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[u/mrichter/AliRoot.git] / EVGEN / AliGenPHOSlib.cxx
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74c62c73 1
886b6f73 2/**************************************************************************
3 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * *
5 * Author: The ALICE Off-line Project. *
6 * Contributors are mentioned in the code where appropriate. *
7 * *
8 * Permission to use, copy, modify and distribute this software and its *
9 * documentation strictly for non-commercial purposes is hereby granted *
10 * without fee, provided that the above copyright notice appears in all *
11 * copies and that both the copyright notice and this permission notice *
12 * appear in the supporting documentation. The authors make no claims *
13 * about the suitability of this software for any purpose. It is *
14 * provided "as is" without express or implied warranty. *
15 **************************************************************************/
16
17/*
18$Log$
b9d0a01d 19Revision 1.7.10.1 2002/06/10 14:57:41 hristov
20Merged with v3-08-02
21
22Revision 1.10 2002/05/02 09:40:50 morsch
23Recover mods from Rev. 1.8
24
a04b490f 25Revision 1.9 2002/04/23 12:54:29 morsch
26New options kPi0Flat y kEtaFlat (Gustavo Conesa)
27
8a1ead98 28Revision 1.7 2001/03/09 13:01:41 morsch
29- enum constants for paramterisation type (particle family) moved to AliGen*lib.h
30- use AliGenGSIlib::kUpsilon, AliGenPHOSlib::kEtaPrime to access the constants
31
34f60c01 32Revision 1.6 2000/11/30 07:12:50 alibrary
33Introducing new Rndm and QA classes
34
65fb704d 35Revision 1.5 2000/06/29 21:08:27 morsch
36All paramatrisation libraries derive from the pure virtual base class AliGenLib.
37This allows to pass a pointer to a library directly to AliGenParam and avoids the
38use of function pointers in Config.C.
39
b22ee262 40Revision 1.4 2000/06/14 15:21:05 morsch
41Include clean-up (IH)
42
5c3fd7ea 43Revision 1.3 2000/06/09 20:32:54 morsch
44All coding rule violations except RS3 corrected
45
f87cfe57 46Revision 1.2 1999/11/04 11:30:48 fca
47Improve comments
48
9ae59e17 49Revision 1.1 1999/11/03 17:43:20 fca
50New version from G.Martinez & A.Morsch
51
886b6f73 52*/
53
54//======================================================================
55// AliGenPHOSlib class contains parameterizations of the
56// pion, kaon, eta, omega, etaprime, phi and baryon (proton,
57// antiproton, neutron and anti-neutron) particles for the
58// study of the neutral background in PHOS detector.
59// These parameterizations are used by the
60// AliGenParam class:
61// AliGenParam(npar, param, AliGenPHOSlib::GetPt(param),
62// AliGenPHOSlib::GetY(param),
63// AliGenPHOSlib::GetIp(param) )
64// param represents the particle to be simulated :
65// Pion, Kaon, Eta, Omega, Etaprime, Phi or Baryon
66// Pt distributions are calculated from the transverse mass scaling
9ae59e17 67// with Pions, using the PtScal function taken from AliGenMUONlib
886b6f73 68// version aliroot 3.01
69//
9ae59e17 70// Gines MARTINEZ. Laurent APHECETCHE and Yves SCHUTZ
71// GPS @ SUBATECH, Nantes , France (October 1999)
886b6f73 72// http://www-subatech.in2p3.fr/~photons/subatech
73// martinez@subatech.in2p3.fr
74//======================================================================
75
65fb704d 76#include "TMath.h"
77#include "TRandom.h"
78
886b6f73 79#include "AliGenPHOSlib.h"
886b6f73 80
81ClassImp(AliGenPHOSlib)
82
83//======================================================================
84// P I O N S
85// (From GetPt, GetY and GetIp as param = Pion)
86// Transverse momentum distribution" PtPion
87// Rapidity distribution YPion
88// Particle distribution IdPion 111, 211 and -211 (pi0, pi+ and pi-)
89//
90 Double_t AliGenPHOSlib::PtPion(Double_t *px, Double_t *)
91{
92// Pion transverse momentum distribtuion taken
9ae59e17 93// from AliGenMUONlib class, version 3.01 of aliroot
886b6f73 94// PT-PARAMETERIZATION CDF, PRL 61(88) 1819
95// POWER LAW FOR PT > 500 MEV
96// MT SCALING BELOW (T=160 MEV)
97//
f87cfe57 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, kxmpi2, ynorm, a;
886b6f73 105 Double_t x=*px;
106 //
f87cfe57 107 y1=TMath::Power(kp0/(kp0+kxlim),kxn);
108 kxmpi2=kxmpi*kxmpi;
109 ynorm=kb*(TMath::Exp(-sqrt(kxlim*kxlim+kxmpi2)/kt));
886b6f73 110 a=ynorm/y1;
f87cfe57 111 if (x > kxlim)
112 y=a*TMath::Power(kp0/(kp0+x),kxn);
886b6f73 113 else
f87cfe57 114 y=kb*TMath::Exp(-sqrt(x*x+kxmpi2)/kt);
886b6f73 115 return y*x;
116}
886b6f73 117 Double_t AliGenPHOSlib::YPion( Double_t *py, Double_t *)
118{
f87cfe57 119//
120// pion y-distribution
121//
122
123 const Double_t ka = 7000.;
124 const Double_t kdy = 4.;
886b6f73 125
126 Double_t y=TMath::Abs(*py);
127 //
f87cfe57 128 Double_t ex = y*y/(2*kdy*kdy);
129 return ka*TMath::Exp(-ex);
886b6f73 130}
f87cfe57 131
65fb704d 132 Int_t AliGenPHOSlib::IpPion(TRandom *ran)
886b6f73 133{
f87cfe57 134// particle composition pi+, pi0, pi-
135//
136
74c62c73 137 Float_t random = ran->Rndm();
138
139 if ( (3.*random) < 1. )
140 {
141 return 211 ;
142 }
143 else
144 {
145 if ( (3.*random) >= 2.)
146 {
147 return -211 ;
148 }
149 else
150 {
886b6f73 151 return 111 ;
152 }
153 }
154}
74c62c73 155
156//End Pions
157//======================================================================
158// Pi 0 Flat Distribution
159// Transverse momentum distribution PtPi0Flat
160// Rapidity distribution YPi0Flat
161// Particle distribution IdPi0Flat 111 (pi0)
162//
163
164Double_t AliGenPHOSlib::PtPi0Flat(Double_t *px, Double_t *)
165{
166// Pion transverse momentum flat distribution
167
168return 1;
169
170}
171
172Double_t AliGenPHOSlib::YPi0Flat( Double_t *py, Double_t *)
173{
174
175// pion y-distribution
176//
177 return 1.;
178}
179
180 Int_t AliGenPHOSlib::IpPi0Flat(TRandom *)
181{
182
183// particle composition pi0
184//
185 return 111 ;
186}
187// End Pi0Flat
886b6f73 188//=============================================================
189//
f87cfe57 190 Double_t AliGenPHOSlib::PtScal(Double_t pt, Int_t np)
191{
886b6f73 192// Mt-scaling
193// Fonction for the calculation of the Pt distribution for a
194// given particle np, from the pion Pt distribution using the
195// mt scaling. This function was taken from AliGenMUONlib
196// aliroot version 3.01, and was extended for baryons
197// np = 1=>Pions 2=>Kaons 3=>Etas 4=>Omegas 5=>ETA' 6=>PHI
198// 7=>BARYONS-BARYONBARS
f87cfe57 199
886b6f73 200 // SCALING EN MASSE PAR RAPPORT A PTPI
201 // MASS 1=>PI, 2=>K, 3=>ETA, 4=>OMEGA, 5=>ETA',6=>PHI
f87cfe57 202 const Double_t khm[10] = {0.1396, 0.494, 0.547, 0.782, 0.957, 1.02,
886b6f73 203 // MASS 7=>BARYON-BARYONBAR
204 0.938, 0. , 0., 0.};
205 // VALUE MESON/PI AT 5 GEV
f87cfe57 206 const Double_t kfmax[10]={1., 1., 1., 1., 1., 1., 1., 1., 1., 1.};
886b6f73 207 np--;
f87cfe57 208 Double_t f5=TMath::Power(((sqrt(100.018215)+2.)/(sqrt(100.+khm[np]*khm[np])+2.0)),12.3);
209 Double_t kfmax2=f5/kfmax[np];
886b6f73 210 // PIONS
211 Double_t ptpion=100.*PtPion(&pt, (Double_t*) 0);
212 Double_t fmtscal=TMath::Power(((sqrt(pt*pt+0.018215)+2.)/
f87cfe57 213 (sqrt(pt*pt+khm[np]*khm[np])+2.0)),12.3)/ kfmax2;
886b6f73 214 return fmtscal*ptpion;
74c62c73 215
886b6f73 216}
217// End Scaling
218//============================================================================
219// K A O N S
886b6f73 220 Double_t AliGenPHOSlib::PtKaon( Double_t *px, Double_t *)
221{
f87cfe57 222// kaon
223// pt-distribution
224//____________________________________________________________
225
886b6f73 226 return PtScal(*px,2); // 2==> Kaon in the PtScal function
227}
228
886b6f73 229 Double_t AliGenPHOSlib::YKaon( Double_t *py, Double_t *)
230{
f87cfe57 231// y-distribution
232//____________________________________________________________
233
234 const Double_t ka = 1000.;
235 const Double_t kdy = 4.;
886b6f73 236
237
238 Double_t y=TMath::Abs(*py);
239 //
f87cfe57 240 Double_t ex = y*y/(2*kdy*kdy);
241 return ka*TMath::Exp(-ex);
886b6f73 242}
243
65fb704d 244 Int_t AliGenPHOSlib::IpKaon(TRandom *ran)
886b6f73 245{
f87cfe57 246// particle composition
247//
248
65fb704d 249 Float_t random = ran->Rndm();
250 Float_t random2 = ran->Rndm();
251 if (random2 < 0.5)
886b6f73 252 {
65fb704d 253 if (random < 0.5) {
886b6f73 254 return 321; // K+
255 } else {
256 return -321; // K-
257 }
258 }
259 else
260 {
65fb704d 261 if (random < 0.5) {
9ae59e17 262 return 130; // K^0 short
886b6f73 263 } else {
9ae59e17 264 return 310; // K^0 long
886b6f73 265 }
266 }
267}
268// End Kaons
269//============================================================================
270//============================================================================
271// E T A S
886b6f73 272 Double_t AliGenPHOSlib::PtEta( Double_t *px, Double_t *)
273{
f87cfe57 274// etas
275// pt-distribution
276//____________________________________________________________
277
886b6f73 278 return PtScal(*px,3); // 3==> Eta in the PtScal function
279}
280
886b6f73 281 Double_t AliGenPHOSlib::YEta( Double_t *py, Double_t *)
282{
f87cfe57 283// y-distribution
284//____________________________________________________________
285
286 const Double_t ka = 1000.;
287 const Double_t kdy = 4.;
886b6f73 288
289
290 Double_t y=TMath::Abs(*py);
291 //
f87cfe57 292 Double_t ex = y*y/(2*kdy*kdy);
293 return ka*TMath::Exp(-ex);
886b6f73 294}
295
65fb704d 296 Int_t AliGenPHOSlib::IpEta(TRandom *)
886b6f73 297{
f87cfe57 298// particle composition
299//
300
886b6f73 301 return 221; // eta
302}
303// End Etas
74c62c73 304
305//======================================================================
306// Eta Flat Distribution
307// Transverse momentum distribution PtEtaFlat
308// Rapidity distribution YEtaFlat
309// Particle distribution IdEtaFlat 111 (pi0)
310//
311
312Double_t AliGenPHOSlib::PtEtaFlat(Double_t *px, Double_t *)
313{
314// Eta transverse momentum flat distribution
315
316 return 1;
317
318}
319
320Double_t AliGenPHOSlib::YEtaFlat( Double_t *py, Double_t *)
321{
322//
323// pion y-distribution
324//
325 return 1.;
326}
327
328 Int_t AliGenPHOSlib::IpEtaFlat(TRandom *)
329{
330//
331// particle composition eta
332//
333 return 221 ;
334}
335// End Pi0Flat
886b6f73 336//============================================================================
337//============================================================================
338// O M E G A S
f87cfe57 339 Double_t AliGenPHOSlib::PtOmega( Double_t *px, Double_t *)
340{
886b6f73 341// omegas
342// pt-distribution
343//____________________________________________________________
f87cfe57 344
886b6f73 345 return PtScal(*px,4); // 4==> Omega in the PtScal function
346}
347
886b6f73 348 Double_t AliGenPHOSlib::YOmega( Double_t *py, Double_t *)
349{
f87cfe57 350// y-distribution
351//____________________________________________________________
352
353 const Double_t ka = 1000.;
354 const Double_t kdy = 4.;
886b6f73 355
356
357 Double_t y=TMath::Abs(*py);
358 //
f87cfe57 359 Double_t ex = y*y/(2*kdy*kdy);
360 return ka*TMath::Exp(-ex);
886b6f73 361}
362
65fb704d 363 Int_t AliGenPHOSlib::IpOmega(TRandom *)
886b6f73 364{
f87cfe57 365// particle composition
366//
367
886b6f73 368 return 223; // Omega
369}
370// End Omega
371//============================================================================
372//============================================================================
373// E T A P R I M E
f87cfe57 374 Double_t AliGenPHOSlib::PtEtaprime( Double_t *px, Double_t *)
375{
886b6f73 376// etaprime
377// pt-distribution
378//____________________________________________________________
f87cfe57 379
886b6f73 380 return PtScal(*px,5); // 5==> Etaprime in the PtScal function
381}
382
886b6f73 383 Double_t AliGenPHOSlib::YEtaprime( Double_t *py, Double_t *)
384{
f87cfe57 385// y-distribution
386//____________________________________________________________
387
388 const Double_t ka = 1000.;
389 const Double_t kdy = 4.;
886b6f73 390
391
392 Double_t y=TMath::Abs(*py);
393 //
f87cfe57 394 Double_t ex = y*y/(2*kdy*kdy);
395 return ka*TMath::Exp(-ex);
886b6f73 396}
397
65fb704d 398 Int_t AliGenPHOSlib::IpEtaprime(TRandom *)
886b6f73 399{
f87cfe57 400// particle composition
401//
402
886b6f73 403 return 331; // Etaprime
404}
405// End EtaPrime
406//===================================================================
407//============================================================================
408// P H I S
f87cfe57 409 Double_t AliGenPHOSlib::PtPhi( Double_t *px, Double_t *)
410{
886b6f73 411// phi
412// pt-distribution
413//____________________________________________________________
f87cfe57 414
886b6f73 415 return PtScal(*px,6); // 6==> Phi in the PtScal function
416}
417
886b6f73 418 Double_t AliGenPHOSlib::YPhi( Double_t *py, Double_t *)
419{
f87cfe57 420// y-distribution
421//____________________________________________________________
422
423 const Double_t ka = 1000.;
424 const Double_t kdy = 4.;
886b6f73 425
426
427 Double_t y=TMath::Abs(*py);
428 //
f87cfe57 429 Double_t ex = y*y/(2*kdy*kdy);
430 return ka*TMath::Exp(-ex);
886b6f73 431}
432
65fb704d 433 Int_t AliGenPHOSlib::IpPhi(TRandom *)
f87cfe57 434{
886b6f73 435// particle composition
436//
f87cfe57 437
886b6f73 438 return 333; // Phi
439}
440// End Phis
441//===================================================================
442//============================================================================
443// B A R Y O N S == protons, protonsbar, neutrons, and neutronsbars
f87cfe57 444 Double_t AliGenPHOSlib::PtBaryon( Double_t *px, Double_t *)
445{
886b6f73 446// baryons
447// pt-distribution
448//____________________________________________________________
f87cfe57 449
886b6f73 450 return PtScal(*px,7); // 7==> Baryon in the PtScal function
451}
452
886b6f73 453 Double_t AliGenPHOSlib::YBaryon( Double_t *py, Double_t *)
454{
f87cfe57 455// y-distribution
456//____________________________________________________________
457
458 const Double_t ka = 1000.;
459 const Double_t kdy = 4.;
886b6f73 460
461
462 Double_t y=TMath::Abs(*py);
463 //
f87cfe57 464 Double_t ex = y*y/(2*kdy*kdy);
465 return ka*TMath::Exp(-ex);
886b6f73 466}
467
65fb704d 468 Int_t AliGenPHOSlib::IpBaryon(TRandom *ran)
886b6f73 469{
f87cfe57 470// particle composition
471//
472
65fb704d 473 Float_t random = ran->Rndm();
474 Float_t random2 = ran->Rndm();
475 if (random2 < 0.5)
886b6f73 476 {
65fb704d 477 if (random < 0.5) {
886b6f73 478 return 2212; // p
479 } else {
480 return -2212; // pbar
481 }
482 }
483 else
484 {
65fb704d 485 if (random < 0.5) {
886b6f73 486 return 2112; // n
487 } else {
488 return -2112; // n bar
489 }
490 }
491}
492// End Baryons
493//===================================================================
494
495
74c62c73 496typedef Double_t (*GenFunc) (Double_t*, Double_t*);
a04b490f 497 GenFunc AliGenPHOSlib::GetPt(Int_t param, const char* tname) const
886b6f73 498{
f87cfe57 499// Return pinter to pT parameterisation
886b6f73 500 GenFunc func;
501
502 switch (param)
503 {
34f60c01 504 case kPion:
886b6f73 505 func=PtPion;
506 break;
74c62c73 507 case kPi0Flat:
508 func=PtPi0Flat;
509 break;
34f60c01 510 case kKaon:
886b6f73 511 func=PtKaon;
512 break;
34f60c01 513 case kEta:
886b6f73 514 func=PtEta;
515 break;
74c62c73 516 case kEtaFlat:
517 func=PtEtaFlat;
518 break;
34f60c01 519 case kOmega:
886b6f73 520 func=PtOmega;
521 break;
34f60c01 522 case kEtaPrime:
886b6f73 523 func=PtEtaprime;
524 break;
34f60c01 525 case kBaryon:
886b6f73 526 func=PtBaryon;
527 break;
528 default:
529 func=0;
530 printf("<AliGenPHOSlib::GetPt> unknown parametrisationn");
531 }
532 return func;
533}
534
a04b490f 535 GenFunc AliGenPHOSlib::GetY(Int_t param, const char* tname) const
886b6f73 536{
f87cfe57 537// Return pointer to Y parameterisation
886b6f73 538 GenFunc func;
539 switch (param)
540 {
34f60c01 541 case kPion:
886b6f73 542 func=YPion;
543 break;
74c62c73 544 case kPi0Flat:
545 func=YPi0Flat;
546 break;
34f60c01 547 case kKaon:
886b6f73 548 func=YKaon;
549 break;
34f60c01 550 case kEta:
886b6f73 551 func=YEta;
552 break;
74c62c73 553 case kEtaFlat:
554 func=YEtaFlat;
555 break;
34f60c01 556 case kOmega:
886b6f73 557 func=YOmega;
558 break;
34f60c01 559 case kEtaPrime:
886b6f73 560 func=YEtaprime;
561 break;
34f60c01 562 case kPhi:
886b6f73 563 func=YPhi;
564 break;
34f60c01 565 case kBaryon:
886b6f73 566 func=YBaryon;
567 break;
568 default:
569 func=0;
570 printf("<AliGenPHOSlib::GetY> unknown parametrisationn");
571 }
572 return func;
573}
65fb704d 574typedef Int_t (*GenFuncIp) (TRandom *);
a04b490f 575 GenFuncIp AliGenPHOSlib::GetIp(Int_t param, const char* tname) const
886b6f73 576{
f87cfe57 577// Return pointer to particle composition
886b6f73 578 GenFuncIp func;
579 switch (param)
580 {
74c62c73 581 case kPion:
886b6f73 582 func=IpPion;
583 break;
74c62c73 584 case kPi0Flat:
585 func=IpPi0Flat;
586 break;
34f60c01 587 case kKaon:
886b6f73 588 func=IpKaon;
589 break;
34f60c01 590 case kEta:
886b6f73 591 func=IpEta;
592 break;
74c62c73 593 case kEtaFlat:
594 func=IpEtaFlat;
595 break;
596
34f60c01 597 case kOmega:
886b6f73 598 func=IpOmega;
599 break;
34f60c01 600 case kEtaPrime:
886b6f73 601 func=IpEtaprime;
602 break;
34f60c01 603 case kPhi:
886b6f73 604 func=IpPhi;
605 break;
34f60c01 606 case kBaryon:
886b6f73 607 func=IpBaryon;
608 break;
609 default:
610 func=0;
611 printf("<AliGenPHOSlib::GetIp> unknown parametrisationn");
612 }
613 return func;
614}
615