effc++ corrections (alberto)
[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
38static Double_t ptpi(Double_t *px, Double_t *)
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()
156 :AliGenHIJINGpara()
157{
158 //
159 // Default constructor
160 //
161 fName="HIGINGparaBa";
162 fTitle="HIJING Parametrisation Particle Generator with Baryons";
163 fETAba = 0;
164 fPtba = 0;
165}
166
167//_____________________________________________________________________________
168AliGenHIJINGparaBa::AliGenHIJINGparaBa(Int_t npart)
169 :AliGenHIJINGpara(npart)
170{
171 //
172 // Standard constructor
173 //
174 fName="HIGINGparaBa";
175 fTitle="HIJING Parametrisation Particle Generator with Baryons";
176 fETAba = 0;
177 fPtba = 0;
178}
179
0af12c00 180AliGenHIJINGparaBa::AliGenHIJINGparaBa(const AliGenHIJINGparaBa& para) : AliGenHIJINGpara(para)
181{
182// Copy constructor
183 para.Copy(*this);
184}
185
388f2c07 186//_____________________________________________________________________________
187AliGenHIJINGparaBa::~AliGenHIJINGparaBa()
188{
189 //
190 // Standard destructor
191 //
192 delete fPtba;
193 delete fETAba;
194}
195
196//_____________________________________________________________________________
197void AliGenHIJINGparaBa::Init()
198{
199 //
200 // Initialise the HIJING parametrisation
201 //
202 Float_t etaMin =-TMath::Log(TMath::Tan(
203 TMath::Min((Double_t)fThetaMax/2,TMath::Pi()/2-1.e-10)));
204 Float_t etaMax = -TMath::Log(TMath::Tan(
205 TMath::Max((Double_t)fThetaMin/2,1.e-10)));
206 fPtpi = new TF1("ptpi",&ptpi,0,20,0);
207 fPtka = new TF1("ptka",&ptka,0,20,0);
208 fPtba = new TF1("ptbaryon",&ptbaryon,0,20,0);
209 fETApic = new TF1("etapic",&etapic,etaMin,etaMax,0);
210 fETAkac = new TF1("etakac",&etakac,etaMin,etaMax,0);
211 fETAba = new TF1("etabaryon",&etabaryon,etaMin,etaMax,0);
212
2a336e15 213 TF1 etaPic0("etapic(-7,7)",&etapic, -7, 7, 0);
214 TF1 etaKac0("etakac(-7,7)",&etakac, -7, 7, 0);
215 TF1 etaBar0("etabar(-7,7)",&etabaryon, -7, 7, 0);
388f2c07 216
2a336e15 217 TF1 ptPic0("ptpi(0,15)", &ptpi, 0., 15., 0);
218 TF1 ptKac0("ptka(0,15)", &ptka, 0., 15., 0);
219 TF1 ptBar0("ptbar(0,15)", &ptbaryon, 0., 15., 0);
388f2c07 220
2a336e15 221 Float_t intETApi = etaPic0.Integral(-0.5, 0.5);
222 Float_t intETAka = etaKac0.Integral(-0.5, 0.5);
223 Float_t intETAba = etaBar0.Integral(-0.5, 0.5);
388f2c07 224
225 Float_t scalePi = 6979./(intETApi/1.5);
226 Float_t scaleKa = 657./(intETAka/2.0);
227 Float_t scaleBa = 364./(intETAba/2.0);
228
229// Fraction of events corresponding to the selected pt-range
2a336e15 230 Float_t intPt = (0.837*ptPic0.Integral(0, 15)+
231 0.105*ptKac0.Integral(0, 15)+
232 0.058*ptBar0.Integral(0, 15));
233 Float_t intPtSel = (0.837*ptPic0.Integral(fPtMin, fPtMax)+
234 0.105*ptKac0.Integral(fPtMin, fPtMax)+
235 0.058*ptBar0.Integral(fPtMin, fPtMax));
388f2c07 236 Float_t ptFrac = intPtSel/intPt;
237
238// Fraction of events corresponding to the selected eta-range
2a336e15 239 Float_t intETASel = (scalePi*etaPic0.Integral(etaMin, etaMax)+
240 scaleKa*etaKac0.Integral(etaMin, etaMax)+
241 scaleBa*etaBar0.Integral(etaMin, etaMax));
388f2c07 242// Fraction of events corresponding to the selected phi-range
243 Float_t phiFrac = (fPhiMax-fPhiMin)/2/TMath::Pi();
244
245 fParentWeight = Float_t(fNpart)/(intETASel*ptFrac*phiFrac);
246
247 printf("%s: The number of particles in the selected kinematic region corresponds to %f percent of a full event \n",
248 ClassName(),100.*fParentWeight);
249
250// Issue warning message if etaMin or etaMax are outside the alowed range
251// of the parametrization
252 if (etaMin < -8.001 || etaMax > 8.001) {
253 printf("\n \n WARNING FROM AliGenHIJINGParaBa !");
254 printf("\n YOU ARE USING THE PARAMETERISATION OUTSIDE ");
255 printf("\n THE ALLOWED PSEUDORAPIDITY RANGE (-8. - 8.)");
256 printf("\n YOUR LIMITS: %f %f \n \n ", etaMin, etaMax);
257 }
258}
259
260//_____________________________________________________________________________
261void AliGenHIJINGparaBa::Generate()
262{
263 //
264 // Generate one trigger
265 //
266
267
268 const Float_t kBorne1 = 0.837;
269 const Float_t kBorne2 = kBorne1+0.105;
270
271 Float_t polar[3]= {0,0,0};
272 //
273 const Int_t kPions[3] = {kPi0, kPiPlus, kPiMinus};
274 const Int_t kKaons[4] = {kK0Long, kK0Short, kKPlus, kKMinus};
275 const Int_t kBaryons[4] = {kProton, kProtonBar, kNeutron, kNeutronBar};
276 //
277 Float_t origin[3];
278 Float_t pt, pl, ptot;
279 Float_t phi, theta;
280 Float_t p[3];
281 Int_t i, part, nt, j;
282 //
283 TF1 *ptf;
284 TF1 *etaf;
285 //
286 Float_t random[6];
287 //
288 for (j=0;j<3;j++) origin[j]=fOrigin[j];
289
290 if(fVertexSmear == kPerEvent) {
291 Float_t dv[3];
292 dv[2] = 1.e10;
293 while(TMath::Abs(dv[2]) > fCutVertexZ*fOsigma[2]) {
294 Rndm(random,6);
295 for (j=0; j < 3; j++) {
296 dv[j] = fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
297 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
298 }
299 }
300 for (j=0; j < 3; j++) origin[j] += dv[j];
301 } // if kPerEvent
302 TArrayF eventVertex;
303 eventVertex.Set(3);
304 eventVertex[0] = origin[0];
305 eventVertex[1] = origin[1];
306 eventVertex[2] = origin[2];
307
308 for(i=0;i<fNpart;i++) {
309 while(1) {
310 Rndm(random,3);
311 if(random[0] < kBorne1) {
312 part = kPions[Int_t (random[1]*3)];
313 ptf = fPtpi;
314 etaf = fETApic;
315 } else if (random[0] < kBorne2) {
316 part = kKaons[Int_t (random[1]*4)];
317 ptf = fPtka;
318 etaf = fETAkac;
319 } else {
320 part = kBaryons[Int_t (random[1]*4)];
321 ptf = fPtba;
322 etaf = fETAba;
323 }
324
325 phi=fPhiMin+random[2]*(fPhiMax-fPhiMin);
326 theta=2*TMath::ATan(TMath::Exp(-etaf->GetRandom()));
327 if(theta<fThetaMin || theta>fThetaMax) continue;
328 pt=ptf->GetRandom();
329 pl=pt/TMath::Tan(theta);
330 ptot=TMath::Sqrt(pt*pt+pl*pl);
331 if(ptot<fPMin || ptot>fPMax) continue;
332 p[0]=pt*TMath::Cos(phi);
333 p[1]=pt*TMath::Sin(phi);
334 p[2]=pl;
335 if(fVertexSmear==kPerTrack) {
336 Rndm(random,6);
337 for (j=0;j<3;j++) {
338 origin[j]=fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
339 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
340 }
341 }
642f15cf 342 PushTrack(fTrackIt,-1,part,p,origin,polar,0,kPPrimary,nt,fParentWeight);
388f2c07 343 break;
344 } // while(1)
345 } // Particle loop
346// Header
347 AliGenEventHeader* header = new AliGenEventHeader("HIJINGparam");
348// Event Vertex
349 header->SetPrimaryVertex(eventVertex);
350 gAlice->SetGenEventHeader(header);
351}
352
353
354