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790bbabf | 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 | ||
88cb7938 | 16 | /* $Id$ */ |
675e9664 | 17 | |
18 | // Parameterisation of pi and K, eta and pt distributions | |
19 | // used for the ALICE TDRs. | |
20 | // eta: according to HIJING (shadowing + quenching) | |
21 | // pT : according to CDF measurement at 1.8 TeV | |
22 | // Author: andreas.morsch@cern.ch | |
23 | ||
24 | ||
790bbabf | 25 | //Begin_Html |
26 | /* | |
27 | <img src="picts/AliGeneratorClass.gif"> | |
28 | </pre> | |
29 | <br clear=left> | |
30 | <font size=+2 color=red> | |
31 | <p>The responsible person for this module is | |
32 | <a href="mailto:andreas.morsch@cern.ch">Andreas Morsch</a>. | |
33 | </font> | |
34 | <pre> | |
35 | */ | |
36 | //End_Html | |
37 | // // | |
38 | /////////////////////////////////////////////////////////////////// | |
39 | ||
971816d4 | 40 | #include <TArrayF.h> |
ac3faee4 | 41 | #include <TCanvas.h> |
2067f62c | 42 | #include <TClonesArray.h> |
116cbefd | 43 | #include <TDatabasePDG.h> |
44 | #include <TF1.h> | |
cc692c80 | 45 | #include <TH1.h> |
116cbefd | 46 | #include <TPDGCode.h> |
ac3faee4 | 47 | #include <TParticle.h> |
828fff0d | 48 | #include <TROOT.h> |
ac3faee4 | 49 | #include <TVirtualMC.h> |
116cbefd | 50 | |
51 | #include "AliConst.h" | |
52 | #include "AliDecayer.h" | |
116cbefd | 53 | #include "AliGenEventHeader.h" |
54 | #include "AliGenHIJINGpara.h" | |
e087ab36 | 55 | #include "AliLog.h" |
116cbefd | 56 | #include "AliRun.h" |
971816d4 | 57 | |
790bbabf | 58 | ClassImp(AliGenHIJINGpara) |
59 | ||
198bb1c7 | 60 | |
790bbabf | 61 | |
62 | //_____________________________________________________________________________ | |
63 | static Double_t ptpi(Double_t *px, Double_t *) | |
64 | { | |
65 | // | |
66 | // PT-PARAMETERIZATION CDF, PRL 61(88) 1819 | |
67 | // POWER LAW FOR PT > 500 MEV | |
68 | // MT SCALING BELOW (T=160 MEV) | |
69 | // | |
cc692c80 | 70 | const Double_t kp0 = 1.3; |
71 | const Double_t kxn = 8.28; | |
72 | const Double_t kxlim = 0.5; | |
73 | const Double_t kt = 0.160; | |
74 | const Double_t kxmpi = 0.139; | |
75 | const Double_t kb = 1.; | |
790bbabf | 76 | Double_t y, y1, xmpi2, ynorm, a; |
cc692c80 | 77 | Double_t x = *px; |
790bbabf | 78 | // |
cc692c80 | 79 | y1 = TMath::Power(kp0 / (kp0 + kxlim), kxn); |
80 | xmpi2 = kxmpi * kxmpi; | |
81 | ynorm = kb * (TMath::Exp(-sqrt(kxlim * kxlim + xmpi2) / kt )); | |
82 | a = ynorm / y1; | |
790bbabf | 83 | if (x > kxlim) |
cc692c80 | 84 | y = a * TMath::Power(kp0 / (kp0 + x), kxn); |
790bbabf | 85 | else |
cc692c80 | 86 | y = kb* TMath::Exp(-sqrt(x * x + xmpi2) / kt); |
87 | ||
790bbabf | 88 | return y*x; |
89 | } | |
90 | ||
91 | //_____________________________________________________________________________ | |
92 | static Double_t ptscal(Double_t pt, Int_t np) | |
93 | { | |
94 | // SCALING EN MASSE PAR RAPPORT A PTPI | |
95 | // MASS PI,K,ETA,RHO,OMEGA,ETA',PHI | |
96 | const Double_t khm[10] = {.13957,.493,.5488,.769,.7826,.958,1.02,0,0,0}; | |
97 | // VALUE MESON/PI AT 5 GEV | |
98 | const Double_t kfmax[10]={1.,0.3,0.55,1.0,1.0,1.0,1.0,0,0,0}; | |
99 | np--; | |
100 | Double_t f5=TMath::Power((( | |
101 | sqrt(100.018215)+2.)/(sqrt(100.+khm[np]*khm[np])+2.0)),12.3); | |
102 | Double_t fmax2=f5/kfmax[np]; | |
103 | // PIONS | |
104 | Double_t ptpion=100.*ptpi(&pt, (Double_t*) 0); | |
105 | Double_t fmtscal=TMath::Power((( | |
106 | sqrt(pt*pt+0.018215)+2.)/ (sqrt(pt*pt+khm[np]*khm[np])+2.0)),12.3)/ | |
107 | fmax2; | |
108 | return fmtscal*ptpion; | |
109 | } | |
110 | ||
111 | //_____________________________________________________________________________ | |
112 | static Double_t ptka( Double_t *px, Double_t *) | |
113 | { | |
114 | // | |
115 | // pt parametrisation for k | |
116 | // | |
117 | return ptscal(*px,2); | |
118 | } | |
119 | ||
120 | ||
121 | //_____________________________________________________________________________ | |
122 | static Double_t etapic( Double_t *py, Double_t *) | |
123 | { | |
124 | // | |
125 | // eta parametrisation for pi | |
126 | // | |
127 | const Double_t ka1 = 4913.; | |
128 | const Double_t ka2 = 1819.; | |
129 | const Double_t keta1 = 0.22; | |
130 | const Double_t keta2 = 3.66; | |
131 | const Double_t kdeta1 = 1.47; | |
132 | const Double_t kdeta2 = 1.51; | |
133 | Double_t y=TMath::Abs(*py); | |
134 | // | |
135 | Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1); | |
136 | Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2); | |
137 | return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2); | |
138 | } | |
139 | ||
140 | //_____________________________________________________________________________ | |
141 | static Double_t etakac( Double_t *py, Double_t *) | |
142 | { | |
143 | // | |
144 | // eta parametrisation for ka | |
145 | // | |
146 | const Double_t ka1 = 497.6; | |
147 | const Double_t ka2 = 215.6; | |
148 | const Double_t keta1 = 0.79; | |
149 | const Double_t keta2 = 4.09; | |
150 | const Double_t kdeta1 = 1.54; | |
151 | const Double_t kdeta2 = 1.40; | |
152 | Double_t y=TMath::Abs(*py); | |
153 | // | |
154 | Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1); | |
155 | Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2); | |
156 | return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2); | |
157 | } | |
158 | ||
159 | //_____________________________________________________________________________ | |
160 | AliGenHIJINGpara::AliGenHIJINGpara() | |
1c56e311 | 161 | :AliGenerator(), |
162 | fNt(-1), | |
163 | fNpartProd(0), | |
164 | fPi0Decays(kFALSE), | |
165 | fPtWgtPi(0.), | |
166 | fPtWgtKa(0.), | |
167 | fPtpi(0), | |
168 | fPtka(0), | |
169 | fETApic(0), | |
170 | fETAkac(0), | |
171 | fDecayer(0) | |
790bbabf | 172 | { |
173 | // | |
174 | // Default constructor | |
175 | // | |
971816d4 | 176 | SetCutVertexZ(); |
6b236b6f | 177 | SetPtRange(); |
790bbabf | 178 | } |
179 | ||
180 | //_____________________________________________________________________________ | |
181 | AliGenHIJINGpara::AliGenHIJINGpara(Int_t npart) | |
1c56e311 | 182 | :AliGenerator(npart), |
183 | fNt(-1), | |
184 | fNpartProd(npart), | |
185 | fPi0Decays(kFALSE), | |
186 | fPtWgtPi(0.), | |
187 | fPtWgtKa(0.), | |
188 | fPtpi(0), | |
189 | fPtka(0), | |
190 | fETApic(0), | |
191 | fETAkac(0), | |
192 | fDecayer(0) | |
790bbabf | 193 | { |
194 | // | |
195 | // Standard constructor | |
196 | // | |
edbba5db | 197 | fName="HIJINGpara"; |
790bbabf | 198 | fTitle="HIJING Parametrisation Particle Generator"; |
971816d4 | 199 | SetCutVertexZ(); |
6b236b6f | 200 | SetPtRange(); |
1c56e311 | 201 | } |
202 | ||
790bbabf | 203 | //_____________________________________________________________________________ |
204 | AliGenHIJINGpara::~AliGenHIJINGpara() | |
205 | { | |
206 | // | |
207 | // Standard destructor | |
208 | // | |
209 | delete fPtpi; | |
210 | delete fPtka; | |
211 | delete fETApic; | |
212 | delete fETAkac; | |
213 | } | |
214 | ||
215 | //_____________________________________________________________________________ | |
216 | void AliGenHIJINGpara::Init() | |
217 | { | |
218 | // | |
219 | // Initialise the HIJING parametrisation | |
220 | // | |
221 | Float_t etaMin =-TMath::Log(TMath::Tan( | |
222 | TMath::Min((Double_t)fThetaMax/2,TMath::Pi()/2-1.e-10))); | |
223 | Float_t etaMax = -TMath::Log(TMath::Tan( | |
224 | TMath::Max((Double_t)fThetaMin/2,1.e-10))); | |
f25521b2 | 225 | fPtpi = new TF1("ptpi",&ptpi,0,20,0); |
828fff0d | 226 | gROOT->GetListOfFunctions()->Remove(fPtpi); |
f25521b2 | 227 | fPtka = new TF1("ptka",&ptka,0,20,0); |
828fff0d | 228 | gROOT->GetListOfFunctions()->Remove(fPtka); |
cc692c80 | 229 | fPtpi->SetNpx(1000); |
230 | fPtka->SetNpx(1000); | |
790bbabf | 231 | fETApic = new TF1("etapic",&etapic,etaMin,etaMax,0); |
828fff0d | 232 | gROOT->GetListOfFunctions()->Remove(fETApic); |
790bbabf | 233 | fETAkac = new TF1("etakac",&etakac,etaMin,etaMax,0); |
828fff0d | 234 | gROOT->GetListOfFunctions()->Remove(fETAkac); |
f25521b2 | 235 | |
bbbc190a | 236 | TF1 etaPic0("etaPic0",&etapic,-7,7,0); |
237 | TF1 etaKac0("etaKac0",&etakac,-7,7,0); | |
f25521b2 | 238 | |
bbbc190a | 239 | TF1 ptPic0("ptPic0",&ptpi,0.,15.,0); |
240 | TF1 ptKac0("ptKac0",&ptka,0.,15.,0); | |
f25521b2 | 241 | |
aecf26a3 | 242 | Float_t intETApi = etaPic0.Integral(-0.5, 0.5); |
243 | Float_t intETAka = etaKac0.Integral(-0.5, 0.5); | |
f25521b2 | 244 | Float_t scalePi = 7316/(intETApi/1.5); |
245 | Float_t scaleKa = 684/(intETAka/2.0); | |
246 | ||
247 | // Fraction of events corresponding to the selected pt-range | |
aecf26a3 | 248 | Float_t intPt = (0.877*ptPic0.Integral(0, 15)+ |
249 | 0.123*ptKac0.Integral(0, 15)); | |
250 | Float_t intPtSel = (0.877*ptPic0.Integral(fPtMin, fPtMax)+ | |
251 | 0.123*ptKac0.Integral(fPtMin, fPtMax)); | |
f25521b2 | 252 | Float_t ptFrac = intPtSel/intPt; |
253 | ||
254 | // Fraction of events corresponding to the selected eta-range | |
aecf26a3 | 255 | Float_t intETASel = (scalePi*etaPic0.Integral(etaMin, etaMax)+ |
256 | scaleKa*etaKac0.Integral(etaMin, etaMax)); | |
f25521b2 | 257 | // Fraction of events corresponding to the selected phi-range |
258 | Float_t phiFrac = (fPhiMax-fPhiMin)/2/TMath::Pi(); | |
259 | ||
0af12c00 | 260 | |
647f0914 | 261 | fParentWeight = (intETASel*ptFrac*phiFrac) / Float_t(fNpart); |
790bbabf | 262 | |
0af12c00 | 263 | if (fAnalog != 0) { |
264 | fPtWgtPi = (fPtMax - fPtMin) / fPtpi->Integral(0., 20.); | |
265 | fPtWgtKa = (fPtMax - fPtMin) / fPtka->Integral(0., 20.); | |
647f0914 | 266 | fParentWeight = (intETASel*phiFrac) / Float_t(fNpart); |
0af12c00 | 267 | } |
268 | ||
269 | ||
e087ab36 | 270 | AliInfo(Form("The number of particles in the selected kinematic region corresponds to %f percent of a full event", |
647f0914 | 271 | 100./ fParentWeight)); |
5b0e4c0f | 272 | |
273 | // Issue warning message if etaMin or etaMax are outside the alowed range | |
274 | // of the parametrization | |
275 | if (etaMin < -8.001 || etaMax > 8.001) { | |
e087ab36 | 276 | AliWarning("\nYOU ARE USING THE PARAMETERISATION OUTSIDE "); |
277 | AliWarning("THE ALLOWED PSEUDORAPIDITY RANGE (-8. - 8.)"); | |
278 | AliWarning(Form("YOUR LIMITS: %f %f \n ", etaMin, etaMax)); | |
5b0e4c0f | 279 | } |
2067f62c | 280 | // |
281 | // | |
2904363f | 282 | if (fPi0Decays && gMC) |
283 | fDecayer = gMC->GetDecayer(); | |
ebf41d7c | 284 | |
285 | if (fPi0Decays) | |
286 | { | |
287 | fDecayer->SetForceDecay(kNeutralPion); | |
288 | fDecayer->Init(); | |
289 | } | |
290 | ||
790bbabf | 291 | } |
292 | ||
2067f62c | 293 | |
790bbabf | 294 | //_____________________________________________________________________________ |
295 | void AliGenHIJINGpara::Generate() | |
296 | { | |
297 | // | |
298 | // Generate one trigger | |
299 | // | |
300 | ||
301 | ||
302 | const Float_t kRaKpic=0.14; | |
303 | const Float_t kBorne=1/(1+kRaKpic); | |
304 | Float_t polar[3]= {0,0,0}; | |
305 | // | |
306 | const Int_t kPions[3] = {kPi0, kPiPlus, kPiMinus}; | |
307 | const Int_t kKaons[4] = {kK0Long, kK0Short, kKPlus, kKMinus}; | |
308 | // | |
309 | Float_t origin[3]; | |
0af12c00 | 310 | Float_t pt, pl, ptot, wgt; |
790bbabf | 311 | Float_t phi, theta; |
312 | Float_t p[3]; | |
1e66857c | 313 | Int_t i, part, j; |
790bbabf | 314 | // |
315 | TF1 *ptf; | |
316 | TF1 *etaf; | |
317 | // | |
318 | Float_t random[6]; | |
319 | // | |
320 | for (j=0;j<3;j++) origin[j]=fOrigin[j]; | |
971816d4 | 321 | |
322 | if(fVertexSmear == kPerEvent) { | |
c8f7f6f9 | 323 | Vertex(); |
324 | for (j=0; j < 3; j++) origin[j] = fVertex[j]; | |
971816d4 | 325 | } // if kPerEvent |
326 | TArrayF eventVertex; | |
327 | eventVertex.Set(3); | |
328 | eventVertex[0] = origin[0]; | |
329 | eventVertex[1] = origin[1]; | |
330 | eventVertex[2] = origin[2]; | |
0af12c00 | 331 | |
790bbabf | 332 | for(i=0;i<fNpart;i++) { |
333 | while(1) { | |
0af12c00 | 334 | Rndm(random,4); |
790bbabf | 335 | if(random[0]<kBorne) { |
336 | part=kPions[Int_t (random[1]*3)]; | |
337 | ptf=fPtpi; | |
2067f62c | 338 | etaf=fETApic; |
0af12c00 | 339 | wgt = fPtWgtPi; |
790bbabf | 340 | } else { |
341 | part=kKaons[Int_t (random[1]*4)]; | |
342 | ptf=fPtka; | |
343 | etaf=fETAkac; | |
0af12c00 | 344 | wgt = fPtWgtKa; |
790bbabf | 345 | } |
346 | phi=fPhiMin+random[2]*(fPhiMax-fPhiMin); | |
347 | theta=2*TMath::ATan(TMath::Exp(-etaf->GetRandom())); | |
348 | if(theta<fThetaMin || theta>fThetaMax) continue; | |
0af12c00 | 349 | |
350 | if (fAnalog == 0) { | |
351 | pt = ptf->GetRandom(); | |
352 | } else { | |
353 | pt = fPtMin + random[3] * (fPtMax - fPtMin); | |
354 | } | |
355 | ||
356 | ||
790bbabf | 357 | pl=pt/TMath::Tan(theta); |
358 | ptot=TMath::Sqrt(pt*pt+pl*pl); | |
359 | if(ptot<fPMin || ptot>fPMax) continue; | |
360 | p[0]=pt*TMath::Cos(phi); | |
361 | p[1]=pt*TMath::Sin(phi); | |
362 | p[2]=pl; | |
aee8290b | 363 | if(fVertexSmear==kPerTrack) { |
65fb704d | 364 | Rndm(random,6); |
790bbabf | 365 | for (j=0;j<3;j++) { |
366 | origin[j]=fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())* | |
367 | TMath::Sqrt(-2*TMath::Log(random[2*j+1])); | |
368 | } | |
369 | } | |
a142c195 | 370 | |
0af12c00 | 371 | if (fAnalog == 0) { |
372 | wgt = fParentWeight; | |
373 | } else { | |
374 | wgt *= (fParentWeight * ptf->Eval(pt)); | |
375 | } | |
376 | ||
377 | ||
1ef5f15d | 378 | if (part == kPi0 && fPi0Decays){ |
2067f62c | 379 | // |
380 | // Decay pi0 if requested | |
647f0914 | 381 | PushTrack(0,-1,part,p,origin,polar,0,kPPrimary,fNt,wgt); |
1e66857c | 382 | KeepTrack(fNt); |
1ef5f15d | 383 | DecayPi0(origin, p); |
384 | } else { | |
a142c195 | 385 | // printf("fNt %d", fNt); |
647f0914 | 386 | PushTrack(fTrackIt,-1,part,p,origin,polar,0,kPPrimary,fNt,wgt); |
a142c195 | 387 | |
1e66857c | 388 | KeepTrack(fNt); |
1ef5f15d | 389 | } |
390 | ||
790bbabf | 391 | break; |
392 | } | |
1e66857c | 393 | SetHighWaterMark(fNt); |
790bbabf | 394 | } |
1e66857c | 395 | // |
396 | ||
971816d4 | 397 | // Header |
398 | AliGenEventHeader* header = new AliGenEventHeader("HIJINGparam"); | |
399 | // Event Vertex | |
400 | header->SetPrimaryVertex(eventVertex); | |
a142c195 | 401 | header->SetNProduced(fNpartProd); |
971816d4 | 402 | gAlice->SetGenEventHeader(header); |
790bbabf | 403 | } |
404 | ||
6b236b6f | 405 | void AliGenHIJINGpara::SetPtRange(Float_t ptmin, Float_t ptmax) { |
2067f62c | 406 | AliGenerator::SetPtRange(ptmin, ptmax); |
6b236b6f | 407 | } |
790bbabf | 408 | |
2067f62c | 409 | void AliGenHIJINGpara::DecayPi0(Float_t* orig, Float_t * p) |
410 | { | |
411 | // | |
412 | // Decay the pi0 | |
413 | // and put decay products on the stack | |
414 | // | |
415 | static TClonesArray *particles; | |
416 | if(!particles) particles = new TClonesArray("TParticle",1000); | |
417 | // | |
418 | const Float_t kMass = TDatabasePDG::Instance()->GetParticle(kPi0)->Mass(); | |
56fcdfe6 | 419 | Float_t e = TMath::Sqrt(p[0] * p[0] + p[1] * p[1] + p[2] * p[2]+ kMass * kMass); |
2067f62c | 420 | // |
421 | // Decay the pi0 | |
422 | TLorentzVector pmom(p[0], p[1], p[2], e); | |
423 | fDecayer->Decay(kPi0, &pmom); | |
56fcdfe6 | 424 | |
2067f62c | 425 | // |
426 | // Put decay particles on the stack | |
427 | // | |
2067f62c | 428 | Float_t polar[3] = {0., 0., 0.}; |
429 | Int_t np = fDecayer->ImportParticles(particles); | |
a142c195 | 430 | fNpartProd += (np-1); |
8f64c44f | 431 | Int_t nt = 0; |
2067f62c | 432 | for (Int_t i = 1; i < np; i++) |
433 | { | |
7b33c00a | 434 | TParticle* iParticle = (TParticle *) particles->At(i); |
435 | p[0] = iParticle->Px(); | |
436 | p[1] = iParticle->Py(); | |
437 | p[2] = iParticle->Pz(); | |
2067f62c | 438 | Int_t part = iParticle->GetPdgCode(); |
1e66857c | 439 | |
642f15cf | 440 | PushTrack(fTrackIt, fNt, part, p, orig, polar, 0, kPDecay, nt, fParentWeight); |
1e66857c | 441 | KeepTrack(nt); |
2067f62c | 442 | } |
1e66857c | 443 | fNt = nt; |
2067f62c | 444 | } |
198bb1c7 | 445 | |
cc692c80 | 446 | void AliGenHIJINGpara::Draw( const char * /*opt*/) |
447 | { | |
448 | // | |
449 | // Draw the pT and y Distributions | |
450 | // | |
451 | TCanvas *c0 = new TCanvas("c0","Canvas 0",400,10,600,700); | |
452 | c0->Divide(2,1); | |
453 | c0->cd(1); | |
454 | fPtpi->Draw(); | |
455 | fPtpi->GetHistogram()->SetXTitle("p_{T} (GeV)"); | |
456 | c0->cd(2); | |
457 | fPtka->Draw(); | |
458 | fPtka->GetHistogram()->SetXTitle("p_{T} (GeV)"); | |
459 | ||
460 | } |