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- Possibility for vertex distribution truncation.
[u/mrichter/AliRoot.git] / EVGEN / AliGenHIJINGpara.cxx
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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
16/*
17$Log$
971816d4 18Revision 1.9 2001/07/27 17:09:36 morsch
19Use local SetTrack, KeepTrack and SetHighWaterMark methods
20to delegate either to local stack or to stack owned by AliRun.
21(Piotr Skowronski, A.M.)
22
a99cf51f 23Revision 1.8 2001/07/20 11:03:58 morsch
24Issue warning message if used outside allowed eta range (-8 to 8).
25
5b0e4c0f 26Revision 1.7 2001/07/17 12:41:01 morsch
27- Calculation of fraction of event corresponding to selected pt-range corrected
28(R. Turrisi)
29- Parent weight corrected.
30
f25521b2 31Revision 1.6 2001/05/16 14:57:10 alibrary
32New files for folders and Stack
33
9e1a0ddb 34Revision 1.5 2000/12/21 16:24:06 morsch
35Coding convention clean-up
36
675e9664 37Revision 1.4 2000/11/30 07:12:50 alibrary
38Introducing new Rndm and QA classes
39
65fb704d 40Revision 1.3 2000/10/02 21:28:06 fca
41Removal of useless dependecies via forward declarations
42
94de3818 43Revision 1.2 2000/07/11 18:24:55 fca
44Coding convention corrections + few minor bug fixes
45
aee8290b 46Revision 1.1 2000/06/09 20:20:30 morsch
47Same class as previously in AliSimpleGen.cxx
48All coding rule violations except RS3 corrected (AM)
49
790bbabf 50*/
675e9664 51
52// Parameterisation of pi and K, eta and pt distributions
53// used for the ALICE TDRs.
54// eta: according to HIJING (shadowing + quenching)
55// pT : according to CDF measurement at 1.8 TeV
56// Author: andreas.morsch@cern.ch
57
58
790bbabf 59//Begin_Html
60/*
61<img src="picts/AliGeneratorClass.gif">
62</pre>
63<br clear=left>
64<font size=+2 color=red>
65<p>The responsible person for this module is
66<a href="mailto:andreas.morsch@cern.ch">Andreas Morsch</a>.
67</font>
68<pre>
69*/
70//End_Html
71// //
72///////////////////////////////////////////////////////////////////
73
74#include "AliGenHIJINGpara.h"
971816d4 75#include "AliGenEventHeader.h"
790bbabf 76#include "AliRun.h"
77#include "AliConst.h"
78#include "AliPDG.h"
79
971816d4 80#include <TF1.h>
81#include <TArrayF.h>
82
790bbabf 83ClassImp(AliGenHIJINGpara)
84
85AliGenHIJINGpara::AliGenHIJINGpara(const AliGenHIJINGpara & para)
86{
87// copy constructor
88}
89
90//_____________________________________________________________________________
91static Double_t ptpi(Double_t *px, Double_t *)
92{
93 //
94 // PT-PARAMETERIZATION CDF, PRL 61(88) 1819
95 // POWER LAW FOR PT > 500 MEV
96 // MT SCALING BELOW (T=160 MEV)
97 //
98 const Double_t kp0 = 1.3;
99 const Double_t kxn = 8.28;
100 const Double_t kxlim=0.5;
101 const Double_t kt=0.160;
102 const Double_t kxmpi=0.139;
103 const Double_t kb=1.;
104 Double_t y, y1, xmpi2, ynorm, a;
105 Double_t x=*px;
106 //
107 y1=TMath::Power(kp0/(kp0+kxlim),kxn);
108 xmpi2=kxmpi*kxmpi;
109 ynorm=kb*(TMath::Exp(-sqrt(kxlim*kxlim+xmpi2)/kt));
110 a=ynorm/y1;
111 if (x > kxlim)
112 y=a*TMath::Power(kp0/(kp0+x),kxn);
113 else
114 y=kb*TMath::Exp(-sqrt(x*x+xmpi2)/kt);
115 return y*x;
116}
117
118//_____________________________________________________________________________
119static Double_t ptscal(Double_t pt, Int_t np)
120{
121 // SCALING EN MASSE PAR RAPPORT A PTPI
122 // MASS PI,K,ETA,RHO,OMEGA,ETA',PHI
123 const Double_t khm[10] = {.13957,.493,.5488,.769,.7826,.958,1.02,0,0,0};
124 // VALUE MESON/PI AT 5 GEV
125 const Double_t kfmax[10]={1.,0.3,0.55,1.0,1.0,1.0,1.0,0,0,0};
126 np--;
127 Double_t f5=TMath::Power(((
128 sqrt(100.018215)+2.)/(sqrt(100.+khm[np]*khm[np])+2.0)),12.3);
129 Double_t fmax2=f5/kfmax[np];
130 // PIONS
131 Double_t ptpion=100.*ptpi(&pt, (Double_t*) 0);
132 Double_t fmtscal=TMath::Power(((
133 sqrt(pt*pt+0.018215)+2.)/ (sqrt(pt*pt+khm[np]*khm[np])+2.0)),12.3)/
134 fmax2;
135 return fmtscal*ptpion;
136}
137
138//_____________________________________________________________________________
139static Double_t ptka( Double_t *px, Double_t *)
140{
141 //
142 // pt parametrisation for k
143 //
144 return ptscal(*px,2);
145}
146
147
148//_____________________________________________________________________________
149static Double_t etapic( Double_t *py, Double_t *)
150{
151 //
152 // eta parametrisation for pi
153 //
154 const Double_t ka1 = 4913.;
155 const Double_t ka2 = 1819.;
156 const Double_t keta1 = 0.22;
157 const Double_t keta2 = 3.66;
158 const Double_t kdeta1 = 1.47;
159 const Double_t kdeta2 = 1.51;
160 Double_t y=TMath::Abs(*py);
161 //
162 Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1);
163 Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2);
164 return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2);
165}
166
167//_____________________________________________________________________________
168static Double_t etakac( Double_t *py, Double_t *)
169{
170 //
171 // eta parametrisation for ka
172 //
173 const Double_t ka1 = 497.6;
174 const Double_t ka2 = 215.6;
175 const Double_t keta1 = 0.79;
176 const Double_t keta2 = 4.09;
177 const Double_t kdeta1 = 1.54;
178 const Double_t kdeta2 = 1.40;
179 Double_t y=TMath::Abs(*py);
180 //
181 Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1);
182 Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2);
183 return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2);
184}
185
186//_____________________________________________________________________________
187AliGenHIJINGpara::AliGenHIJINGpara()
188 :AliGenerator()
189{
190 //
191 // Default constructor
192 //
193 fPtpi = 0;
194 fPtka = 0;
195 fETApic = 0;
196 fETAkac = 0;
971816d4 197 SetCutVertexZ();
790bbabf 198}
199
200//_____________________________________________________________________________
201AliGenHIJINGpara::AliGenHIJINGpara(Int_t npart)
202 :AliGenerator(npart)
203{
204 //
205 // Standard constructor
206 //
207 fName="HIGINGpara";
208 fTitle="HIJING Parametrisation Particle Generator";
209 fPtpi = 0;
210 fPtka = 0;
211 fETApic = 0;
212 fETAkac = 0;
971816d4 213 SetCutVertexZ();
790bbabf 214}
215
216//_____________________________________________________________________________
217AliGenHIJINGpara::~AliGenHIJINGpara()
218{
219 //
220 // Standard destructor
221 //
222 delete fPtpi;
223 delete fPtka;
224 delete fETApic;
225 delete fETAkac;
226}
227
228//_____________________________________________________________________________
229void AliGenHIJINGpara::Init()
230{
231 //
232 // Initialise the HIJING parametrisation
233 //
234 Float_t etaMin =-TMath::Log(TMath::Tan(
235 TMath::Min((Double_t)fThetaMax/2,TMath::Pi()/2-1.e-10)));
236 Float_t etaMax = -TMath::Log(TMath::Tan(
237 TMath::Max((Double_t)fThetaMin/2,1.e-10)));
f25521b2 238 fPtpi = new TF1("ptpi",&ptpi,0,20,0);
239 fPtka = new TF1("ptka",&ptka,0,20,0);
790bbabf 240 fETApic = new TF1("etapic",&etapic,etaMin,etaMax,0);
241 fETAkac = new TF1("etakac",&etakac,etaMin,etaMax,0);
f25521b2 242
790bbabf 243 TF1 *etaPic0 = new TF1("etapic",&etapic,-7,7,0);
244 TF1 *etaKac0 = new TF1("etakac",&etakac,-7,7,0);
f25521b2 245
246 TF1 *ptPic0 = new TF1("ptpi",&ptpi,0.,15.,0);
247 TF1 *ptKac0 = new TF1("ptka",&ptka,0.,15.,0);
248
790bbabf 249 Float_t intETApi = etaPic0->Integral(-0.5, 0.5);
250 Float_t intETAka = etaKac0->Integral(-0.5, 0.5);
f25521b2 251 Float_t scalePi = 7316/(intETApi/1.5);
252 Float_t scaleKa = 684/(intETAka/2.0);
253
254// Fraction of events corresponding to the selected pt-range
255 Float_t intPt = (0.877*ptPic0->Integral(0, 15)+
256 0.123*ptKac0->Integral(0, 15));
257 Float_t intPtSel = (0.877*ptPic0->Integral(fPtMin, fPtMax)+
258 0.123*ptKac0->Integral(fPtMin, fPtMax));
259 Float_t ptFrac = intPtSel/intPt;
260
261// Fraction of events corresponding to the selected eta-range
790bbabf 262 Float_t intETASel = (scalePi*etaPic0->Integral(etaMin, etaMax)+
263 scaleKa*etaKac0->Integral(etaMin, etaMax));
f25521b2 264// Fraction of events corresponding to the selected phi-range
265 Float_t phiFrac = (fPhiMax-fPhiMin)/2/TMath::Pi();
266
267 fParentWeight = Float_t(fNpart)/(intETASel*ptFrac*phiFrac);
790bbabf 268
9e1a0ddb 269 printf("%s: The number of particles in the selected kinematic region corresponds to %f percent of a full event\n ",
270 ClassName(),100.*fParentWeight);
5b0e4c0f 271
272// Issue warning message if etaMin or etaMax are outside the alowed range
273// of the parametrization
274 if (etaMin < -8.001 || etaMax > 8.001) {
275 printf("\n \n WARNING FROM AliGenHIJINGPara !");
276 printf("\n YOU ARE USING THE PARAMETERISATION OUTSIDE ");
277 printf("\n THE ALLOWED PSEUDORAPIDITY RANGE (-8. - 8.)");
278 printf("\n YOUR LIMITS: %f %f \n \n ", etaMin, etaMax);
279 }
790bbabf 280}
281
282//_____________________________________________________________________________
283void AliGenHIJINGpara::Generate()
284{
285 //
286 // Generate one trigger
287 //
288
289
290 const Float_t kRaKpic=0.14;
291 const Float_t kBorne=1/(1+kRaKpic);
292 Float_t polar[3]= {0,0,0};
293 //
294 const Int_t kPions[3] = {kPi0, kPiPlus, kPiMinus};
295 const Int_t kKaons[4] = {kK0Long, kK0Short, kKPlus, kKMinus};
296 //
297 Float_t origin[3];
298 Float_t pt, pl, ptot;
299 Float_t phi, theta;
300 Float_t p[3];
301 Int_t i, part, nt, j;
302 //
303 TF1 *ptf;
304 TF1 *etaf;
305 //
306 Float_t random[6];
307 //
308 for (j=0;j<3;j++) origin[j]=fOrigin[j];
971816d4 309
310 if(fVertexSmear == kPerEvent) {
311 Float_t dv[3];
312 dv[2] = 1.e10;
313 while(TMath::Abs(dv[2]) > fCutVertexZ*fOsigma[2]) {
314 Rndm(random,6);
315 for (j=0; j < 3; j++) {
316 dv[j] = fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
317 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
318 }
790bbabf 319 }
971816d4 320 for (j=0; j < 3; j++) origin[j] += dv[j];
321 } // if kPerEvent
322 TArrayF eventVertex;
323 eventVertex.Set(3);
324 eventVertex[0] = origin[0];
325 eventVertex[1] = origin[1];
326 eventVertex[2] = origin[2];
327
790bbabf 328 for(i=0;i<fNpart;i++) {
329 while(1) {
65fb704d 330 Rndm(random,3);
790bbabf 331 if(random[0]<kBorne) {
332 part=kPions[Int_t (random[1]*3)];
333 ptf=fPtpi;
334 etaf=fETApic;
335 } else {
336 part=kKaons[Int_t (random[1]*4)];
337 ptf=fPtka;
338 etaf=fETAkac;
339 }
340 phi=fPhiMin+random[2]*(fPhiMax-fPhiMin);
341 theta=2*TMath::ATan(TMath::Exp(-etaf->GetRandom()));
342 if(theta<fThetaMin || theta>fThetaMax) continue;
343 pt=ptf->GetRandom();
344 pl=pt/TMath::Tan(theta);
345 ptot=TMath::Sqrt(pt*pt+pl*pl);
346 if(ptot<fPMin || ptot>fPMax) continue;
347 p[0]=pt*TMath::Cos(phi);
348 p[1]=pt*TMath::Sin(phi);
349 p[2]=pl;
aee8290b 350 if(fVertexSmear==kPerTrack) {
65fb704d 351 Rndm(random,6);
790bbabf 352 for (j=0;j<3;j++) {
353 origin[j]=fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
354 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
355 }
356 }
a99cf51f 357 SetTrack(fTrackIt,-1,part,p,origin,polar,0,kPPrimary,nt,fParentWeight);
790bbabf 358 break;
359 }
360 }
971816d4 361// Header
362 AliGenEventHeader* header = new AliGenEventHeader("HIJINGparam");
363// Event Vertex
364 header->SetPrimaryVertex(eventVertex);
365 gAlice->SetGenEventHeader(header);
790bbabf 366}
367
368AliGenHIJINGpara& AliGenHIJINGpara::operator=(const AliGenHIJINGpara& rhs)
369{
370// Assignment operator
371 return *this;
372}
373
374