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Pile-up vertices added to AODEvent. (F. Prino)
[u/mrichter/AliRoot.git] / ZDC / AliZDCFragment.cxx
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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// ******************************************************************
18//
19// Class for nuclear fragments formation
20//
21// ******************************************************************
22
23// --- Standard libraries
24#include <stdlib.h>
25
26// --- ROOT system
27#include <TRandom.h>
28#include <TF1.h>
29
30// --- AliRoot classes
31#include "AliZDCFragment.h"
32
33ClassImp(AliZDCFragment)
34
35int comp(const void *i,const void *j) {return *(int *)i - *(int *)j;}
36
37
38//_____________________________________________________________________________
39AliZDCFragment::AliZDCFragment():
40 fB(0),
41 fZbAverage(0),
42 fNimf(0),
43 fZmax(0),
44 fTau(0),
45 fNalpha(0),
46 fZtot(0),
47 fNtot(0)
48{
49 //
50 // Default constructor
51 //
52}
53
54//_____________________________________________________________________________
55AliZDCFragment::AliZDCFragment(Float_t b):
56 TNamed(" "," "),
57 fB(b),
58 fZbAverage(0),
59 fNimf(0),
60 fZmax(0),
61 fTau(0),
62 fNalpha(0),
63 fZtot(0),
64 fNtot(0)
65{
66 //
67 // Standard constructor
68 //
69 for(Int_t i=0; i<=99; i++){
70 fZZ[i] = 0;
71 fNN[i] = 0;
72 }
73
74}
75
76//_____________________________________________________________________________
77void AliZDCFragment::GenerateIMF()
78{
79
80 // Loop variables
81 Int_t i,j;
82
83 // Coefficients of polynomial for average number of IMF
84 const Float_t kParamNimf[5]={0.011236,1.8364,56.572,-116.24,58.289};
85 // Coefficients of polynomial for fluctuations on average number of IMF
86 const Float_t kParamFluctNimf[4]={-0.13176,2.9392,-5.2147,2.3092};
87 // Coefficients of polynomial for average maximum Z of fragments
88 const Float_t kParamZmax[4]={0.16899,14.203,-2.8284,65.036};
89 // Coefficients of polynomial for fluctuations on maximum Z of fragments
90 const Float_t kParamFluctZmax[5]={0.013782,-0.17282,1.5065,1.0654,-2.4317};
91 // Coefficients of polynomial for exponent tau of fragments Z distribution
92 const Float_t kParamTau[3]={6.7233,-15.85,13.047};
93 //Coefficients of polynomial for average number of alphas
94 const Float_t kParamNalpha[4]={-0.68554,39.605,-68.311,30.165};
95 // Coefficients of polynomial for fluctuations on average number of alphas
96 const Float_t kParamFluctNalpha[5]={0.283,6.2141,-17.113,17.394,-6.6084};
97 // Coefficients of function for Pb nucleus skin
98 const Float_t kParamSkinPb[2]={0.93,11.05};
99
100 // Thickness of nuclear surface
101 const Float_t kNuclearThick = 0.52;
102 // Maximum impact parameter for U [r0*A**(1/3)]
103 const Float_t kbMaxU = 14.87;
104 // Maximum impact parameter for Pb [r0*A**(1/3)]
105 const Float_t kbMaxPb = 14.22;
106 // Z of the projectile
107 const Float_t kZProj = 82.;
108
109 // From b(Pb) to b(U)
110 Float_t bU = fB*kbMaxU/kbMaxPb;
111
112 // From b(U) to Zbound(U)
113 // --- A.Schuttauf et al, Nuc.Phys. A607 (1996) 457 ---------------
114 // From geometrical consideration and from dsigma/dZbound for U+U,
115 // which is approx. constant, the constant value is found
116 // integrating the nucleus cross surface from 0 to bmax=R1+R2 where
117 // R = 1.2*A**(1/3). This value has been measured in Aladin (U+U).
118 Float_t zbU = bU*bU*TMath::Pi()/7.48;
119
120 // Rescale Zbound for Pb
121 fZbAverage = kZProj/92.*zbU;
122
123 // Zbound is proportional to b**2 up to b < kbMaxPb-2*kNuclearThick
124 // and then it is an increasing exponential, imposing that at
125 // b=kbMaxPb-2kNuclearThick the two functions have the same derivative
126 Float_t bCore = kbMaxPb-2*kNuclearThick;
127 if(fB>bCore){
128 fZbAverage=kZProj*(1.-TMath::Exp(-kParamSkinPb[0]*(fB-kParamSkinPb[1])));
129 }
130 if(fZbAverage>kZProj) fZbAverage = kZProj;
131 Float_t zbNorm = fZbAverage/kZProj;
132 Float_t bNorm = fB/kbMaxPb;
133
134 // From Zbound to <Nimf>,<Zmax>,tau
135 // Polinomial fits to Aladin distribution
136 // --- A.Schuttauf et al, Nuc.Phys. A607 (1996) 457.
137 Float_t averageNimf = kParamNimf[0]+kParamNimf[1]*zbNorm+kParamNimf[2]*
138 TMath::Power(zbNorm,2)+kParamNimf[3]*TMath::Power(zbNorm,3)+
139 kParamNimf[4]*TMath::Power(zbNorm,4);
140
141 // Add fluctuation: from Singh et al.
142 Float_t fluctNimf = kParamFluctNimf[0]+kParamFluctNimf[1]*zbNorm+
143 kParamFluctNimf[2]*TMath::Power(zbNorm,2)+kParamFluctNimf[3]
144 *TMath::Power(zbNorm,3);
145 Float_t xx = gRandom->Gaus(0.0,1.0);
146 fluctNimf = fluctNimf*xx;
147 fNimf = Int_t(averageNimf+fluctNimf);
148 Float_t y = gRandom->Rndm();
149 if(y < ((averageNimf+fluctNimf)-fNimf)) fNimf += 1;
150 if(fNimf ==0 && zbNorm>0.75) fNimf = 1;
151
152 Float_t averageZmax = kParamZmax[0]+kParamZmax[1]*zbNorm+kParamZmax[2]*
153 TMath::Power(zbNorm,2)+kParamZmax[3]*TMath::Power(zbNorm,3);
154 fTau = kParamTau[0]+kParamTau[1]*zbNorm+kParamTau[2]*TMath::Power(zbNorm,2);
155
156 // Add fluctuation to mean value of Zmax (see Hubele)
157 Float_t fluctZmax = kParamFluctZmax[0]+kParamFluctZmax[1]*zbNorm+
158 kParamFluctZmax[2]*TMath::Power(zbNorm,2)+kParamFluctZmax[3]*
159 TMath::Power(zbNorm,3)+kParamFluctZmax[4]*TMath::Power(zbNorm,4);
160 fluctZmax = fluctZmax*kZProj/6.;
161 Float_t xg = gRandom->Gaus(0.0,1.0);
162 fluctZmax = fluctZmax*xg;
163 fZmax = averageZmax+fluctZmax;
164 if(fZmax>kZProj) fZmax = kZProj;
165
166// printf("\n\n ------------------------------------------------------------");
167// printf("\n Generation of nuclear fragments\n");
168// printf("\n fNimf = %d\n", fNimf);
169// printf("\n fZmax = %f\n", fZmax);
170
171 // Find the number of alpha particles
172 // from Singh et al. : Pb+emulsion
173 Float_t averageAlpha = kParamNalpha[0]+kParamNalpha[1]*zbNorm+
174 kParamNalpha[2]*TMath::Power(zbNorm,2)+kParamNalpha[3]*
175 TMath::Power(zbNorm,3);
176 Float_t fluctAlpha = kParamFluctNalpha[0]+kParamFluctNalpha[1]*
177 zbNorm+kParamFluctNalpha[2]*TMath::Power(zbNorm,2)+
178 kParamFluctNalpha[3]*TMath::Power(zbNorm,3)+
179 kParamFluctNalpha[4]*TMath::Power(zbNorm,4);
180 Float_t xxx = gRandom->Gaus(0.0,1.0);
181 fluctAlpha = fluctAlpha*xxx;
182 fNalpha = Int_t(averageAlpha+fluctAlpha);
183 Float_t yy = gRandom->Rndm();
184 if(yy < ((averageAlpha+fluctAlpha)-fNalpha)) fNalpha += 1;
185
186 // 2 possibilities:
187 // 1) for bNorm < 0.9 ==> first remove alphas, then fragments
188 // 2) for bNorm > 0.9 ==> first remove fragments, then alphas
189
190 Int_t choice = 0;
191 Float_t zbFrag = 0, sumZ = 0.;
192
193 if(bNorm<=0.9) {
194 // remove alpha from zbound to find zbound for fragments (Z>=3)
195 zbFrag = fZbAverage-fNalpha*2;
196 choice = 1;
197 }
198 else {
199 zbFrag = fZbAverage;
200 choice = 0;
201 }
202// printf("\n choice = %d, fZbAverage = %f, zbFrag = %f \n", choice, fZbAverage, zbFrag);
203
204
205 // Check if zbFrag < fZmax
206 if(zbFrag<=fZmax) {
207 if(fNimf>0 && zbFrag>=2){
208 fNimf = 1;
209 fZZ[0] = Int_t(zbFrag);
210 sumZ = zbFrag;
211 }
212 else {
213 fNimf = 0;
214 }
215 return;
216 }
217
218 // Prepare the exponential charge distribution dN/dZ
219 if(fZmax <= 0.01) {
220 fNimf = 0;
221 return;
222 }
223 if(fNimf == 0) {
224 fNimf = 0;
225 return;
226 }
227
228 TF1 *funTau = new TF1("funTau","1./(x**[0])",0.01,fZmax);
229 funTau->SetParameter(0,fTau);
230
231 // Extract randomly the charge of the fragments from the distribution
232
233 Float_t * zz = new Float_t[fNimf];
234 for(j=0; j<fNimf; j++){
235 zz[j] =0;
236 }
237 for(i=0; i<fNimf; i++){
238 zz[i] = Float_t(funTau->GetRandom());
239// printf("\n zz[%d] = %f \n",i,zz[i]);
240 }
241 delete funTau;
242
243 // Sorting vector in ascending order with C function QSORT
244 qsort((void*)zz,fNimf,sizeof(Float_t),comp);
245
246
247// for(Int_t i=0; i<fNimf; i++){
248// printf("\n After sorting -> zz[%d] = %f \n",i,zz[i]);
249// }
250
251 // Rescale the maximum charge to fZmax
252 for(j=0; j<fNimf; j++){
253 fZZ[j] = Int_t (zz[j]*fZmax/zz[fNimf-1]);
254 if(fZZ[j]<3) fZZ[j] = 3;
255// printf("\n fZZ[%d] = %d \n",j,fZZ[j]);
256 }
257
258 delete[] zz;
259
260 // Check that the sum of the bound charges is not > than Zbound-Zalfa
261
262 for(Int_t ii=0; ii<fNimf; ii++){
263 sumZ += fZZ[ii];
264 }
265
266 Int_t k = 0;
267 if(sumZ>zbFrag){
268 for(i=0; i< fNimf; i++){
269 k += 1;
270 sumZ -= fZZ[i];
271 if(sumZ<=zbFrag){
272 fNimf -= (i+1);
273 break;
274 }
275 }
276 }
277 else {
278 if(choice == 1) return;
279 Int_t iDiff = Int_t((zbFrag-sumZ)/2);
280 if(iDiff<fNalpha){
281 fNalpha=iDiff;
282 return;
283 }
284 else{
285 return;
286 }
287 }
288
289 fNimf += k;
290 for(i=0; i<fNimf; i++){
291 fZZ[i] = fZZ[i+k];
292 }
293 fNimf -= k;
294
295 sumZ=0;
296 for(i=0; i<fNimf; i++){
297 sumZ += fZZ[i];
298 }
299
300}
301
302//_____________________________________________________________________________
303void AliZDCFragment::AttachNeutrons()
304{
305//
306// Prepare nuclear fragment by attaching a suitable number of neutrons
307//
308 const Float_t kAIon[68]={1.87612,2.80943,3.7284,5.60305,6.53536,
309 6.53622,8.39479,9.32699,10.2551,11.17793,
310 13.04378,14.89917,17.6969,18.62284,21.41483,
311 22.34193,25.13314,26.06034,28.85188,29.7818,
312 32.57328,33.50356,36.29447,37.22492,41.87617,
313 44.66324,47.45401,48.38228,51.17447,52.10307,
314 54.89593,53.96644,58.61856,59.54963,68.85715,
315 74.44178,78.16309,81.88358,83.74571,91.19832,
316 98.64997,106.10997,111.68821,122.86796,
317 128.45793,
318 130.32111,141.51236,
319 141.55,146.477,148.033,152.699,153.631,
320 155.802,157.357,162.022,162.984,166.2624,
321 168.554,171.349,173.4536,177.198,179.0518,
322 180.675,183.473,188.1345,190.77,193.729,
323 221.74295};
324 const Int_t kZIon[68]={1,1,2,3,3,
325 4,4,5,5,6,
326 7,8,9,10,11,
327 12,13,14,15,16,
328 17,18,19,20,21,
329 22,23,24,25,26,
330 27,28,29,30,32,
331 34,36,38,40,42,
332 46,48,50,54,56,
333 58,62,
334 63,64,65,66,67,
335 68,69,70,71,72,
336 73,74,75,76,77,
337 78,79,80,81,82,
338 92};
339
340 Int_t iZ, iA;
341// printf("\n fNimf=%d\n",fNimf);
342
343 for(Int_t i=0; i<fNimf; i++) {
344 for(Int_t j=0; j<68; j++) {
345 iZ = kZIon[j];
346 if((fZZ[i]-iZ) == 0){
347 iA = Int_t(kAIon[j]/0.93149432+0.5);
348 fNN[i] = iA - iZ;
349 break;
350 }
351 else if((fZZ[i]-iZ) < 0){
352 fZZ[i] = kZIon[j-1];
353 iA = Int_t (kAIon[j-1]/0.93149432+0.5);
354 fNN[i] = iA - kZIon[j-1];
355 break;
356 }
357 }
358 fZtot += fZZ[i];
359 fNtot += fNN[i];
360 }
361
362
363}
364
365//_____________________________________________________________________________
366Float_t AliZDCFragment::DeuteronNumber()
367{
368 // Calculates the fraction of deuterum nucleus produced
369 //
370 Float_t deuteronProdPar[2] = {-0.068,0.0385};
371 Float_t deutNum = deuteronProdPar[0] + deuteronProdPar[1]*fB;
372 if(deutNum<0.) deutNum = 0.;
373 return deutNum;
374}