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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 | |
61 | AliGenHIJINGpara::AliGenHIJINGpara(const AliGenHIJINGpara & para): | |
62 | AliGenerator(para) | |
790bbabf | 63 | { |
198bb1c7 | 64 | // Copy constructor |
65 | para.Copy(*this); | |
790bbabf | 66 | } |
67 | ||
68 | //_____________________________________________________________________________ | |
69 | static Double_t ptpi(Double_t *px, Double_t *) | |
70 | { | |
71 | // | |
72 | // PT-PARAMETERIZATION CDF, PRL 61(88) 1819 | |
73 | // POWER LAW FOR PT > 500 MEV | |
74 | // MT SCALING BELOW (T=160 MEV) | |
75 | // | |
cc692c80 | 76 | const Double_t kp0 = 1.3; |
77 | const Double_t kxn = 8.28; | |
78 | const Double_t kxlim = 0.5; | |
79 | const Double_t kt = 0.160; | |
80 | const Double_t kxmpi = 0.139; | |
81 | const Double_t kb = 1.; | |
790bbabf | 82 | Double_t y, y1, xmpi2, ynorm, a; |
cc692c80 | 83 | Double_t x = *px; |
790bbabf | 84 | // |
cc692c80 | 85 | y1 = TMath::Power(kp0 / (kp0 + kxlim), kxn); |
86 | xmpi2 = kxmpi * kxmpi; | |
87 | ynorm = kb * (TMath::Exp(-sqrt(kxlim * kxlim + xmpi2) / kt )); | |
88 | a = ynorm / y1; | |
790bbabf | 89 | if (x > kxlim) |
cc692c80 | 90 | y = a * TMath::Power(kp0 / (kp0 + x), kxn); |
790bbabf | 91 | else |
cc692c80 | 92 | y = kb* TMath::Exp(-sqrt(x * x + xmpi2) / kt); |
93 | ||
790bbabf | 94 | return y*x; |
95 | } | |
96 | ||
97 | //_____________________________________________________________________________ | |
98 | static Double_t ptscal(Double_t pt, Int_t np) | |
99 | { | |
100 | // SCALING EN MASSE PAR RAPPORT A PTPI | |
101 | // MASS PI,K,ETA,RHO,OMEGA,ETA',PHI | |
102 | const Double_t khm[10] = {.13957,.493,.5488,.769,.7826,.958,1.02,0,0,0}; | |
103 | // VALUE MESON/PI AT 5 GEV | |
104 | const Double_t kfmax[10]={1.,0.3,0.55,1.0,1.0,1.0,1.0,0,0,0}; | |
105 | np--; | |
106 | Double_t f5=TMath::Power((( | |
107 | sqrt(100.018215)+2.)/(sqrt(100.+khm[np]*khm[np])+2.0)),12.3); | |
108 | Double_t fmax2=f5/kfmax[np]; | |
109 | // PIONS | |
110 | Double_t ptpion=100.*ptpi(&pt, (Double_t*) 0); | |
111 | Double_t fmtscal=TMath::Power((( | |
112 | sqrt(pt*pt+0.018215)+2.)/ (sqrt(pt*pt+khm[np]*khm[np])+2.0)),12.3)/ | |
113 | fmax2; | |
114 | return fmtscal*ptpion; | |
115 | } | |
116 | ||
117 | //_____________________________________________________________________________ | |
118 | static Double_t ptka( Double_t *px, Double_t *) | |
119 | { | |
120 | // | |
121 | // pt parametrisation for k | |
122 | // | |
123 | return ptscal(*px,2); | |
124 | } | |
125 | ||
126 | ||
127 | //_____________________________________________________________________________ | |
128 | static Double_t etapic( Double_t *py, Double_t *) | |
129 | { | |
130 | // | |
131 | // eta parametrisation for pi | |
132 | // | |
133 | const Double_t ka1 = 4913.; | |
134 | const Double_t ka2 = 1819.; | |
135 | const Double_t keta1 = 0.22; | |
136 | const Double_t keta2 = 3.66; | |
137 | const Double_t kdeta1 = 1.47; | |
138 | const Double_t kdeta2 = 1.51; | |
139 | Double_t y=TMath::Abs(*py); | |
140 | // | |
141 | Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1); | |
142 | Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2); | |
143 | return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2); | |
144 | } | |
145 | ||
146 | //_____________________________________________________________________________ | |
147 | static Double_t etakac( Double_t *py, Double_t *) | |
148 | { | |
149 | // | |
150 | // eta parametrisation for ka | |
151 | // | |
152 | const Double_t ka1 = 497.6; | |
153 | const Double_t ka2 = 215.6; | |
154 | const Double_t keta1 = 0.79; | |
155 | const Double_t keta2 = 4.09; | |
156 | const Double_t kdeta1 = 1.54; | |
157 | const Double_t kdeta2 = 1.40; | |
158 | Double_t y=TMath::Abs(*py); | |
159 | // | |
160 | Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1); | |
161 | Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2); | |
162 | return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2); | |
163 | } | |
164 | ||
165 | //_____________________________________________________________________________ | |
166 | AliGenHIJINGpara::AliGenHIJINGpara() | |
167 | :AliGenerator() | |
168 | { | |
169 | // | |
170 | // Default constructor | |
171 | // | |
1e66857c | 172 | fPtpi = 0; |
173 | fPtka = 0; | |
174 | fETApic = 0; | |
175 | fETAkac = 0; | |
176 | fDecayer = 0; | |
177 | fNt = -1; | |
971816d4 | 178 | SetCutVertexZ(); |
6b236b6f | 179 | SetPtRange(); |
2067f62c | 180 | SetPi0Decays(); |
790bbabf | 181 | } |
182 | ||
183 | //_____________________________________________________________________________ | |
184 | AliGenHIJINGpara::AliGenHIJINGpara(Int_t npart) | |
185 | :AliGenerator(npart) | |
186 | { | |
187 | // | |
188 | // Standard constructor | |
189 | // | |
edbba5db | 190 | fName="HIJINGpara"; |
790bbabf | 191 | fTitle="HIJING Parametrisation Particle Generator"; |
1e66857c | 192 | fPtpi = 0; |
193 | fPtka = 0; | |
194 | fETApic = 0; | |
195 | fETAkac = 0; | |
196 | fDecayer = 0; | |
197 | fNt = -1; | |
971816d4 | 198 | SetCutVertexZ(); |
6b236b6f | 199 | SetPtRange(); |
2067f62c | 200 | SetPi0Decays(); |
790bbabf | 201 | } |
202 | ||
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(); | |
790bbabf | 284 | } |
285 | ||
2067f62c | 286 | |
790bbabf | 287 | //_____________________________________________________________________________ |
288 | void AliGenHIJINGpara::Generate() | |
289 | { | |
290 | // | |
291 | // Generate one trigger | |
292 | // | |
293 | ||
294 | ||
295 | const Float_t kRaKpic=0.14; | |
296 | const Float_t kBorne=1/(1+kRaKpic); | |
297 | Float_t polar[3]= {0,0,0}; | |
298 | // | |
299 | const Int_t kPions[3] = {kPi0, kPiPlus, kPiMinus}; | |
300 | const Int_t kKaons[4] = {kK0Long, kK0Short, kKPlus, kKMinus}; | |
301 | // | |
302 | Float_t origin[3]; | |
0af12c00 | 303 | Float_t pt, pl, ptot, wgt; |
790bbabf | 304 | Float_t phi, theta; |
305 | Float_t p[3]; | |
1e66857c | 306 | Int_t i, part, j; |
790bbabf | 307 | // |
308 | TF1 *ptf; | |
309 | TF1 *etaf; | |
310 | // | |
311 | Float_t random[6]; | |
312 | // | |
313 | for (j=0;j<3;j++) origin[j]=fOrigin[j]; | |
971816d4 | 314 | |
315 | if(fVertexSmear == kPerEvent) { | |
c8f7f6f9 | 316 | Vertex(); |
317 | for (j=0; j < 3; j++) origin[j] = fVertex[j]; | |
971816d4 | 318 | } // if kPerEvent |
319 | TArrayF eventVertex; | |
320 | eventVertex.Set(3); | |
321 | eventVertex[0] = origin[0]; | |
322 | eventVertex[1] = origin[1]; | |
323 | eventVertex[2] = origin[2]; | |
0af12c00 | 324 | |
790bbabf | 325 | for(i=0;i<fNpart;i++) { |
326 | while(1) { | |
0af12c00 | 327 | Rndm(random,4); |
790bbabf | 328 | if(random[0]<kBorne) { |
329 | part=kPions[Int_t (random[1]*3)]; | |
330 | ptf=fPtpi; | |
2067f62c | 331 | etaf=fETApic; |
0af12c00 | 332 | wgt = fPtWgtPi; |
790bbabf | 333 | } else { |
334 | part=kKaons[Int_t (random[1]*4)]; | |
335 | ptf=fPtka; | |
336 | etaf=fETAkac; | |
0af12c00 | 337 | wgt = fPtWgtKa; |
790bbabf | 338 | } |
339 | phi=fPhiMin+random[2]*(fPhiMax-fPhiMin); | |
340 | theta=2*TMath::ATan(TMath::Exp(-etaf->GetRandom())); | |
341 | if(theta<fThetaMin || theta>fThetaMax) continue; | |
0af12c00 | 342 | |
343 | if (fAnalog == 0) { | |
344 | pt = ptf->GetRandom(); | |
345 | } else { | |
346 | pt = fPtMin + random[3] * (fPtMax - fPtMin); | |
347 | } | |
348 | ||
349 | ||
790bbabf | 350 | pl=pt/TMath::Tan(theta); |
351 | ptot=TMath::Sqrt(pt*pt+pl*pl); | |
352 | if(ptot<fPMin || ptot>fPMax) continue; | |
353 | p[0]=pt*TMath::Cos(phi); | |
354 | p[1]=pt*TMath::Sin(phi); | |
355 | p[2]=pl; | |
aee8290b | 356 | if(fVertexSmear==kPerTrack) { |
65fb704d | 357 | Rndm(random,6); |
790bbabf | 358 | for (j=0;j<3;j++) { |
359 | origin[j]=fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())* | |
360 | TMath::Sqrt(-2*TMath::Log(random[2*j+1])); | |
361 | } | |
362 | } | |
0af12c00 | 363 | |
364 | if (fAnalog == 0) { | |
365 | wgt = fParentWeight; | |
366 | } else { | |
367 | wgt *= (fParentWeight * ptf->Eval(pt)); | |
368 | } | |
369 | ||
370 | ||
1ef5f15d | 371 | if (part == kPi0 && fPi0Decays){ |
2067f62c | 372 | // |
373 | // Decay pi0 if requested | |
647f0914 | 374 | PushTrack(0,-1,part,p,origin,polar,0,kPPrimary,fNt,wgt); |
1e66857c | 375 | KeepTrack(fNt); |
1ef5f15d | 376 | DecayPi0(origin, p); |
377 | } else { | |
647f0914 | 378 | PushTrack(fTrackIt,-1,part,p,origin,polar,0,kPPrimary,fNt,wgt); |
1e66857c | 379 | KeepTrack(fNt); |
1ef5f15d | 380 | } |
381 | ||
790bbabf | 382 | break; |
383 | } | |
1e66857c | 384 | SetHighWaterMark(fNt); |
790bbabf | 385 | } |
1e66857c | 386 | // |
387 | ||
971816d4 | 388 | // Header |
389 | AliGenEventHeader* header = new AliGenEventHeader("HIJINGparam"); | |
390 | // Event Vertex | |
391 | header->SetPrimaryVertex(eventVertex); | |
392 | gAlice->SetGenEventHeader(header); | |
790bbabf | 393 | } |
394 | ||
6b236b6f | 395 | void AliGenHIJINGpara::SetPtRange(Float_t ptmin, Float_t ptmax) { |
2067f62c | 396 | AliGenerator::SetPtRange(ptmin, ptmax); |
6b236b6f | 397 | } |
790bbabf | 398 | |
2067f62c | 399 | void AliGenHIJINGpara::DecayPi0(Float_t* orig, Float_t * p) |
400 | { | |
401 | // | |
402 | // Decay the pi0 | |
403 | // and put decay products on the stack | |
404 | // | |
405 | static TClonesArray *particles; | |
406 | if(!particles) particles = new TClonesArray("TParticle",1000); | |
407 | // | |
408 | const Float_t kMass = TDatabasePDG::Instance()->GetParticle(kPi0)->Mass(); | |
56fcdfe6 | 409 | Float_t e = TMath::Sqrt(p[0] * p[0] + p[1] * p[1] + p[2] * p[2]+ kMass * kMass); |
2067f62c | 410 | // |
411 | // Decay the pi0 | |
412 | TLorentzVector pmom(p[0], p[1], p[2], e); | |
413 | fDecayer->Decay(kPi0, &pmom); | |
56fcdfe6 | 414 | |
2067f62c | 415 | // |
416 | // Put decay particles on the stack | |
417 | // | |
2067f62c | 418 | Float_t polar[3] = {0., 0., 0.}; |
419 | Int_t np = fDecayer->ImportParticles(particles); | |
1e66857c | 420 | Int_t nt; |
2067f62c | 421 | for (Int_t i = 1; i < np; i++) |
422 | { | |
7b33c00a | 423 | TParticle* iParticle = (TParticle *) particles->At(i); |
424 | p[0] = iParticle->Px(); | |
425 | p[1] = iParticle->Py(); | |
426 | p[2] = iParticle->Pz(); | |
2067f62c | 427 | Int_t part = iParticle->GetPdgCode(); |
1e66857c | 428 | |
642f15cf | 429 | PushTrack(fTrackIt, fNt, part, p, orig, polar, 0, kPDecay, nt, fParentWeight); |
1e66857c | 430 | KeepTrack(nt); |
2067f62c | 431 | } |
1e66857c | 432 | fNt = nt; |
2067f62c | 433 | } |
198bb1c7 | 434 | |
dc1d768c | 435 | void AliGenHIJINGpara::Copy(TObject &) const |
198bb1c7 | 436 | { |
437 | Fatal("Copy","Not implemented!\n"); | |
438 | } | |
cc692c80 | 439 | |
440 | ||
441 | void AliGenHIJINGpara::Draw( const char * /*opt*/) | |
442 | { | |
443 | // | |
444 | // Draw the pT and y Distributions | |
445 | // | |
446 | TCanvas *c0 = new TCanvas("c0","Canvas 0",400,10,600,700); | |
447 | c0->Divide(2,1); | |
448 | c0->cd(1); | |
449 | fPtpi->Draw(); | |
450 | fPtpi->GetHistogram()->SetXTitle("p_{T} (GeV)"); | |
451 | c0->cd(2); | |
452 | fPtka->Draw(); | |
453 | fPtka->GetHistogram()->SetXTitle("p_{T} (GeV)"); | |
454 | ||
455 | } |