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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 | // --- 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" |
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25 | |
5a881c97 |
26 | ClassImp(AliZDCFragment) |
27 | |
28 | int comp(const void *i,const void *j) {return *(int *)i - *(int *)j;} |
29 | |
30 | |
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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; |
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52 | for(Int_t i=0; i<=99; i++){ |
53 | fZZ[i] = 0; |
54 | fNN[i] = 0; |
55 | } |
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56 | fNalpha = 0; |
57 | fZtot = 0; |
58 | fNtot = 0; |
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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 | |
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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}; |
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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}; |
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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}; |
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77 | // Coefficients of polynomial for exponent tau of fragments Z distribution |
86d81a3c |
78 | const Float_t kParamTau[3]={6.7233,-15.85,13.047}; |
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79 | //Coefficients of polynomial for average number of alphas |
86d81a3c |
80 | const Float_t kParamNalpha[4]={-0.68554,39.605,-68.311,30.165}; |
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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.; |
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94 | |
95 | // From b(Pb) to b(U) |
86d81a3c |
96 | Float_t bU = fB*kbMaxU/kbMaxPb; |
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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; |
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105 | |
106 | // Rescale Zbound for Pb |
86d81a3c |
107 | fZbAverage = kZProj/92.*zbU; |
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108 | |
86d81a3c |
109 | // Zbound is proportional to b**2 up to b < kbMaxPb-2*kNuclearThick |
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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; |
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113 | if(fB>bCore){ |
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114 | fZbAverage=kZProj*(1.-TMath::Exp(-kParamSkinPb[0]*(fB-kParamSkinPb[1]))); |
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115 | } |
86d81a3c |
116 | if(fZbAverage>kZProj) fZbAverage = kZProj; |
117 | Float_t zbNorm = fZbAverage/kZProj; |
118 | Float_t bNorm = fB/kbMaxPb; |
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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); |
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126 | |
127 | // Add fluctuation: from Singh et al. |
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128 | Float_t fluctNimf = kParamFluctNimf[0]+kParamFluctNimf[1]*zbNorm+ |
129 | kParamFluctNimf[2]*TMath::Power(zbNorm,2)+kParamFluctNimf[3] |
130 | *TMath::Power(zbNorm,3); |
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131 | Float_t xx = gRandom->Gaus(0.0,1.0); |
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132 | fluctNimf = fluctNimf*xx; |
133 | fNimf = Int_t(averageNimf+fluctNimf); |
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134 | Float_t y = gRandom->Rndm(); |
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135 | if(y < ((averageNimf+fluctNimf)-fNimf)) fNimf += 1; |
136 | if(fNimf ==0 && zbNorm>0.75) fNimf = 1; |
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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); |
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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.; |
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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; |
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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); |
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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); |
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169 | Float_t yy = gRandom->Rndm(); |
86d81a3c |
170 | if(yy < ((averageAlpha+fluctAlpha)-fNalpha)) fNalpha += 1; |
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171 | |
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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.; |
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178 | |
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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); |
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189 | |
190 | |
86d81a3c |
191 | // Check if zbFrag < fZmax |
192 | if(zbFrag<=fZmax) { |
193 | if(fNimf>0 && zbFrag>=2){ |
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194 | fNimf = 1; |
86d81a3c |
195 | fZZ[0] = Int_t(zbFrag); |
196 | sumZ = zbFrag; |
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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 | |
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219 | Float_t * zz = new Float_t[fNimf]; |
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220 | for(j=0; j<fNimf; j++){ |
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221 | zz[j] =0; |
222 | } |
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223 | for(i=0; i<fNimf; i++){ |
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224 | zz[i] = Float_t(funTau->GetRandom()); |
225 | // printf("\n zz[%d] = %f \n",i,zz[i]); |
226 | } |
227 | delete funTau; |
228 | |
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229 | // Sorting vector in ascending order with C function QSORT |
4b016189 |
230 | qsort((void*)zz,fNimf,sizeof(Float_t),comp); |
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231 | |
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232 | |
233 | // for(Int_t i=0; i<fNimf; i++){ |
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234 | // printf("\n After sorting -> zz[%d] = %f \n",i,zz[i]); |
5a881c97 |
235 | // } |
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236 | |
237 | // Rescale the maximum charge to fZmax |
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238 | for(j=0; j<fNimf; j++){ |
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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; |
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245 | |
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246 | // Check that the sum of the bound charges is not > than Zbound-Zalfa |
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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++){ |
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255 | k += 1; |
86d81a3c |
256 | sumZ -= fZZ[i]; |
257 | if(sumZ<=zbFrag){ |
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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); |
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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 | } |