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ReadDecayTable() and WriteDecayTable() methods added.
[u/mrichter/AliRoot.git] / EVGEN / AliGenSTRANGElib.cxx
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87f8f72e 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//======================================================================
18// AliGenSTRANGElib class contains parameterizations of the
19// kaon, phi and hyperon (Lambda, Anti-Lambda, Xi, anti-Xi, Omega,
20// anti-Omega) for the PPR study of the strange particle production.
21// These parameterizations are used by the
22// AliGenParam class:
23// AliGenParam(npar, param, AliGenSTRANGElib::GetPt(param),
24// AliGenSTRANGElib::GetY(param),
25// AliGenSTRANGElib::GetIp(param) )
26// param represents the particle to be simulated.
27// ?????????
28// Pt distributions are calculated from the transverse mass scaling
29// with Pions, using the PtScal function taken from AliGenMUONlib
30// version aliroot 3.01
31//
32// Rocco CALIANDRO. Rosa Anna FINI, Tiziano VIRGILI
33// Rocco.Caliandro@cern.ch Rosanna.Fini@ba.infn.it,
34// Tiziano.Virgili@roma1.infn.it
35//======================================================================
36
37/*
38$Log$
39*/
40
41#include "TMath.h"
42#include "TRandom.h"
43
44#include "AliGenSTRANGElib.h"
45
46ClassImp(AliGenSTRANGElib)
47
48//=============================================================
49//
50 Double_t AliGenSTRANGElib::PtScal(Double_t pt, Int_t np)
51{
52// Mt-scaling
53// Function for the calculation of the Pt distribution for a
54// given particle np, from the pion Pt distribution using the
55// mt scaling. This function was taken from AliGenMUONlib
56// aliroot version 3.01, and was extended for hyperons.
57// np = 1=>Pions 2=>Kaons 3=>Etas 4=>Omegas 5=>ETA' 6=>PHI
58// 7=>BARYONS-BARYONBARS
59// 8=>Lambda-antiLambda
60// 9=>Xi-antiXi
61// 10=>Omega-antiOmega
62
63 // MASS SCALING RESPECT TO PIONS
64 // MASS 1=>PI, 2=>K, 3=>ETA,4=>OMEGA,5=>ETA',6=>PHI
65 const Double_t khm[10] = {0.1396, 0.494,0.547, 0.782, 0.957, 1.02,
66 // MASS 7=>BARYON-BARYONBAR
67 0.938,
68 // MASS 8=>Lambda-antiLambda
69 1.1157,
70 // MASS 9=>Xi-antiXi
71 1.3213,
72 // MASS 10=>Omega-antiOmega
73 1.6725};
74 // VALUE MESON/PI AT 5 GEV
75 const Double_t kfmax[10]={1., 1., 1., 1., 1., 1., 1., 1., 1., 1.};
76 np--;
77 Double_t f5=TMath::Power(((sqrt(100.018215)+2.)/(sqrt(100.+khm[np]*khm[np])+2.0)),12.3);
78 Double_t kfmax2=f5/kfmax[np];
79 // PIONS
80 Double_t ptpion=100.*PtPion(&pt, (Double_t*) 0);
81 Double_t fmtscal=TMath::Power(((sqrt(pt*pt+0.018215)+2.)/
82 (sqrt(pt*pt+khm[np]*khm[np])+2.0)),12.3)/ kfmax2;
83 return fmtscal*ptpion;
84}
85//=============================================================
86//
87 Double_t AliGenSTRANGElib::PtPion(Double_t *px, Double_t *)
88{
89// Pion transverse momentum distribtuion taken
90// from AliGenMUONlib class, version 3.01 of aliroot
91// PT-PARAMETERIZATION CDF, PRL 61(88) 1819
92// POWER LAW FOR PT > 500 MEV
93// MT SCALING BELOW (T=160 MEV)
94//
95 const Double_t kp0 = 1.3;
96 const Double_t kxn = 8.28;
97 const Double_t kxlim=0.5;
98 const Double_t kt=0.160;
99 const Double_t kxmpi=0.139;
100 const Double_t kb=1.;
101 Double_t y, y1, kxmpi2, ynorm, a;
102 Double_t x=*px;
103 //
104 y1=TMath::Power(kp0/(kp0+kxlim),kxn);
105 kxmpi2=kxmpi*kxmpi;
106 ynorm=kb*(TMath::Exp(-sqrt(kxlim*kxlim+kxmpi2)/kt));
107 a=ynorm/y1;
108 if (x > kxlim)
109 y=a*TMath::Power(kp0/(kp0+x),kxn);
110 else
111 y=kb*TMath::Exp(-sqrt(x*x+kxmpi2)/kt);
112 return y*x;
113}
114// End Scaling
115//============================================================================
116// K A O N
117 Double_t AliGenSTRANGElib::PtKaon( Double_t *px, Double_t *)
118{
119// kaon
120// pt-distribution
121//____________________________________________________________
122
123 return PtScal(*px,2); // 2==> Kaon in the PtScal function
124}
125
126 Double_t AliGenSTRANGElib::YKaon( Double_t *py, Double_t *)
127{
128// y-distribution
129//____________________________________________________________
130
131 const Double_t ka = 1000.;
132 const Double_t kdy = 4.;
133
134
135 Double_t y=TMath::Abs(*py);
136 //
137 Double_t ex = y*y/(2*kdy*kdy);
138 return ka*TMath::Exp(-ex);
139}
140
141 Int_t AliGenSTRANGElib::IpKaon(TRandom *ran)
142{
143// particle composition
144//
145
146 Float_t random = ran->Rndm();
147 Float_t random2 = ran->Rndm();
148 if (random2 < 0.5)
149 {
150 if (random < 0.5) {
151 return 321; // K+
152 } else {
153 return -321; // K-
154 }
155 }
156 else
157 {
158 if (random < 0.5) {
159 return 130; // K^0 short
160 } else {
161 return 310; // K^0 long
162 }
163 }
164}
165// End Kaons
166//============================================================================
167//============================================================================
168// P H I
169 Double_t AliGenSTRANGElib::PtPhi( Double_t *px, Double_t *)
170{
171// phi
172// pt-distribution
173//____________________________________________________________
174
175 return PtScal(*px,6); // 6==> Phi in the PtScal function
176}
177
178 Double_t AliGenSTRANGElib::YPhi( Double_t *py, Double_t *)
179{
180// y-distribution
181//____________________________________________________________
182
183 const Double_t ka = 1000.;
184 const Double_t kdy = 4.;
185
186
187 Double_t y=TMath::Abs(*py);
188 //
189 Double_t ex = y*y/(2*kdy*kdy);
190 return ka*TMath::Exp(-ex);
191}
192
193 Int_t AliGenSTRANGElib::IpPhi(TRandom *)
194{
195// particle composition
196//
197
198 return 333; // Phi
199}
200// End Phis
201//===================================================================
202//============================================================================
203// Lambda
204 Double_t AliGenSTRANGElib::PtLambda( Double_t *px, Double_t *)
205{
206// Lambda
207// pt-distribution
208//____________________________________________________________
209
210 return PtScal(*px,8); // 8==> Lambda-antiLambda in the PtScal function
211}
212
213 Double_t AliGenSTRANGElib::YLambda( Double_t *py, Double_t *)
214{
215// y-distribution
216//____________________________________________________________
217
218 const Double_t ka = 1000.;
219 const Double_t kdy = 4.;
220
221
222 Double_t y=TMath::Abs(*py);
223 //
224 Double_t ex = y*y/(2*kdy*kdy);
225 return ka*TMath::Exp(-ex);
226}
227
228 Int_t AliGenSTRANGElib::IpLambda(TRandom *)
229{
230// particle composition
231// generation of fixed type of particle
232//
233
234 return 3122; // Lambda
235}
236// End Lambda
237//============================================================================
238// XIminus
239 Double_t AliGenSTRANGElib::PtXiMinus( Double_t *px, Double_t *)
240{
241// Xi
242// pt-distribution
243//____________________________________________________________
244
245 return PtScal(*px,9); // 9==> Xi-antiXi in the PtScal function
246}
247
248 Double_t AliGenSTRANGElib::YXiMinus( Double_t *py, Double_t *)
249{
250// y-distribution
251//____________________________________________________________
252
253 const Double_t ka = 1000.;
254 const Double_t kdy = 4.;
255
256
257 Double_t y=TMath::Abs(*py);
258 //
259 Double_t ex = y*y/(2*kdy*kdy);
260 return ka*TMath::Exp(-ex);
261}
262
263 Int_t AliGenSTRANGElib::IpXiMinus(TRandom *)
264{
265// particle composition
266// generation of fixed type of particle
267//
268
269 return 3312; // Xi- (only)
270// return -3312; // Xi+
271}
272// End Ximinus
273//============================================================================
274// Omegaminus
275 Double_t AliGenSTRANGElib::PtOmegaMinus( Double_t *px, Double_t *)
276{
277// Omega
278// pt-distribution
279//____________________________________________________________
280
281 return PtScal(*px,10); // 10==> Omega-antiOmega in the PtScal function
282}
283
284 Double_t AliGenSTRANGElib::YOmegaMinus( Double_t *py, Double_t *)
285{
286// y-distribution
287//____________________________________________________________
288
289 const Double_t ka = 1000.;
290 const Double_t kdy = 4.;
291
292
293 Double_t y=TMath::Abs(*py);
294 //
295 Double_t ex = y*y/(2*kdy*kdy);
296 return ka*TMath::Exp(-ex);
297}
298
299 Int_t AliGenSTRANGElib::IpOmegaMinus(TRandom *)
300{
301// particle composition
302// generation of fixed type of particle
303//
304
305 return 3334; // Omega-
306}
307// End Omegaminus
308//============================================================================
309
310
311typedef Double_t (*GenFunc) (Double_t*, Double_t*);
312 GenFunc AliGenSTRANGElib::GetPt(Int_t param, const char* tname)
313{
314// Return pinter to pT parameterisation
315 GenFunc func;
316
317 switch (param)
318 {
319 case kKaon:
320 func=PtKaon;
321 break;
322 case kPhi:
323 func=PtPhi;
324 break;
325 case kLambda:
326 func=PtLambda;
327 break;
328 case kXiMinus:
329 func=PtXiMinus;
330 break;
331 case kOmegaMinus:
332 func=PtOmegaMinus;
333 break;
334 default:
335 func=0;
336 printf("<AliGenSTRANGElib::GetPt> unknown parametrisationn");
337 }
338 return func;
339}
340
341 GenFunc AliGenSTRANGElib::GetY(Int_t param, const char* tname)
342{
343// Return pointer to Y parameterisation
344 GenFunc func;
345 switch (param)
346 {
347 case kKaon:
348 func=YKaon;
349 break;
350 case kPhi:
351 func=YPhi;
352 break;
353 case kLambda:
354 func=YLambda;
355 break;
356 case kXiMinus:
357 func=YXiMinus;
358 break;
359 case kOmegaMinus:
360 func=YOmegaMinus;
361 break;
362 default:
363 func=0;
364 printf("<AliGenSTRANGElib::GetY> unknown parametrisationn");
365 }
366 return func;
367}
368typedef Int_t (*GenFuncIp) (TRandom *);
369 GenFuncIp AliGenSTRANGElib::GetIp(Int_t param, const char* tname)
370{
371// Return pointer to particle composition
372 GenFuncIp func;
373 switch (param)
374 {
375 case kKaon:
376 func=IpKaon;
377 break;
378 case kPhi:
379 func=IpPhi;
380 break;
381 case kLambda:
382 func=IpLambda;
383 break;
384 case kXiMinus:
385 func=IpXiMinus;
386 break;
387 case kOmegaMinus:
388 func=IpOmegaMinus;
389 break;
390 default:
391 func=0;
392 printf("<AliGenSTRANGElib::GetIp> unknown parametrisationn");
393 }
394 return func;
395}
396