2 /**************************************************************************
3 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
5 * Author: The ALICE Off-line Project. *
6 * Contributors are mentioned in the code where appropriate. *
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 **************************************************************************/
19 Revision 1.7.10.1 2002/06/10 14:57:41 hristov
22 Revision 1.10 2002/05/02 09:40:50 morsch
23 Recover mods from Rev. 1.8
25 Revision 1.9 2002/04/23 12:54:29 morsch
26 New options kPi0Flat y kEtaFlat (Gustavo Conesa)
28 Revision 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
32 Revision 1.6 2000/11/30 07:12:50 alibrary
33 Introducing new Rndm and QA classes
35 Revision 1.5 2000/06/29 21:08:27 morsch
36 All paramatrisation libraries derive from the pure virtual base class AliGenLib.
37 This allows to pass a pointer to a library directly to AliGenParam and avoids the
38 use of function pointers in Config.C.
40 Revision 1.4 2000/06/14 15:21:05 morsch
43 Revision 1.3 2000/06/09 20:32:54 morsch
44 All coding rule violations except RS3 corrected
46 Revision 1.2 1999/11/04 11:30:48 fca
49 Revision 1.1 1999/11/03 17:43:20 fca
50 New version from G.Martinez & A.Morsch
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
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
67 // with Pions, using the PtScal function taken from AliGenMUONlib
68 // version aliroot 3.01
70 // Gines MARTINEZ. Laurent APHECETCHE and Yves SCHUTZ
71 // GPS @ SUBATECH, Nantes , France (October 1999)
72 // http://www-subatech.in2p3.fr/~photons/subatech
73 // martinez@subatech.in2p3.fr
74 //======================================================================
79 #include "AliGenPHOSlib.h"
81 ClassImp(AliGenPHOSlib)
83 //======================================================================
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-)
90 Double_t AliGenPHOSlib::PtPion(Double_t *px, Double_t *)
92 // Pion transverse momentum distribtuion taken
93 // from AliGenMUONlib class, version 3.01 of aliroot
94 // PT-PARAMETERIZATION CDF, PRL 61(88) 1819
95 // POWER LAW FOR PT > 500 MEV
96 // MT SCALING BELOW (T=160 MEV)
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;
107 y1=TMath::Power(kp0/(kp0+kxlim),kxn);
109 ynorm=kb*(TMath::Exp(-sqrt(kxlim*kxlim+kxmpi2)/kt));
112 y=a*TMath::Power(kp0/(kp0+x),kxn);
114 y=kb*TMath::Exp(-sqrt(x*x+kxmpi2)/kt);
117 Double_t AliGenPHOSlib::YPion( Double_t *py, Double_t *)
120 // pion y-distribution
123 const Double_t ka = 7000.;
124 const Double_t kdy = 4.;
126 Double_t y=TMath::Abs(*py);
128 Double_t ex = y*y/(2*kdy*kdy);
129 return ka*TMath::Exp(-ex);
132 Int_t AliGenPHOSlib::IpPion(TRandom *ran)
134 // particle composition pi+, pi0, pi-
137 Float_t random = ran->Rndm();
139 if ( (3.*random) < 1. )
145 if ( (3.*random) >= 2.)
157 //======================================================================
158 // Pi 0 Flat Distribution
159 // Transverse momentum distribution PtPi0Flat
160 // Rapidity distribution YPi0Flat
161 // Particle distribution IdPi0Flat 111 (pi0)
164 Double_t AliGenPHOSlib::PtPi0Flat(Double_t *px, Double_t *)
166 // Pion transverse momentum flat distribution
172 Double_t AliGenPHOSlib::YPi0Flat( Double_t *py, Double_t *)
175 // pion y-distribution
180 Int_t AliGenPHOSlib::IpPi0Flat(TRandom *)
183 // particle composition pi0
188 //=============================================================
190 Double_t AliGenPHOSlib::PtScal(Double_t pt, Int_t np)
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
200 // SCALING EN MASSE PAR RAPPORT A PTPI
201 // MASS 1=>PI, 2=>K, 3=>ETA, 4=>OMEGA, 5=>ETA',6=>PHI
202 const Double_t khm[10] = {0.1396, 0.494, 0.547, 0.782, 0.957, 1.02,
203 // MASS 7=>BARYON-BARYONBAR
205 // VALUE MESON/PI AT 5 GEV
206 const Double_t kfmax[10]={1., 1., 1., 1., 1., 1., 1., 1., 1., 1.};
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];
211 Double_t ptpion=100.*PtPion(&pt, (Double_t*) 0);
212 Double_t fmtscal=TMath::Power(((sqrt(pt*pt+0.018215)+2.)/
213 (sqrt(pt*pt+khm[np]*khm[np])+2.0)),12.3)/ kfmax2;
214 return fmtscal*ptpion;
218 //============================================================================
220 Double_t AliGenPHOSlib::PtKaon( Double_t *px, Double_t *)
224 //____________________________________________________________
226 return PtScal(*px,2); // 2==> Kaon in the PtScal function
229 Double_t AliGenPHOSlib::YKaon( Double_t *py, Double_t *)
232 //____________________________________________________________
234 const Double_t ka = 1000.;
235 const Double_t kdy = 4.;
238 Double_t y=TMath::Abs(*py);
240 Double_t ex = y*y/(2*kdy*kdy);
241 return ka*TMath::Exp(-ex);
244 Int_t AliGenPHOSlib::IpKaon(TRandom *ran)
246 // particle composition
249 Float_t random = ran->Rndm();
250 Float_t random2 = ran->Rndm();
262 return 130; // K^0 short
264 return 310; // K^0 long
269 //============================================================================
270 //============================================================================
272 Double_t AliGenPHOSlib::PtEta( Double_t *px, Double_t *)
276 //____________________________________________________________
278 return PtScal(*px,3); // 3==> Eta in the PtScal function
281 Double_t AliGenPHOSlib::YEta( Double_t *py, Double_t *)
284 //____________________________________________________________
286 const Double_t ka = 1000.;
287 const Double_t kdy = 4.;
290 Double_t y=TMath::Abs(*py);
292 Double_t ex = y*y/(2*kdy*kdy);
293 return ka*TMath::Exp(-ex);
296 Int_t AliGenPHOSlib::IpEta(TRandom *)
298 // particle composition
305 //======================================================================
306 // Eta Flat Distribution
307 // Transverse momentum distribution PtEtaFlat
308 // Rapidity distribution YEtaFlat
309 // Particle distribution IdEtaFlat 111 (pi0)
312 Double_t AliGenPHOSlib::PtEtaFlat(Double_t *px, Double_t *)
314 // Eta transverse momentum flat distribution
320 Double_t AliGenPHOSlib::YEtaFlat( Double_t *py, Double_t *)
323 // pion y-distribution
328 Int_t AliGenPHOSlib::IpEtaFlat(TRandom *)
331 // particle composition eta
336 //============================================================================
337 //============================================================================
339 Double_t AliGenPHOSlib::PtOmega( Double_t *px, Double_t *)
343 //____________________________________________________________
345 return PtScal(*px,4); // 4==> Omega in the PtScal function
348 Double_t AliGenPHOSlib::YOmega( Double_t *py, Double_t *)
351 //____________________________________________________________
353 const Double_t ka = 1000.;
354 const Double_t kdy = 4.;
357 Double_t y=TMath::Abs(*py);
359 Double_t ex = y*y/(2*kdy*kdy);
360 return ka*TMath::Exp(-ex);
363 Int_t AliGenPHOSlib::IpOmega(TRandom *)
365 // particle composition
371 //============================================================================
372 //============================================================================
374 Double_t AliGenPHOSlib::PtEtaprime( Double_t *px, Double_t *)
378 //____________________________________________________________
380 return PtScal(*px,5); // 5==> Etaprime in the PtScal function
383 Double_t AliGenPHOSlib::YEtaprime( Double_t *py, Double_t *)
386 //____________________________________________________________
388 const Double_t ka = 1000.;
389 const Double_t kdy = 4.;
392 Double_t y=TMath::Abs(*py);
394 Double_t ex = y*y/(2*kdy*kdy);
395 return ka*TMath::Exp(-ex);
398 Int_t AliGenPHOSlib::IpEtaprime(TRandom *)
400 // particle composition
403 return 331; // Etaprime
406 //===================================================================
407 //============================================================================
409 Double_t AliGenPHOSlib::PtPhi( Double_t *px, Double_t *)
413 //____________________________________________________________
415 return PtScal(*px,6); // 6==> Phi in the PtScal function
418 Double_t AliGenPHOSlib::YPhi( Double_t *py, Double_t *)
421 //____________________________________________________________
423 const Double_t ka = 1000.;
424 const Double_t kdy = 4.;
427 Double_t y=TMath::Abs(*py);
429 Double_t ex = y*y/(2*kdy*kdy);
430 return ka*TMath::Exp(-ex);
433 Int_t AliGenPHOSlib::IpPhi(TRandom *)
435 // particle composition
441 //===================================================================
442 //============================================================================
443 // B A R Y O N S == protons, protonsbar, neutrons, and neutronsbars
444 Double_t AliGenPHOSlib::PtBaryon( Double_t *px, Double_t *)
448 //____________________________________________________________
450 return PtScal(*px,7); // 7==> Baryon in the PtScal function
453 Double_t AliGenPHOSlib::YBaryon( Double_t *py, Double_t *)
456 //____________________________________________________________
458 const Double_t ka = 1000.;
459 const Double_t kdy = 4.;
462 Double_t y=TMath::Abs(*py);
464 Double_t ex = y*y/(2*kdy*kdy);
465 return ka*TMath::Exp(-ex);
468 Int_t AliGenPHOSlib::IpBaryon(TRandom *ran)
470 // particle composition
473 Float_t random = ran->Rndm();
474 Float_t random2 = ran->Rndm();
480 return -2212; // pbar
488 return -2112; // n bar
493 //===================================================================
496 typedef Double_t (*GenFunc) (Double_t*, Double_t*);
497 GenFunc AliGenPHOSlib::GetPt(Int_t param, const char* tname) const
499 // Return pinter to pT parameterisation
530 printf("<AliGenPHOSlib::GetPt> unknown parametrisationn");
535 GenFunc AliGenPHOSlib::GetY(Int_t param, const char* tname) const
537 // Return pointer to Y parameterisation
570 printf("<AliGenPHOSlib::GetY> unknown parametrisationn");
574 typedef Int_t (*GenFuncIp) (TRandom *);
575 GenFuncIp AliGenPHOSlib::GetIp(Int_t param, const char* tname) const
577 // Return pointer to particle composition
611 printf("<AliGenPHOSlib::GetIp> unknown parametrisationn");