doxy: MUON macros, refs, src links, no coll graph
[u/mrichter/AliRoot.git] / EVGEN / AliGenHIJINGparaBa.cxx
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388f2c07 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
803d1ab0 16/* $Id$ */
88cb7938 17
388f2c07 18///////////////////////////////////////////////////////////////////
19// Parameterisation of pi, K, n and p eta and pt distributions //
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///////////////////////////////////////////////////////////////////
25
116cbefd 26#include <TArrayF.h>
27#include <TF1.h>
28#include <TPDGCode.h>
29
30#include "AliConst.h"
388f2c07 31#include "AliGenEventHeader.h"
116cbefd 32#include "AliGenHIJINGparaBa.h"
388f2c07 33#include "AliRun.h"
388f2c07 34
35ClassImp(AliGenHIJINGparaBa)
36
37
4a33c50d 38static Double_t ptpi(const Double_t *px, const Double_t *)
388f2c07 39{
40 //
41 // PT-PARAMETERIZATION CDF, PRL 61(88) 1819
42 // POWER LAW FOR PT > 500 MEV
43 // MT SCALING BELOW (T=160 MEV)
44 //
45 const Double_t kp0 = 1.3;
46 const Double_t kxn = 8.28;
47 const Double_t kxlim=0.5;
48 const Double_t kt=0.160;
49 const Double_t kxmpi=0.139;
50 const Double_t kb=1.;
51 Double_t y, y1, xmpi2, ynorm, a;
52 Double_t x=*px;
53 //
54 y1=TMath::Power(kp0/(kp0+kxlim),kxn);
55 xmpi2=kxmpi*kxmpi;
56 ynorm=kb*(TMath::Exp(-sqrt(kxlim*kxlim+xmpi2)/kt));
57 a=ynorm/y1;
58 if (x > kxlim)
59 y=a*TMath::Power(kp0/(kp0+x),kxn);
60 else
61 y=kb*TMath::Exp(-sqrt(x*x+xmpi2)/kt);
62 return y*x;
63}
64
65//_____________________________________________________________________________
66static Double_t ptscal(Double_t pt, Int_t np)
67{
68 // SCALING EN MASSE PAR RAPPORT A PTPI
69 // MASS PI,K,ETA,RHO,OMEGA,ETA',PHI
70 const Double_t khm[10] = {.13957,.493,.5488,.769,.7826,.958,1.02,0,0,0};
71 // VALUE MESON/PI AT 5 GEV
72 const Double_t kfmax[10]={1.,0.3,0.55,1.0,1.0,1.0,1.0,0,0,0};
73 np--;
74 Double_t f5=TMath::Power(((
75 sqrt(100.018215)+2.)/(sqrt(100.+khm[np]*khm[np])+2.0)),12.3);
76 Double_t fmax2=f5/kfmax[np];
77 // PIONS
78 Double_t ptpion=100.*ptpi(&pt, (Double_t*) 0);
79 Double_t fmtscal=TMath::Power(((
80 sqrt(pt*pt+0.018215)+2.)/ (sqrt(pt*pt+khm[np]*khm[np])+2.0)),12.3)/
81 fmax2;
82 return fmtscal*ptpion;
83}
84
85//_____________________________________________________________________________
86static Double_t ptka( Double_t *px, Double_t *)
87{
88 //
89 // pt parametrisation for k
90 //
91 return ptscal(*px,2);
92}
93
94
95//_____________________________________________________________________________
96static Double_t etapic( Double_t *py, Double_t *)
97{
98 //
99 // eta parametrisation for pi
100 //
101 const Double_t ka1 = 4913.;
102 const Double_t ka2 = 1819.;
103 const Double_t keta1 = 0.22;
104 const Double_t keta2 = 3.66;
105 const Double_t kdeta1 = 1.47;
106 const Double_t kdeta2 = 1.51;
107 Double_t y=TMath::Abs(*py);
108 //
109 Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1);
110 Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2);
111 return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2);
112}
113
114//_____________________________________________________________________________
115static Double_t etakac( Double_t *py, Double_t *)
116{
117 //
118 // eta parametrisation for ka
119 //
120 const Double_t ka1 = 497.6;
121 const Double_t ka2 = 215.6;
122 const Double_t keta1 = 0.79;
123 const Double_t keta2 = 4.09;
124 const Double_t kdeta1 = 1.54;
125 const Double_t kdeta2 = 1.40;
126 Double_t y=TMath::Abs(*py);
127 //
128 Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1);
129 Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2);
130 return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2);
131}
132
133 static Double_t ptbaryon( Double_t *px, Double_t *)
134{
135// baryons
136// pt-distribution
137//____________________________________________________________
138
139 return ptscal(*px,7); // 7==> Baryon in the PtScal function
140}
141
142 static Double_t etabaryon( Double_t *py, Double_t *)
143{
144// eta-distribution
145//____________________________________________________________
0af12c00 146 const Float_t kp0 = 1.10343e+02;
147 const Float_t kp1 = 1.73247e+01;
148 const Float_t kp2 = -7.23808e+00;
149 const Float_t kp3 = 4.48334e-01;
150 const Double_t ky = TMath::Abs(*py);
388f2c07 151//
0af12c00 152 return (kp0+kp1*ky+kp2*ky*ky+kp3*ky*ky*ky)/20.;
388f2c07 153}
154
155AliGenHIJINGparaBa::AliGenHIJINGparaBa()
1c56e311 156 :AliGenHIJINGpara(),
157 fPtba(0),
158 fETAba(0)
388f2c07 159{
160 //
161 // Default constructor
162 //
163 fName="HIGINGparaBa";
164 fTitle="HIJING Parametrisation Particle Generator with Baryons";
388f2c07 165}
166
167//_____________________________________________________________________________
168AliGenHIJINGparaBa::AliGenHIJINGparaBa(Int_t npart)
1c56e311 169 :AliGenHIJINGpara(npart),
170 fPtba(0),
171 fETAba(0)
388f2c07 172{
173 //
174 // Standard constructor
175 //
176 fName="HIGINGparaBa";
177 fTitle="HIJING Parametrisation Particle Generator with Baryons";
388f2c07 178}
179
180//_____________________________________________________________________________
181AliGenHIJINGparaBa::~AliGenHIJINGparaBa()
182{
183 //
184 // Standard destructor
185 //
186 delete fPtba;
187 delete fETAba;
188}
189
190//_____________________________________________________________________________
191void AliGenHIJINGparaBa::Init()
192{
193 //
194 // Initialise the HIJING parametrisation
195 //
196 Float_t etaMin =-TMath::Log(TMath::Tan(
197 TMath::Min((Double_t)fThetaMax/2,TMath::Pi()/2-1.e-10)));
198 Float_t etaMax = -TMath::Log(TMath::Tan(
199 TMath::Max((Double_t)fThetaMin/2,1.e-10)));
200 fPtpi = new TF1("ptpi",&ptpi,0,20,0);
201 fPtka = new TF1("ptka",&ptka,0,20,0);
202 fPtba = new TF1("ptbaryon",&ptbaryon,0,20,0);
203 fETApic = new TF1("etapic",&etapic,etaMin,etaMax,0);
204 fETAkac = new TF1("etakac",&etakac,etaMin,etaMax,0);
205 fETAba = new TF1("etabaryon",&etabaryon,etaMin,etaMax,0);
206
2a336e15 207 TF1 etaPic0("etapic(-7,7)",&etapic, -7, 7, 0);
208 TF1 etaKac0("etakac(-7,7)",&etakac, -7, 7, 0);
209 TF1 etaBar0("etabar(-7,7)",&etabaryon, -7, 7, 0);
388f2c07 210
2a336e15 211 TF1 ptPic0("ptpi(0,15)", &ptpi, 0., 15., 0);
212 TF1 ptKac0("ptka(0,15)", &ptka, 0., 15., 0);
213 TF1 ptBar0("ptbar(0,15)", &ptbaryon, 0., 15., 0);
388f2c07 214
2a336e15 215 Float_t intETApi = etaPic0.Integral(-0.5, 0.5);
216 Float_t intETAka = etaKac0.Integral(-0.5, 0.5);
217 Float_t intETAba = etaBar0.Integral(-0.5, 0.5);
388f2c07 218
219 Float_t scalePi = 6979./(intETApi/1.5);
220 Float_t scaleKa = 657./(intETAka/2.0);
221 Float_t scaleBa = 364./(intETAba/2.0);
222
223// Fraction of events corresponding to the selected pt-range
2a336e15 224 Float_t intPt = (0.837*ptPic0.Integral(0, 15)+
225 0.105*ptKac0.Integral(0, 15)+
226 0.058*ptBar0.Integral(0, 15));
227 Float_t intPtSel = (0.837*ptPic0.Integral(fPtMin, fPtMax)+
228 0.105*ptKac0.Integral(fPtMin, fPtMax)+
229 0.058*ptBar0.Integral(fPtMin, fPtMax));
388f2c07 230 Float_t ptFrac = intPtSel/intPt;
231
232// Fraction of events corresponding to the selected eta-range
2a336e15 233 Float_t intETASel = (scalePi*etaPic0.Integral(etaMin, etaMax)+
234 scaleKa*etaKac0.Integral(etaMin, etaMax)+
235 scaleBa*etaBar0.Integral(etaMin, etaMax));
388f2c07 236// Fraction of events corresponding to the selected phi-range
237 Float_t phiFrac = (fPhiMax-fPhiMin)/2/TMath::Pi();
238
239 fParentWeight = Float_t(fNpart)/(intETASel*ptFrac*phiFrac);
240
241 printf("%s: The number of particles in the selected kinematic region corresponds to %f percent of a full event \n",
242 ClassName(),100.*fParentWeight);
243
244// Issue warning message if etaMin or etaMax are outside the alowed range
245// of the parametrization
246 if (etaMin < -8.001 || etaMax > 8.001) {
247 printf("\n \n WARNING FROM AliGenHIJINGParaBa !");
248 printf("\n YOU ARE USING THE PARAMETERISATION OUTSIDE ");
249 printf("\n THE ALLOWED PSEUDORAPIDITY RANGE (-8. - 8.)");
250 printf("\n YOUR LIMITS: %f %f \n \n ", etaMin, etaMax);
251 }
252}
253
254//_____________________________________________________________________________
255void AliGenHIJINGparaBa::Generate()
256{
257 //
258 // Generate one trigger
259 //
260
261
262 const Float_t kBorne1 = 0.837;
263 const Float_t kBorne2 = kBorne1+0.105;
264
265 Float_t polar[3]= {0,0,0};
266 //
267 const Int_t kPions[3] = {kPi0, kPiPlus, kPiMinus};
268 const Int_t kKaons[4] = {kK0Long, kK0Short, kKPlus, kKMinus};
269 const Int_t kBaryons[4] = {kProton, kProtonBar, kNeutron, kNeutronBar};
270 //
271 Float_t origin[3];
21391258 272 Float_t time;
388f2c07 273 Float_t pt, pl, ptot;
274 Float_t phi, theta;
275 Float_t p[3];
276 Int_t i, part, nt, j;
277 //
278 TF1 *ptf;
279 TF1 *etaf;
280 //
281 Float_t random[6];
282 //
283 for (j=0;j<3;j++) origin[j]=fOrigin[j];
21391258 284 time = fTimeOrigin;
388f2c07 285
286 if(fVertexSmear == kPerEvent) {
287 Float_t dv[3];
288 dv[2] = 1.e10;
289 while(TMath::Abs(dv[2]) > fCutVertexZ*fOsigma[2]) {
290 Rndm(random,6);
291 for (j=0; j < 3; j++) {
292 dv[j] = fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
293 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
294 }
295 }
296 for (j=0; j < 3; j++) origin[j] += dv[j];
21391258 297
298 Rndm(random,2);
299 time += fOsigma[2]/TMath::Ccgs()*
300 TMath::Cos(2*random[0]*TMath::Pi())*
301 TMath::Sqrt(-2*TMath::Log(random[1]));
388f2c07 302 } // if kPerEvent
303 TArrayF eventVertex;
304 eventVertex.Set(3);
305 eventVertex[0] = origin[0];
306 eventVertex[1] = origin[1];
307 eventVertex[2] = origin[2];
21391258 308 Float_t eventTime = time;
388f2c07 309
310 for(i=0;i<fNpart;i++) {
311 while(1) {
312 Rndm(random,3);
313 if(random[0] < kBorne1) {
314 part = kPions[Int_t (random[1]*3)];
315 ptf = fPtpi;
316 etaf = fETApic;
317 } else if (random[0] < kBorne2) {
318 part = kKaons[Int_t (random[1]*4)];
319 ptf = fPtka;
320 etaf = fETAkac;
321 } else {
322 part = kBaryons[Int_t (random[1]*4)];
323 ptf = fPtba;
324 etaf = fETAba;
325 }
326
327 phi=fPhiMin+random[2]*(fPhiMax-fPhiMin);
328 theta=2*TMath::ATan(TMath::Exp(-etaf->GetRandom()));
329 if(theta<fThetaMin || theta>fThetaMax) continue;
330 pt=ptf->GetRandom();
331 pl=pt/TMath::Tan(theta);
332 ptot=TMath::Sqrt(pt*pt+pl*pl);
333 if(ptot<fPMin || ptot>fPMax) continue;
334 p[0]=pt*TMath::Cos(phi);
335 p[1]=pt*TMath::Sin(phi);
336 p[2]=pl;
337 if(fVertexSmear==kPerTrack) {
338 Rndm(random,6);
339 for (j=0;j<3;j++) {
340 origin[j]=fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
341 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
342 }
21391258 343
344 Rndm(random,2);
345 time = fTimeOrigin + fOsigma[2]/TMath::Ccgs()*
346 TMath::Cos(2*random[0]*TMath::Pi())*
347 TMath::Sqrt(-2*TMath::Log(random[1]));
388f2c07 348 }
21391258 349 PushTrack(fTrackIt,-1,part,p,origin,polar,time,kPPrimary,nt,fParentWeight);
388f2c07 350 break;
351 } // while(1)
352 } // Particle loop
353// Header
354 AliGenEventHeader* header = new AliGenEventHeader("HIJINGparam");
355// Event Vertex
356 header->SetPrimaryVertex(eventVertex);
21391258 357 header->SetInteractionTime(eventTime);
388f2c07 358 gAlice->SetGenEventHeader(header);
359}
360
361
362