]>
Commit | Line | Data |
---|---|---|
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 | ||
16 | /* | |
17 | $Log$ | |
18 | */ | |
19 | /////////////////////////////////////////////////////////////////// | |
20 | // Parameterisation of pi, K, n and p eta and pt distributions // | |
21 | // eta: according to HIJING (shadowing + quenching) // | |
22 | // pT : according to CDF measurement at 1.8 TeV // | |
23 | // Author: andreas.morsch@cern.ch // | |
24 | // // | |
25 | /////////////////////////////////////////////////////////////////// | |
26 | ||
27 | #include "AliGenHIJINGparaBa.h" | |
28 | #include "AliGenEventHeader.h" | |
29 | #include "AliRun.h" | |
30 | #include "AliConst.h" | |
31 | #include "AliPDG.h" | |
32 | ||
33 | #include <TF1.h> | |
34 | #include <TArrayF.h> | |
35 | ||
36 | ClassImp(AliGenHIJINGparaBa) | |
37 | ||
38 | ||
39 | static Double_t ptpi(Double_t *px, Double_t *) | |
40 | { | |
41 | // | |
42 | // PT-PARAMETERIZATION CDF, PRL 61(88) 1819 | |
43 | // POWER LAW FOR PT > 500 MEV | |
44 | // MT SCALING BELOW (T=160 MEV) | |
45 | // | |
46 | const Double_t kp0 = 1.3; | |
47 | const Double_t kxn = 8.28; | |
48 | const Double_t kxlim=0.5; | |
49 | const Double_t kt=0.160; | |
50 | const Double_t kxmpi=0.139; | |
51 | const Double_t kb=1.; | |
52 | Double_t y, y1, xmpi2, ynorm, a; | |
53 | Double_t x=*px; | |
54 | // | |
55 | y1=TMath::Power(kp0/(kp0+kxlim),kxn); | |
56 | xmpi2=kxmpi*kxmpi; | |
57 | ynorm=kb*(TMath::Exp(-sqrt(kxlim*kxlim+xmpi2)/kt)); | |
58 | a=ynorm/y1; | |
59 | if (x > kxlim) | |
60 | y=a*TMath::Power(kp0/(kp0+x),kxn); | |
61 | else | |
62 | y=kb*TMath::Exp(-sqrt(x*x+xmpi2)/kt); | |
63 | return y*x; | |
64 | } | |
65 | ||
66 | //_____________________________________________________________________________ | |
67 | static Double_t ptscal(Double_t pt, Int_t np) | |
68 | { | |
69 | // SCALING EN MASSE PAR RAPPORT A PTPI | |
70 | // MASS PI,K,ETA,RHO,OMEGA,ETA',PHI | |
71 | const Double_t khm[10] = {.13957,.493,.5488,.769,.7826,.958,1.02,0,0,0}; | |
72 | // VALUE MESON/PI AT 5 GEV | |
73 | const Double_t kfmax[10]={1.,0.3,0.55,1.0,1.0,1.0,1.0,0,0,0}; | |
74 | np--; | |
75 | Double_t f5=TMath::Power((( | |
76 | sqrt(100.018215)+2.)/(sqrt(100.+khm[np]*khm[np])+2.0)),12.3); | |
77 | Double_t fmax2=f5/kfmax[np]; | |
78 | // PIONS | |
79 | Double_t ptpion=100.*ptpi(&pt, (Double_t*) 0); | |
80 | Double_t fmtscal=TMath::Power((( | |
81 | sqrt(pt*pt+0.018215)+2.)/ (sqrt(pt*pt+khm[np]*khm[np])+2.0)),12.3)/ | |
82 | fmax2; | |
83 | return fmtscal*ptpion; | |
84 | } | |
85 | ||
86 | //_____________________________________________________________________________ | |
87 | static Double_t ptka( Double_t *px, Double_t *) | |
88 | { | |
89 | // | |
90 | // pt parametrisation for k | |
91 | // | |
92 | return ptscal(*px,2); | |
93 | } | |
94 | ||
95 | ||
96 | //_____________________________________________________________________________ | |
97 | static Double_t etapic( Double_t *py, Double_t *) | |
98 | { | |
99 | // | |
100 | // eta parametrisation for pi | |
101 | // | |
102 | const Double_t ka1 = 4913.; | |
103 | const Double_t ka2 = 1819.; | |
104 | const Double_t keta1 = 0.22; | |
105 | const Double_t keta2 = 3.66; | |
106 | const Double_t kdeta1 = 1.47; | |
107 | const Double_t kdeta2 = 1.51; | |
108 | Double_t y=TMath::Abs(*py); | |
109 | // | |
110 | Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1); | |
111 | Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2); | |
112 | return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2); | |
113 | } | |
114 | ||
115 | //_____________________________________________________________________________ | |
116 | static Double_t etakac( Double_t *py, Double_t *) | |
117 | { | |
118 | // | |
119 | // eta parametrisation for ka | |
120 | // | |
121 | const Double_t ka1 = 497.6; | |
122 | const Double_t ka2 = 215.6; | |
123 | const Double_t keta1 = 0.79; | |
124 | const Double_t keta2 = 4.09; | |
125 | const Double_t kdeta1 = 1.54; | |
126 | const Double_t kdeta2 = 1.40; | |
127 | Double_t y=TMath::Abs(*py); | |
128 | // | |
129 | Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1); | |
130 | Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2); | |
131 | return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2); | |
132 | } | |
133 | ||
134 | static Double_t ptbaryon( Double_t *px, Double_t *) | |
135 | { | |
136 | // baryons | |
137 | // pt-distribution | |
138 | //____________________________________________________________ | |
139 | ||
140 | return ptscal(*px,7); // 7==> Baryon in the PtScal function | |
141 | } | |
142 | ||
143 | static Double_t etabaryon( Double_t *py, Double_t *) | |
144 | { | |
145 | // eta-distribution | |
146 | //____________________________________________________________ | |
147 | const Float_t p0 = 1.10343e+02; | |
148 | const Float_t p1 = 1.73247e+01; | |
149 | const Float_t p2 = -7.23808e+00; | |
150 | const Float_t p3 = 4.48334e-01; | |
151 | const Double_t y = TMath::Abs(*py); | |
152 | // | |
153 | return (p0+p1*y+p2*y*y+p3*y*y*y)/20.; | |
154 | } | |
155 | ||
156 | AliGenHIJINGparaBa::AliGenHIJINGparaBa() | |
157 | :AliGenHIJINGpara() | |
158 | { | |
159 | // | |
160 | // Default constructor | |
161 | // | |
162 | fName="HIGINGparaBa"; | |
163 | fTitle="HIJING Parametrisation Particle Generator with Baryons"; | |
164 | fETAba = 0; | |
165 | fPtba = 0; | |
166 | } | |
167 | ||
168 | //_____________________________________________________________________________ | |
169 | AliGenHIJINGparaBa::AliGenHIJINGparaBa(Int_t npart) | |
170 | :AliGenHIJINGpara(npart) | |
171 | { | |
172 | // | |
173 | // Standard constructor | |
174 | // | |
175 | fName="HIGINGparaBa"; | |
176 | fTitle="HIJING Parametrisation Particle Generator with Baryons"; | |
177 | fETAba = 0; | |
178 | fPtba = 0; | |
179 | } | |
180 | ||
181 | //_____________________________________________________________________________ | |
182 | AliGenHIJINGparaBa::~AliGenHIJINGparaBa() | |
183 | { | |
184 | // | |
185 | // Standard destructor | |
186 | // | |
187 | delete fPtba; | |
188 | delete fETAba; | |
189 | } | |
190 | ||
191 | //_____________________________________________________________________________ | |
192 | void AliGenHIJINGparaBa::Init() | |
193 | { | |
194 | // | |
195 | // Initialise the HIJING parametrisation | |
196 | // | |
197 | Float_t etaMin =-TMath::Log(TMath::Tan( | |
198 | TMath::Min((Double_t)fThetaMax/2,TMath::Pi()/2-1.e-10))); | |
199 | Float_t etaMax = -TMath::Log(TMath::Tan( | |
200 | TMath::Max((Double_t)fThetaMin/2,1.e-10))); | |
201 | fPtpi = new TF1("ptpi",&ptpi,0,20,0); | |
202 | fPtka = new TF1("ptka",&ptka,0,20,0); | |
203 | fPtba = new TF1("ptbaryon",&ptbaryon,0,20,0); | |
204 | fETApic = new TF1("etapic",&etapic,etaMin,etaMax,0); | |
205 | fETAkac = new TF1("etakac",&etakac,etaMin,etaMax,0); | |
206 | fETAba = new TF1("etabaryon",&etabaryon,etaMin,etaMax,0); | |
207 | ||
208 | TF1 *etaPic0 = new TF1("etapic",&etapic, -7, 7, 0); | |
209 | TF1 *etaKac0 = new TF1("etakac",&etakac, -7, 7, 0); | |
210 | TF1 *etaBar0 = new TF1("etabar",&etabaryon, -7, 7, 0); | |
211 | ||
212 | TF1 *ptPic0 = new TF1("ptpi", &ptpi, 0., 15., 0); | |
213 | TF1 *ptKac0 = new TF1("ptka", &ptka, 0., 15., 0); | |
214 | TF1 *ptBar0 = new TF1("ptbar", &ptbaryon, 0., 15., 0); | |
215 | ||
216 | Float_t intETApi = etaPic0->Integral(-0.5, 0.5); | |
217 | Float_t intETAka = etaKac0->Integral(-0.5, 0.5); | |
218 | Float_t intETAba = etaBar0->Integral(-0.5, 0.5); | |
219 | ||
220 | Float_t scalePi = 6979./(intETApi/1.5); | |
221 | Float_t scaleKa = 657./(intETAka/2.0); | |
222 | Float_t scaleBa = 364./(intETAba/2.0); | |
223 | ||
224 | // Fraction of events corresponding to the selected pt-range | |
225 | Float_t intPt = (0.837*ptPic0->Integral(0, 15)+ | |
226 | 0.105*ptKac0->Integral(0, 15)+ | |
227 | 0.058*ptBar0->Integral(0, 15)); | |
228 | Float_t intPtSel = (0.837*ptPic0->Integral(fPtMin, fPtMax)+ | |
229 | 0.105*ptKac0->Integral(fPtMin, fPtMax)+ | |
230 | 0.058*ptBar0->Integral(fPtMin, fPtMax)); | |
231 | Float_t ptFrac = intPtSel/intPt; | |
232 | ||
233 | // Fraction of events corresponding to the selected eta-range | |
234 | Float_t intETASel = (scalePi*etaPic0->Integral(etaMin, etaMax)+ | |
235 | scaleKa*etaKac0->Integral(etaMin, etaMax)+ | |
236 | scaleBa*etaBar0->Integral(etaMin, etaMax)); | |
237 | // Fraction of events corresponding to the selected phi-range | |
238 | Float_t phiFrac = (fPhiMax-fPhiMin)/2/TMath::Pi(); | |
239 | ||
240 | fParentWeight = Float_t(fNpart)/(intETASel*ptFrac*phiFrac); | |
241 | ||
242 | printf("%s: The number of particles in the selected kinematic region corresponds to %f percent of a full event \n", | |
243 | ClassName(),100.*fParentWeight); | |
244 | ||
245 | // Issue warning message if etaMin or etaMax are outside the alowed range | |
246 | // of the parametrization | |
247 | if (etaMin < -8.001 || etaMax > 8.001) { | |
248 | printf("\n \n WARNING FROM AliGenHIJINGParaBa !"); | |
249 | printf("\n YOU ARE USING THE PARAMETERISATION OUTSIDE "); | |
250 | printf("\n THE ALLOWED PSEUDORAPIDITY RANGE (-8. - 8.)"); | |
251 | printf("\n YOUR LIMITS: %f %f \n \n ", etaMin, etaMax); | |
252 | } | |
253 | } | |
254 | ||
255 | //_____________________________________________________________________________ | |
256 | void AliGenHIJINGparaBa::Generate() | |
257 | { | |
258 | // | |
259 | // Generate one trigger | |
260 | // | |
261 | ||
262 | ||
263 | const Float_t kBorne1 = 0.837; | |
264 | const Float_t kBorne2 = kBorne1+0.105; | |
265 | ||
266 | Float_t polar[3]= {0,0,0}; | |
267 | // | |
268 | const Int_t kPions[3] = {kPi0, kPiPlus, kPiMinus}; | |
269 | const Int_t kKaons[4] = {kK0Long, kK0Short, kKPlus, kKMinus}; | |
270 | const Int_t kBaryons[4] = {kProton, kProtonBar, kNeutron, kNeutronBar}; | |
271 | // | |
272 | Float_t origin[3]; | |
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]; | |
284 | ||
285 | if(fVertexSmear == kPerEvent) { | |
286 | Float_t dv[3]; | |
287 | dv[2] = 1.e10; | |
288 | while(TMath::Abs(dv[2]) > fCutVertexZ*fOsigma[2]) { | |
289 | Rndm(random,6); | |
290 | for (j=0; j < 3; j++) { | |
291 | dv[j] = fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())* | |
292 | TMath::Sqrt(-2*TMath::Log(random[2*j+1])); | |
293 | } | |
294 | } | |
295 | for (j=0; j < 3; j++) origin[j] += dv[j]; | |
296 | } // if kPerEvent | |
297 | TArrayF eventVertex; | |
298 | eventVertex.Set(3); | |
299 | eventVertex[0] = origin[0]; | |
300 | eventVertex[1] = origin[1]; | |
301 | eventVertex[2] = origin[2]; | |
302 | ||
303 | for(i=0;i<fNpart;i++) { | |
304 | while(1) { | |
305 | Rndm(random,3); | |
306 | if(random[0] < kBorne1) { | |
307 | part = kPions[Int_t (random[1]*3)]; | |
308 | ptf = fPtpi; | |
309 | etaf = fETApic; | |
310 | } else if (random[0] < kBorne2) { | |
311 | part = kKaons[Int_t (random[1]*4)]; | |
312 | ptf = fPtka; | |
313 | etaf = fETAkac; | |
314 | } else { | |
315 | part = kBaryons[Int_t (random[1]*4)]; | |
316 | ptf = fPtba; | |
317 | etaf = fETAba; | |
318 | } | |
319 | ||
320 | phi=fPhiMin+random[2]*(fPhiMax-fPhiMin); | |
321 | theta=2*TMath::ATan(TMath::Exp(-etaf->GetRandom())); | |
322 | if(theta<fThetaMin || theta>fThetaMax) continue; | |
323 | pt=ptf->GetRandom(); | |
324 | pl=pt/TMath::Tan(theta); | |
325 | ptot=TMath::Sqrt(pt*pt+pl*pl); | |
326 | if(ptot<fPMin || ptot>fPMax) continue; | |
327 | p[0]=pt*TMath::Cos(phi); | |
328 | p[1]=pt*TMath::Sin(phi); | |
329 | p[2]=pl; | |
330 | if(fVertexSmear==kPerTrack) { | |
331 | Rndm(random,6); | |
332 | for (j=0;j<3;j++) { | |
333 | origin[j]=fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())* | |
334 | TMath::Sqrt(-2*TMath::Log(random[2*j+1])); | |
335 | } | |
336 | } | |
337 | SetTrack(fTrackIt,-1,part,p,origin,polar,0,kPPrimary,nt,fParentWeight); | |
338 | break; | |
339 | } // while(1) | |
340 | } // Particle loop | |
341 | // Header | |
342 | AliGenEventHeader* header = new AliGenEventHeader("HIJINGparam"); | |
343 | // Event Vertex | |
344 | header->SetPrimaryVertex(eventVertex); | |
345 | gAlice->SetGenEventHeader(header); | |
346 | } | |
347 | ||
348 | ||
349 |