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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 | /* $Id$ */ | |
17 | ||
18 | ////////////////////////////////////////////////////////////////////////////// | |
19 | // | |
20 | // AliGeVSimParticle is a helper class for GeVSim (AliGenGeVSim) event generator. | |
21 | // An object of this class represents one particle type and contain | |
22 | // information about particle type thermal parameters. | |
23 | // | |
24 | ////////////////////////////////////////////////////////////////////////////// | |
25 | // | |
26 | // For examples, parameters and testing macros refer to: | |
27 | // http:/home.cern.ch/radomski | |
28 | // | |
29 | // for more detailed description refer to ALICE NOTE | |
30 | // "GeVSim Monte-Carlo Event Generator" | |
31 | // S.Radosmki, P. Foka. | |
32 | // | |
33 | // Author: | |
34 | // Sylwester Radomski, | |
35 | // GSI, March 2002 | |
36 | // | |
37 | // S.Radomski@gsi.de | |
38 | // | |
39 | //////////////////////////////////////////////////////////////////////////////// | |
40 | // | |
41 | // Updated and revised: September 2002, S. Radomski, GSI | |
42 | // | |
43 | //////////////////////////////////////////////////////////////////////////////// | |
44 | ||
45 | ||
46 | #include "TMath.h" | |
47 | #include "AliGeVSimParticle.h" | |
48 | ||
49 | ClassImp(AliGeVSimParticle); | |
50 | ||
51 | //////////////////////////////////////////////////////////////////////////////////////////////////// | |
52 | ||
53 | AliGeVSimParticle::AliGeVSimParticle(Int_t pdg, Int_t model, Float_t multiplicity, | |
54 | Float_t T, Float_t dY, Float_t exp) { | |
55 | // | |
56 | // pdg - Particle type code in PDG standard (see: http://pdg.lbl.gov) | |
57 | // model - momentum distribution model (1 - 7) | |
58 | // multiplicity - multiplicity of particle type | |
59 | // T - Inverse slope parameter ("temperature") | |
60 | // dY - Raridity Width (only for model 1) | |
61 | // exp - expansion velocity (only for model 4) | |
62 | ||
63 | fPDG = pdg; | |
64 | fT = T; | |
65 | fSigmaY = dY; | |
66 | fExpansion = exp; | |
67 | ||
68 | fN = multiplicity; | |
69 | fMultTotal = kTRUE; | |
70 | fIsSetMult = kFALSE; | |
71 | ||
72 | SetModel(model); | |
73 | ||
74 | fV1[0] = fV1[1] = fV1[2] = fV1[3] = 0.; | |
75 | fV2[0] = fV2[1] = fV2[2] = 0.; | |
76 | ||
77 | fIsEllipticSimple = fIsDirectedSimple = kTRUE; | |
78 | fIsEllipticOld = kFALSE; | |
79 | } | |
80 | ||
81 | //////////////////////////////////////////////////////////////////////////////////////////////////// | |
82 | ||
83 | AliGeVSimParticle::AliGeVSimParticle(Int_t pdg, Int_t model, Float_t multiplicity) { | |
84 | // | |
85 | // pdg - Particle type code in PDG standard (see: http://pdg.lbl.gov) | |
86 | // | |
87 | // Note that multiplicity can be interpreted by GeVSim | |
88 | // either as Total multiplicity in the acceptance or dN/dY | |
89 | // | |
90 | ||
91 | fPDG = pdg; | |
92 | fN = multiplicity; | |
93 | fMultTotal = kTRUE; | |
94 | fIsSetMult = kFALSE; | |
95 | ||
96 | SetModel(model); | |
97 | ||
98 | fT = 0.; | |
99 | fSigmaY = 0.; | |
100 | fExpansion = 0.; | |
101 | ||
102 | fV1[0] = fV1[1] = fV1[2] = fV1[3] = 0.; | |
103 | fV2[0] = fV2[1] = fV2[2] = 0.; | |
104 | ||
105 | fIsEllipticSimple = fIsDirectedSimple = kTRUE; | |
106 | fIsEllipticOld = kFALSE; | |
107 | } | |
108 | ||
109 | //////////////////////////////////////////////////////////////////////////////////////////////////// | |
110 | ||
111 | void AliGeVSimParticle::SetModel(Int_t model) { | |
112 | // | |
113 | // Set Model (1-7) | |
114 | // For details about standard and custom models refer to ALICE NOTE | |
115 | // | |
116 | ||
117 | if (model < 1 || model > 7) | |
118 | Error("SetModel","Model Id ( %d ) out of range [1..7]", model); | |
119 | ||
120 | fModel = model; | |
121 | } | |
122 | ||
123 | //////////////////////////////////////////////////////////////////////////////////////////////////// | |
124 | ||
125 | void AliGeVSimParticle::SetMultiplicity(Float_t mult) { | |
126 | // | |
127 | // Set multiplicity. The value is interpreted either as a total multiplciity | |
128 | // in the acceptance or as a multiplicity density - dN/dY at midrapidity | |
129 | // | |
130 | ||
131 | fN = mult; | |
132 | } | |
133 | ||
134 | //////////////////////////////////////////////////////////////////////////////////////////////////// | |
135 | ||
136 | void AliGeVSimParticle::SetMultTotal(Bool_t isTotal) { | |
137 | // | |
138 | // Switch between total multiplicity (kTRUE) and | |
139 | // multiplciity density (kFALSE) | |
140 | // | |
141 | // If this method is used its overrides mode in AliGenGeVSim | |
142 | // | |
143 | ||
144 | fMultTotal = isTotal; | |
145 | fIsSetMult = kTRUE; | |
146 | } | |
147 | ||
148 | //////////////////////////////////////////////////////////////////////////////////////////////////// | |
149 | ||
150 | void AliGeVSimParticle::SetDirectedSimple(Float_t v1) { | |
151 | // | |
152 | // Set directed flow coefficient to a value independent | |
153 | // of transverse momentum and rapidity | |
154 | // | |
155 | ||
156 | fV1[0] = v1; | |
157 | fIsDirectedSimple = kTRUE; | |
158 | } | |
159 | ||
160 | //////////////////////////////////////////////////////////////////////////////////////////////////// | |
161 | ||
162 | void AliGeVSimParticle::SetEllipticSimple(Float_t v2) { | |
163 | // | |
164 | // Set elliptic flow coefficient to a value independent | |
165 | // of transverse momentum and rapidity | |
166 | // | |
167 | ||
168 | fV2[0] = v2; | |
169 | fIsEllipticSimple = kTRUE; | |
170 | } | |
171 | ||
172 | //////////////////////////////////////////////////////////////////////////////////////////////////// | |
173 | ||
174 | Bool_t AliGeVSimParticle::IsFlowSimple() const | |
175 | { | |
176 | // | |
177 | // Function used by AliGenGeVSim | |
178 | // | |
179 | // Returns true if both Elliptic and Directed flow has a simple model. | |
180 | // If at least one is parametrised returns false. | |
181 | // | |
182 | ||
183 | return (fIsDirectedSimple && fIsEllipticSimple); | |
184 | } | |
185 | ||
186 | //////////////////////////////////////////////////////////////////////////////////////////////////// | |
187 | ||
188 | void AliGeVSimParticle::SetDirectedParam(Float_t v11, Float_t v12, Float_t v13, Float_t v14) { | |
189 | // | |
190 | // Set parameters for Directed Flow | |
191 | // Actual flow coefficient is calculated as follows | |
192 | // | |
193 | // V1(Pt,Y) = (V11 + V12*Pt) * sign(Y) * (V13 + V14 * Y^3) | |
194 | // | |
195 | // where sign = 1 for Y > 0 and -1 for Y < 0 | |
196 | // | |
197 | // Defaults values | |
198 | // v12 = v14 = 0 | |
199 | // v13 = 1 | |
200 | // | |
201 | ||
202 | fV1[0] = v11; | |
203 | fV1[1] = v12; | |
204 | fV1[2] = v13; | |
205 | fV1[3] = v14; | |
206 | ||
207 | fIsDirectedSimple = kFALSE; | |
208 | } | |
209 | ||
210 | //////////////////////////////////////////////////////////////////////////////////////////////////// | |
211 | ||
212 | void AliGeVSimParticle::SetEllipticParam(Float_t v21, Float_t pTmax, Float_t v22) { | |
213 | // | |
214 | // Set parameters for Elliptic Flow | |
215 | // Actual flow coefficient is calculated as follows | |
216 | // | |
217 | // pTmax is in GeV | |
218 | // v21 - flow value at saturation | |
219 | // | |
220 | // | |
221 | // V2 = v21 * (pT/pTMax ) * exp (-v22 * y^2) where pT <= pTmax | |
222 | // v21 * exp (-v22 * y^2) where pT > pTmax | |
223 | // | |
224 | // Default values: | |
225 | // v22 = 0 | |
226 | // | |
227 | // The parametrisation is suitable for relativistic particles | |
228 | // eg. Pions (at RHIC energies) | |
229 | // | |
230 | ||
231 | ||
232 | fV2[0] = v21; | |
233 | fV2[1] = pTmax; | |
234 | fV2[2] = v22; | |
235 | ||
236 | fIsEllipticSimple = kFALSE; | |
237 | fIsEllipticOld = kFALSE; | |
238 | } | |
239 | ||
240 | //////////////////////////////////////////////////////////////////////////////////////////////////// | |
241 | ||
242 | void AliGeVSimParticle::SetEllipticOld(Float_t v21, Float_t v22, Float_t v23) { | |
243 | // | |
244 | // Set parameters for Elliptic Flow | |
245 | // Actual flow coefficient is calculated as follows | |
246 | // | |
247 | // V2 = (V21 + V22 pT^2) * exp (-v22 * y^2) | |
248 | // | |
249 | // The parameterisation is suitable for heavy particles: proton, kaon | |
250 | // | |
251 | ||
252 | fV2[0] = v21; | |
253 | fV2[1] = v22; | |
254 | fV2[2] = v23; | |
255 | ||
256 | fIsEllipticSimple = kFALSE; | |
257 | fIsEllipticOld = kTRUE; | |
258 | } | |
259 | ||
260 | //////////////////////////////////////////////////////////////////////////////////////////////////// | |
261 | ||
262 | Float_t AliGeVSimParticle::GetDirectedFlow(Float_t pt, Float_t y) { | |
263 | // | |
264 | // Return coefficient of a directed flow for a given pt and y. | |
265 | // For coefficient calculation method refer to SetDirectedParam() | |
266 | // | |
267 | ||
268 | if (fIsDirectedSimple) return fV1[0]; | |
269 | ||
270 | Float_t v; | |
271 | ||
272 | v = (fV1[0] + fV1[1]* pt) * TMath::Sign((Float_t)1.,y) * | |
273 | (fV1[2] + fV1[3] * TMath::Abs(y*y*y) ); | |
274 | ||
275 | return v; | |
276 | } | |
277 | ||
278 | //////////////////////////////////////////////////////////////////////////////////////////////////// | |
279 | ||
280 | Float_t AliGeVSimParticle::GetEllipticFlow(Float_t pt, Float_t y) { | |
281 | // | |
282 | // Return coefficient of a elliptic flow for a given pt and y. | |
283 | // For coefficient calculation method refer to SetEllipticParam() | |
284 | // | |
285 | ||
286 | if (fIsEllipticSimple) return fV2[0]; | |
287 | ||
288 | if (fIsEllipticOld) { | |
289 | ||
290 | // old parametrisation | |
291 | return (fV2[0]+fV2[1]*pt*pt) * TMath::Exp(-fV2[2]*y*y); | |
292 | ||
293 | } else { | |
294 | ||
295 | // new "pionic" parameterisation | |
296 | if (pt < fV2[1]) return ( (pt / fV2[1]) * fV2[0] * TMath::Exp(-fV2[2]*y*y) ); | |
297 | else return ( fV2[0] * TMath::Exp(-fV2[2]*y*y) ); | |
298 | } | |
299 | } | |
300 | ||
301 | //////////////////////////////////////////////////////////////////////////////////////////////////// | |
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