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866d8d78 | 1 | // AliAODDimuon: a class for AODs for the MUON Arm of the ALICE Experiment |
2 | // Author: P. Cortese, Universita' del Piemonte Orientale in Alessandria and | |
3 | // INFN of Torino - Italy | |
4 | // | |
5 | // The class defines a dimuon pair object from two AliAODTrack objects. | |
6 | // AliAODDimuon objects are supposed to be added to the AliAODEvent structure | |
7 | // during analysis. They would then allow to calculate the dimuon-related | |
8 | // kinematic variables with a minimal disk occupancy. | |
9 | // The payload of the class has been reduced to two pointers to the two | |
10 | // tracks. An instance of this class has also to be added to the AliAODEvent | |
11 | // structure to provide additional information that is specific to MUON and | |
12 | // therefore has not been included into the AOD header. | |
13 | // Two transient data members are not stored on file as they can be recomputed | |
14 | // at runtime. | |
15 | // | |
16 | ||
17 | #include "AliAODDimuon.h" | |
18 | #include "TLorentzVector.h" | |
19 | #define AliAODDimuon_CXX | |
20 | ||
21 | ClassImp(AliAODDimuon) | |
22 | ||
23 | //______________________________________________________________________________ | |
24 | AliAODDimuon::AliAODDimuon():AliVParticle(),fP(0),fMProton(0.93827231) | |
25 | { | |
26 | // default constructor | |
27 | fMu[0]=0; | |
28 | fMu[1]=0; | |
29 | } | |
30 | ||
31 | //______________________________________________________________________________ | |
32 | AliAODDimuon::AliAODDimuon(const AliAODDimuon& dimu): | |
33 | AliVParticle(dimu), | |
34 | fP(0),fMProton(0.93827231) | |
35 | { | |
36 | // copy constructor | |
37 | fMu[0]=dimu.Mu(0); | |
38 | fMu[1]=dimu.Mu(1); | |
39 | } | |
40 | ||
41 | //______________________________________________________________________________ | |
42 | AliAODDimuon &AliAODDimuon::operator=(const AliAODDimuon& dimu) | |
43 | { | |
44 | // assignment operator | |
45 | if(&dimu != this){ | |
46 | fP=0; | |
47 | fMProton=0.93827231; | |
48 | fMu[0]=dimu.Mu(0); | |
49 | fMu[1]=dimu.Mu(1); | |
50 | } | |
51 | return *this; | |
52 | } | |
53 | ||
54 | //______________________________________________________________________________ | |
55 | AliAODDimuon::AliAODDimuon(TObject *mu0, TObject *mu1): | |
56 | fP(0),fMProton(0.93827231) | |
57 | { | |
58 | // Creates a dimuon pair from two tracks | |
59 | ||
60 | //printf("Creating dimuon from %p %p\n",mu0,mu1); | |
61 | fMu[0]=mu0; | |
62 | fMu[1]=mu1; | |
63 | } | |
64 | ||
65 | //______________________________________________________________________________ | |
66 | AliAODDimuon::~AliAODDimuon() | |
67 | { | |
68 | // destructor | |
69 | if(fP)delete fP; | |
70 | fP=0; | |
71 | } | |
72 | ||
73 | //______________________________________________________________________________ | |
74 | void AliAODDimuon::BookP(){ | |
75 | // Fills the dimuon momentum if not filled yet | |
76 | static UInt_t unID[2]={0,0}; | |
77 | if(!fP){ | |
78 | fP=new TLorentzVector(Px(),Py(),Pz(),E()); | |
79 | unID[0]=fMu[0].GetUniqueID(); | |
80 | unID[1]=fMu[1].GetUniqueID(); | |
81 | } | |
82 | // For efficiency reasons | |
83 | if((unID[0]!=fMu[0].GetUniqueID())||(unID[1]!=fMu[1].GetUniqueID())){ | |
84 | fP->SetPxPyPzE(Px(),Py(),Pz(),E()); | |
85 | unID[0]=fMu[0].GetUniqueID(); | |
86 | unID[1]=fMu[1].GetUniqueID(); | |
87 | } | |
88 | } | |
89 | ||
90 | //______________________________________________________________________________ | |
91 | Double_t AliAODDimuon::Px() const { | |
92 | // Px of the dimuon | |
93 | if(this->CheckPointers())return -999999999; | |
94 | return ((AliAODTrack*)fMu[0].GetObject())->Px()+ | |
95 | ((AliAODTrack*)fMu[1].GetObject())->Px(); | |
96 | } | |
97 | ||
98 | //______________________________________________________________________________ | |
99 | Double_t AliAODDimuon::Py() const { | |
100 | // Py of the dimuon | |
101 | if(this->CheckPointers())return -999999999; | |
102 | return ((AliAODTrack*)fMu[0].GetObject())->Py()+ | |
103 | ((AliAODTrack*)fMu[1].GetObject())->Py(); | |
104 | } | |
105 | ||
106 | //______________________________________________________________________________ | |
107 | Double_t AliAODDimuon::Pz() const { | |
108 | // Pz of the dimuon | |
109 | if(this->CheckPointers())return -999999999; | |
110 | return ((AliAODTrack*)fMu[0].GetObject())->Pz()+ | |
111 | ((AliAODTrack*)fMu[1].GetObject())->Pz(); | |
112 | } | |
113 | ||
114 | //______________________________________________________________________________ | |
115 | Double_t AliAODDimuon::Pt() const { | |
116 | // Pt of the dimuon | |
117 | if(this->CheckPointers())return -999999999; | |
118 | Double_t px=Px(); | |
119 | Double_t py=Py(); | |
120 | return TMath::Sqrt(px*px+py*py); | |
121 | return -999999999; | |
122 | } | |
123 | ||
124 | //______________________________________________________________________________ | |
125 | Double_t AliAODDimuon::E() const { | |
126 | // Dimuon energy | |
127 | if(this->CheckPointers())return -999999999; | |
128 | return ((AliAODTrack*)fMu[0].GetObject())->E()+ | |
129 | ((AliAODTrack*)fMu[1].GetObject())->E(); | |
130 | } | |
131 | ||
132 | //______________________________________________________________________________ | |
133 | Double_t AliAODDimuon::P() const { | |
134 | // This is just to override the virtual function | |
135 | printf("You should never call: Double_t AliAODDimuon::P() const\n"); | |
136 | return -999999999; | |
137 | } | |
138 | ||
139 | //______________________________________________________________________________ | |
140 | Double_t AliAODDimuon::P() { | |
141 | // Dimuon momentum | |
142 | if(this->CheckPointers())return -999999999; | |
143 | BookP(); | |
144 | return fP->P(); | |
145 | } | |
146 | ||
147 | //______________________________________________________________________________ | |
148 | Double_t AliAODDimuon::M() const { | |
149 | // This is just to override the virtual function | |
150 | printf("You should never call: Double_t AliAODDimuon::M() const\n"); | |
151 | return -999999999; | |
152 | } | |
153 | ||
154 | //______________________________________________________________________________ | |
155 | Double_t AliAODDimuon::M() { | |
156 | // Dimuon invariant mass | |
157 | if(this->CheckPointers())return -999999999; | |
158 | BookP(); | |
159 | return fP->M(); | |
160 | } | |
161 | ||
162 | //______________________________________________________________________________ | |
163 | Double_t AliAODDimuon::Mass() { | |
164 | // Dimuon invariant mass | |
165 | if(this->CheckPointers())return -999999999; | |
166 | BookP(); | |
167 | return fP->M(); | |
168 | } | |
169 | ||
170 | //______________________________________________________________________________ | |
171 | Double_t AliAODDimuon::Eta() const { | |
172 | // This is just to override the virtual function | |
173 | printf("You should never call: Double_t AliAODDimuon::Eta() const\n"); | |
174 | return -999999999; | |
175 | } | |
176 | ||
177 | //______________________________________________________________________________ | |
178 | Double_t AliAODDimuon::Eta() { | |
179 | // Dimuon pseudorapidity | |
180 | if(this->CheckPointers())return -999999999; | |
181 | BookP(); | |
182 | return fP->Eta(); | |
183 | } | |
184 | ||
185 | //______________________________________________________________________________ | |
186 | Double_t AliAODDimuon::Phi() const { | |
187 | // This is just to override the virtual function | |
188 | printf("You should never call: Double_t AliAODDimuon::Phi() const\n"); | |
189 | return -999999999; | |
190 | } | |
191 | ||
192 | //______________________________________________________________________________ | |
193 | Double_t AliAODDimuon::Phi() { | |
194 | // Dimuon asimuthal angle | |
195 | if(this->CheckPointers())return -999999999; | |
196 | BookP(); | |
197 | return fP->Phi(); | |
198 | } | |
199 | //______________________________________________________________________________ | |
200 | Double_t AliAODDimuon::Theta() const { | |
201 | // This is just to override the virtual function | |
202 | printf("You should never call: Double_t AliAODDimuon::Theta() const\n"); | |
203 | return -999999999; | |
204 | } | |
205 | ||
206 | //______________________________________________________________________________ | |
207 | Double_t AliAODDimuon::Theta() { | |
208 | // Dimuon polar angle | |
209 | if(this->CheckPointers())return -999999999; | |
210 | BookP(); | |
211 | return fP->Theta(); | |
212 | } | |
213 | ||
214 | //______________________________________________________________________________ | |
215 | Double_t AliAODDimuon::Y() const { | |
216 | // This is just to override the virtual function | |
217 | printf("You should never call: Double_t AliAODDimuon::Y() const\n"); | |
218 | return -999999999; | |
219 | } | |
220 | ||
221 | //______________________________________________________________________________ | |
222 | Double_t AliAODDimuon::Y() { | |
223 | // Dimuon rapidity | |
224 | if(this->CheckPointers())return -999999999; | |
225 | BookP(); | |
226 | return fP->Rapidity(); | |
227 | } | |
228 | ||
229 | //______________________________________________________________________________ | |
230 | Short_t AliAODDimuon::Charge() const { | |
231 | // Dimuon charge | |
232 | if(this->CheckPointers())return -999; | |
233 | return ((AliAODTrack*)fMu[0].GetObject())->Charge()+ | |
234 | ((AliAODTrack*)fMu[1].GetObject())->Charge(); | |
235 | } | |
236 | ||
237 | //______________________________________________________________________________ | |
238 | Int_t AliAODDimuon::CheckPointers() const{ | |
239 | // Checks if the track pointers have been initialized | |
240 | if(fMu[0]==0||fMu[1]==0){ | |
241 | printf("Dimuon not initialized\n"); | |
242 | return -999; | |
243 | } | |
244 | if((fMu[0].GetObject())==0||(fMu[1].GetObject())==0){ | |
245 | printf("Can not get objects. Got: %p %p\n",fMu[0].GetObject(),fMu[1].GetObject()); | |
246 | return -999; | |
247 | } | |
248 | return 0; | |
249 | } | |
250 | ||
251 | //______________________________________________________________________________ | |
252 | void AliAODDimuon::SetMu(Int_t imu, AliAODTrack *mu){ | |
253 | // Assign a track pointer | |
254 | if (imu==0||imu==1){ | |
255 | fMu[imu]=mu; | |
256 | } | |
257 | } | |
258 | ||
259 | //______________________________________________________________________________ | |
260 | void AliAODDimuon::SetMuons(AliAODTrack *mu0, AliAODTrack *mu1){ | |
261 | // Assign the track pointers | |
262 | fMu[0]=mu0; | |
263 | fMu[1]=mu1; | |
264 | } | |
265 | ||
266 | //______________________________________________________________________________ | |
267 | Double_t AliAODDimuon::XF() { | |
268 | // Dimuon Feynman x | |
269 | //Double_t ebeam=((AliAODEventInfo*)fEi.GetObject())->EBeam(); | |
270 | Double_t ebeam = 3500.; // temporary | |
271 | if(ebeam<=0){ | |
272 | printf("AliAODDimuon::xf: can not compute xf with EBeam=%f\n",ebeam); | |
273 | return -999999999; | |
274 | } | |
275 | if(this->CheckPointers())return -999999999; | |
276 | BookP(); | |
277 | Double_t mDimu=M(); | |
278 | Double_t pMax=TMath::Sqrt(ebeam*ebeam-mDimu*mDimu); | |
279 | return Pz()/pMax; | |
280 | } | |
281 | ||
282 | //______________________________________________________________________________ | |
283 | // Calculation the Collins-Soper angle (adapted from code by R. Arnaldi) | |
284 | Double_t AliAODDimuon::CostCS(){ | |
285 | // Cosinus of the Collins-Soper polar decay angle | |
286 | if(CheckPointers())return -999999999; | |
287 | Double_t ebeam=3500.; //temporary | |
288 | if(ebeam<=0){ | |
289 | printf("Can not compute costCS with EBeam=%f\n",ebeam); | |
290 | return -999999999; | |
291 | } | |
292 | Double_t mp=fMProton; | |
293 | Double_t pbeam=TMath::Sqrt(ebeam*ebeam-mp*mp); | |
294 | Double_t pla10=((AliAODTrack*)fMu[0].GetObject())->Px(); | |
295 | Double_t pla11=((AliAODTrack*)fMu[0].GetObject())->Py(); | |
296 | Double_t pla12=((AliAODTrack*)fMu[0].GetObject())->Pz(); | |
297 | Double_t e1=((AliAODTrack*)fMu[0].GetObject())->E(); | |
298 | Double_t mu1Charge=((AliAODTrack*)fMu[0].GetObject())->Charge(); | |
299 | Double_t pla20=((AliAODTrack*)fMu[1].GetObject())->Px(); | |
300 | Double_t pla21=((AliAODTrack*)fMu[1].GetObject())->Py(); | |
301 | Double_t pla22=((AliAODTrack*)fMu[1].GetObject())->Pz(); | |
302 | Double_t e2=((AliAODTrack*)fMu[1].GetObject())->E(); | |
303 | Double_t mu2Charge=((AliAODTrack*)fMu[1].GetObject())->Charge(); | |
304 | ||
305 | // Fill the Lorentz vector for projectile and target | |
306 | // For the moment we do not consider the crossing angle | |
307 | // Projectile runs towards the MUON arm | |
308 | TLorentzVector pProjLab(0.,0.,-pbeam,ebeam); // projectile | |
309 | TLorentzVector pTargLab(0.,0., pbeam,ebeam); // target | |
310 | // | |
311 | // --- Get the muons parameters in the LAB frame | |
312 | // | |
313 | TLorentzVector pMu1Lab(pla10,pla11,pla12,e1); | |
314 | TLorentzVector pMu2Lab(pla20,pla21,pla22,e2); | |
315 | // | |
316 | // --- Obtain the dimuon parameters in the LAB frame | |
317 | // | |
318 | TLorentzVector pDimuLab=pMu1Lab+pMu2Lab; | |
319 | // | |
320 | // --- Translate the dimuon parameters in the dimuon rest frame | |
321 | // | |
322 | TVector3 beta=(-1./pDimuLab.E())*pDimuLab.Vect(); | |
323 | TLorentzVector pMu1Dimu=pMu1Lab; | |
324 | TLorentzVector pMu2Dimu=pMu2Lab; | |
325 | TLorentzVector pProjDimu=pProjLab; | |
326 | TLorentzVector pTargDimu=pTargLab; | |
327 | pMu1Dimu.Boost(beta); | |
328 | pMu2Dimu.Boost(beta); | |
329 | pProjDimu.Boost(beta); | |
330 | pTargDimu.Boost(beta); | |
331 | // | |
332 | // --- Determine the z axis for the CS angle | |
333 | // | |
334 | TVector3 zaxisCS=(((pProjDimu.Vect()).Unit())-((pTargDimu.Vect()).Unit())).Unit(); | |
335 | // | |
336 | // --- Determine the CS angle (angle between mu+ and the z axis defined above) | |
337 | // | |
338 | Double_t cost; | |
339 | if(mu1Charge > 0) { | |
340 | cost = zaxisCS.Dot((pMu1Dimu.Vect()).Unit()); | |
341 | // Theta CS is not properly defined for Like-Sign muons | |
342 | if(mu2Charge > 0 && cost<0) cost=-cost; | |
343 | } else { | |
344 | // Theta CS is not properly defined for Like-Sign muons | |
345 | cost = zaxisCS.Dot((pMu2Dimu.Vect()).Unit()); | |
346 | if(mu2Charge < 0 && cost<0) cost=-cost; | |
347 | } | |
348 | return cost; | |
349 | } | |
350 | ||
351 | //______________________________________________________________________________ | |
352 | // Calculation the Helicity polarization angle (adapted from code by R. Arnaldi) | |
353 | Double_t AliAODDimuon::CostHe(){ | |
354 | // Cosinus of the polar decay angle in the Helicity reference frame | |
355 | if(CheckPointers())return -999999999; | |
356 | Double_t ebeam=3500; //temporary | |
357 | if(ebeam<=0){ | |
358 | printf("Can not compute costCS with EBeam=%f\n",ebeam); | |
359 | return -999999999; | |
360 | } | |
361 | Double_t pbeam=TMath::Sqrt(ebeam*ebeam-fMProton*fMProton); | |
362 | Double_t pla10=((AliAODTrack*)fMu[0].GetObject())->Px(); | |
363 | Double_t pla11=((AliAODTrack*)fMu[0].GetObject())->Py(); | |
364 | Double_t pla12=((AliAODTrack*)fMu[0].GetObject())->Pz(); | |
365 | Double_t e1=((AliAODTrack*)fMu[0].GetObject())->E(); | |
366 | Double_t mu1Charge=((AliAODTrack*)fMu[0].GetObject())->Charge(); | |
367 | Double_t pla20=((AliAODTrack*)fMu[1].GetObject())->Px(); | |
368 | Double_t pla21=((AliAODTrack*)fMu[1].GetObject())->Py(); | |
369 | Double_t pla22=((AliAODTrack*)fMu[1].GetObject())->Pz(); | |
370 | Double_t e2=((AliAODTrack*)fMu[1].GetObject())->E(); | |
371 | Double_t mu2Charge=((AliAODTrack*)fMu[1].GetObject())->Charge(); | |
372 | ||
373 | // Fill the Lorentz vector for projectile and target | |
374 | // For the moment we consider no crossing angle | |
375 | // Projectile runs towards the MUON arm | |
376 | TLorentzVector pProjLab(0.,0.,-pbeam,ebeam); // projectile | |
377 | TLorentzVector pTargLab(0.,0., pbeam,ebeam); // target | |
378 | // | |
379 | // --- Get the muons parameters in the LAB frame | |
380 | // | |
381 | TLorentzVector pMu1Lab(pla10,pla11,pla12,e1); | |
382 | TLorentzVector pMu2Lab(pla20,pla21,pla22,e2); | |
383 | // | |
384 | // --- Obtain the dimuon parameters in the LAB frame | |
385 | // | |
386 | TLorentzVector pDimuLab=pMu1Lab+pMu2Lab; | |
387 | // | |
388 | // --- Translate the dimuon parameters in the dimuon rest frame | |
389 | // | |
390 | TVector3 beta=(-1./pDimuLab.E())*pDimuLab.Vect(); | |
391 | TLorentzVector pMu1Dimu=pMu1Lab; | |
392 | TLorentzVector pMu2Dimu=pMu2Lab; | |
393 | pMu1Dimu.Boost(beta); | |
394 | pMu2Dimu.Boost(beta); | |
395 | // | |
396 | // --- Translate the dimuon parameters in the CM frame | |
397 | // | |
398 | TLorentzVector pDimuCM; //CM frame | |
399 | TVector3 beta2; | |
400 | beta2=(-1./(fMProton+pProjLab.E()))*pProjLab.Vect(); | |
401 | pDimuCM=pDimuLab; | |
402 | pDimuCM.Boost(beta2); | |
403 | // | |
404 | // --- Determine the z axis for the calculation of the polarization angle | |
405 | // (i.e. the direction of the dimuon in the CM system) | |
406 | // | |
407 | TVector3 zaxis; | |
408 | zaxis=(pDimuCM.Vect()).Unit(); | |
409 | // | |
410 | // --- Calculation of the polarization angle (Helicity) | |
411 | // (angle between mu+ and the z axis defined above) | |
412 | // | |
413 | Double_t cost; | |
414 | if(mu1Charge > 0) { | |
415 | cost = zaxis.Dot((pMu1Dimu.Vect()).Unit()); | |
416 | // Theta Helicity is not properly defined for Like-Sign muons | |
417 | if(mu2Charge > 0 && cost<0) cost=-cost; | |
418 | } else { | |
419 | cost = zaxis.Dot((pMu2Dimu.Vect()).Unit()); | |
420 | // Theta Helicity is not properly defined for Like-Sign muons | |
421 | if(mu2Charge < 0 && cost<0) cost=-cost; | |
422 | } | |
423 | return cost; | |
424 | } | |
425 | ||
426 | //______________________________________________________________________________ | |
427 | Int_t AliAODDimuon::AnyPt(){ | |
428 | // Test if the two muons match two trigger tracks | |
429 | if(this->CheckPointers())return 0; | |
430 | return (((AliAODTrack*)fMu[0].GetObject())->MatchTrigger())&& | |
431 | (((AliAODTrack*)fMu[0].GetObject())->MatchTrigger()); | |
432 | } | |
433 | ||
434 | //______________________________________________________________________________ | |
435 | Int_t AliAODDimuon::LowPt(){ | |
436 | // Test if the two muons match two trigger tracks with a "Low Pt" cut | |
437 | if(this->CheckPointers())return 0; | |
438 | return (((AliAODTrack*)fMu[0].GetObject())->MatchTriggerLowPt())&& | |
439 | (((AliAODTrack*)fMu[0].GetObject())->MatchTriggerLowPt()); | |
440 | } | |
441 | ||
442 | //______________________________________________________________________________ | |
443 | Int_t AliAODDimuon::HighPt(){ | |
444 | // Test if the two muons match two trigger tracks with a "High Pt" cut | |
445 | if(this->CheckPointers())return 0; | |
446 | return (((AliAODTrack*)fMu[0].GetObject())->MatchTriggerHighPt())&& | |
447 | (((AliAODTrack*)fMu[0].GetObject())->MatchTriggerHighPt()); | |
448 | } | |
449 | ||
450 | //______________________________________________________________________________ | |
451 | Double_t AliAODDimuon::MaxChi2Match(){ | |
452 | // Maximum matching Chi2 between track and trigger track | |
453 | if(this->CheckPointers())return -999999999; | |
454 | return TMath::Max((((AliAODTrack*)fMu[0].GetObject())->GetChi2MatchTrigger()), | |
455 | (((AliAODTrack*)fMu[0].GetObject())->GetChi2MatchTrigger())); | |
456 | } |