1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
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 **************************************************************************/
18 // Library class for particle pt and y distributions used for
19 // muon spectrometer simulations.
20 // To be used with AliGenParam.
21 // The following particle typed can be simulated:
22 // pi, K, phi, omega, eta, J/Psi, Upsilon, charm and beauty mesons.
24 // andreas.morsch@cern.ch
30 #include "AliGenMUONlib.h"
32 ClassImp(AliGenMUONlib)
35 Double_t AliGenMUONlib::PtPion(Double_t *px, Double_t *dummy)
38 // PT-PARAMETERIZATION CDF, PRL 61(88) 1819
39 // POWER LAW FOR PT > 500 MEV
40 // MT SCALING BELOW (T=160 MEV)
42 const Double_t kp0 = 1.3;
43 const Double_t kxn = 8.28;
44 const Double_t kxlim=0.5;
45 const Double_t kt=0.160;
46 const Double_t kxmpi=0.139;
48 Double_t y, y1, xmpi2, ynorm, a;
51 y1=TMath::Power(kp0/(kp0+kxlim),kxn);
53 ynorm=kb*(TMath::Exp(-sqrt(kxlim*kxlim+xmpi2)/kt));
56 y=a*TMath::Power(kp0/(kp0+x),kxn);
58 y=kb*TMath::Exp(-sqrt(x*x+xmpi2)/kt);
64 Double_t AliGenMUONlib::YPion( Double_t *py, Double_t *dummy)
67 Double_t y=TMath::Abs(*py);
69 const Double_t ka = 7000.;
70 const Double_t kdy = 4.;
71 Double_t ex = y*y/(2*kdy*kdy);
72 return ka*TMath::Exp(-ex);
74 return 1.16526e+04+y*-3.79886e+03+y*y*4.31130e+02;
77 // particle composition
79 Int_t AliGenMUONlib::IpPion(TRandom *ran)
82 if (ran->Rndm() < 0.5) {
89 //____________________________________________________________
93 Double_t AliGenMUONlib::PtScal(Double_t pt, Int_t np)
95 // SCALING EN MASSE PAR RAPPORT A PTPI
96 // MASS PI,K,ETA,RHO,OMEGA,ETA',PHI
97 const Double_t khm[10] = {.13957,.493,.5488,.769,.7826,.958,1.02,0,0,0};
98 // VALUE MESON/PI AT 5 GEV
99 const Double_t kfmax[10]={1.,0.3,0.55,1.0,1.0,1.0,1.0,0,0,0};
101 Double_t f5=TMath::Power(((sqrt(100.018215)+2.)/(sqrt(100.+khm[np]*khm[np])+2.0)),12.3);
102 Double_t fmax2=f5/kfmax[np];
104 Double_t ptpion=100.*PtPion(&pt, (Double_t*) 0);
105 Double_t fmtscal=TMath::Power(((sqrt(pt*pt+0.018215)+2.)/
106 (sqrt(pt*pt+khm[np]*khm[np])+2.0)),12.3)/ fmax2;
107 return fmtscal*ptpion;
113 //____________________________________________________________
114 Double_t AliGenMUONlib::PtKaon( Double_t *px, Double_t *dummy)
117 return PtScal(*px,2);
121 //____________________________________________________________
122 Double_t AliGenMUONlib::YKaon( Double_t *py, Double_t *dummy)
125 Double_t y=TMath::Abs(*py);
127 const Double_t ka = 1000.;
128 const Double_t kdy = 4.;
130 Double_t ex = y*y/(2*kdy*kdy);
131 return ka*TMath::Exp(-ex);
134 return 1.16526e+04+y*-3.79886e+03+y*y*4.31130e+02;
137 // particle composition
139 Int_t AliGenMUONlib::IpKaon(TRandom *ran)
142 if (ran->Rndm() < 0.5) {
153 //____________________________________________________________
154 Double_t AliGenMUONlib::PtJpsi( Double_t *px, Double_t *dummy)
157 const Double_t kpt0 = 4.;
158 const Double_t kxn = 3.6;
161 Double_t pass1 = 1.+(x/kpt0)*(x/kpt0);
162 return x/TMath::Power(pass1,kxn);
165 Double_t AliGenMUONlib::PtJpsiPbPb( Double_t *px, Double_t *dummy)
172 // mc = 1.4 GeV, pt-kick 1 GeV
176 -2.13098e+00, 9.46552e+00, -5.06799e+00, 1.27260e+00,
177 -1.83806e-01, 1.55853e-02, -7.23241e-04, 1.42105e-05
184 while (j > 0) y = y * x +c[--j];
185 y = x * TMath::Exp(y);
191 Double_t AliGenMUONlib::PtJpsiPP( Double_t *px, Double_t *dummy)
198 // mc = 1.4 GeV, pt-kick 1 GeV
201 Float_t c[4] = {8.47471e+00, -1.93567e+00, 1.50271e-01, -5.51212e-03};
207 while (j > 0) y = y * x +c[--j];
208 y = x * TMath::Exp(y);
217 //____________________________________________________________
218 Double_t AliGenMUONlib::YJpsi(Double_t *py, Double_t *dummy)
221 const Double_t ky0 = 4.;
222 const Double_t kb=1.;
224 Double_t y=TMath::Abs(*py);
229 yj=kb*TMath::Exp(-(y-ky0)*(y-ky0)/2);
234 Double_t AliGenMUONlib::YJpsiPbPb( Double_t *px, Double_t *dummy)
244 // mc = 1.4 GeV, pt-kick 1 GeV
246 Double_t c[5] = {-6.03425e+02, 4.98257e+02, -1.38794e+02, 1.62209e+01, -6.85955e-01};
247 Double_t x = TMath::Abs(px[0]);
255 while (j > 0) y = y * x + c[--j];
263 Double_t AliGenMUONlib::YJpsiPP( Double_t *px, Double_t *dummy)
273 // mc = 1.4 GeV, pt-kick 1 GeV
276 Double_t c[5] = {1.38532e+00, 1.00596e+02, -3.46378e+01, 3.94172e+00, -1.48319e-01};
277 Double_t x = TMath::Abs(px[0]);
281 y = 96.455 - 0.8483 * x * x;
282 } else if (x < 7.9) {
285 while (j > 0) y = y * x + c[--j];
293 // particle composition
295 Int_t AliGenMUONlib::IpJpsi(TRandom *)
305 //____________________________________________________________
306 Double_t AliGenMUONlib::PtUpsilon( Double_t *px, Double_t *dummy )
309 const Double_t kpt0 = 5.3;
310 const Double_t kxn = 2.5;
313 Double_t pass1 = 1.+(x/kpt0)*(x/kpt0);
314 return x/TMath::Power(pass1,kxn);
317 Double_t AliGenMUONlib::PtUpsilonPbPb( Double_t *px, Double_t *dummy)
327 // mc = 1.4 GeV, pt-kick 1 GeV
331 -1.03488e+01, 1.28065e+01, -6.60500e+00, 1.66140e+00,
332 -2.34293e-01, 1.86925e-02, -7.80708e-04, 1.30610e-05
338 while (j > 0) y = y * x +c[--j];
339 y = x * TMath::Exp(y);
346 Double_t AliGenMUONlib::PtUpsilonPP( Double_t *px, Double_t *dummy)
356 // mc = 1.4 GeV, pt-kick 1 GeV
359 Double_t c[8] = {-7.93955e+00, 1.06306e+01, -5.21392e+00, 1.19703e+00,
360 -1.45718e-01, 8.95151e-03, -2.04806e-04, -1.13053e-06};
366 while (j > 0) y = y * x +c[--j];
367 y = x * TMath::Exp(y);
377 //____________________________________________________________
378 Double_t AliGenMUONlib::YUpsilon(Double_t *py, Double_t *dummy)
381 const Double_t ky0 = 3.;
382 const Double_t kb=1.;
384 Double_t y=TMath::Abs(*py);
389 yu=kb*TMath::Exp(-(y-ky0)*(y-ky0)/2);
394 Double_t AliGenMUONlib::YUpsilonPbPb( Double_t *px, Double_t *dummy)
404 // mc = 1.4 GeV, pt-kick 1 GeV
407 Double_t c[7] = {3.40036e-01, -3.98882e-07, -4.48398e-03, 8.46411e-08, -6.10854e-04,
408 -2.99753e-09, 1.28895e-05};
411 if (TMath::Abs(x) > 5.55) return 0.;
413 Double_t y = c[j = 6];
414 while (j > 0) y = y * x +c[--j];
418 Double_t AliGenMUONlib::YUpsilonPP( Double_t *px, Double_t *dummy)
428 // mc = 1.4 GeV, pt-kick 1 GeV
430 Double_t c[7] = {8.91936e-01, -6.46645e-07, -1.52774e-02, 4.28677e-08, -7.01517e-04,
431 -6.20539e-10, 1.29943e-05};
434 if (TMath::Abs(x) > 6.2) return 0.;
436 Double_t y = c[j = 6];
437 while (j > 0) y = y * x +c[--j];
441 // particle composition
443 Int_t AliGenMUONlib::IpUpsilon(TRandom *)
453 // pt-distribution (by scaling of pion distribution)
454 //____________________________________________________________
455 Double_t AliGenMUONlib::PtPhi( Double_t *px, Double_t *dummy)
458 return PtScal(*px,7);
461 Double_t AliGenMUONlib::YPhi( Double_t *px, Double_t *dummy)
465 return YJpsi(px,dum);
467 // particle composition
469 Int_t AliGenMUONlib::IpPhi(TRandom *)
479 // pt-distribution (by scaling of pion distribution)
480 //____________________________________________________________
481 Double_t AliGenMUONlib::PtOmega( Double_t *px, Double_t *dummy)
484 return PtScal(*px,5);
487 Double_t AliGenMUONlib::YOmega( Double_t *px, Double_t *dummy)
491 return YJpsi(px,dum);
493 // particle composition
495 Int_t AliGenMUONlib::IpOmega(TRandom *)
506 // pt-distribution (by scaling of pion distribution)
507 //____________________________________________________________
508 Double_t AliGenMUONlib::PtEta( Double_t *px, Double_t *dummy)
511 return PtScal(*px,3);
514 Double_t AliGenMUONlib::YEta( Double_t *px, Double_t *dummy)
518 return YJpsi(px,dum);
520 // particle composition
522 Int_t AliGenMUONlib::IpEta(TRandom *)
533 //____________________________________________________________
534 Double_t AliGenMUONlib::PtCharm( Double_t *px, Double_t *dummy)
537 const Double_t kpt0 = 4.08;
538 const Double_t kxn = 9.40;
542 Double_t pass1 = 1.+(x/kpt0);
543 return x/TMath::Power(pass1,kxn);
546 Double_t AliGenMUONlib::YCharm( Double_t *px, Double_t *dummy)
550 return YJpsi(px,dum);
553 Int_t AliGenMUONlib::IpCharm(TRandom *ran)
559 random = ran->Rndm();
562 } else if (random < 0.75) {
564 } else if (random < 0.90) {
569 if (ran->Rndm() < 0.5) {ip=-ip;}
580 //____________________________________________________________
581 Double_t AliGenMUONlib::PtBeauty( Double_t *px, Double_t *dummy)
584 const Double_t kpt0 = 4.;
585 const Double_t kxn = 3.6;
588 Double_t pass1 = 1.+(x/kpt0)*(x/kpt0);
589 return x/TMath::Power(pass1,kxn);
592 Double_t AliGenMUONlib::YBeauty( Double_t *px, Double_t *dummy)
596 return YJpsi(px,dum);
599 Int_t AliGenMUONlib::IpBeauty(TRandom *ran)
601 // Beauty Composition
604 random = ran->Rndm();
607 } else if (random < 0.75) {
609 } else if (random < 0.90) {
614 if (ran->Rndm() < 0.5) {ip=-ip;}
619 typedef Double_t (*GenFunc) (Double_t*, Double_t*);
620 GenFunc AliGenMUONlib::GetPt(Int_t param, const char* tname) const
622 // Return pointer to pT parameterisation
623 TString sname = TString(tname);
637 if (sname == "Vogt" || sname == "Vogt PbPb") {
639 } else if (sname == "Vogt pp") {
646 if (sname == "Vogt" || sname == "Vogt PbPb") {
648 } else if (sname == "Vogt pp") {
668 printf("<AliGenMUONlib::GetPt> unknown parametrisation\n");
673 GenFunc AliGenMUONlib::GetY(Int_t param, const char* tname) const
675 TString sname = TString(tname);
677 // Return pointer to y- parameterisation
691 if (sname == "Vogt" || sname == "Vogt PbPb") {
693 } else if (sname == "Vogt pp"){
701 if (sname == "Vogt" || sname == "Vogt PbPb") {
703 } else if (sname == "Vogt pp") {
723 printf("<AliGenMUONlib::GetY> unknown parametrisation\n");
727 typedef Int_t (*GenFuncIp) (TRandom *);
728 GenFuncIp AliGenMUONlib::GetIp(Int_t param, const char* tname) const
730 // Return pointer to particle type parameterisation
763 printf("<AliGenMUONlib::GetIp> unknown parametrisation\n");
770 Float_t AliGenMUONlib::Interpolate(Float_t x, Float_t* y, Float_t x0,
775 // Neville's alorithm for interpolation
781 // n: number of data points
782 // no: order of polynom
784 Float_t* c = new Float_t[n];
785 Float_t* d = new Float_t[n];
787 for (i = 0; i < n; i++) {
792 Int_t ns = int((x - x0)/dx);
796 for (m = 0; m < no; m++) {
797 for (i = 0; i < n-m; i++) {
798 Float_t ho = x0 + Float_t(i) * dx - x;
799 Float_t hp = x0 + Float_t(i+m+1) * dx - x;
800 Float_t w = c[i+1] - d[i];
808 if (2*ns < (n-m-1)) {