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 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 GetAvarageDistance();//returns avarage distnace between two tracks
51 virtual Double_t GetDeltaP(); //return difference of momenta
52 virtual Double_t GetDeltaPt();
53 virtual Double_t GetDeltaPx();
54 virtual Double_t GetDeltaPy();
55 virtual Double_t GetDeltaPz();
57 virtual Double_t GetDeltaTheta();
58 virtual Double_t GetDeltaPhi();
60 virtual Double_t GetGammaToCMSLC();
61 virtual Double_t GetWeight();
62 virtual Double_t GetPIDProb() const {return fPart1->GetPidProb()*fPart2->GetPidProb();}
65 AliHBTParticle* fPart1; //pointer to first particle
66 AliHBTParticle* fPart2; //pointer to second particle
68 AliHBTPair* fSwapedPair; //pointer to swapped pair
70 /************************************************************/
71 /************CMS (LC) Q's *********************************/
72 /************************************************************/
73 //Center Mass System - Longitudinally Comoving
75 Double_t fQSideCMSLC; //value of Q side CMS longitudially co-moving
76 Bool_t fQSideCMSLCNotCalc; //flag indicating if fQSideCMSLC is already calculated for this pair
78 Double_t fQOutCMSLC; //value of Q out CMS longitudially co-moving
79 Bool_t fQOutCMSLCNotCalc;//flag indicating if fQOutCMSLC is already calculated for this pair
81 Double_t fQLongCMSLC; //value of Q long CMS longitudially co-moving
82 Bool_t fQLongCMSLCNotCalc;//flag indicating if fQLongCMSLC is already calculated for this pair
83 /************************************************************/
84 /************************************************************/
85 Double_t fQInv; //half of differnece of 4-momenta
86 Bool_t fQInvNotCalc;//flag indicating if fQInv is already calculated for this pair
88 Double_t fInvMass; //invariant mass
89 Bool_t fInvMassNotCalc;//flag indicating if fInvMass is already calculated for this pair
91 Double_t fKt; //K == sum vector of particle's momenta. Kt transverse component
92 Bool_t fKtNotCalc;//flag indicating if fKt is already calculated for this pair
94 Double_t fKStar; // KStar
95 Bool_t fKStarNotCalc;// flag indicating if fKStar is calculated
97 Double_t fPInv; //invariant momentum
99 Double_t fQSide; //Q Side
100 Double_t fOut;//Q Out
101 Double_t fQLong;//Q Long
103 Double_t fMt;//Transverse coordinate of Inv. Mass
104 Bool_t fMtNotCalc;//flag indicating if Mt is calculated for current pair
106 Double_t fInvMassSqr;//squre of invariant mass
107 Bool_t fMassSqrNotCalc; //flag indicating if fInvMassSqr for this pair
108 void CalculateInvMassSqr();
110 Double_t fQInvL; //Qinv in longitudional direction
111 Bool_t fQInvLNotCalc;//flag indicating if fQInvL is calculated for current pair
112 void CalculateQInvL();
114 Double_t fWeight;//Value of the weight
115 Bool_t fWeightNotCalc;//flag indicating if fWeight is calculated for current pair
117 Double_t fAvarageDistance;//value of the avarage distance calculated out of track points
118 Bool_t fAvarageDistanceNotCalc;//flag indicating if the avarage distance is calculated
120 Double_t fPxSum;// Sum of Px momenta
121 Double_t fPySum;// Sum of Py momenta
122 Double_t fPzSum;// Sum of Pz momenta
123 Double_t fESum;// Sum of energies
124 Bool_t fSumsNotCalc;//flag indicating if fPxSum,fPxSum,fPxSum and fESum is calculated for current pair
125 void CalculateSums();
127 Double_t fPxDiff;// Difference of Px momenta
128 Double_t fPyDiff;// Difference of Px momenta
129 Double_t fPzDiff;// Difference of Px momenta
130 Double_t fEDiff;// Difference of Px momenta
131 Bool_t fDiffsNotCalc;//flag indicating if fPxDiff,fPxDiff,fPxDiff and fEDiff is calculated for current pair
132 void CalculateDiffs();
134 Double_t fGammaCMSLC;//gamma of boost in CMSLC
135 Bool_t fGammaCMSLCNotCalc;//flag indicating if fGammaCMSLC is calculated for current pair
136 /***************************************************/
137 Bool_t fChanged;//flag indicating if object has been changed
139 void CalculateBase();
140 Double_t AvDistance();
144 ClassDef(AliHBTPair,1)
146 /****************************************************************/
148 void AliHBTPair::SetParticles(AliHBTParticle* p1,AliHBTParticle* p2)
150 //sets the particle to the pair
154 if (fSwapedPair) //if we have Swaped (so we are not)
155 fSwapedPair->SetParticles(p2,p1); //set particles for him too
157 //and do nothing until will be asked for
159 /****************************************************************/
162 void AliHBTPair::Changed()
164 // Resel all calculations (flags)
166 fSumsNotCalc = kTRUE;
167 fDiffsNotCalc = kTRUE;
168 fMassSqrNotCalc = kTRUE;
169 fInvMassNotCalc = kTRUE;
170 fQInvNotCalc = kTRUE;
172 fQSideCMSLCNotCalc = kTRUE;
173 fQOutCMSLCNotCalc = kTRUE;
174 fQLongCMSLCNotCalc = kTRUE;
176 fKStarNotCalc = kTRUE;
177 fQInvLNotCalc = kTRUE;
178 fGammaCMSLCNotCalc = kTRUE;
179 fWeightNotCalc = kTRUE;
180 fAvarageDistanceNotCalc = kTRUE;
182 /****************************************************************/
184 void AliHBTPair::CalculateInvMassSqr()
186 //calculates square of qinv
191 Double_t fPart12s= (fPxSum*fPxSum) + (fPySum*fPySum) + (fPzSum*fPzSum);
193 fInvMassSqr=fESum*fESum-fPart12s;
195 fMassSqrNotCalc = kFALSE;
198 /****************************************************************/
200 void AliHBTPair::CalculateQInvL()
202 //Calculates square root of Qinv
206 fQInvL = fEDiff*fEDiff - ( fPxDiff*fPxDiff + fPyDiff*fPyDiff + fPzDiff*fPzDiff );
207 fQInvLNotCalc = kFALSE;
210 /****************************************************************/
212 void AliHBTPair::CalculateSums()
214 //calculates momenta and energy sums
217 fPxSum = fPart1->Px()+fPart2->Px();
218 fPySum = fPart1->Py()+fPart2->Py();
219 fPzSum = fPart1->Pz()+fPart2->Pz();
220 fESum = fPart1->Energy() + fPart2->Energy();
221 fSumsNotCalc = kFALSE;
224 /****************************************************************/
226 void AliHBTPair::CalculateDiffs()
228 //calculates momenta and energy differences
231 fPxDiff = fPart1->Px()-fPart2->Px();
232 fPyDiff = fPart1->Py()-fPart2->Py();
233 fPzDiff = fPart1->Pz()-fPart2->Pz();
234 fEDiff = fPart1->Energy() - fPart2->Energy();
235 fDiffsNotCalc = kFALSE;
239 /****************************************************************/
241 Double_t AliHBTPair::GetDeltaP() //return difference of momenta
243 //returns difference of momenta (length of vector)
245 return TMath::Sqrt(fPxDiff*fPxDiff + fPyDiff*fPyDiff + fPzDiff*fPzDiff);
247 /****************************************************************/
250 Double_t AliHBTPair::GetDeltaPt()
252 //returns difference of Pz
253 return fPart1->Pt()-fPart2->Pt();
255 /****************************************************************/
258 Double_t AliHBTPair::GetDeltaPx()
260 //returns difference of Pz
264 /****************************************************************/
266 Double_t AliHBTPair::GetDeltaPy()
268 //returns difference of Py
273 /****************************************************************/
275 Double_t AliHBTPair::GetDeltaPz()
277 //returns difference of Pz
281 /****************************************************************/
284 Double_t AliHBTPair::GetDeltaPhi()
286 //returns difference of Pz
287 return fPart1->Phi()-fPart2->Phi();
289 /****************************************************************/
292 Double_t AliHBTPair::GetDeltaTheta()
294 //returns difference of Pz
295 return fPart1->Theta()-fPart2->Theta();
297 /****************************************************************/