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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$Log$
18Revision 1.14.6.1 2002/06/10 14:57:41 hristov
19Merged with v3-08-02
20
21Revision 1.15 2002/04/17 10:11:51 morsch
22Coding Rule violations corrected.
23
24Revision 1.14 2002/02/22 17:26:43 morsch
25Eta and omega added.
26
27Revision 1.13 2001/03/27 11:01:04 morsch
28Charm pt-distribution corrected. More realistic y-distribution for pi and K.
29
30Revision 1.12 2001/03/09 13:01:41 morsch
31- enum constants for paramterisation type (particle family) moved to AliGen*lib.h
32- use AliGenGSIlib::kUpsilon, AliGenPHOSlib::kEtaPrime to access the constants
33
34Revision 1.11 2000/11/30 07:12:50 alibrary
35Introducing new Rndm and QA classes
36
37Revision 1.10 2000/06/29 21:08:27 morsch
38All paramatrisation libraries derive from the pure virtual base class AliGenLib.
39This allows to pass a pointer to a library directly to AliGenParam and avoids the
40use of function pointers in Config.C.
41
42Revision 1.9 2000/06/14 15:20:56 morsch
43Include clean-up (IH)
44
45Revision 1.8 2000/06/09 20:32:11 morsch
46All coding rule violations except RS3 corrected
47
48Revision 1.7 2000/05/02 08:12:13 morsch
49Coding rule violations corrected.
50
51Revision 1.6 1999/09/29 09:24:14 fca
52Introduction of the Copyright and cvs Log
53
54*/
55
56// Library class for particle pt and y distributions used for
57// muon spectrometer simulations.
58// To be used with AliGenParam.
59// The following particle typed can be simulated:
60// pi, K, phi, omega, eta, J/Psi, Upsilon, charm and beauty mesons.
61//
62// andreas.morsch@cern.ch
63//
64
65#include "TMath.h"
66#include "TRandom.h"
67
68#include "AliGenMUONlib.h"
69
70ClassImp(AliGenMUONlib)
71//
72// Pions
73Double_t AliGenMUONlib::PtPion(Double_t *px, Double_t *dummy)
74{
75//
76// PT-PARAMETERIZATION CDF, PRL 61(88) 1819
77// POWER LAW FOR PT > 500 MEV
78// MT SCALING BELOW (T=160 MEV)
79//
80 const Double_t kp0 = 1.3;
81 const Double_t kxn = 8.28;
82 const Double_t kxlim=0.5;
83 const Double_t kt=0.160;
84 const Double_t kxmpi=0.139;
85 const Double_t kb=1.;
86 Double_t y, y1, xmpi2, ynorm, a;
87 Double_t x=*px;
88 //
89 y1=TMath::Power(kp0/(kp0+kxlim),kxn);
90 xmpi2=kxmpi*kxmpi;
91 ynorm=kb*(TMath::Exp(-sqrt(kxlim*kxlim+xmpi2)/kt));
92 a=ynorm/y1;
93 if (x > kxlim)
94 y=a*TMath::Power(kp0/(kp0+x),kxn);
95 else
96 y=kb*TMath::Exp(-sqrt(x*x+xmpi2)/kt);
97 return y*x;
98}
99//
100// y-distribution
101//
102Double_t AliGenMUONlib::YPion( Double_t *py, Double_t *dummy)
103{
104// Pion y
105 Double_t y=TMath::Abs(*py);
106/*
107 const Double_t ka = 7000.;
108 const Double_t kdy = 4.;
109 Double_t ex = y*y/(2*kdy*kdy);
110 return ka*TMath::Exp(-ex);
111*/
112 return 1.16526e+04+y*-3.79886e+03+y*y*4.31130e+02;
113
114}
115// particle composition
116//
117Int_t AliGenMUONlib::IpPion(TRandom *ran)
118{
119// Pion composition
120 if (ran->Rndm() < 0.5) {
121 return 211;
122 } else {
123 return -211;
124 }
125}
126
127//____________________________________________________________
128//
129// Mt-scaling
130
131Double_t AliGenMUONlib::PtScal(Double_t pt, Int_t np)
132{
133 // SCALING EN MASSE PAR RAPPORT A PTPI
134 // MASS PI,K,ETA,RHO,OMEGA,ETA',PHI
135 const Double_t khm[10] = {.13957,.493,.5488,.769,.7826,.958,1.02,0,0,0};
136 // VALUE MESON/PI AT 5 GEV
137 const Double_t kfmax[10]={1.,0.3,0.55,1.0,1.0,1.0,1.0,0,0,0};
138 np--;
139 Double_t f5=TMath::Power(((sqrt(100.018215)+2.)/(sqrt(100.+khm[np]*khm[np])+2.0)),12.3);
140 Double_t fmax2=f5/kfmax[np];
141 // PIONS
142 Double_t ptpion=100.*PtPion(&pt, (Double_t*) 0);
143 Double_t fmtscal=TMath::Power(((sqrt(pt*pt+0.018215)+2.)/
144 (sqrt(pt*pt+khm[np]*khm[np])+2.0)),12.3)/ fmax2;
145 return fmtscal*ptpion;
146}
147//
148// kaon
149//
150// pt-distribution
151//____________________________________________________________
152Double_t AliGenMUONlib::PtKaon( Double_t *px, Double_t *dummy)
153{
154// Kaon pT
155 return PtScal(*px,2);
156}
157
158// y-distribution
159//____________________________________________________________
160Double_t AliGenMUONlib::YKaon( Double_t *py, Double_t *dummy)
161{
162// Kaon y
163 Double_t y=TMath::Abs(*py);
164/*
165 const Double_t ka = 1000.;
166 const Double_t kdy = 4.;
167 //
168 Double_t ex = y*y/(2*kdy*kdy);
169 return ka*TMath::Exp(-ex);
170*/
171
172 return 1.16526e+04+y*-3.79886e+03+y*y*4.31130e+02;
173}
174
175// particle composition
176//
177Int_t AliGenMUONlib::IpKaon(TRandom *ran)
178{
179// Kaon composition
180 if (ran->Rndm() < 0.5) {
181 return 321;
182 } else {
183 return -321;
184 }
185}
186
187// J/Psi
188//
189//
190// pt-distribution
191//____________________________________________________________
192Double_t AliGenMUONlib::PtJpsi( Double_t *px, Double_t *dummy)
193{
194// J/Psi pT
195 const Double_t kpt0 = 4.;
196 const Double_t kxn = 3.6;
197 Double_t x=*px;
198 //
199 Double_t pass1 = 1.+(x/kpt0)*(x/kpt0);
200 return x/TMath::Power(pass1,kxn);
201}
202//
203// y-distribution
204//____________________________________________________________
205Double_t AliGenMUONlib::YJpsi(Double_t *py, Double_t *dummy)
206{
207// J/psi y
208 const Double_t ky0 = 4.;
209 const Double_t kb=1.;
210 Double_t yj;
211 Double_t y=TMath::Abs(*py);
212 //
213 if (y < ky0)
214 yj=kb;
215 else
216 yj=kb*TMath::Exp(-(y-ky0)*(y-ky0)/2);
217 return yj;
218}
219// particle composition
220//
221Int_t AliGenMUONlib::IpJpsi(TRandom *)
222{
223// J/Psi composition
224 return 443;
225}
226
227// Upsilon
228//
229//
230// pt-distribution
231//____________________________________________________________
232Double_t AliGenMUONlib::PtUpsilon( Double_t *px, Double_t *dummy )
233{
234// Upsilon pT
235 const Double_t kpt0 = 5.3;
236 const Double_t kxn = 2.5;
237 Double_t x=*px;
238 //
239 Double_t pass1 = 1.+(x/kpt0)*(x/kpt0);
240 return x/TMath::Power(pass1,kxn);
241}
242//
243// y-distribution
244//
245//____________________________________________________________
246Double_t AliGenMUONlib::YUpsilon(Double_t *py, Double_t *dummy)
247{
248// Upsilon y
249 const Double_t ky0 = 3.;
250 const Double_t kb=1.;
251 Double_t yu;
252 Double_t y=TMath::Abs(*py);
253 //
254 if (y < ky0)
255 yu=kb;
256 else
257 yu=kb*TMath::Exp(-(y-ky0)*(y-ky0)/2);
258 return yu;
259}
260// particle composition
261//
262Int_t AliGenMUONlib::IpUpsilon(TRandom *)
263{
264// y composition
265 return 553;
266}
267
268//
269// Phi
270//
271//
272// pt-distribution (by scaling of pion distribution)
273//____________________________________________________________
274Double_t AliGenMUONlib::PtPhi( Double_t *px, Double_t *dummy)
275{
276// Phi pT
277 return PtScal(*px,7);
278}
279// y-distribution
280Double_t AliGenMUONlib::YPhi( Double_t *px, Double_t *dummy)
281{
282// Phi y
283 Double_t *dum=0;
284 return YJpsi(px,dum);
285}
286// particle composition
287//
288Int_t AliGenMUONlib::IpPhi(TRandom *)
289{
290// Phi composition
291 return 333;
292}
293
294//
295// omega
296//
297//
298// pt-distribution (by scaling of pion distribution)
299//____________________________________________________________
300Double_t AliGenMUONlib::PtOmega( Double_t *px, Double_t *dummy)
301{
302// Omega pT
303 return PtScal(*px,5);
304}
305// y-distribution
306Double_t AliGenMUONlib::YOmega( Double_t *px, Double_t *dummy)
307{
308// Omega y
309 Double_t *dum=0;
310 return YJpsi(px,dum);
311}
312// particle composition
313//
314Int_t AliGenMUONlib::IpOmega(TRandom *)
315{
316// Omega composition
317 return 223;
318}
319
320
321//
322// Eta
323//
324//
325// pt-distribution (by scaling of pion distribution)
326//____________________________________________________________
327Double_t AliGenMUONlib::PtEta( Double_t *px, Double_t *dummy)
328{
329// Eta pT
330 return PtScal(*px,3);
331}
332// y-distribution
333Double_t AliGenMUONlib::YEta( Double_t *px, Double_t *dummy)
334{
335// Eta y
336 Double_t *dum=0;
337 return YJpsi(px,dum);
338}
339// particle composition
340//
341Int_t AliGenMUONlib::IpEta(TRandom *)
342{
343// Eta composition
344 return 221;
345}
346
347//
348// Charm
349//
350//
351// pt-distribution
352//____________________________________________________________
353Double_t AliGenMUONlib::PtCharm( Double_t *px, Double_t *dummy)
354{
355// Charm pT
356 const Double_t kpt0 = 4.08;
357 const Double_t kxn = 9.40;
358
359 Double_t x=*px;
360 //
361 Double_t pass1 = 1.+(x/kpt0);
362 return x/TMath::Power(pass1,kxn);
363}
364// y-distribution
365Double_t AliGenMUONlib::YCharm( Double_t *px, Double_t *dummy)
366{
367// Charm y
368 Double_t *dum=0;
369 return YJpsi(px,dum);
370}
371
372Int_t AliGenMUONlib::IpCharm(TRandom *ran)
373{
374// Charm composition
375 Float_t random;
376 Int_t ip;
377// 411,421,431,4122
378 random = ran->Rndm();
379 if (random < 0.5) {
380 ip=411;
381 } else if (random < 0.75) {
382 ip=421;
383 } else if (random < 0.90) {
384 ip=431;
385 } else {
386 ip=4122;
387 }
388 if (ran->Rndm() < 0.5) {ip=-ip;}
389
390 return ip;
391}
392
393
394//
395// Beauty
396//
397//
398// pt-distribution
399//____________________________________________________________
400Double_t AliGenMUONlib::PtBeauty( Double_t *px, Double_t *dummy)
401{
402// Beauty pT
403 const Double_t kpt0 = 4.;
404 const Double_t kxn = 3.6;
405 Double_t x=*px;
406 //
407 Double_t pass1 = 1.+(x/kpt0)*(x/kpt0);
408 return x/TMath::Power(pass1,kxn);
409}
410// y-distribution
411Double_t AliGenMUONlib::YBeauty( Double_t *px, Double_t *dummy)
412{
413// Beauty y
414 Double_t *dum=0;
415 return YJpsi(px,dum);
416}
417
418Int_t AliGenMUONlib::IpBeauty(TRandom *ran)
419{
420// Beauty Composition
421 Float_t random;
422 Int_t ip;
423 random = ran->Rndm();
424 if (random < 0.5) {
425 ip=511;
426 } else if (random < 0.75) {
427 ip=521;
428 } else if (random < 0.90) {
429 ip=531;
430 } else {
431 ip=5122;
432 }
433 if (ran->Rndm() < 0.5) {ip=-ip;}
434
435 return ip;
436}
437
438typedef Double_t (*GenFunc) (Double_t*, Double_t*);
439GenFunc AliGenMUONlib::GetPt(Int_t param, const char* tname) const
440{
441// Return pointer to pT parameterisation
442 GenFunc func;
443 switch (param)
444 {
445 case kPhi:
446 func=PtPhi;
447 break;
448 case kOmega:
449 func=PtOmega;
450 break;
451 case kEta:
452 func=PtEta;
453 break;
454 case kJpsi:
455 func=PtJpsi;
456 break;
457 case kUpsilon:
458 func=PtUpsilon;
459 break;
460 case kCharm:
461 func=PtCharm;
462 break;
463 case kBeauty:
464 func=PtBeauty;
465 break;
466 case kPion:
467 func=PtPion;
468 break;
469 case kKaon:
470 func=PtKaon;
471 break;
472 default:
473 func=0;
474 printf("<AliGenMUONlib::GetPt> unknown parametrisation\n");
475 }
476 return func;
477}
478
479GenFunc AliGenMUONlib::GetY(Int_t param, const char* tname) const
480{
481// Return pointer to y- parameterisation
482 GenFunc func;
483 switch (param)
484 {
485 case kPhi:
486 func=YPhi;
487 break;
488 case kEta:
489 func=YEta;
490 break;
491 case kOmega:
492 func=YOmega;
493 break;
494 case kJpsi:
495 func=YJpsi;
496 break;
497 case kUpsilon:
498 func=YUpsilon;
499 break;
500 case kCharm:
501 func=YCharm;
502 break;
503 case kBeauty:
504 func=YBeauty;
505 break;
506 case kPion:
507 func=YPion;
508 break;
509 case kKaon:
510 func=YKaon;
511 break;
512 default:
513 func=0;
514 printf("<AliGenMUONlib::GetY> unknown parametrisation\n");
515 }
516 return func;
517}
518typedef Int_t (*GenFuncIp) (TRandom *);
519GenFuncIp AliGenMUONlib::GetIp(Int_t param, const char* tname) const
520{
521// Return pointer to particle type parameterisation
522 GenFuncIp func;
523 switch (param)
524 {
525 case kPhi:
526 func=IpPhi;
527 break;
528 case kEta:
529 func=IpEta;
530 break;
531 case kOmega:
532 func=IpOmega;
533 break;
534 case kJpsi:
535 func=IpJpsi;
536 break;
537 case kUpsilon:
538 func=IpUpsilon;
539 break;
540 case kCharm:
541 func=IpCharm;
542 break;
543 case kBeauty:
544 func=IpBeauty;
545 break;
546 case kPion:
547 func=IpPion;
548 break;
549 case kKaon:
550 func=IpKaon;
551 break;
552 default:
553 func=0;
554 printf("<AliGenMUONlib::GetIp> unknown parametrisation\n");
555 }
556 return func;
557}
558
559
560
561