3 //_________________________________________________________________________
4 ///////////////////////////////////////////////////////////////////////////
8 // class implements pair of particles and taking care of caluclation (almost)
9 // all of pair properties (Qinv, InvMass,...)
10 // more info: http://alisoft.cern.ch/people/skowron/analyzer/index.html
12 ////////////////////////////////////////////////////////////////////////////
15 #include "AliHBTParticle.h"
18 class AliHBTPair: public TObject
21 AliHBTPair(Bool_t rev = kFALSE); //contructor
22 AliHBTPair(AliHBTParticle* part1, AliHBTParticle* part2, Bool_t rev = kFALSE); //contructor
23 AliHBTPair(const AliHBTPair& in);
25 virtual ~AliHBTPair(){}
27 const AliHBTPair& operator=(const AliHBTPair& in);
29 void SetParticles(AliHBTParticle* p1,AliHBTParticle* p2); //sets particles in the pair
30 AliHBTPair* GetSwapedPair() {return fSwapedPair;} //returns pair with swapped particles
32 AliHBTParticle* Particle1() const {return fPart1;} //returns pointer to first particle
33 AliHBTParticle* Particle2() const {return fPart2;} //returns pointer to decond particle
36 //Center Mass System - Longitudinally Comoving
38 virtual Double_t GetInvMass(); //returns invariant mass of the pair
39 virtual Double_t GetMt();
40 virtual Double_t GetQInv(); //returns Q invariant
41 virtual Double_t GetQSideCMSLC(); //returns Q Side CMS longitudionally co-moving
42 virtual Double_t GetQOutCMSLC(); //returns Q out CMS longitudionally co-moving
43 virtual Double_t GetQLongCMSLC(); //returns Q Long CMS longitudionally co-moving
46 virtual Double_t GetKt(); //returns K transverse
47 virtual Double_t GetKStar();
49 virtual Double_t GetDeltaP(); //return difference of momenta
50 virtual Double_t GetDeltaPx();
51 virtual Double_t GetDeltaPy();
52 virtual Double_t GetDeltaPz();
54 virtual Double_t GetGammaToCMSLC();
57 AliHBTParticle* fPart1; //pointer to first particle
58 AliHBTParticle* fPart2; //pointer to second particle
60 AliHBTPair* fSwapedPair; //pointer to swapped pair
62 /************************************************************/
63 /************CMS (LC) Q's *********************************/
64 /************************************************************/
65 //Center Mass System - Longitudinally Comoving
67 Double_t fQSideCMSLC; //value of Q side CMS longitudially co-moving
68 Bool_t fQSideCMSLCNotCalc; //flag indicating if fQSideCMSLC is already calculated for this pair
70 Double_t fQOutCMSLC; //value of Q out CMS longitudially co-moving
71 Bool_t fQOutCMSLCNotCalc;//flag indicating if fQOutCMSLC is already calculated for this pair
73 Double_t fQLongCMSLC; //value of Q long CMS longitudially co-moving
74 Bool_t fQLongCMSLCNotCalc;//flag indicating if fQLongCMSLC is already calculated for this pair
75 /************************************************************/
76 /************************************************************/
77 Double_t fQInv; //half of differnece of 4-momenta
78 Bool_t fQInvNotCalc;//flag indicating if fQInv is already calculated for this pair
80 Double_t fInvMass; //invariant mass
81 Bool_t fInvMassNotCalc;//flag indicating if fInvMass is already calculated for this pair
83 Double_t fKt; //K == sum vector of particle's momenta. Kt transverse component
84 Bool_t fKtNotCalc;//flag indicating if fKt is already calculated for this pair
86 Double_t fKStar; // KStar
87 Bool_t fKStarNotCalc;// flag indicating if fKStar is calculated
89 Double_t fPInv; //invariant momentum
91 Double_t fQSide; //Q Side
93 Double_t fQLong;//Q Long
95 Double_t fMt;//Transverse coordinate of Inv. Mass
96 Bool_t fMtNotCalc;//flag indicating if Mt is calculated for current pair
98 Double_t fInvMassSqr;//squre of invariant mass
99 Bool_t fMassSqrNotCalc; //flag indicating if fInvMassSqr for this pair
100 void CalculateInvMassSqr();
102 Double_t fQInvL; //Qinv in longitudional direction
103 Bool_t fQInvLNotCalc;//flag indicating if fQInvL is calculated for current pair
104 void CalculateQInvL();
106 Double_t fWeight;//Value of the weight
107 Bool_t fWeightNotCalc;//flag indicating if fWeight is calculated for current pair
109 Double_t fPxSum;// Sum of Px momenta
110 Double_t fPySum;// Sum of Py momenta
111 Double_t fPzSum;// Sum of Pz momenta
112 Double_t fESum;// Sum of energies
113 Bool_t fSumsNotCalc;//flag indicating if fPxSum,fPxSum,fPxSum and fESum is calculated for current pair
114 void CalculateSums();
116 Double_t fPxDiff;// Difference of Px momenta
117 Double_t fPyDiff;// Difference of Px momenta
118 Double_t fPzDiff;// Difference of Px momenta
119 Double_t fEDiff;// Difference of Px momenta
120 Bool_t fDiffsNotCalc;//flag indicating if fPxDiff,fPxDiff,fPxDiff and fEDiff is calculated for current pair
121 void CalculateDiffs();
123 Double_t fGammaCMSLC;//gamma of boost in CMSLC
124 Bool_t fGammaCMSLCNotCalc;//flag indicating if fGammaCMSLC is calculated for current pair
125 /***************************************************/
126 void CalculateBase();
127 Bool_t fChanged;//flag indicating if object has been changed
131 ClassDef(AliHBTPair,1)
133 /****************************************************************/
135 void AliHBTPair::SetParticles(AliHBTParticle* p1,AliHBTParticle* p2)
137 //sets the particle to the pair
141 if (fSwapedPair) //if we have Swaped (so we are not)
142 fSwapedPair->SetParticles(p2,p1); //set particles for him too
144 //and do nothing until will be asked for
146 /****************************************************************/
149 void AliHBTPair::Changed()
151 // Resel all calculations (flags)
153 fSumsNotCalc = kTRUE;
154 fDiffsNotCalc = kTRUE;
155 fMassSqrNotCalc = kTRUE;
156 fInvMassNotCalc = kTRUE;
157 fQInvNotCalc = kTRUE;
159 fQSideCMSLCNotCalc = kTRUE;
160 fQOutCMSLCNotCalc = kTRUE;
161 fQLongCMSLCNotCalc = kTRUE;
163 fKStarNotCalc = kTRUE;
164 fQInvLNotCalc = kTRUE;
165 fGammaCMSLCNotCalc = kTRUE;
166 fWeightNotCalc = kTRUE;
168 /****************************************************************/
170 void AliHBTPair::CalculateInvMassSqr()
172 //calculates square of qinv
177 Double_t fPart12s= (fPxSum*fPxSum) + (fPySum*fPySum) + (fPzSum*fPzSum);
179 fInvMassSqr=fESum*fESum-fPart12s;
181 fMassSqrNotCalc = kFALSE;
184 /****************************************************************/
186 void AliHBTPair::CalculateQInvL()
188 //Calculates square root of Qinv
192 fQInvL = fEDiff*fEDiff - ( fPxDiff*fPxDiff + fPyDiff*fPyDiff + fPzDiff*fPzDiff );
193 fQInvLNotCalc = kFALSE;
196 /****************************************************************/
198 void AliHBTPair::CalculateSums()
200 //calculates momenta and energy sums
203 fPxSum = fPart1->Px()+fPart2->Px();
204 fPySum = fPart1->Py()+fPart2->Py();
205 fPzSum = fPart1->Pz()+fPart2->Pz();
206 fESum = fPart1->Energy() + fPart2->Energy();
207 fSumsNotCalc = kFALSE;
210 /****************************************************************/
212 void AliHBTPair::CalculateDiffs()
214 //calculates momenta and energy differences
217 fPxDiff = fPart1->Px()-fPart2->Px();
218 fPyDiff = fPart1->Py()-fPart2->Py();
219 fPzDiff = fPart1->Pz()-fPart2->Pz();
220 fEDiff = fPart1->Energy() - fPart2->Energy();
221 fDiffsNotCalc = kFALSE;
225 /****************************************************************/
227 Double_t AliHBTPair::GetDeltaP() //return difference of momenta
229 //returns difference of momenta
231 return TMath::Sqrt(fPxDiff*fPxDiff + fPyDiff*fPyDiff + fPzDiff*fPzDiff);
233 /****************************************************************/
235 Double_t AliHBTPair::GetDeltaPx()
237 //returns difference of Pz
241 /****************************************************************/
243 Double_t AliHBTPair::GetDeltaPy()
245 //returns difference of Py
250 /****************************************************************/
252 Double_t AliHBTPair::GetDeltaPz()
254 //returns difference of Pz