]>
Commit | Line | Data |
---|---|---|
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" | |
2dab9030 | 34 | #include "AliRsnDaughter.h" |
d7712d44 | 35 | #include "AliRsnEvent.h" |
36 | ||
2dab9030 | 37 | #include "AliRsnMother.h" |
38 | ||
39 | ClassImp(AliRsnMother) | |
40 | ||
f34f960b | 41 | //__________________________________________________________________________________________________ |
2a1c7696 | 42 | AliRsnMother::AliRsnMother(const AliRsnMother &obj) : |
43 | TObject(obj), | |
d7712d44 | 44 | fRefEvent(obj.fRefEvent), |
2a1c7696 | 45 | fSum(obj.fSum), |
110620ce | 46 | fSumMC(obj.fSumMC), |
47 | fRef(obj.fRef), | |
48 | fRefMC(obj.fRefMC) | |
2dab9030 | 49 | { |
50 | // | |
51 | // Copy constructor. | |
2dab9030 | 52 | // Does not duplicate pointers. |
53 | // | |
54 | ||
2a1c7696 | 55 | Int_t i; |
56 | for (i = 0; i < 2; i++) fDaughter[i] = obj.fDaughter[i]; | |
2dab9030 | 57 | } |
58 | ||
f34f960b | 59 | //__________________________________________________________________________________________________ |
2dab9030 | 60 | AliRsnMother& AliRsnMother::operator=(const AliRsnMother &obj) |
61 | { | |
62 | // | |
63 | // Assignment operator. | |
2dab9030 | 64 | // Does not duplicate pointers. |
65 | // | |
66 | ||
2a1c7696 | 67 | fSum = obj.fSum; |
f34f960b | 68 | fRef = obj.fRef; |
110620ce | 69 | fSumMC = obj.fSumMC; |
70 | fRefMC = obj.fRefMC; | |
d7712d44 | 71 | fRefEvent = obj.fRefEvent; |
f34f960b | 72 | fDaughter[0] = obj.fDaughter[0]; |
73 | fDaughter[1] = obj.fDaughter[1]; | |
74 | ||
2a1c7696 | 75 | return (*this); |
2dab9030 | 76 | } |
77 | ||
f34f960b | 78 | //__________________________________________________________________________________________________ |
2dab9030 | 79 | AliRsnMother::~AliRsnMother() |
80 | { | |
81 | // | |
82 | // Desctructor. | |
83 | // Does nothing, since pointers are not created in this class. | |
84 | // | |
85 | } | |
86 | ||
f34f960b | 87 | //_______________________________________________________________________________________________________________________ |
88 | void AliRsnMother::Reset() | |
2dab9030 | 89 | { |
90 | // | |
7356f978 | 91 | // Resets the mother, zeroing all data members. |
2dab9030 | 92 | // |
93 | ||
2a1c7696 | 94 | Int_t i; |
95 | for (i = 0; i < 2; i++) fDaughter[i] = 0x0; | |
d7712d44 | 96 | fRefEvent = 0x0; |
f34f960b | 97 | fSum.SetXYZM(0.0, 0.0, 0.0, 0.0); |
98 | fRef.SetXYZM(0.0, 0.0, 0.0, 0.0); | |
2dab9030 | 99 | } |
100 | ||
f34f960b | 101 | //__________________________________________________________________________________________________ |
102 | Int_t AliRsnMother::CommonMother() const | |
d7712d44 | 103 | { |
104 | // | |
f34f960b | 105 | // If MC info is available, checks if the two tracks in the pair have the same mother. |
106 | // If the mother label is the same, the function returns the PDG code of mother, | |
107 | // otherwise it returns 0. | |
108 | // The two arguments passed by reference contain the GEANT labels of the mother | |
109 | // of the two particles to which the two daughters point. This is for being able | |
110 | // to check if they are really coming from a resonance (indexes >= 0) or not. | |
d7712d44 | 111 | // |
112 | ||
f34f960b | 113 | Int_t m1 = fDaughter[0]->GetMother(); |
114 | Int_t m2 = fDaughter[1]->GetMother(); | |
115 | Int_t out = 0; | |
116 | ||
117 | // a true mother makes sense only if both mothers | |
118 | // are not-negative and equal | |
119 | if (m1 >= 0 && m2 >= 0 && m1 == m2) { | |
120 | out = TMath::Abs(fDaughter[0]->GetMotherPDG()); | |
121 | AliDebugClass(1, Form("Mothers are: %d %d --> EQUAL (PDG = %d)", m1, m2, out)); | |
122 | } | |
d7712d44 | 123 | |
f34f960b | 124 | return out; |
d7712d44 | 125 | } |
126 | ||
f34f960b | 127 | //__________________________________________________________________________________________________ |
d7712d44 | 128 | Double_t AliRsnMother::AngleToLeading(Bool_t &success) |
129 | { | |
130 | // | |
131 | // Compute the angle betwee this and the leading particls | |
132 | // of the reference event (if this was set properly). | |
133 | // In case one of the two daughters is the leading, return | |
134 | // a meaningless value, in order to skip this pair. | |
135 | // if second argument is kTRUE, use MC values. | |
136 | // | |
137 | ||
138 | if (!fRefEvent) { | |
139 | success = kFALSE; | |
140 | return -99.0; | |
141 | } | |
142 | ||
143 | Int_t id1 = fDaughter[0]->GetID(); | |
144 | Int_t id2 = fDaughter[1]->GetID(); | |
f34f960b | 145 | Int_t idL = fRefEvent->GetLeadingIndex(); |
d7712d44 | 146 | |
147 | if (id1 == idL || id2 == idL) { | |
148 | success = kFALSE; | |
149 | return -99.0; | |
150 | } | |
151 | ||
f34f960b | 152 | AliRsnDaughter leading = fRefEvent->GetDaughter(idL, kFALSE); |
d7712d44 | 153 | AliVParticle *ref = leading.GetRef(); |
154 | Double_t angle = ref->Phi() - fSum.Phi(); | |
155 | ||
156 | //return angle w.r.t. leading particle in the range -pi/2, 3/2pi | |
157 | while (angle >= 1.5 * TMath::Pi()) angle -= 2 * TMath::Pi(); | |
158 | while (angle < -0.5 * TMath::Pi()) angle += 2 * TMath::Pi(); | |
159 | success = kTRUE; | |
160 | ||
161 | return angle; | |
162 | } | |
163 | ||
f34f960b | 164 | //__________________________________________________________________________________________________ |
165 | void AliRsnMother::ComputeSum(Double_t mass0, Double_t mass1, Double_t motherMass) | |
166 | { | |
167 | // | |
168 | // Sets the masses for the 4-momenta of the daughters and then | |
169 | // sums them, taking into account that the space part is set to | |
170 | // each of them when the reference object is set (see AliRsnDaughter::SetRef) | |
171 | // | |
172 | ||
173 | fDaughter[0]->FillP(mass0); | |
174 | fDaughter[1]->FillP(mass1); | |
175 | ||
176 | // sum | |
177 | fSum = fDaughter[0]->Prec() + fDaughter[1]->Prec(); | |
178 | fSumMC = fDaughter[0]->Psim() + fDaughter[1]->Psim(); | |
179 | ||
180 | // reference | |
181 | fRef.SetXYZM(fSum.X(), fSum.Y(), fSum.Z(), motherMass); | |
182 | fRefMC.SetXYZM(fSumMC.X(), fSumMC.Y(), fSumMC.Z(), motherMass); | |
183 | } | |
184 | ||
185 | //__________________________________________________________________________________________________ | |
2e521c29 | 186 | Double_t AliRsnMother::CosThetaStar(Bool_t first, Bool_t useMC) |
cadcd9e0 | 187 | { |
7356f978 | 188 | // |
189 | // Computes the cosine of theta*, which is the angle of one of the daughters | |
190 | // with respect to the total momentum of the resonance, in its rest frame. | |
191 | // The arguments are needed to choose which of the daughters one want to use | |
192 | // and if reconstructed or MC momentum must be used. | |
193 | // [Contribution from Z. Feckova] | |
194 | // | |
195 | ||
f34f960b | 196 | TLorentzVector &mother = Sum(useMC); |
197 | TLorentzVector &daughter0 = (first ? fDaughter[0]->P(useMC) : fDaughter[1]->P(useMC)); | |
198 | TLorentzVector &daughter1 = (first ? fDaughter[1]->P(useMC) : fDaughter[0]->P(useMC)); | |
2a1c7696 | 199 | TVector3 momentumM(mother.Vect()); |
200 | TVector3 normal(mother.Y() / momentumM.Mag(), -mother.X() / momentumM.Mag(), 0.0); | |
201 | ||
202 | // Computes first the invariant mass of the mother | |
7356f978 | 203 | Double_t mass0 = fDaughter[0]->P(useMC).M(); |
204 | Double_t mass1 = fDaughter[1]->P(useMC).M(); | |
205 | Double_t p0 = daughter0.Vect().Mag(); | |
206 | Double_t p1 = daughter1.Vect().Mag(); | |
207 | Double_t E0 = TMath::Sqrt(mass0 * mass0 + p0 * p0); | |
208 | Double_t E1 = TMath::Sqrt(mass1 * mass1 + p1 * p1); | |
209 | Double_t MotherMass = TMath::Sqrt((E0 + E1) * (E0 + E1) - (p0 * p0 + 2.0 * daughter0.Vect().Dot(daughter1.Vect()) + p1 * p1)); | |
2a1c7696 | 210 | MotherMass = fSum.M(); |
211 | ||
212 | // Computes components of beta | |
213 | Double_t betaX = -mother.X() / mother.E(); | |
214 | Double_t betaY = -mother.Y() / mother.E(); | |
215 | Double_t betaZ = -mother.Z() / mother.E(); | |
216 | ||
217 | // Computes Lorentz transformation of the momentum of the first daughter | |
218 | // into the rest frame of the mother and theta* | |
219 | daughter0.Boost(betaX, betaY, betaZ); | |
220 | TVector3 momentumD = daughter0.Vect(); | |
221 | ||
222 | Double_t cosThetaStar = normal.Dot(momentumD) / momentumD.Mag(); | |
223 | ||
224 | return cosThetaStar; | |
cadcd9e0 | 225 | } |
226 | ||
f34f960b | 227 | //__________________________________________________________________________________________________ |
2dab9030 | 228 | void AliRsnMother::PrintInfo(const Option_t * /*option*/) const |
229 | { | |
230 | // | |
231 | // Print some info of the pair. | |
232 | // The options are passed to the AliRsnDaughter::Print() method | |
233 | // | |
234 | ||
2a1c7696 | 235 | AliInfo("======== BEGIN PAIR INFO ==========="); |
236 | AliInfo("Track #1"); | |
237 | fDaughter[0]->Print(); | |
238 | AliInfo("Track #2"); | |
239 | fDaughter[1]->Print(); | |
240 | AliInfo("========= END PAIR INFO ==========="); | |
2dab9030 | 241 | } |
242 | ||
f34f960b | 243 | //__________________________________________________________________________________________________ |
0206329d | 244 | Bool_t AliRsnMother::CheckPair(Bool_t checkMC) const |
2dab9030 | 245 | { |
246 | // | |
247 | // Checks that the pair is well initialized: | |
248 | // - both daughters are good pointers | |
249 | // - if MC is required, both daughters have a MC reference | |
250 | // | |
251 | ||
2a1c7696 | 252 | if (!fDaughter[0] || !fDaughter[1]) { |
253 | AliError("One of the two tracks is NULL in this pair!"); | |
2dab9030 | 254 | return kFALSE; |
2a1c7696 | 255 | } |
256 | ||
0206329d | 257 | if (checkMC) { |
2a1c7696 | 258 | if (fDaughter[0]->GetRefMC() == 0x0 || fDaughter[1]->GetRefMC() == 0x0) { |
259 | AliError("Required MC info but not all MC refs are available"); | |
260 | return kFALSE; | |
261 | } | |
262 | } | |
263 | ||
264 | return kTRUE; | |
2dab9030 | 265 | } |