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28e0901a | 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 | // --- Standard libraries | |
17 | #include <stdlib.h> | |
28e0901a | 18 | |
19 | // --- ROOT system | |
20 | #include <TRandom.h> | |
21 | #include <TF1.h> | |
22 | ||
23 | // --- AliRoot classes | |
24 | #include "AliZDCFragment.h" | |
28e0901a | 25 | |
5a881c97 | 26 | ClassImp(AliZDCFragment) |
27 | ||
28 | int comp(const void *i,const void *j) {return *(int *)i - *(int *)j;} | |
29 | ||
30 | ||
28e0901a | 31 | //_____________________________________________________________________________ |
32 | AliZDCFragment::AliZDCFragment() | |
33 | { | |
34 | // | |
35 | // Default constructor | |
36 | // | |
37 | fB = 0; | |
38 | } | |
39 | ||
40 | //_____________________________________________________________________________ | |
41 | AliZDCFragment::AliZDCFragment(Float_t b) | |
42 | : TNamed(" "," ") | |
43 | { | |
44 | // | |
45 | // Standard constructor | |
46 | // | |
47 | fB = b; | |
48 | fZbAverage = 0; | |
49 | fNimf = 0; | |
50 | fZmax = 0; | |
51 | fTau = 0; | |
28e0901a | 52 | for(Int_t i=0; i<=99; i++){ |
53 | fZZ[i] = 0; | |
54 | fNN[i] = 0; | |
55 | } | |
5a881c97 | 56 | fNalpha = 0; |
57 | fZtot = 0; | |
58 | fNtot = 0; | |
28e0901a | 59 | |
60 | } | |
61 | ||
62 | //_____________________________________________________________________________ | |
63 | void AliZDCFragment::GenerateIMF(Int_t* fZZ, Int_t &fNalpha) | |
64 | { | |
583731c7 | 65 | |
66 | // Loop variables | |
67 | Int_t i,j; | |
68 | ||
28e0901a | 69 | // Coefficients of polynomial for average number of IMF |
86d81a3c | 70 | const Float_t kParamNimf[5]={0.011236,1.8364,56.572,-116.24,58.289}; |
28e0901a | 71 | // Coefficients of polynomial for fluctuations on average number of IMF |
86d81a3c | 72 | const Float_t kParamFluctNimf[4]={-0.13176,2.9392,-5.2147,2.3092}; |
28e0901a | 73 | // Coefficients of polynomial for average maximum Z of fragments |
86d81a3c | 74 | const Float_t kParamZmax[4]={0.16899,14.203,-2.8284,65.036}; |
28e0901a | 75 | // Coefficients of polynomial for fluctuations on maximum Z of fragments |
86d81a3c | 76 | const Float_t kParamFluctZmax[5]={0.013782,-0.17282,1.5065,1.0654,-2.4317}; |
28e0901a | 77 | // Coefficients of polynomial for exponent tau of fragments Z distribution |
86d81a3c | 78 | const Float_t kParamTau[3]={6.7233,-15.85,13.047}; |
28e0901a | 79 | //Coefficients of polynomial for average number of alphas |
86d81a3c | 80 | const Float_t kParamNalpha[4]={-0.68554,39.605,-68.311,30.165}; |
28e0901a | 81 | // Coefficients of polynomial for fluctuations on average number of alphas |
86d81a3c | 82 | const Float_t kParamFluctNalpha[5]={0.283,6.2141,-17.113,17.394,-6.6084}; |
28e0901a | 83 | // Coefficients of function for Pb nucleus skin |
86d81a3c | 84 | const Float_t kParamSkinPb[2]={0.93,11.05}; |
28e0901a | 85 | |
86 | // Thickness of nuclear surface | |
86d81a3c | 87 | const Float_t kNuclearThick = 0.52; |
28e0901a | 88 | // Maximum impact parameter for U [r0*A**(1/3)] |
86d81a3c | 89 | const Float_t kbMaxU = 14.87; |
28e0901a | 90 | // Maximum impact parameter for Pb [r0*A**(1/3)] |
86d81a3c | 91 | const Float_t kbMaxPb = 14.22; |
28e0901a | 92 | // Z of the projectile |
86d81a3c | 93 | const Float_t kZProj = 82.; |
28e0901a | 94 | |
95 | // From b(Pb) to b(U) | |
86d81a3c | 96 | Float_t bU = fB*kbMaxU/kbMaxPb; |
28e0901a | 97 | |
98 | // From b(U) to Zbound(U) | |
99 | // --- A.Schuttauf et al, Nuc.Phys. A607 (1996) 457 --------------- | |
100 | // From geometrical consideration and from dsigma/dZbound for U+U, | |
101 | // which is approx. constant, the constant value is found | |
102 | // integrating the nucleus cross surface from 0 to bmax=R1+R2 where | |
103 | // R = 1.2*A**(1/3). This value has been measured in Aladin (U+U). | |
86d81a3c | 104 | Float_t zbU = bU*bU*TMath::Pi()/7.48; |
28e0901a | 105 | |
106 | // Rescale Zbound for Pb | |
86d81a3c | 107 | fZbAverage = kZProj/92.*zbU; |
28e0901a | 108 | |
86d81a3c | 109 | // Zbound is proportional to b**2 up to b < kbMaxPb-2*kNuclearThick |
28e0901a | 110 | // and then it is an increasing exponential, imposing that at |
86d81a3c | 111 | // b=kbMaxPb-2kNuclearThick the two functions have the same derivative |
112 | Float_t bCore = kbMaxPb-2*kNuclearThick; | |
28e0901a | 113 | if(fB>bCore){ |
86d81a3c | 114 | fZbAverage=kZProj*(1.-TMath::Exp(-kParamSkinPb[0]*(fB-kParamSkinPb[1]))); |
28e0901a | 115 | } |
86d81a3c | 116 | if(fZbAverage>kZProj) fZbAverage = kZProj; |
117 | Float_t zbNorm = fZbAverage/kZProj; | |
118 | Float_t bNorm = fB/kbMaxPb; | |
28e0901a | 119 | |
120 | // From Zbound to <Nimf>,<Zmax>,tau | |
121 | // Polinomial fits to Aladin distribution | |
122 | // --- A.Schuttauf et al, Nuc.Phys. A607 (1996) 457. | |
86d81a3c | 123 | Float_t averageNimf = kParamNimf[0]+kParamNimf[1]*zbNorm+kParamNimf[2]* |
124 | TMath::Power(zbNorm,2)+kParamNimf[3]*TMath::Power(zbNorm,3)+ | |
125 | kParamNimf[4]*TMath::Power(zbNorm,4); | |
28e0901a | 126 | |
127 | // Add fluctuation: from Singh et al. | |
86d81a3c | 128 | Float_t fluctNimf = kParamFluctNimf[0]+kParamFluctNimf[1]*zbNorm+ |
129 | kParamFluctNimf[2]*TMath::Power(zbNorm,2)+kParamFluctNimf[3] | |
130 | *TMath::Power(zbNorm,3); | |
28e0901a | 131 | Float_t xx = gRandom->Gaus(0.0,1.0); |
86d81a3c | 132 | fluctNimf = fluctNimf*xx; |
133 | fNimf = Int_t(averageNimf+fluctNimf); | |
28e0901a | 134 | Float_t y = gRandom->Rndm(); |
86d81a3c | 135 | if(y < ((averageNimf+fluctNimf)-fNimf)) fNimf += 1; |
136 | if(fNimf ==0 && zbNorm>0.75) fNimf = 1; | |
28e0901a | 137 | |
86d81a3c | 138 | Float_t averageZmax = kParamZmax[0]+kParamZmax[1]*zbNorm+kParamZmax[2]* |
139 | TMath::Power(zbNorm,2)+kParamZmax[3]*TMath::Power(zbNorm,3); | |
140 | fTau = kParamTau[0]+kParamTau[1]*zbNorm+kParamTau[2]*TMath::Power(zbNorm,2); | |
28e0901a | 141 | |
142 | // Add fluctuation to mean value of Zmax (see Hubele) | |
86d81a3c | 143 | Float_t fluctZmax = kParamFluctZmax[0]+kParamFluctZmax[1]*zbNorm+ |
144 | kParamFluctZmax[2]*TMath::Power(zbNorm,2)+kParamFluctZmax[3]* | |
145 | TMath::Power(zbNorm,3)+kParamFluctZmax[4]*TMath::Power(zbNorm,4); | |
146 | fluctZmax = fluctZmax*kZProj/6.; | |
28e0901a | 147 | Float_t xg = gRandom->Gaus(0.0,1.0); |
86d81a3c | 148 | fluctZmax = fluctZmax*xg; |
149 | fZmax = averageZmax+fluctZmax; | |
150 | if(fZmax>kZProj) fZmax = kZProj; | |
5a881c97 | 151 | |
152 | // printf("\n\n ------------------------------------------------------------"); | |
153 | // printf("\n Generation of nuclear fragments\n"); | |
154 | // printf("\n fNimf = %d\n", fNimf); | |
155 | // printf("\n fZmax = %f\n", fZmax); | |
28e0901a | 156 | |
157 | // Find the number of alpha particles | |
158 | // from Singh et al. : Pb+emulsion | |
86d81a3c | 159 | Float_t averageAlpha = kParamNalpha[0]+kParamNalpha[1]*zbNorm+ |
160 | kParamNalpha[2]*TMath::Power(zbNorm,2)+kParamNalpha[3]* | |
161 | TMath::Power(zbNorm,3); | |
162 | Float_t fluctAlpha = kParamFluctNalpha[0]+kParamFluctNalpha[1]* | |
163 | zbNorm+kParamFluctNalpha[2]*TMath::Power(zbNorm,2)+ | |
164 | kParamFluctNalpha[3]*TMath::Power(zbNorm,3)+ | |
165 | kParamFluctNalpha[4]*TMath::Power(zbNorm,4); | |
28e0901a | 166 | Float_t xxx = gRandom->Gaus(0.0,1.0); |
86d81a3c | 167 | fluctAlpha = fluctAlpha*xxx; |
168 | fNalpha = Int_t(averageAlpha+fluctAlpha); | |
28e0901a | 169 | Float_t yy = gRandom->Rndm(); |
86d81a3c | 170 | if(yy < ((averageAlpha+fluctAlpha)-fNalpha)) fNalpha += 1; |
28e0901a | 171 | |
28e0901a | 172 | // 2 possibilities: |
173 | // 1) for bNorm < 0.9 ==> first remove alphas, then fragments | |
174 | // 2) for bNorm > 0.9 ==> first remove fragments, then alphas | |
175 | ||
86d81a3c | 176 | Int_t choice = 0; |
177 | Float_t zbFrag = 0, sumZ = 0.; | |
5a881c97 | 178 | |
28e0901a | 179 | if(bNorm<=0.9) { |
180 | // remove alpha from zbound to find zbound for fragments (Z>=3) | |
86d81a3c | 181 | zbFrag = fZbAverage-fNalpha*2; |
182 | choice = 1; | |
28e0901a | 183 | } |
184 | else { | |
86d81a3c | 185 | zbFrag = fZbAverage; |
186 | choice = 0; | |
28e0901a | 187 | } |
86d81a3c | 188 | // printf("\n choice = %d, fZbAverage = %f, zbFrag = %f \n", choice, fZbAverage, zbFrag); |
28e0901a | 189 | |
190 | ||
86d81a3c | 191 | // Check if zbFrag < fZmax |
192 | if(zbFrag<=fZmax) { | |
193 | if(fNimf>0 && zbFrag>=2){ | |
28e0901a | 194 | fNimf = 1; |
86d81a3c | 195 | fZZ[0] = Int_t(zbFrag); |
196 | sumZ = zbFrag; | |
28e0901a | 197 | } |
198 | else { | |
199 | fNimf = 0; | |
200 | } | |
201 | return; | |
202 | } | |
203 | ||
204 | // Prepare the exponential charge distribution dN/dZ | |
205 | if(fZmax <= 0.01) { | |
206 | fNimf = 0; | |
207 | return; | |
208 | } | |
209 | if(fNimf == 0) { | |
210 | fNimf = 0; | |
211 | return; | |
212 | } | |
213 | ||
214 | TF1 *funTau = new TF1("funTau","1./(x**[0])",0.01,fZmax); | |
215 | funTau->SetParameter(0,fTau); | |
216 | ||
217 | // Extract randomly the charge of the fragments from the distribution | |
218 | ||
4b016189 | 219 | Float_t * zz = new Float_t[fNimf]; |
583731c7 | 220 | for(j=0; j<fNimf; j++){ |
28e0901a | 221 | zz[j] =0; |
222 | } | |
583731c7 | 223 | for(i=0; i<fNimf; i++){ |
28e0901a | 224 | zz[i] = Float_t(funTau->GetRandom()); |
225 | // printf("\n zz[%d] = %f \n",i,zz[i]); | |
226 | } | |
227 | delete funTau; | |
228 | ||
5a881c97 | 229 | // Sorting vector in ascending order with C function QSORT |
4b016189 | 230 | qsort((void*)zz,fNimf,sizeof(Float_t),comp); |
28e0901a | 231 | |
5a881c97 | 232 | |
233 | // for(Int_t i=0; i<fNimf; i++){ | |
28e0901a | 234 | // printf("\n After sorting -> zz[%d] = %f \n",i,zz[i]); |
5a881c97 | 235 | // } |
28e0901a | 236 | |
237 | // Rescale the maximum charge to fZmax | |
583731c7 | 238 | for(j=0; j<fNimf; j++){ |
28e0901a | 239 | fZZ[j] = Int_t (zz[j]*fZmax/zz[fNimf-1]); |
240 | if(fZZ[j]<3) fZZ[j] = 3; | |
5a881c97 | 241 | // printf("\n fZZ[%d] = %d \n",j,fZZ[j]); |
28e0901a | 242 | } |
4b016189 | 243 | |
244 | delete[] zz; | |
28e0901a | 245 | |
5a881c97 | 246 | // Check that the sum of the bound charges is not > than Zbound-Zalfa |
28e0901a | 247 | |
248 | for(Int_t ii=0; ii<fNimf; ii++){ | |
86d81a3c | 249 | sumZ += fZZ[ii]; |
28e0901a | 250 | } |
251 | ||
252 | Int_t k = 0; | |
86d81a3c | 253 | if(sumZ>zbFrag){ |
583731c7 | 254 | for(i=0; i< fNimf; i++){ |
28e0901a | 255 | k += 1; |
86d81a3c | 256 | sumZ -= fZZ[i]; |
257 | if(sumZ<=zbFrag){ | |
28e0901a | 258 | fNimf -= (i+1); |
259 | break; | |
260 | } | |
261 | } | |
262 | } | |
263 | else { | |
86d81a3c | 264 | if(choice == 1) return; |
265 | Int_t iDiff = Int_t((zbFrag-sumZ)/2); | |
28e0901a | 266 | if(iDiff<fNalpha){ |
267 | fNalpha=iDiff; | |
268 | return; | |
269 | } | |
270 | else{ | |
271 | return; | |
272 | } | |
273 | } | |
274 | ||
275 | fNimf += k; | |
583731c7 | 276 | for(i=0; i<fNimf; i++){ |
28e0901a | 277 | fZZ[i] = fZZ[i+k]; |
278 | } | |
279 | fNimf -= k; | |
280 | ||
86d81a3c | 281 | sumZ=0; |
583731c7 | 282 | for(i=0; i<fNimf; i++){ |
86d81a3c | 283 | sumZ += fZZ[i]; |
28e0901a | 284 | } |
28e0901a | 285 | |
286 | } | |
287 | ||
28e0901a | 288 | //_____________________________________________________________________________ |
289 | void AliZDCFragment::AttachNeutrons(Int_t *fZZ, Int_t *fNN, Int_t &fZtot,Int_t &fNtot) | |
290 | { | |
86d81a3c | 291 | // |
292 | // Prepare nuclear fragment by attaching a suitable number of neutrons | |
293 | // | |
294 | const Float_t kAIon[68]={1.87612,2.80943,3.7284,5.60305,6.53536, | |
28e0901a | 295 | 6.53622,8.39479,9.32699,10.2551,11.17793, |
296 | 13.04378,14.89917,17.6969,18.62284,21.41483, | |
297 | 22.34193,25.13314,26.06034,28.85188,29.7818, | |
298 | 32.57328,33.50356,36.29447,37.22492,41.87617, | |
299 | 44.66324,47.45401,48.38228,51.17447,52.10307, | |
300 | 54.89593,53.96644,58.61856,59.54963,68.85715, | |
301 | 74.44178,78.16309,81.88358,83.74571,91.19832, | |
302 | 98.64997,106.10997,111.68821,122.86796, | |
303 | 128.45793, | |
304 | 130.32111,141.51236, | |
305 | 141.55,146.477,148.033,152.699,153.631, | |
306 | 155.802,157.357,162.022,162.984,166.2624, | |
307 | 168.554,171.349,173.4536,177.198,179.0518, | |
308 | 180.675,183.473,188.1345,190.77,193.729, | |
309 | 221.74295}; | |
86d81a3c | 310 | const Int_t kZIon[68]={1,1,2,3,3, |
28e0901a | 311 | 4,4,5,5,6, |
312 | 7,8,9,10,11, | |
313 | 12,13,14,15,16, | |
314 | 17,18,19,20,21, | |
315 | 22,23,24,25,26, | |
316 | 27,28,29,30,32, | |
317 | 34,36,38,40,42, | |
318 | 46,48,50,54,56, | |
319 | 58,62, | |
320 | 63,64,65,66,67, | |
321 | 68,69,70,71,72, | |
322 | 73,74,75,76,77, | |
323 | 78,79,80,81,82, | |
324 | 92}; | |
325 | ||
326 | Int_t iZ, iA; | |
5a881c97 | 327 | // printf("\n fNimf=%d\n",fNimf); |
328 | ||
28e0901a | 329 | for(Int_t i=0; i<fNimf; i++) { |
330 | for(Int_t j=0; j<68; j++) { | |
86d81a3c | 331 | iZ = kZIon[j]; |
28e0901a | 332 | if((fZZ[i]-iZ) == 0){ |
86d81a3c | 333 | iA = Int_t(kAIon[j]/0.93149432+0.5); |
28e0901a | 334 | fNN[i] = iA - iZ; |
28e0901a | 335 | break; |
336 | } | |
337 | else if((fZZ[i]-iZ) < 0){ | |
86d81a3c | 338 | fZZ[i] = kZIon[j-1]; |
339 | iA = Int_t (kAIon[j-1]/0.93149432+0.5); | |
340 | fNN[i] = iA - kZIon[j-1]; | |
28e0901a | 341 | break; |
342 | } | |
343 | } | |
344 | fZtot += fZZ[i]; | |
345 | fNtot += fNN[i]; | |
346 | } | |
347 | ||
348 | ||
349 | } |