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7356f978 | 1 | /************************************************************************** |
2 | * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. * | |
3 | * * | |
4 | * Author: The ALICE Off-line Project. * | |
5 | * Contributors are mentioned in the code where appropriate. * | |
6 | * * | |
7 | * Permission to use, copy, modify and distribute this software and its * | |
8 | * documentation strictly for non-commercial purposes is hereby granted * | |
9 | * without fee, provided that the above copyright notice appears in all * | |
10 | * copies and that both the copyright notice and this permission notice * | |
11 | * appear in the supporting documentation. The authors make no claims * | |
12 | * about the suitability of this software for any purpose. It is * | |
13 | * provided "as is" without express or implied warranty. * | |
14 | **************************************************************************/ | |
15 | ||
16 | //////////////////////////////////////////////////////////////////////////////// | |
17 | // | |
18 | // This class implements a candidate resonance. It has two pointers to its | |
19 | // two candidate daughters, whose 4-momenta are combined to obtain the mother | |
20 | // invariant mass and other kinematical quantities. | |
21 | // This class contains also some methods used to compute kinematical relations | |
22 | // between the candidate resonance and other particles. | |
23 | // | |
24 | // authors: A. Pulvirenti (alberto.pulvirenti@ct.infn.it) | |
25 | // M. Vala (martin.vala@cern.ch) | |
26 | // | |
27 | //////////////////////////////////////////////////////////////////////////////// | |
747592c1 | 28 | |
2dab9030 | 29 | #include <Riostream.h> |
4820b1ae | 30 | #include <TVector3.h> |
747592c1 | 31 | |
ec927a7d | 32 | #include "AliAODMCParticle.h" |
33 | #include "AliMCParticle.h" | |
d7712d44 | 34 | #include "AliRsnEvent.h" |
35 | ||
2dab9030 | 36 | #include "AliRsnMother.h" |
37 | ||
38 | ClassImp(AliRsnMother) | |
39 | ||
f34f960b | 40 | //__________________________________________________________________________________________________ |
2a1c7696 | 41 | AliRsnMother::AliRsnMother(const AliRsnMother &obj) : |
42 | TObject(obj), | |
d7712d44 | 43 | fRefEvent(obj.fRefEvent), |
2a1c7696 | 44 | fSum(obj.fSum), |
110620ce | 45 | fSumMC(obj.fSumMC), |
46 | fRef(obj.fRef), | |
47 | fRefMC(obj.fRefMC) | |
2dab9030 | 48 | { |
49 | // | |
50 | // Copy constructor. | |
2dab9030 | 51 | // Does not duplicate pointers. |
52 | // | |
53 | ||
2a1c7696 | 54 | Int_t i; |
55 | for (i = 0; i < 2; i++) fDaughter[i] = obj.fDaughter[i]; | |
2dab9030 | 56 | } |
57 | ||
f34f960b | 58 | //__________________________________________________________________________________________________ |
61f275d1 | 59 | AliRsnMother &AliRsnMother::operator=(const AliRsnMother &obj) |
2dab9030 | 60 | { |
61 | // | |
62 | // Assignment operator. | |
2dab9030 | 63 | // Does not duplicate pointers. |
64 | // | |
61f275d1 | 65 | if (this == &obj) |
66 | return *this; | |
67 | ||
68 | fSum = obj.fSum; | |
69 | fRef = obj.fRef; | |
70 | fSumMC = obj.fSumMC; | |
71 | fRefMC = obj.fRefMC; | |
72 | fRefEvent = obj.fRefEvent; | |
73 | fDaughter[0] = obj.fDaughter[0]; | |
74 | fDaughter[1] = obj.fDaughter[1]; | |
75 | ||
76 | return (*this); | |
2dab9030 | 77 | } |
78 | ||
f34f960b | 79 | //__________________________________________________________________________________________________ |
2dab9030 | 80 | AliRsnMother::~AliRsnMother() |
81 | { | |
82 | // | |
83 | // Desctructor. | |
84 | // Does nothing, since pointers are not created in this class. | |
85 | // | |
86 | } | |
87 | ||
f34f960b | 88 | //_______________________________________________________________________________________________________________________ |
89 | void AliRsnMother::Reset() | |
2dab9030 | 90 | { |
91 | // | |
7356f978 | 92 | // Resets the mother, zeroing all data members. |
2dab9030 | 93 | // |
94 | ||
2a1c7696 | 95 | Int_t i; |
96 | for (i = 0; i < 2; i++) fDaughter[i] = 0x0; | |
d7712d44 | 97 | fRefEvent = 0x0; |
f34f960b | 98 | fSum.SetXYZM(0.0, 0.0, 0.0, 0.0); |
99 | fRef.SetXYZM(0.0, 0.0, 0.0, 0.0); | |
2dab9030 | 100 | } |
101 | ||
f34f960b | 102 | //__________________________________________________________________________________________________ |
103 | Int_t AliRsnMother::CommonMother() const | |
d7712d44 | 104 | { |
105 | // | |
f34f960b | 106 | // If MC info is available, checks if the two tracks in the pair have the same mother. |
107 | // If the mother label is the same, the function returns the PDG code of mother, | |
108 | // otherwise it returns 0. | |
109 | // The two arguments passed by reference contain the GEANT labels of the mother | |
61f275d1 | 110 | // of the two particles to which the two daughters point. This is for being able |
f34f960b | 111 | // to check if they are really coming from a resonance (indexes >= 0) or not. |
d7712d44 | 112 | // |
113 | ||
f34f960b | 114 | Int_t m1 = fDaughter[0]->GetMother(); |
115 | Int_t m2 = fDaughter[1]->GetMother(); | |
116 | Int_t out = 0; | |
61f275d1 | 117 | |
f34f960b | 118 | // a true mother makes sense only if both mothers |
119 | // are not-negative and equal | |
120 | if (m1 >= 0 && m2 >= 0 && m1 == m2) { | |
121 | out = TMath::Abs(fDaughter[0]->GetMotherPDG()); | |
122 | AliDebugClass(1, Form("Mothers are: %d %d --> EQUAL (PDG = %d)", m1, m2, out)); | |
61f275d1 | 123 | } |
124 | ||
f34f960b | 125 | return out; |
d7712d44 | 126 | } |
127 | ||
f34f960b | 128 | //__________________________________________________________________________________________________ |
d7712d44 | 129 | Double_t AliRsnMother::AngleToLeading(Bool_t &success) |
130 | { | |
131 | // | |
132 | // Compute the angle betwee this and the leading particls | |
133 | // of the reference event (if this was set properly). | |
134 | // In case one of the two daughters is the leading, return | |
135 | // a meaningless value, in order to skip this pair. | |
136 | // if second argument is kTRUE, use MC values. | |
137 | // | |
138 | ||
139 | if (!fRefEvent) { | |
140 | success = kFALSE; | |
141 | return -99.0; | |
142 | } | |
61f275d1 | 143 | |
d7712d44 | 144 | Int_t id1 = fDaughter[0]->GetID(); |
145 | Int_t id2 = fDaughter[1]->GetID(); | |
f34f960b | 146 | Int_t idL = fRefEvent->GetLeadingIndex(); |
61f275d1 | 147 | |
d7712d44 | 148 | if (id1 == idL || id2 == idL) { |
149 | success = kFALSE; | |
150 | return -99.0; | |
151 | } | |
61f275d1 | 152 | |
f34f960b | 153 | AliRsnDaughter leading = fRefEvent->GetDaughter(idL, kFALSE); |
d7712d44 | 154 | AliVParticle *ref = leading.GetRef(); |
155 | Double_t angle = ref->Phi() - fSum.Phi(); | |
61f275d1 | 156 | |
d7712d44 | 157 | //return angle w.r.t. leading particle in the range -pi/2, 3/2pi |
158 | while (angle >= 1.5 * TMath::Pi()) angle -= 2 * TMath::Pi(); | |
159 | while (angle < -0.5 * TMath::Pi()) angle += 2 * TMath::Pi(); | |
160 | success = kTRUE; | |
61f275d1 | 161 | |
d7712d44 | 162 | return angle; |
163 | } | |
164 | ||
f34f960b | 165 | //__________________________________________________________________________________________________ |
166 | void AliRsnMother::ComputeSum(Double_t mass0, Double_t mass1, Double_t motherMass) | |
167 | { | |
168 | // | |
169 | // Sets the masses for the 4-momenta of the daughters and then | |
170 | // sums them, taking into account that the space part is set to | |
171 | // each of them when the reference object is set (see AliRsnDaughter::SetRef) | |
172 | // | |
173 | ||
174 | fDaughter[0]->FillP(mass0); | |
175 | fDaughter[1]->FillP(mass1); | |
176 | ||
177 | // sum | |
178 | fSum = fDaughter[0]->Prec() + fDaughter[1]->Prec(); | |
179 | fSumMC = fDaughter[0]->Psim() + fDaughter[1]->Psim(); | |
61f275d1 | 180 | |
f34f960b | 181 | // reference |
182 | fRef.SetXYZM(fSum.X(), fSum.Y(), fSum.Z(), motherMass); | |
183 | fRefMC.SetXYZM(fSumMC.X(), fSumMC.Y(), fSumMC.Z(), motherMass); | |
184 | } | |
185 | ||
186 | //__________________________________________________________________________________________________ | |
2e521c29 | 187 | Double_t AliRsnMother::CosThetaStar(Bool_t first, Bool_t useMC) |
cadcd9e0 | 188 | { |
7356f978 | 189 | // |
190 | // Computes the cosine of theta*, which is the angle of one of the daughters | |
191 | // with respect to the total momentum of the resonance, in its rest frame. | |
192 | // The arguments are needed to choose which of the daughters one want to use | |
193 | // and if reconstructed or MC momentum must be used. | |
194 | // [Contribution from Z. Feckova] | |
195 | // | |
196 | ||
f34f960b | 197 | TLorentzVector &mother = Sum(useMC); |
198 | TLorentzVector &daughter0 = (first ? fDaughter[0]->P(useMC) : fDaughter[1]->P(useMC)); | |
199 | TLorentzVector &daughter1 = (first ? fDaughter[1]->P(useMC) : fDaughter[0]->P(useMC)); | |
2a1c7696 | 200 | TVector3 momentumM(mother.Vect()); |
201 | TVector3 normal(mother.Y() / momentumM.Mag(), -mother.X() / momentumM.Mag(), 0.0); | |
202 | ||
203 | // Computes first the invariant mass of the mother | |
7356f978 | 204 | Double_t mass0 = fDaughter[0]->P(useMC).M(); |
205 | Double_t mass1 = fDaughter[1]->P(useMC).M(); | |
206 | Double_t p0 = daughter0.Vect().Mag(); | |
207 | Double_t p1 = daughter1.Vect().Mag(); | |
208 | Double_t E0 = TMath::Sqrt(mass0 * mass0 + p0 * p0); | |
209 | Double_t E1 = TMath::Sqrt(mass1 * mass1 + p1 * p1); | |
210 | Double_t MotherMass = TMath::Sqrt((E0 + E1) * (E0 + E1) - (p0 * p0 + 2.0 * daughter0.Vect().Dot(daughter1.Vect()) + p1 * p1)); | |
2a1c7696 | 211 | MotherMass = fSum.M(); |
212 | ||
213 | // Computes components of beta | |
214 | Double_t betaX = -mother.X() / mother.E(); | |
215 | Double_t betaY = -mother.Y() / mother.E(); | |
216 | Double_t betaZ = -mother.Z() / mother.E(); | |
217 | ||
218 | // Computes Lorentz transformation of the momentum of the first daughter | |
219 | // into the rest frame of the mother and theta* | |
220 | daughter0.Boost(betaX, betaY, betaZ); | |
221 | TVector3 momentumD = daughter0.Vect(); | |
222 | ||
223 | Double_t cosThetaStar = normal.Dot(momentumD) / momentumD.Mag(); | |
224 | ||
225 | return cosThetaStar; | |
cadcd9e0 | 226 | } |
227 | ||
f34f960b | 228 | //__________________________________________________________________________________________________ |
2dab9030 | 229 | void AliRsnMother::PrintInfo(const Option_t * /*option*/) const |
230 | { | |
231 | // | |
232 | // Print some info of the pair. | |
233 | // The options are passed to the AliRsnDaughter::Print() method | |
234 | // | |
235 | ||
2a1c7696 | 236 | AliInfo("======== BEGIN PAIR INFO ==========="); |
237 | AliInfo("Track #1"); | |
238 | fDaughter[0]->Print(); | |
239 | AliInfo("Track #2"); | |
240 | fDaughter[1]->Print(); | |
241 | AliInfo("========= END PAIR INFO ==========="); | |
2dab9030 | 242 | } |
243 | ||
f34f960b | 244 | //__________________________________________________________________________________________________ |
0206329d | 245 | Bool_t AliRsnMother::CheckPair(Bool_t checkMC) const |
2dab9030 | 246 | { |
247 | // | |
248 | // Checks that the pair is well initialized: | |
249 | // - both daughters are good pointers | |
250 | // - if MC is required, both daughters have a MC reference | |
251 | // | |
252 | ||
2a1c7696 | 253 | if (!fDaughter[0] || !fDaughter[1]) { |
254 | AliError("One of the two tracks is NULL in this pair!"); | |
2dab9030 | 255 | return kFALSE; |
2a1c7696 | 256 | } |
257 | ||
0206329d | 258 | if (checkMC) { |
2a1c7696 | 259 | if (fDaughter[0]->GetRefMC() == 0x0 || fDaughter[1]->GetRefMC() == 0x0) { |
260 | AliError("Required MC info but not all MC refs are available"); | |
261 | return kFALSE; | |
262 | } | |
263 | } | |
264 | ||
265 | return kTRUE; | |
2dab9030 | 266 | } |