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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 | ||
ac3faee4 | 37 | /* $Id$ */ |
87f8f72e | 38 | |
7d245e03 | 39 | #include <TMath.h> |
7d245e03 | 40 | #include <TRandom.h> |
87f8f72e | 41 | |
42 | #include "AliGenSTRANGElib.h" | |
43 | ||
44 | ClassImp(AliGenSTRANGElib) | |
45 | ||
46 | //============================================================= | |
47 | // | |
48 | Double_t AliGenSTRANGElib::PtScal(Double_t pt, Int_t np) | |
49 | { | |
50 | // Mt-scaling | |
51 | // Function for the calculation of the Pt distribution for a | |
52 | // given particle np, from the pion Pt distribution using the | |
53 | // mt scaling. This function was taken from AliGenMUONlib | |
54 | // aliroot version 3.01, and was extended for hyperons. | |
55 | // np = 1=>Pions 2=>Kaons 3=>Etas 4=>Omegas 5=>ETA' 6=>PHI | |
56 | // 7=>BARYONS-BARYONBARS | |
57 | // 8=>Lambda-antiLambda | |
58 | // 9=>Xi-antiXi | |
59 | // 10=>Omega-antiOmega | |
60 | ||
61 | // MASS SCALING RESPECT TO PIONS | |
0db2f441 | 62 | // MASS 0=>PI, 1=>K, 2=>ETA,3=>OMEGA,4=>ETA',5=>PHI |
13313168 | 63 | const Double_t khm[11] = {0.1396, 0.494,0.547, 0.782, 0.957, 1.02, |
0db2f441 | 64 | // MASS 6=>BARYON-BARYONBAR |
87f8f72e | 65 | 0.938, |
0db2f441 | 66 | // MASS 7=>Lambda-antiLambda |
87f8f72e | 67 | 1.1157, |
0db2f441 | 68 | // MASS 8=>Xi-antiXi |
87f8f72e | 69 | 1.3213, |
0db2f441 | 70 | // MASS 9=>Omega-antiOmega |
13313168 | 71 | 1.6725, |
0db2f441 | 72 | // MASS 10=>Lambda(1520) |
13313168 | 73 | 1.5195}; |
87f8f72e | 74 | // VALUE MESON/PI AT 5 GEV |
13313168 | 75 | const Double_t kfmax[11]={1., 1., 1., 1., 1., 1., 1., 1., 1., 1., 1.}; |
87f8f72e | 76 | Double_t f5=TMath::Power(((sqrt(100.018215)+2.)/(sqrt(100.+khm[np]*khm[np])+2.0)),12.3); |
77 | Double_t kfmax2=f5/kfmax[np]; | |
78 | // PIONS | |
79 | Double_t ptpion=100.*PtPion(&pt, (Double_t*) 0); | |
80 | Double_t fmtscal=TMath::Power(((sqrt(pt*pt+0.018215)+2.)/ | |
81 | (sqrt(pt*pt+khm[np]*khm[np])+2.0)),12.3)/ kfmax2; | |
82 | return fmtscal*ptpion; | |
83 | } | |
84 | //============================================================= | |
85 | // | |
75e0cc59 | 86 | Double_t AliGenSTRANGElib::PtPion(const Double_t *px, const Double_t *) |
87f8f72e | 87 | { |
88 | // Pion transverse momentum distribtuion taken | |
89 | // from AliGenMUONlib class, version 3.01 of aliroot | |
90 | // PT-PARAMETERIZATION CDF, PRL 61(88) 1819 | |
91 | // POWER LAW FOR PT > 500 MEV | |
92 | // MT SCALING BELOW (T=160 MEV) | |
93 | // | |
94 | const Double_t kp0 = 1.3; | |
95 | const Double_t kxn = 8.28; | |
96 | const Double_t kxlim=0.5; | |
97 | const Double_t kt=0.160; | |
98 | const Double_t kxmpi=0.139; | |
99 | const Double_t kb=1.; | |
100 | Double_t y, y1, kxmpi2, ynorm, a; | |
101 | Double_t x=*px; | |
102 | // | |
103 | y1=TMath::Power(kp0/(kp0+kxlim),kxn); | |
104 | kxmpi2=kxmpi*kxmpi; | |
105 | ynorm=kb*(TMath::Exp(-sqrt(kxlim*kxlim+kxmpi2)/kt)); | |
106 | a=ynorm/y1; | |
107 | if (x > kxlim) | |
108 | y=a*TMath::Power(kp0/(kp0+x),kxn); | |
109 | else | |
110 | y=kb*TMath::Exp(-sqrt(x*x+kxmpi2)/kt); | |
111 | return y*x; | |
112 | } | |
113 | // End Scaling | |
114 | //============================================================================ | |
115 | // K A O N | |
75e0cc59 | 116 | Double_t AliGenSTRANGElib::PtKaon( const Double_t *px, const Double_t *) |
87f8f72e | 117 | { |
118 | // kaon | |
119 | // pt-distribution | |
120 | //____________________________________________________________ | |
121 | ||
0db2f441 | 122 | return PtScal(*px,1); // 1==> Kaon in the PtScal function |
87f8f72e | 123 | } |
124 | ||
75e0cc59 | 125 | Double_t AliGenSTRANGElib::YKaon( const Double_t *py, const Double_t *) |
87f8f72e | 126 | { |
127 | // y-distribution | |
128 | //____________________________________________________________ | |
129 | ||
130 | const Double_t ka = 1000.; | |
131 | const Double_t kdy = 4.; | |
132 | ||
133 | ||
134 | Double_t y=TMath::Abs(*py); | |
135 | // | |
136 | Double_t ex = y*y/(2*kdy*kdy); | |
137 | return ka*TMath::Exp(-ex); | |
138 | } | |
139 | ||
140 | Int_t AliGenSTRANGElib::IpKaon(TRandom *ran) | |
141 | { | |
142 | // particle composition | |
143 | // | |
144 | ||
145 | Float_t random = ran->Rndm(); | |
146 | Float_t random2 = ran->Rndm(); | |
147 | if (random2 < 0.5) | |
148 | { | |
149 | if (random < 0.5) { | |
150 | return 321; // K+ | |
151 | } else { | |
152 | return -321; // K- | |
153 | } | |
154 | } | |
155 | else | |
156 | { | |
157 | if (random < 0.5) { | |
158 | return 130; // K^0 short | |
159 | } else { | |
160 | return 310; // K^0 long | |
161 | } | |
162 | } | |
163 | } | |
164 | // End Kaons | |
165 | //============================================================================ | |
166 | //============================================================================ | |
167 | // P H I | |
75e0cc59 | 168 | Double_t AliGenSTRANGElib::PtPhi( const Double_t *px, const Double_t *) |
87f8f72e | 169 | { |
170 | // phi | |
171 | // pt-distribution | |
172 | //____________________________________________________________ | |
173 | ||
0db2f441 | 174 | return PtScal(*px,5); // 5==> Phi in the PtScal function |
87f8f72e | 175 | } |
176 | ||
75e0cc59 | 177 | Double_t AliGenSTRANGElib::YPhi( const Double_t *py, const Double_t *) |
87f8f72e | 178 | { |
179 | // y-distribution | |
180 | //____________________________________________________________ | |
181 | ||
182 | const Double_t ka = 1000.; | |
183 | const Double_t kdy = 4.; | |
184 | ||
185 | ||
186 | Double_t y=TMath::Abs(*py); | |
187 | // | |
188 | Double_t ex = y*y/(2*kdy*kdy); | |
189 | return ka*TMath::Exp(-ex); | |
190 | } | |
191 | ||
192 | Int_t AliGenSTRANGElib::IpPhi(TRandom *) | |
193 | { | |
194 | // particle composition | |
195 | // | |
196 | ||
197 | return 333; // Phi | |
198 | } | |
199 | // End Phis | |
200 | //=================================================================== | |
201 | //============================================================================ | |
202 | // Lambda | |
75e0cc59 | 203 | Double_t AliGenSTRANGElib::PtLambda( const Double_t *px, const Double_t *) |
87f8f72e | 204 | { |
205 | // Lambda | |
206 | // pt-distribution | |
207 | //____________________________________________________________ | |
208 | ||
0db2f441 | 209 | return PtScal(*px,7); // 7==> Lambda-antiLambda in the PtScal function |
87f8f72e | 210 | } |
211 | ||
75e0cc59 | 212 | Double_t AliGenSTRANGElib::YLambda( const Double_t *py, const Double_t *) |
87f8f72e | 213 | { |
214 | // y-distribution | |
215 | //____________________________________________________________ | |
216 | ||
217 | const Double_t ka = 1000.; | |
218 | const Double_t kdy = 4.; | |
219 | ||
220 | ||
221 | Double_t y=TMath::Abs(*py); | |
222 | // | |
223 | Double_t ex = y*y/(2*kdy*kdy); | |
224 | return ka*TMath::Exp(-ex); | |
225 | } | |
226 | ||
48b91885 | 227 | Int_t AliGenSTRANGElib::IpLambda(TRandom *ran) |
87f8f72e | 228 | { |
229 | // particle composition | |
230 | // generation of fixed type of particle | |
231 | // | |
48b91885 | 232 | Float_t random = ran->Rndm(); |
233 | if (random < 0.5) { | |
234 | return 3122; // Lambda | |
235 | } else { | |
236 | return -3122; // Anti-Lambda | |
237 | } | |
87f8f72e | 238 | } |
239 | // End Lambda | |
240 | //============================================================================ | |
241 | // XIminus | |
75e0cc59 | 242 | Double_t AliGenSTRANGElib::PtXiMinus( const Double_t *px, const Double_t *) |
87f8f72e | 243 | { |
244 | // Xi | |
245 | // pt-distribution | |
246 | //____________________________________________________________ | |
247 | ||
0db2f441 | 248 | return PtScal(*px,8); // 8==> Xi-antiXi in the PtScal function |
87f8f72e | 249 | } |
250 | ||
75e0cc59 | 251 | Double_t AliGenSTRANGElib::YXiMinus( const Double_t *py, const Double_t *) |
87f8f72e | 252 | { |
253 | // y-distribution | |
254 | //____________________________________________________________ | |
255 | ||
256 | const Double_t ka = 1000.; | |
257 | const Double_t kdy = 4.; | |
258 | ||
259 | ||
260 | Double_t y=TMath::Abs(*py); | |
261 | // | |
262 | Double_t ex = y*y/(2*kdy*kdy); | |
263 | return ka*TMath::Exp(-ex); | |
264 | } | |
265 | ||
48b91885 | 266 | Int_t AliGenSTRANGElib::IpXiMinus(TRandom *ran) |
87f8f72e | 267 | { |
268 | // particle composition | |
269 | // generation of fixed type of particle | |
270 | // | |
48b91885 | 271 | Float_t random = ran->Rndm(); |
272 | if (random < 0.5) { | |
273 | return 3312; // Xi- | |
274 | } else { | |
275 | return -3312; // Xi+ | |
276 | } | |
87f8f72e | 277 | } |
278 | // End Ximinus | |
279 | //============================================================================ | |
280 | // Omegaminus | |
75e0cc59 | 281 | Double_t AliGenSTRANGElib::PtOmegaMinus( const Double_t *px, const Double_t *) |
87f8f72e | 282 | { |
283 | // Omega | |
284 | // pt-distribution | |
285 | //____________________________________________________________ | |
286 | ||
0db2f441 | 287 | return PtScal(*px,9); // 9==> Omega-antiOmega in the PtScal function |
87f8f72e | 288 | } |
289 | ||
75e0cc59 | 290 | Double_t AliGenSTRANGElib::YOmegaMinus( const Double_t *py, const Double_t *) |
87f8f72e | 291 | { |
292 | // y-distribution | |
293 | //____________________________________________________________ | |
294 | ||
295 | const Double_t ka = 1000.; | |
296 | const Double_t kdy = 4.; | |
297 | ||
298 | ||
299 | Double_t y=TMath::Abs(*py); | |
300 | // | |
301 | Double_t ex = y*y/(2*kdy*kdy); | |
302 | return ka*TMath::Exp(-ex); | |
303 | } | |
304 | ||
48b91885 | 305 | Int_t AliGenSTRANGElib::IpOmegaMinus(TRandom * ran) |
87f8f72e | 306 | { |
307 | // particle composition | |
308 | // generation of fixed type of particle | |
309 | // | |
310 | ||
48b91885 | 311 | Float_t random = ran->Rndm(); |
312 | if (random < 0.5) { | |
313 | return 3334; // Omega- | |
314 | } else { | |
315 | return -3334; // Omega+ | |
316 | } | |
87f8f72e | 317 | } |
318 | // End Omegaminus | |
319 | //============================================================================ | |
13313168 | 320 | // Lambda(1520) |
75e0cc59 | 321 | Double_t AliGenSTRANGElib::PtLambda1520( const Double_t *px, const Double_t *) |
13313168 | 322 | { |
323 | // Lambda(1520) | |
324 | // pt-distribution | |
325 | //____________________________________________________________ | |
326 | ||
0db2f441 | 327 | return PtScal(*px,10); // 10=> Lambda(1520) in the PtScal function |
13313168 | 328 | } |
87f8f72e | 329 | |
75e0cc59 | 330 | Double_t AliGenSTRANGElib::YLambda1520( const Double_t *py, const Double_t *) |
13313168 | 331 | { |
332 | // y-distribution | |
333 | //____________________________________________________________ | |
334 | ||
335 | const Double_t ka = 1000.; | |
336 | const Double_t kdy = 4.; | |
337 | ||
338 | ||
339 | Double_t y=TMath::Abs(*py); | |
340 | // | |
341 | Double_t ex = y*y/(2*kdy*kdy); | |
342 | return ka*TMath::Exp(-ex); | |
343 | } | |
344 | ||
345 | Int_t AliGenSTRANGElib::IpLambda1520(TRandom * ran) | |
346 | { | |
347 | // particle composition | |
348 | // generation of fixed type of particle | |
349 | // | |
350 | ||
351 | Float_t random = ran->Rndm(); | |
352 | if (random < 0.5) { | |
353 | return 3124; // Lambda(1520) | |
354 | } else { | |
355 | return -3124; // antiLambda(1520) | |
356 | } | |
357 | } | |
358 | // End Lambda(1520) | |
359 | //============================================================================ | |
87f8f72e | 360 | |
75e0cc59 | 361 | typedef Double_t (*GenFunc) (const Double_t*, const Double_t*); |
198bb1c7 | 362 | GenFunc AliGenSTRANGElib::GetPt(Int_t param, const char* /*tname*/) const |
87f8f72e | 363 | { |
364 | // Return pinter to pT parameterisation | |
365 | GenFunc func; | |
366 | ||
367 | switch (param) | |
368 | { | |
369 | case kKaon: | |
370 | func=PtKaon; | |
371 | break; | |
372 | case kPhi: | |
373 | func=PtPhi; | |
374 | break; | |
375 | case kLambda: | |
376 | func=PtLambda; | |
377 | break; | |
378 | case kXiMinus: | |
379 | func=PtXiMinus; | |
380 | break; | |
381 | case kOmegaMinus: | |
382 | func=PtOmegaMinus; | |
383 | break; | |
13313168 | 384 | case kLambda1520: |
385 | func=PtLambda1520; | |
386 | break; | |
87f8f72e | 387 | default: |
388 | func=0; | |
389 | printf("<AliGenSTRANGElib::GetPt> unknown parametrisationn"); | |
390 | } | |
391 | return func; | |
392 | } | |
393 | ||
198bb1c7 | 394 | GenFunc AliGenSTRANGElib::GetY(Int_t param, const char* /*tname*/) const |
87f8f72e | 395 | { |
396 | // Return pointer to Y parameterisation | |
397 | GenFunc func; | |
398 | switch (param) | |
399 | { | |
400 | case kKaon: | |
401 | func=YKaon; | |
402 | break; | |
403 | case kPhi: | |
404 | func=YPhi; | |
405 | break; | |
406 | case kLambda: | |
407 | func=YLambda; | |
408 | break; | |
409 | case kXiMinus: | |
410 | func=YXiMinus; | |
411 | break; | |
412 | case kOmegaMinus: | |
413 | func=YOmegaMinus; | |
414 | break; | |
13313168 | 415 | case kLambda1520: |
416 | func=YLambda1520; | |
417 | break; | |
87f8f72e | 418 | default: |
419 | func=0; | |
420 | printf("<AliGenSTRANGElib::GetY> unknown parametrisationn"); | |
421 | } | |
422 | return func; | |
423 | } | |
424 | typedef Int_t (*GenFuncIp) (TRandom *); | |
198bb1c7 | 425 | GenFuncIp AliGenSTRANGElib::GetIp(Int_t param, const char* /*tname*/) const |
87f8f72e | 426 | { |
427 | // Return pointer to particle composition | |
428 | GenFuncIp func; | |
429 | switch (param) | |
430 | { | |
431 | case kKaon: | |
432 | func=IpKaon; | |
433 | break; | |
434 | case kPhi: | |
435 | func=IpPhi; | |
436 | break; | |
437 | case kLambda: | |
438 | func=IpLambda; | |
439 | break; | |
440 | case kXiMinus: | |
441 | func=IpXiMinus; | |
442 | break; | |
443 | case kOmegaMinus: | |
444 | func=IpOmegaMinus; | |
445 | break; | |
13313168 | 446 | case kLambda1520: |
447 | func=IpLambda1520; | |
448 | break; | |
87f8f72e | 449 | default: |
450 | func=0; | |
451 | printf("<AliGenSTRANGElib::GetIp> unknown parametrisationn"); | |
452 | } | |
453 | return func; | |
454 | } | |
455 |