1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
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 **************************************************************************/
18 Revision 1.6 1999/11/03 17:43:20 fca
19 New version from G.Martinez & A.Morsch
21 Revision 1.5 1999/09/29 09:24:14 fca
22 Introduction of the Copyright and cvs Log
26 ///////////////////////////////////////////////////////////////////
28 // Generate the final state of the interaction as the input //
29 // to the MonteCarlo //
33 <img src="picts/AliGeneratorClass.gif">
36 <font size=+2 color=red>
37 <p>The responsible person for this module is
38 <a href="mailto:andreas.morsch@cern.ch">Andreas Morsch</a>.
44 ///////////////////////////////////////////////////////////////////
46 #include "AliSimpleGen.h"
50 ClassImp(AliGenHIJINGpara)
52 //_____________________________________________________________________________
53 static Double_t ptpi(Double_t *px, Double_t *)
56 // PT-PARAMETERIZATION CDF, PRL 61(88) 1819
57 // POWER LAW FOR PT > 500 MEV
58 // MT SCALING BELOW (T=160 MEV)
60 const Double_t p0 = 1.3;
61 const Double_t xn = 8.28;
62 const Double_t xlim=0.5;
63 const Double_t t=0.160;
64 const Double_t xmpi=0.139;
66 Double_t y, y1, xmpi2, ynorm, a;
69 y1=TMath::Power(p0/(p0+xlim),xn);
71 ynorm=b*(TMath::Exp(-sqrt(xlim*xlim+xmpi2)/t));
74 y=a*TMath::Power(p0/(p0+x),xn);
76 y=b*TMath::Exp(-sqrt(x*x+xmpi2)/t);
80 //_____________________________________________________________________________
81 static Double_t ptscal(Double_t pt, Int_t np)
83 // SCALING EN MASSE PAR RAPPORT A PTPI
84 // MASS PI,K,ETA,RHO,OMEGA,ETA',PHI
85 const Double_t hm[10] = {.13957,.493,.5488,.769,.7826,.958,1.02,0,0,0};
86 // VALUE MESON/PI AT 5 GEV
87 const Double_t fmax[10]={1.,0.3,0.55,1.0,1.0,1.0,1.0,0,0,0};
89 Double_t f5=TMath::Power(((sqrt(100.018215)+2.)/(sqrt(100.+hm[np]*hm[np])+2.0)),12.3);
90 Double_t fmax2=f5/fmax[np];
92 Double_t ptpion=100.*ptpi(&pt, (Double_t*) 0);
93 Double_t fmtscal=TMath::Power(((sqrt(pt*pt+0.018215)+2.)/
94 (sqrt(pt*pt+hm[np]*hm[np])+2.0)),12.3)/ fmax2;
95 return fmtscal*ptpion;
98 //_____________________________________________________________________________
99 static Double_t ptka( Double_t *px, Double_t *)
102 // pt parametrisation for k
104 return ptscal(*px,2);
108 //_____________________________________________________________________________
109 static Double_t etapic( Double_t *py, Double_t *)
112 // eta parametrisation for pi
114 const Double_t a1 = 4913.;
115 const Double_t a2 = 1819.;
116 const Double_t eta1 = 0.22;
117 const Double_t eta2 = 3.66;
118 const Double_t deta1 = 1.47;
119 const Double_t deta2 = 1.51;
120 Double_t y=TMath::Abs(*py);
122 Double_t ex1 = (y-eta1)*(y-eta1)/(2*deta1*deta1);
123 Double_t ex2 = (y-eta2)*(y-eta2)/(2*deta2*deta2);
124 return a1*TMath::Exp(-ex1)+a2*TMath::Exp(-ex2);
127 //_____________________________________________________________________________
128 static Double_t etakac( Double_t *py, Double_t *)
131 // eta parametrisation for ka
133 const Double_t a1 = 497.6;
134 const Double_t a2 = 215.6;
135 const Double_t eta1 = 0.79;
136 const Double_t eta2 = 4.09;
137 const Double_t deta1 = 1.54;
138 const Double_t deta2 = 1.40;
139 Double_t y=TMath::Abs(*py);
141 Double_t ex1 = (y-eta1)*(y-eta1)/(2*deta1*deta1);
142 Double_t ex2 = (y-eta2)*(y-eta2)/(2*deta2*deta2);
143 return a1*TMath::Exp(-ex1)+a2*TMath::Exp(-ex2);
146 //_____________________________________________________________________________
147 AliGenHIJINGpara::AliGenHIJINGpara()
151 // Default constructor
159 //_____________________________________________________________________________
160 AliGenHIJINGpara::AliGenHIJINGpara(Int_t npart)
164 // Standard constructor
167 fTitle="HIJING Parametrisation Particle Generator";
174 //_____________________________________________________________________________
175 AliGenHIJINGpara::~AliGenHIJINGpara()
178 // Standard destructor
186 //_____________________________________________________________________________
187 void AliGenHIJINGpara::Init()
190 // Initialise the HIJING parametrisation
192 Float_t etaMin = -TMath::Log(TMath::Tan(TMath::Min((Double_t)fThetaMax/2,TMath::Pi()/2-1.e-10)));
193 Float_t etaMax = -TMath::Log(TMath::Tan(TMath::Max((Double_t)fThetaMin/2, 1.e-10)));
194 fPtpi = new TF1("ptpi",&ptpi,0,20,0);
195 fPtka = new TF1("ptka",&ptka,0,20,0);
196 fETApic = new TF1("etapic",&etapic,etaMin,etaMax,0);
197 fETAkac = new TF1("etakac",&etakac,etaMin,etaMax,0);
198 TF1 *ETApic0 = new TF1("etapic",&etapic,-7,7,0);
199 TF1 *ETAkac0 = new TF1("etakac",&etakac,-7,7,0);
200 Float_t IntETApi = ETApic0->Integral(-0.5, 0.5);
201 Float_t IntETAka = ETAkac0->Integral(-0.5, 0.5);
202 Float_t scalePi=7316/(IntETApi/1.5);
203 Float_t scaleKa= 684/(IntETAka/2.0);
205 Float_t IntPt = (0.877*ETApic0->Integral(0, 15)+
206 0.123*ETAkac0->Integral(0, 15));
207 Float_t IntPtSel = (0.877*ETApic0->Integral(fPtMin, fPtMax)+
208 0.123*ETAkac0->Integral(fPtMin, fPtMax));
209 Float_t PtFrac = IntPtSel/IntPt;
212 Float_t IntETASel = (scalePi*ETApic0->Integral(etaMin, etaMax)+
213 scaleKa*ETAkac0->Integral(etaMin, etaMax));
214 Float_t PhiFrac = (fPhiMax-fPhiMin)/2/TMath::Pi();
215 fParentWeight = Float_t(fNpart)/IntETASel*PtFrac*PhiFrac;
217 printf("\n The number of particles in the selected kinematic region corresponds to %f percent of a full event\n ", 100.*fParentWeight);
221 //_____________________________________________________________________________
222 void AliGenHIJINGpara::Generate()
225 // Generate one trigger
229 const Float_t raKpic=0.14;
230 const Float_t borne=1/(1+raKpic);
231 Float_t polar[3]= {0,0,0};
233 const Int_t pions[3] = {kPi0, kPiPlus, kPiMinus};
234 const Int_t kaons[4] = {kK0Long, kK0Short, kKPlus, kKMinus};
237 Float_t pt, pl, ptot;
240 Int_t i, part, nt, j;
247 for (j=0;j<3;j++) origin[j]=fOrigin[j];
248 if(fVertexSmear==perEvent) {
251 origin[j]+=fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
252 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
255 for(i=0;i<fNpart;i++) {
258 if(random[0]<borne) {
259 part=pions[Int_t (random[1]*3)];
263 part=kaons[Int_t (random[1]*4)];
267 phi=fPhiMin+random[2]*(fPhiMax-fPhiMin);
268 theta=2*TMath::ATan(TMath::Exp(-etaf->GetRandom()));
269 if(theta<fThetaMin || theta>fThetaMax) continue;
271 pl=pt/TMath::Tan(theta);
272 ptot=TMath::Sqrt(pt*pt+pl*pl);
273 if(ptot<fPMin || ptot>fPMax) continue;
274 p[0]=pt*TMath::Cos(phi);
275 p[1]=pt*TMath::Sin(phi);
277 if(fVertexSmear==perTrack) {
280 origin[j]=fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
281 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
284 gAlice->SetTrack(fTrackIt,-1,part,p,origin,polar,0,"Primary",nt,fParentWeight);
290 ClassImp(AliGenFixed)
292 //_____________________________________________________________________________
293 AliGenFixed::AliGenFixed()
297 // Default constructor
302 //_____________________________________________________________________________
303 AliGenFixed::AliGenFixed(Int_t npart)
307 // Standard constructor
310 fTitle="Fixed Particle Generator";
311 // Generate Proton by default
315 //_____________________________________________________________________________
316 void AliGenFixed::Generate()
319 // Generate one trigger
321 Float_t polar[3]= {0,0,0};
322 Float_t p[3] = {fPMin*TMath::Cos(fPhiMin)*TMath::Sin(fThetaMin),
323 fPMin*TMath::Sin(fPhiMin)*TMath::Sin(fThetaMin),
324 fPMin*TMath::Cos(fThetaMin)};
327 for(i=0;i<fNpart;i++) {
328 gAlice->SetTrack(fTrackIt,-1,fIpart,p,fOrigin.GetArray(),polar,0,"Primary",nt);
332 //_____________________________________________________________________________
333 void AliGenFixed::SetSigma(Float_t, Float_t, Float_t)
336 // Set the interaction point sigma
338 printf("Vertex smearing not implemented for fixed generator\n");
344 //_____________________________________________________________________________
345 AliGenBox::AliGenBox()
349 // Default constructor
354 //_____________________________________________________________________________
355 AliGenBox::AliGenBox(Int_t npart)
359 // Standard constructor
362 fTitle="Box particle generator";
363 // Generate Proton by default
367 //_____________________________________________________________________________
368 void AliGenBox::Generate()
371 // Generate one trigger
374 Float_t polar[3]= {0,0,0};
379 Float_t pmom, theta, phi;
383 for (j=0;j<3;j++) origin[j]=fOrigin[j];
384 if(fVertexSmear==perEvent) {
387 origin[j]+=fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
388 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
391 for(i=0;i<fNpart;i++) {
394 pmom=fPMin+random[0]*(fPMax-fPMin);
395 theta=fThetaMin+random[1]*(fThetaMax-fThetaMin);
396 phi=fPhiMin+random[2]*(fPhiMax-fPhiMin);
397 p[0] = pmom*TMath::Cos(phi)*TMath::Sin(theta);
398 p[1] = pmom*TMath::Sin(phi)*TMath::Sin(theta);
399 p[2] = pmom*TMath::Cos(theta);
400 } while (fPtMin<=TMath::Sqrt(p[0]*p[0]+p[1]*p[1]) &&
401 TMath::Sqrt(p[0]*p[0]+p[1]*p[1])<=fPtMax);
402 if(fVertexSmear==perTrack) {
405 origin[j]=fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
406 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
409 gAlice->SetTrack(fTrackIt,-1,fIpart,p,origin,polar,0,"Primary",nt);