters and two masses
-// which will be assigned to them, in order to recompute their 4-momenta
-// and sum them into the datamembers of this object.
+// Compute the angle betwee this and the leading particls
+// of the reference event (if this was set properly).
+// In case one of the two daughters is the leading, return
+// a meaningless value, in order to skip this pair.
+// if second argument is kTRUE, use MC values.
//
- if (d0) fDaughter[0] = d0;
- if (d1) fDaughter[1] = d1;
-
- if (!d0 || !d1) return;
-
- fDaughter[0]->SetMass(mass0);
- fDaughter[1]->SetMass(mass1);
-
- fSum = fDaughter[0]->P(kFALSE) + fDaughter[1]->P(kFALSE);
- fSumMC = fDaughter[0]->P(kTRUE) + fDaughter[1]->P(kTRUE);
-
- fRef .SetXYZM(fSum .X(), fSum .Y(), fSum .Z(), fDefaultMass);
- fRefMC.SetXYZM(fSumMC.X(), fSumMC.Y(), fSumMC.Z(), fDefaultMass);
+ if (!fRefEvent) {
+ success = kFALSE;
+ return -99.0;
+ }
+
+ Int_t id1 = fDaughter[0]->GetID();
+ Int_t id2 = fDaughter[1]->GetID();
+ Int_t idL = fRefEvent->GetLeadingIndex();
+
+ if (id1 == idL || id2 == idL) {
+ success = kFALSE;
+ return -99.0;
+ }
+
+ AliRsnDaughter leading = fRefEvent->GetDaughter(idL, kFALSE);
+ AliVParticle *ref = leading.GetRef();
+ Double_t angle = ref->Phi() - fSum.Phi();
+
+ //return angle w.r.t. leading particle in the range -pi/2, 3/2pi
+ while (angle >= 1.5 * TMath::Pi()) angle -= 2 * TMath::Pi();
+ while (angle < -0.5 * TMath::Pi()) angle += 2 * TMath::Pi();
+ success = kTRUE;
+
+ return angle;
}
-//_____________________________________________________________________________
-void AliRsnMother::ResetPair()
+//__________________________________________________________________________________________________
+void AliRsnMother::ComputeSum(Double_t mass0, Double_t mass1, Double_t motherMass)
{
//
-// Resets the mother, nullifying all data members
+// Sets the masses for the 4-momenta of the daughters and then
+// sums them, taking into account that the space part is set to
+// each of them when the reference object is set (see AliRsnDaughter::SetRef)
//
- Int_t i;
- for (i = 0; i < 2; i++) fDaughter[i] = 0x0;
-
- fSum .SetXYZM(0.0, 0.0, 0.0, 0.0);
- fRef .SetXYZM(0.0, 0.0, 0.0, 0.0);
- fSumMC.SetXYZM(0.0, 0.0, 0.0, 0.0);
- fRefMC.SetXYZM(0.0, 0.0, 0.0, 0.0);
+ fDaughter[0]->FillP(mass0);
+ fDaughter[1]->FillP(mass1);
+
+ // sum
+ fSum = fDaughter[0]->Prec() + fDaughter[1]->Prec();
+ fSumMC = fDaughter[0]->Psim() + fDaughter[1]->Psim();
+
+ // reference
+ fRef.SetXYZM(fSum.X(), fSum.Y(), fSum.Z(), motherMass);
+ fRefMC.SetXYZM(fSumMC.X(), fSumMC.Y(), fSumMC.Z(), motherMass);
}
-//_____________________________________________________________________________
-Double_t AliRsnMother::ThetaStar(Bool_t first, Bool_t useMC)
+//__________________________________________________________________________________________________
+Double_t AliRsnMother::CosThetaStar(Bool_t first, Bool_t useMC)
{
//
-// Returns the theta* as the angle of the first daughter
-// w.r. to the mother momentum, in its rest frame
+// Computes the cosine of theta*, which is the angle of one of the daughters
+// with respect to the total momentum of the resonance, in its rest frame.
+// The arguments are needed to choose which of the daughters one want to use
+// and if reconstructed or MC momentum must be used.
+// [Contribution from Z. Feckova]
//
- TLorentzVector &mother = (useMC ? fSumMC : fSum);
- TLorentzVector &daughter = (first ? fDaughter[0]->P() : fDaughter[1]->P());
-
- Double_t theta = mother.Vect().Theta();
- Double_t phi = mother.Vect().Phi();
- Double_t beta = mother.Beta();
-
- Double_t betax = beta * TMath::Sin(theta) * TMath::Cos(phi);
- Double_t betay = beta * TMath::Sin(theta) * TMath::Sin(phi);
- Double_t betaz = beta * TMath::Cos(theta);
- Double_t gamx = 1.0 / TMath::Sqrt(1.0 - betax*betax);
- Double_t gamy = 1.0 / TMath::Sqrt(1.0 - betay*betay);
- Double_t gamz = 1.0 / TMath::Sqrt(1.0 - betaz*betaz);
-
- Double_t pstarx = gamx * (daughter.Vect().X() - betax * daughter.E());
- Double_t pstary = gamy * (daughter.Vect().Y() - betay * daughter.E());
- Double_t pstarz = gamz * (daughter.Vect().Z() - betaz * daughter.E());
-
- TVector3 dstar(pstarx, pstary, pstarz);
- TVector3 vnorm(mother.Vect().Y() / mother.Perp(), mother.Vect().X() / mother.Perp(), 0.0);
-
- Double_t cosThetaStar = dstar.Dot(vnorm) / dstar.Mag();
-
- return cosThetaStar;
+ TLorentzVector &mother = Sum(useMC);
+ TLorentzVector &daughter0 = (first ? fDaughter[0]->P(useMC) : fDaughter[1]->P(useMC));
+ TLorentzVector &daughter1 = (first ? fDaughter[1]->P(useMC) : fDaughter[0]->P(useMC));
+ TVector3 momentumM(mother.Vect());
+ TVector3 normal(mother.Y() / momentumM.Mag(), -mother.X() / momentumM.Mag(), 0.0);
+
+ // Computes first the invariant mass of the mother
+ Double_t mass0 = fDaughter[0]->P(useMC).M();
+ Double_t mass1 = fDaughter[1]->P(useMC).M();
+ Double_t p0 = daughter0.Vect().Mag();
+ Double_t p1 = daughter1.Vect().Mag();
+ Double_t E0 = TMath::Sqrt(mass0 * mass0 + p0 * p0);
+ Double_t E1 = TMath::Sqrt(mass1 * mass1 + p1 * p1);
+ Double_t MotherMass = TMath::Sqrt((E0 + E1) * (E0 + E1) - (p0 * p0 + 2.0 * daughter0.Vect().Dot(daughter1.Vect()) + p1 * p1));
+ MotherMass = fSum.M();
+
+ // Computes components of beta
+ Double_t betaX = -mother.X() / mother.E();
+ Double_t betaY = -mother.Y() / mother.E();
+ Double_t betaZ = -mother.Z() / mother.E();
+
+ // Computes Lorentz transformation of the momentum of the first daughter
+ // into the rest frame of the mother and theta*
+ daughter0.Boost(betaX, betaY, betaZ);
+ TVector3 momentumD = daughter0.Vect();
+
+ Double_t cosThetaStar = normal.Dot(momentumD) / momentumD.Mag();
+
+ return cosThetaStar;
}
-//_____________________________________________________________________________
+//__________________________________________________________________________________________________
void AliRsnMother::PrintInfo(const Option_t * /*option*/) const
{
//
// The options are passed to the AliRsnDaughter::Print() method
//
- AliInfo("======== BEGIN PAIR INFO ===========");
- AliInfo("Track #1");
- fDaughter[0]->Print();
- AliInfo("Track #2");
- fDaughter[1]->Print();
- AliInfo("========= END PAIR INFO ===========");
+ AliInfo("======== BEGIN PAIR INFO ===========");
+ AliInfo("Track #1");
+ fDaughter[0]->Print();
+ AliInfo("Track #2");
+ fDaughter[1]->Print();
+ AliInfo("========= END PAIR INFO ===========");
}
-//_____________________________________________________________________________
-Bool_t AliRsnMother::CheckPair() const
+//__________________________________________________________________________________________________
+Bool_t AliRsnMother::CheckPair(Bool_t checkMC) const
{
//
// Checks that the pair is well initialized:
// - if MC is required, both daughters have a MC reference
//
- if (!fDaughter[0] || !fDaughter[1])
- {
- AliError("One of the two tracks is NULL in this pair!");
- return kFALSE;
- }
-
- if (fUseMC)
- {
- if (fDaughter[0]->GetRefMC() == 0x0 || fDaughter[1]->GetRefMC() == 0x0)
- {
- AliError("Required MC info but not all MC refs are available");
+ if (!fDaughter[0] || !fDaughter[1]) {
+ AliError("One of the two tracks is NULL in this pair!");
return kFALSE;
- }
- }
-
- return kTRUE;
-}
+ }
-//_____________________________________________________________________________
-Bool_t AliRsnMother::MatchesDef(AliRsnPairDef *def)
-{
-//
-// Checks if the daughters, in any order, do match a given decay channel,
-// using the specified identification method, which can be the 'true' one
-// or the 'realistic' one only.
-//
+ if (checkMC) {
+ if (fDaughter[0]->GetRefMC() == 0x0 || fDaughter[1]->GetRefMC() == 0x0) {
+ AliError("Required MC info but not all MC refs are available");
+ return kFALSE;
+ }
+ }
- if (!def) return kFALSE;
- if (!fDaughter[0]->GetRefMC()) return kFALSE;
- if (!fDaughter[1]->GetRefMC()) return kFALSE;
-
- Bool_t decayMatch = kFALSE;
- Int_t pdg[2], ref[2];
- pdg[0] = fDaughter[0]->GetRefMC()->Particle()->GetPdgCode();
- pdg[1] = fDaughter[1]->GetRefMC()->Particle()->GetPdgCode();
- ref[0] = TMath::Abs(AliPID::ParticleCode(def->GetPID(0)));
- ref[1] = TMath::Abs(AliPID::ParticleCode(def->GetPID(1)));
-
- // check #1:
- // if first member of pairDef has same sign as first member of this,
- // daughter[0] perfect PID must match first member of pairDef
- // daughter[1] perfect PID must march second member of pairDef
- if (fDaughter[0]->IsSign(def->GetCharge(0)) && fDaughter[1]->IsSign(def->GetCharge(1)))
- {
- decayMatch = (pdg[0] == ref[0] && pdg[1] == ref[1]);
- }
-
- // check #2:
- // if first member of pairDef has same sign as second member of this,
- // daughter[0] perfect PID must match second member of pairDef
- // daughter[1] perfect PID must march first member of pairDef
- if (fDaughter[1]->IsSign(def->GetCharge(0)) && fDaughter[0]->IsSign(def->GetCharge(1)))
- {
- decayMatch = (pdg[0] == ref[1] && pdg[1] == ref[0]);
- }
-
- return (decayMatch && (CommonMother() == def->GetMotherPDG()));
+ return kTRUE;
}
git://git.uio.no / u / mrichter / AliRoot.git / blobdiff