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();
63 AliHBTParticle* fPart1; //pointer to first particle
64 AliHBTParticle* fPart2; //pointer to second particle
66 AliHBTPair* fSwapedPair; //pointer to swapped pair
68 /************************************************************/
69 /************CMS (LC) Q's *********************************/
70 /************************************************************/
71 //Center Mass System - Longitudinally Comoving
73 Double_t fQSideCMSLC; //value of Q side CMS longitudially co-moving
74 Bool_t fQSideCMSLCNotCalc; //flag indicating if fQSideCMSLC is already calculated for this pair
76 Double_t fQOutCMSLC; //value of Q out CMS longitudially co-moving
77 Bool_t fQOutCMSLCNotCalc;//flag indicating if fQOutCMSLC is already calculated for this pair
79 Double_t fQLongCMSLC; //value of Q long CMS longitudially co-moving
80 Bool_t fQLongCMSLCNotCalc;//flag indicating if fQLongCMSLC is already calculated for this pair
81 /************************************************************/
82 /************************************************************/
83 Double_t fQInv; //half of differnece of 4-momenta
84 Bool_t fQInvNotCalc;//flag indicating if fQInv is already calculated for this pair
86 Double_t fInvMass; //invariant mass
87 Bool_t fInvMassNotCalc;//flag indicating if fInvMass is already calculated for this pair
89 Double_t fKt; //K == sum vector of particle's momenta. Kt transverse component
90 Bool_t fKtNotCalc;//flag indicating if fKt is already calculated for this pair
92 Double_t fKStar; // KStar
93 Bool_t fKStarNotCalc;// flag indicating if fKStar is calculated
95 Double_t fPInv; //invariant momentum
97 Double_t fQSide; //Q Side
99 Double_t fQLong;//Q Long
101 Double_t fMt;//Transverse coordinate of Inv. Mass
102 Bool_t fMtNotCalc;//flag indicating if Mt is calculated for current pair
104 Double_t fInvMassSqr;//squre of invariant mass
105 Bool_t fMassSqrNotCalc; //flag indicating if fInvMassSqr for this pair
106 void CalculateInvMassSqr();
108 Double_t fQInvL; //Qinv in longitudional direction
109 Bool_t fQInvLNotCalc;//flag indicating if fQInvL is calculated for current pair
110 void CalculateQInvL();
112 Double_t fWeight;//Value of the weight
113 Bool_t fWeightNotCalc;//flag indicating if fWeight is calculated for current pair
115 Double_t fAvarageDistance;//value of the avarage distance calculated out of track points
116 Bool_t fAvarageDistanceNotCalc;//flag indicating if the avarage distance is calculated
118 Double_t fPxSum;// Sum of Px momenta
119 Double_t fPySum;// Sum of Py momenta
120 Double_t fPzSum;// Sum of Pz momenta
121 Double_t fESum;// Sum of energies
122 Bool_t fSumsNotCalc;//flag indicating if fPxSum,fPxSum,fPxSum and fESum is calculated for current pair
123 void CalculateSums();
125 Double_t fPxDiff;// Difference of Px momenta
126 Double_t fPyDiff;// Difference of Px momenta
127 Double_t fPzDiff;// Difference of Px momenta
128 Double_t fEDiff;// Difference of Px momenta
129 Bool_t fDiffsNotCalc;//flag indicating if fPxDiff,fPxDiff,fPxDiff and fEDiff is calculated for current pair
130 void CalculateDiffs();
132 Double_t fGammaCMSLC;//gamma of boost in CMSLC
133 Bool_t fGammaCMSLCNotCalc;//flag indicating if fGammaCMSLC is calculated for current pair
134 /***************************************************/
135 Bool_t fChanged;//flag indicating if object has been changed
137 void CalculateBase();
138 Double_t AvDistance();
142 ClassDef(AliHBTPair,1)
144 /****************************************************************/
146 void AliHBTPair::SetParticles(AliHBTParticle* p1,AliHBTParticle* p2)
148 //sets the particle to the pair
152 if (fSwapedPair) //if we have Swaped (so we are not)
153 fSwapedPair->SetParticles(p2,p1); //set particles for him too
155 //and do nothing until will be asked for
157 /****************************************************************/
160 void AliHBTPair::Changed()
162 // Resel all calculations (flags)
164 fSumsNotCalc = kTRUE;
165 fDiffsNotCalc = kTRUE;
166 fMassSqrNotCalc = kTRUE;
167 fInvMassNotCalc = kTRUE;
168 fQInvNotCalc = kTRUE;
170 fQSideCMSLCNotCalc = kTRUE;
171 fQOutCMSLCNotCalc = kTRUE;
172 fQLongCMSLCNotCalc = kTRUE;
174 fKStarNotCalc = kTRUE;
175 fQInvLNotCalc = kTRUE;
176 fGammaCMSLCNotCalc = kTRUE;
177 fWeightNotCalc = kTRUE;
178 fAvarageDistanceNotCalc = kTRUE;
180 /****************************************************************/
182 void AliHBTPair::CalculateInvMassSqr()
184 //calculates square of qinv
189 Double_t fPart12s= (fPxSum*fPxSum) + (fPySum*fPySum) + (fPzSum*fPzSum);
191 fInvMassSqr=fESum*fESum-fPart12s;
193 fMassSqrNotCalc = kFALSE;
196 /****************************************************************/
198 void AliHBTPair::CalculateQInvL()
200 //Calculates square root of Qinv
204 fQInvL = fEDiff*fEDiff - ( fPxDiff*fPxDiff + fPyDiff*fPyDiff + fPzDiff*fPzDiff );
205 fQInvLNotCalc = kFALSE;
208 /****************************************************************/
210 void AliHBTPair::CalculateSums()
212 //calculates momenta and energy sums
215 fPxSum = fPart1->Px()+fPart2->Px();
216 fPySum = fPart1->Py()+fPart2->Py();
217 fPzSum = fPart1->Pz()+fPart2->Pz();
218 fESum = fPart1->Energy() + fPart2->Energy();
219 fSumsNotCalc = kFALSE;
222 /****************************************************************/
224 void AliHBTPair::CalculateDiffs()
226 //calculates momenta and energy differences
229 fPxDiff = fPart1->Px()-fPart2->Px();
230 fPyDiff = fPart1->Py()-fPart2->Py();
231 fPzDiff = fPart1->Pz()-fPart2->Pz();
232 fEDiff = fPart1->Energy() - fPart2->Energy();
233 fDiffsNotCalc = kFALSE;
237 /****************************************************************/
239 Double_t AliHBTPair::GetDeltaP() //return difference of momenta
241 //returns difference of momenta (length of vector)
243 return TMath::Sqrt(fPxDiff*fPxDiff + fPyDiff*fPyDiff + fPzDiff*fPzDiff);
245 /****************************************************************/
248 Double_t AliHBTPair::GetDeltaPt()
250 //returns difference of Pz
251 return fPart1->Pt()-fPart2->Pt();
253 /****************************************************************/
256 Double_t AliHBTPair::GetDeltaPx()
258 //returns difference of Pz
262 /****************************************************************/
264 Double_t AliHBTPair::GetDeltaPy()
266 //returns difference of Py
271 /****************************************************************/
273 Double_t AliHBTPair::GetDeltaPz()
275 //returns difference of Pz
279 /****************************************************************/
282 Double_t AliHBTPair::GetDeltaPhi()
284 //returns difference of Pz
285 return fPart1->Phi()-fPart2->Phi();
287 /****************************************************************/
290 Double_t AliHBTPair::GetDeltaTheta()
292 //returns difference of Pz
293 return fPart1->Theta()-fPart2->Theta();
295 /****************************************************************/