4c039060 |
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 | $Log$ |
18 | */ |
19 | |
d88f97cc |
20 | #include "AliTrack.h" |
21 | |
22 | ClassImp(AliTrack) // Class implementation to enable ROOT I/O |
23 | |
24 | AliTrack::AliTrack() |
25 | { |
26 | // Default constructor |
27 | // All variables initialised to 0 |
28 | fDecays=0; |
29 | Reset(); |
30 | } |
31 | /////////////////////////////////////////////////////////////////////////// |
32 | AliTrack::~AliTrack() |
33 | { |
34 | // Destructor to delete memory allocated for decay tracks array |
35 | if (fDecays) |
36 | { |
37 | fDecays->Delete(); |
38 | delete fDecays; |
39 | fDecays=0; |
40 | } |
41 | } |
42 | /////////////////////////////////////////////////////////////////////////// |
43 | void AliTrack::Reset() |
44 | { |
45 | // Reset all variables to 0 |
46 | fM=0; |
47 | fQ=0; |
48 | fNdec=0; |
49 | Double_t a[4]={0,0,0,0}; |
50 | SetVector(a,"sph"); |
51 | if (fDecays) |
52 | { |
53 | fDecays->Delete(); |
54 | delete fDecays; |
55 | fDecays=0; |
56 | } |
57 | } |
58 | /////////////////////////////////////////////////////////////////////////// |
59 | void AliTrack::Set3Momentum(Ali3Vector& p) |
60 | { |
61 | // Set the track parameters according to the 3-momentum p |
62 | Double_t E=sqrt(p.Dot(p)+fM*fM); |
63 | SetVector(E,p); |
64 | } |
65 | /////////////////////////////////////////////////////////////////////////// |
66 | void AliTrack::Set4Momentum(Ali4Vector& p) |
67 | { |
68 | // Set the track parameters according to the 4-momentum p |
69 | Double_t E=p.GetScalar(); |
70 | Ali3Vector pv=p.Get3Vector(); |
71 | SetVector(E,pv); |
72 | |
73 | Double_t m2=p.Dot(p); |
74 | fM=0; |
75 | if (m2 > 0.) fM=sqrt(m2); |
76 | } |
77 | /////////////////////////////////////////////////////////////////////////// |
78 | void AliTrack::SetMass(Double_t m) |
79 | { |
80 | // Set the particle mass |
81 | fM=m; |
82 | Ali3Vector p=Get3Vector(); |
83 | Double_t E=sqrt(p.Dot(p)+fM*fM); |
84 | SetVector(E,p); |
85 | } |
86 | /////////////////////////////////////////////////////////////////////////// |
87 | void AliTrack::SetCharge(Float_t q) |
88 | { |
89 | // Set the particle charge |
90 | fQ=q; |
91 | } |
92 | /////////////////////////////////////////////////////////////////////////// |
93 | void AliTrack::Info(TString f) |
94 | { |
95 | // Provide track information within the coordinate frame f |
96 | cout << " *AliTrack::Info* Mass : " << fM << " Charge : " << fQ |
97 | << " Momentum : " << GetMomentum() << " Ntracks : " << fNdec << endl; |
98 | cout << " "; |
99 | Ali4Vector::Info(f); |
100 | } |
101 | /////////////////////////////////////////////////////////////////////////// |
102 | void AliTrack::List(TString f) |
103 | { |
104 | // Provide current track and decay level 1 information within coordinate frame f |
105 | |
106 | Info(f); // Information of the current track |
107 | |
108 | // Decay products of this track |
109 | AliTrack* td; |
110 | for (Int_t id=1; id<=fNdec; id++) |
111 | { |
112 | td=GetDecayTrack(id); |
113 | if (td) |
114 | { |
115 | cout << " ---Level 1 sec. track no. " << id << endl; |
116 | cout << " "; |
117 | td->Info(f); |
118 | } |
119 | else |
120 | { |
121 | cout << " *AliTrack::List* Error : No decay track present." << endl; |
122 | } |
123 | } |
124 | } |
125 | /////////////////////////////////////////////////////////////////////////// |
126 | void AliTrack::ListAll(TString f) |
127 | { |
128 | // Provide complete track and decay information within the coordinate frame f |
129 | |
130 | Info(f); // Information of the current track |
131 | |
132 | AliTrack* t=this; |
133 | Dump(t,1,f); // Information of all decay products |
134 | } |
135 | ////////////////////////////////////////////////////////////////////////// |
136 | void AliTrack::Dump(AliTrack* t,Int_t n,TString f) |
137 | { |
138 | // Recursively provide the info of all decay levels of this track |
139 | AliTrack* td; |
140 | for (Int_t id=1; id<=t->GetNdecay(); id++) |
141 | { |
142 | td=t->GetDecayTrack(id); |
143 | if (td) |
144 | { |
145 | cout << " ---Level " << n << " sec. track no. " << id << endl; |
146 | cout << " "; |
147 | td->Info(f); |
148 | |
149 | // Go for next decay level of this decay track recursively |
150 | Dump(td,n+1,f); |
151 | } |
152 | else |
153 | { |
154 | cout << " *AliTrack::Dump* Error : No decay track present." << endl; |
155 | } |
156 | } |
157 | } |
158 | ////////////////////////////////////////////////////////////////////////// |
159 | Double_t AliTrack::GetMomentum() |
160 | { |
161 | // Provide the value of the track 3-momentum |
162 | Ali3Vector p=Get3Vector(); |
163 | return sqrt(p.Dot(p)); |
164 | } |
165 | /////////////////////////////////////////////////////////////////////////// |
166 | Ali3Vector AliTrack::Get3Momentum() |
167 | { |
168 | // Provide the track 3-momentum |
169 | return (Ali3Vector)Get3Vector(); |
170 | } |
171 | /////////////////////////////////////////////////////////////////////////// |
172 | Double_t AliTrack::GetMass() |
173 | { |
174 | // Provide the particle mass |
175 | return fM; |
176 | } |
177 | /////////////////////////////////////////////////////////////////////////// |
178 | Float_t AliTrack::GetCharge() |
179 | { |
180 | // Provide the particle charge |
181 | return fQ; |
182 | } |
183 | /////////////////////////////////////////////////////////////////////////// |
184 | Double_t AliTrack::GetEnergy() |
185 | { |
186 | // Provide the particle's energy |
187 | return GetScalar(); |
188 | } |
189 | /////////////////////////////////////////////////////////////////////////// |
190 | void AliTrack::Decay(Double_t m1,Double_t m2,Double_t thcms,Double_t phicms) |
191 | { |
192 | // Perform 2-body decay of current track |
193 | // m1 : mass of decay product 1 |
194 | // m2 : mass of decay product 2 |
195 | // thcms : cms theta decay angle (in rad.) of m1 |
196 | // phicms : cms phi decay angle (in rad.) of m1 |
197 | |
198 | fNdec=2; // it's a 2-body decay |
199 | |
200 | // Compute the 4-momenta of the decay products in the cms |
201 | // Note : p2=p1=pnorm for a 2-body decay |
202 | Double_t e1=((fM*fM)+(m1*m1)-(m2*m2))/(2.*fM); |
203 | Double_t e2=((fM*fM)+(m2*m2)-(m1*m1))/(2.*fM); |
204 | Double_t pnorm=(e1*e1)-(m1*m1); |
205 | if (pnorm>0.) |
206 | { |
207 | pnorm=sqrt(pnorm); |
208 | } |
209 | else |
210 | { |
211 | pnorm=0; |
212 | } |
213 | |
214 | Double_t a[3]; |
215 | a[0]=pnorm; |
216 | a[1]=thcms; |
217 | a[2]=phicms; |
218 | Ali3Vector p; |
219 | p.SetVector(a,"sph"); |
220 | |
221 | Ali4Vector pprim1; |
222 | pprim1.SetVector(e1,p); |
223 | |
224 | Ali4Vector pprim2; |
225 | p*=-1; |
226 | pprim2.SetVector(e2,p); |
227 | |
228 | // Determine boost parameters from the parent particle |
229 | Double_t E=GetScalar(); |
230 | p=Get3Vector(); |
231 | Ali4Vector pmu; |
232 | pmu.SetVector(E,p); |
233 | |
234 | AliBoost q; |
235 | q.Set4Momentum(pmu); |
236 | |
237 | Ali4Vector p1=q.Inverse(pprim1); // Boost decay product 1 |
238 | Ali4Vector p2=q.Inverse(pprim2); // Boost decay product 2 |
239 | |
240 | // Enter the boosted data into the decay tracks array |
241 | if (fDecays) |
242 | { |
243 | fDecays->Delete(); |
244 | delete fDecays; |
245 | } |
246 | fDecays=new TObjArray(); |
247 | |
248 | fDecays->Add(new AliTrack); |
249 | ((AliTrack*)fDecays->At(0))->Set4Momentum(p1); |
250 | fDecays->Add(new AliTrack); |
251 | ((AliTrack*)fDecays->At(1))->Set4Momentum(p2); |
252 | |
253 | // Set the mass values to m1 and m2 to omit roundoff errors |
254 | ((AliTrack*)fDecays->At(0))->SetMass(m1); |
255 | ((AliTrack*)fDecays->At(1))->SetMass(m2); |
256 | } |
257 | /////////////////////////////////////////////////////////////////////////// |
258 | Int_t AliTrack::GetNdecay() |
259 | { |
260 | // Provide the number of decay produced tracks |
261 | return fNdec; |
262 | } |
263 | /////////////////////////////////////////////////////////////////////////// |
264 | AliTrack* AliTrack::GetDecayTrack(Int_t j) |
265 | { |
266 | // Provide decay produced track number j |
267 | // Note : j=1 denotes the first decay track |
268 | if ((j >= 1) && (j <= fNdec)) |
269 | { |
270 | return (AliTrack*)fDecays->At(j-1); |
271 | } |
272 | else |
273 | { |
274 | cout << " *AliTrack* decay track number : " << j << " out of range." << endl; |
275 | cout << " -- Decay track number 1 (if any) returned." << endl; |
276 | return (AliTrack*)fDecays->At(0); |
277 | } |
278 | } |
279 | /////////////////////////////////////////////////////////////////////////// |