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1 | //#include <TClonesArray.h> | |
2 | ||
3 | #include <TDatabasePDG.h> | |
4 | #include <TFile.h> | |
5 | #include "AliConst.h" | |
6 | #include "AliGenMUONLMR.h" | |
7 | #include "AliMC.h" | |
8 | #include "AliRun.h" | |
9 | #include "AliGenEventHeader.h" | |
10 | ||
11 | ClassImp(AliGenMUONLMR) | |
12 | ||
13 | ||
14 | AliGenMUONLMR::AliGenMUONLMR (Double_t energy) : AliGenMC(), | |
15 | fNMuMin(2), | |
16 | fGenSingleProc(-1), | |
17 | fCosTheta(0x0), | |
18 | fRhoLineShape(0x0), | |
19 | fHMultMu(0x0), | |
20 | fHNProc(0x0) { | |
21 | // | |
22 | // default constructor | |
23 | // | |
24 | // initialize pt and y distributions according to a fit to | |
25 | // Pythia simulation at sqrt(s) = 7 TeV | |
26 | for (Int_t ipart=0; ipart < fgkNpart; ipart++) fScaleMult[ipart] = 1; | |
27 | fScaleMult[kPionLMR] = 0; // set pion multiplicity to zero | |
28 | fScaleMult[kKaonLMR] = 0; // set kaon multiplicity to zero | |
29 | Int_t pdg[7] = {211, 321, 221, 113, 223, 333, 331}; | |
30 | const char* fptname[7] = {"fPtPion","fPtKaon","fPtEta","fPtRho","fPtOmega","fPtPhi","fPtEtaPrime"}; | |
31 | const char* fyname[7] = {"fYPion","fYKaon","fYEta","fYRho","fYOmega","fYPhi","fYEtaPrime"}; | |
32 | const char* fnname[7] = {"fMultPion","fMultKaon","fMultEta","fMultRho","fMultOmega","fMultPhi","fMultEtaPrime"}; | |
33 | const char* fdname[2] = {"fDecPion","fDecKaon"}; | |
34 | Double_t ctau[2] = {7.8045, 3.712}; | |
35 | Double_t ptparam[7][9]; | |
36 | Double_t yparam[7][9]; | |
37 | Double_t nparam[7][9]; | |
38 | ||
39 | // parameters for 7 TeV generation | |
40 | if (energy==7.0) { | |
41 | printf ("AliGenMUONLMR: using pp parameterization at 7 TeV\n"); | |
42 | Double_t ptparam7000[7][9] = {{1,0.427,2.52,0,0,0,0,0,0}, // pions from Pythia | |
43 | {1,0.58,2.57,0,0,0,0,0,0}, // kaons from Pythia | |
44 | {1,0.641,2.62,0,0,0,0,0,0}, // eta from Pythia | |
45 | {1,1.44,3.16,0,0,0,0,0,0}, // rho+omega from ALICE muon | |
46 | {1,1.44,3.16,0,0,0,0,0,0}, // rho+omega from ALICE muon | |
47 | {1,1.16,2.74,0,0,0,0,0,0}, // phi from ALICE muon | |
48 | {1,0.72,2.5,0,0,0,0,0,0}}; // etaPrime from Pythia | |
49 | ||
50 | Double_t yparam7000[7][9] = {{1,0.8251,3.657,0,0,0,0,0,0}, // pions from pythia | |
51 | {1,1.83,2.698,0,0,0,0,0,0}, // kaons from pythia | |
52 | {1,1.169,3.282,0,0,0,0,0,0}, // eta from pythia | |
53 | {1,1.234,3.264,0,0,0,0,0,0}, // rho from pythia | |
54 | {1,1.311,3.223,0,0,0,0,0,0}, // omega from pythia | |
55 | {1,2.388,2.129,0,0,0,0,0,0}, // phi from pythia | |
56 | {1,1.13,3.3,0,0,0,0,0,0}}; // eta prime from pythia | |
57 | ||
58 | // multiplicity parameters from pythia | |
59 | Double_t nparam7000[7][9] = {{353.582, 6.76263, 1.66979, 998.445, 9.73281, 12.6704, 175.187, 29.08, 40.2531}, | |
60 | {1.e4, 0.2841, 0,0,0,0,0,0,0}, | |
61 | {1.e4, 0.2647, 0,0,0,0,0,0,0}, | |
62 | {7055, 0.1786, 0,0,0,0,0,0,0}, | |
63 | {7500, 0.1896, 0,0,0,0,0,0,0}, | |
64 | {5.e4, 1.167, 0,0,0,0,0,0,0}, | |
65 | {2.9e4, 0.714, 0,0,0,0,0,0,0}}; | |
66 | ||
67 | for (Int_t i=0; i<fgkNpart; i++) { | |
68 | for (Int_t j=0; j<9; j++) { | |
69 | ptparam[i][j] = ptparam7000[i][j]; | |
70 | yparam[i][j] = yparam7000[i][j]; | |
71 | nparam[i][j] = nparam7000[i][j]; | |
72 | } | |
73 | } | |
74 | } | |
75 | ||
76 | // parameters for 2.76 generation | |
77 | // pt params has been determined as <pt>ALICE_2.76 = <pt>ALICE_7 * <pt>PYTHIA_2.76 / <pt>PYTHIA_7 | |
78 | if (energy == 2.76){ | |
79 | printf ("AliGenMUONLMR: using pp parameterization at 2.76 TeV\n"); | |
80 | Double_t yparam2760[7][9] = {{1,0.8251,3.657,0,0,0,0,0,0}, // pions from pythia | |
81 | {1,1.83,2.698,0,0,0,0,0,0}, // kaons from pythia | |
82 | {1,0.011,3.474,0,0,0,0,0,0}, // eta from pythia | |
83 | {1,-0.01,3.409,0,0,0,0,0,0}, // rho from pythia | |
84 | {1,-0.037,3.294,0,0,0,0,0,0}, // omega from pythia | |
85 | {1,-0.016,2.717,0,0,0,0,0,0}, // phi from pythia | |
86 | {1,-0.010,3.312,0,0,0,0,0,0}}; // eta prime from pythia | |
87 | ||
88 | Double_t ptparam2760[7][9] = {{1,0.1665,8.878,0,0,0,0,0,0}, // pions from Pythia | |
89 | {1,0.1657,8.591,0,0,0,0,0,0}, // kaons from Pythia | |
90 | {1,0.641,2.62,0,0,0,0,0,0}, // eta from ALICE 7 TeV | |
91 | {1,1.3551,3.16,0,0,0,0,0,0}, // rho with <pt> scaled | |
92 | {1,1.3551,3.16,0,0,0,0,0,0}, // omega with <pt> scaled | |
93 | {1,1.0811,2.74,0,0,0,0,0,0}, // phi with <pt> scaled | |
94 | {1,0.72,2.5,0,0,0,0,0,0}}; // etaPrime from ALICE 7 TeV | |
95 | ||
96 | Double_t nparam2760[7][9] = {{9752,-2.693,3.023,9.5e9,-84.68,16.75,-14.06,635.3,-423.2}, // pions | |
97 | {1.e5, 1.538, 0,0,0,0,0,0,0}, // kaons | |
98 | {1.e4, 0.351, 0,0,0,0,0,0,0}, // eta | |
99 | {1.e4, 0.2471, 0,0,0,0,0,0,0}, // rho | |
100 | {1.e4, 0.2583, 0,0,0,0,0,0,0}, // omega | |
101 | {1.e5, 1.393, 0,0,0,0,0,0,0}, // phi | |
102 | {1.e4, 0.9005, 0,0,0,0,0,0,0}}; // etaPrime | |
103 | ||
104 | for (Int_t i=0; i<fgkNpart; i++) { | |
105 | for (Int_t j=0; j<9; j++) { | |
106 | ptparam[i][j] = ptparam2760[i][j]; | |
107 | yparam[i][j] = yparam2760[i][j]; | |
108 | nparam[i][j] = nparam2760[i][j]; | |
109 | } | |
110 | } | |
111 | } | |
112 | ||
113 | for (Int_t i=0; i<fgkNpart; i++) { | |
114 | fPDG[i] = pdg[i]; | |
115 | if (i!=0) { | |
116 | fMult[i] = new TF1(fnname[i],"[0]*exp(-[1]*x)",0,30); | |
117 | fMult[i]->SetParameters(nparam[i][0],nparam[i][1]); | |
118 | } | |
119 | else { | |
120 | fMult[i] = new TF1(fnname[i],"gaus(0)+gaus(3)+gaus(6)",0,150); | |
121 | for (Int_t j=0; j<9; j++) fMult[i]->SetParameter(j,nparam[i][j]); | |
122 | } | |
123 | ||
124 | fPt[i] = new TF1(fptname[i],AliGenMUONLMR::PtDistr,0,20,3); | |
125 | fPt[i]->SetParameters(ptparam[i][0], ptparam[i][1], ptparam[i][2]); | |
126 | fY[i] = new TF1(fyname[i],AliGenMUONLMR::YDistr,-10,10,3); | |
127 | fY[i]->SetParameters(yparam[i][0], yparam[i][1], yparam[i][2]); | |
128 | } | |
129 | ||
130 | for(Int_t i = 0; i<2; i++){ | |
131 | fDecay[i] = new TF1(fdname[i],"exp(-x/[0])",0,150); | |
132 | fDecay[i]->SetParameter(0,ctau[i]); | |
133 | } | |
134 | ||
135 | for (Int_t ipart = 0; ipart < fgkNpart; ipart++) { | |
136 | fParticle[ipart] = new TParticle(); | |
137 | fParticle[ipart]->SetPdgCode(fPDG[ipart]); | |
138 | } | |
139 | ||
140 | TDatabasePDG *pdgdb = TDatabasePDG::Instance(); | |
141 | Double_t mumass = pdgdb->GetParticle(13)->Mass(); | |
142 | fMu[0] = new TParticle(); | |
143 | fMu[0]->SetPdgCode(-13); | |
144 | fMu[0]->SetCalcMass(mumass); | |
145 | fMu[1] = new TParticle(); | |
146 | fMu[1]->SetPdgCode(13); | |
147 | fMu[1]->SetCalcMass(mumass); | |
148 | ||
149 | // function for polarized theta distributions | |
150 | fCosTheta = new TF1 ("fCosTheta","1+[0]*x*x",-1,1); | |
151 | fCosTheta->SetParameter(0,1); | |
152 | ||
153 | // Dalitz decays | |
154 | Int_t nbins = 1000; | |
155 | Double_t xmin = 0, xmax = 2; | |
156 | fDalitz[0] = new TH1F("hDalitzEta","",nbins,xmin,xmax); | |
157 | fDalitz[1] = new TH1F("hDalitzOmega","",nbins,xmin,xmax); | |
158 | fDalitz[2] = new TH1F("hDalitzEtaPrime","",nbins,xmin,xmax); | |
159 | ||
160 | Double_t meta = pdgdb->GetParticle("eta")->Mass(); | |
161 | Double_t momega = pdgdb->GetParticle("omega")->Mass(); | |
162 | Double_t metaPrime = pdgdb->GetParticle("eta'")->Mass(); | |
163 | Double_t mpi0 = pdgdb->GetParticle("pi0")->Mass(); | |
164 | Double_t md3 = 0, mres = 0; | |
165 | ||
166 | for (Int_t index = 0; index < 3; index++) { | |
167 | if (index == 0) { | |
168 | mres = meta; | |
169 | md3 = 0; | |
170 | } | |
171 | else if (index == 1) { | |
172 | mres = momega; | |
173 | md3 = mpi0; | |
174 | } | |
175 | else if (index == 2) { | |
176 | mres = metaPrime; | |
177 | md3 = 0; | |
178 | } | |
179 | Double_t delta = md3 * md3 / (mres * mres); | |
180 | Double_t epsilon = mumass * mumass / (mres * mres); | |
181 | nbins = fDalitz[index]->GetNbinsX(); | |
182 | xmin = fDalitz[index]->GetXaxis()->GetXmin(); | |
183 | Double_t deltax = fDalitz[index]->GetBinWidth(1); | |
184 | Double_t xd = xmin - deltax/2.; | |
185 | for (Int_t ibin = 0; ibin< nbins; ibin++) { | |
186 | Double_t dalval = 0; | |
187 | xd += deltax; | |
188 | if (xd > 4. *epsilon) { | |
189 | Double_t bracket = TMath::Power(1. + xd/(1. - delta),2) | |
190 | - 4. * xd / ((1. - delta) * (1. - delta)); | |
191 | if (bracket > 0) { | |
192 | dalval = TMath::Power(bracket,1.5) /xd * | |
193 | TMath::Sqrt(1 - 4 * epsilon / xd) * (1 + 2 * epsilon / xd) * | |
194 | FormFactor(xd * mres * mres, index); | |
195 | fDalitz[index]->Fill(xd,dalval); | |
196 | } | |
197 | } | |
198 | } | |
199 | } | |
200 | ||
201 | fRhoLineShape = new TF1("fRhoLineShape",RhoLineShapeNew,0,2,2); | |
202 | fHMultMu = new TH1D("fHMultMu","Muon multiplicity",20,-0.5,19.5); | |
203 | fHNProc = new TH1D("fHNProc","Number of gen. evts. per process in 4 pi",9,-0.5,8.5); | |
204 | } | |
205 | ||
206 | //----------------------------------------------------------- | |
207 | ||
208 | AliGenMUONLMR::AliGenMUONLMR (AliGenMUONLMR &gen) : AliGenMC(), | |
209 | fNMuMin(gen.fNMuMin), | |
210 | fGenSingleProc(gen.fGenSingleProc), | |
211 | fCosTheta(gen.fCosTheta), | |
212 | fRhoLineShape(gen.fRhoLineShape), | |
213 | fHMultMu(gen.fHMultMu), | |
214 | fHNProc(gen.fHNProc) { | |
215 | for (Int_t i=0; i < fgkNpart; i++) { | |
216 | fPDG[i] = gen.fPDG[i]; | |
217 | fScaleMult[i] = gen.fScaleMult[i]; | |
218 | fPt[i] = (TF1*) gen.fPt[i]->Clone(); | |
219 | fY[i] = (TF1*) gen.fY[i]->Clone(); | |
220 | fMult[i] = (TF1*) gen.fMult[i]->Clone(); | |
221 | fParticle[i] = (TParticle*) gen.fParticle[i]->Clone(); | |
222 | } | |
223 | ||
224 | for(Int_t i = 0; i<2; i++) fDecay[i] = (TF1*) gen.fDecay[i]->Clone(); | |
225 | for(Int_t i = 0; i<3; i++) fDalitz[i] = (TH1F*) gen.fDalitz[i]->Clone(); | |
226 | for(Int_t i = 0; i<2; i++) fMu[i] = (TParticle*) gen.fMu[i]->Clone(); | |
227 | } | |
228 | ||
229 | //----------------------------------------------------------- | |
230 | ||
231 | AliGenMUONLMR& AliGenMUONLMR::operator=(const AliGenMUONLMR &gen) { | |
232 | // Assignment operator | |
233 | if (this!=&gen) { | |
234 | fNMuMin = gen.fNMuMin; | |
235 | fGenSingleProc = gen.fGenSingleProc; | |
236 | fCosTheta = (TF1*) gen.fCosTheta->Clone(); | |
237 | fRhoLineShape = (TF1*) gen.fRhoLineShape->Clone(); | |
238 | fHMultMu = (TH1D*) gen.fHMultMu->Clone(); | |
239 | fHNProc = (TH1D*) gen.fHNProc->Clone(); | |
240 | ||
241 | for (Int_t i=0; i < fgkNpart; i++) { | |
242 | fPDG[i] = gen.fPDG[i]; | |
243 | fScaleMult[i] = gen.fScaleMult[i]; | |
244 | fPt[i] = (TF1*) gen.fPt[i]->Clone(); | |
245 | fY[i] = (TF1*) gen.fY[i]->Clone(); | |
246 | fMult[i] = (TF1*) gen.fMult[i]->Clone(); | |
247 | fParticle[i] = (TParticle*) gen.fParticle[i]->Clone(); | |
248 | } | |
249 | ||
250 | for(Int_t i = 0; i<2; i++) fDecay[i] = (TF1*) gen.fDecay[i]->Clone(); | |
251 | for(Int_t i = 0; i<3; i++) fDalitz[i] = (TH1F*) gen.fDalitz[i]->Clone(); | |
252 | for(Int_t i = 0; i<2; i++) fMu[i] = (TParticle*) gen.fMu[i]->Clone(); | |
253 | } | |
254 | return *this; | |
255 | } | |
256 | ||
257 | ||
258 | //----------------------------------------------------------- | |
259 | ||
260 | AliGenMUONLMR::~AliGenMUONLMR() | |
261 | { | |
262 | // Default destructor | |
263 | for (Int_t i=0; i<7; i++) { | |
264 | delete fPt[i]; | |
265 | delete fY[i]; | |
266 | delete fMult[i]; | |
267 | delete fParticle[i]; | |
268 | } | |
269 | ||
270 | for (Int_t i=0; i<2; i++) { | |
271 | delete fDecay[i]; | |
272 | delete fMu[i]; | |
273 | } | |
274 | ||
275 | for (Int_t i=0; i<3; i++) delete fDalitz[i]; | |
276 | ||
277 | delete fCosTheta; fCosTheta = 0; | |
278 | delete fRhoLineShape; fRhoLineShape = 0; | |
279 | delete fHMultMu; fHMultMu = 0; | |
280 | delete fHNProc; fHNProc = 0; | |
281 | } | |
282 | ||
283 | //----------------------------------------------------------- | |
284 | ||
285 | void AliGenMUONLMR::FinishRun(){ | |
286 | // save some histograms to an output file | |
287 | Int_t nbins = fHNProc->GetNbinsX(); | |
288 | for (Int_t ibin=1; ibin <= nbins; ibin++) printf ("ibin = %d nEvProc = %g\n", | |
289 | ibin,fHNProc->GetBinContent(ibin)); | |
290 | TFile *fout = new TFile("AliGenMUONLMR_histos.root","recreate"); | |
291 | fHMultMu->Write(); | |
292 | fHNProc->Write(); | |
293 | fout->Close(); | |
294 | } | |
295 | ||
296 | //----------------------------------------------------------- | |
297 | ||
298 | Double_t AliGenMUONLMR::YDistr(Double_t *px, Double_t *par){ | |
299 | // function for rapidity distribution: plateau at par[0] + | |
300 | // gaussian tails centered at par[1] and with par[2]=sigma | |
301 | Double_t x = TMath::Abs(px[0]); | |
302 | Double_t func = 0; | |
303 | if (x<par[1]) func = par[0]; | |
304 | else { | |
305 | Double_t z = (x-par[1])/(par[2]); | |
306 | func = par[0] * TMath::Exp(-0.5 * z * z); | |
307 | } | |
308 | return func; | |
309 | } | |
310 | ||
311 | //----------------------------------------------------------- | |
312 | ||
313 | Double_t AliGenMUONLMR::PtDistr(Double_t *px, Double_t *par){ | |
314 | // pt distribution: power law | |
315 | Double_t x = px[0]; | |
316 | Double_t func = par[0] * x / TMath::Power((1+(x/par[1])*(x/par[1])),par[2]); | |
317 | return func; | |
318 | } | |
319 | ||
320 | //----------------------------------------------------------- | |
321 | ||
322 | void AliGenMUONLMR::Generate() { | |
323 | // | |
324 | // generate the low mass resonances and their decays according to | |
325 | // the multiplicity parameterized by pythia and BR from PDG | |
326 | // rapidity distributions parametrized from pythia | |
327 | // pt distributions from data (or pythia for etaprime) | |
328 | // | |
329 | Double_t pxPushed[100], pyPushed[100], pzPushed[100], ePushed[100]; | |
330 | Int_t nmuons = -1, npartPushed = 0, pdgPushed[100]; | |
331 | Double_t polar[3]= {0,0,0}; // Polarisation of the parent particle (for GEANT tracking) | |
332 | Double_t origin0[3]; // Origin of the generated parent particle (for GEANT tracking) | |
333 | // Calculating vertex position per event | |
334 | for (Int_t j=0;j<3;j++) origin0[j]=fOrigin[j]; | |
335 | if(fVertexSmear==kPerEvent) { | |
336 | Vertex(); | |
337 | for (Int_t j=0;j<3;j++) origin0[j]=fVertex[j]; | |
338 | } | |
339 | ||
340 | printf ("In Generate()\n"); | |
341 | TParticle *mother; | |
342 | TDatabasePDG* pdg = TDatabasePDG::Instance(); | |
343 | ||
344 | Double_t pt, y, phi, mass, px, py, pz, ene, mt; | |
345 | ||
346 | const Int_t nproc = 9; | |
347 | Int_t idRes[nproc] = {kEtaLMR, kEtaLMR, kRhoLMR, kOmegaLMR, kOmegaLMR, kPhiLMR, kEtaPrimeLMR, kPionLMR, kKaonLMR}; | |
348 | Double_t BR[nproc] = {5.8e-6, 3.1e-4, 4.55e-5, 7.28e-5, 1.3e-4, 2.86e-4, 1.04e-4, 1, 0.6344}; | |
349 | // Double_t BR[nproc] = {1, 1, 1, 1, 1, 1, 1, 1, 1}; | |
350 | Int_t idDec[nproc] = {0, 1, 0, 0, 1, 0, 1, 2, 2}; // 0:2body, 1:Dalitz, 2:pi/K | |
351 | Int_t mult[nproc] = {0,0,0,0,0,0,0,0,0}; | |
352 | ||
353 | while (nmuons < fNMuMin) { | |
354 | ||
355 | nmuons = 0; | |
356 | npartPushed = 0; | |
357 | for (Int_t iproc=0; iproc<nproc; iproc++) { | |
358 | if (fGenSingleProc == -1) { | |
359 | mult[iproc] = Int_t(fMult[idRes[iproc]]->GetRandom()*fScaleMult[idRes[iproc]]); | |
360 | } | |
361 | else { | |
362 | if (iproc==fGenSingleProc) { | |
363 | mult[iproc] = 1; | |
364 | BR[iproc] = 1; | |
365 | } | |
366 | else { | |
367 | mult[iproc] = 0; | |
368 | BR[iproc] = 0; | |
369 | } | |
370 | } | |
371 | } | |
372 | ||
373 | if (fGenSingleProc == -1) { | |
374 | mult[1] = mult[0]; | |
375 | mult[4] = mult[3]; | |
376 | } | |
377 | ||
378 | for (Int_t iproc = 0; iproc < nproc; iproc++) { | |
379 | // printf ("Multiplicity for process %d is %d\n",iproc,mult[iproc]); | |
380 | for (Int_t imult=0; imult<mult[iproc]; imult++) { | |
381 | if (gRandom->Rndm() < BR[iproc]) { | |
382 | fHNProc->Fill(iproc); | |
383 | Int_t ipart = idRes[iproc]; | |
384 | pt = fPt[ipart]->GetRandom(); | |
385 | y = fY[ipart]->GetRandom(); | |
386 | phi = gRandom->Rndm() * 2 * TMath::Pi(); | |
387 | mass = pdg->GetParticle(fPDG[ipart])->Mass(); | |
388 | px = pt * TMath::Cos(phi); | |
389 | py = pt * TMath::Sin(phi); | |
390 | mt = TMath::Sqrt(pt * pt + mass * mass); | |
391 | pz = mt * TMath::SinH(y); | |
392 | ene = mt * TMath::CosH(y); | |
393 | ||
394 | mother = fParticle[ipart]; | |
395 | mother->SetMomentum(px,py,pz,ene); | |
396 | mother->SetCalcMass(mass); | |
397 | if (!KinematicSelection(mother,0)) continue; | |
398 | ||
399 | Bool_t hasDecayed = kTRUE; | |
400 | if (idDec[iproc] == 0) Decay2Body(mother); | |
401 | else if (idDec[iproc] == 1) DalitzDecay(mother); | |
402 | else DecayPiK(mother,hasDecayed); | |
403 | if (!hasDecayed) continue; | |
404 | Bool_t isMu0Acc = KinematicSelection(fMu[0],1); | |
405 | Bool_t isMu1Acc = KinematicSelection(fMu[1],1); | |
406 | Bool_t isMuFromPiKAcc = kTRUE; | |
407 | ||
408 | if (idDec[iproc] == 2) isMuFromPiKAcc = (mother->GetPdgCode()>0) ? isMu0Acc : isMu1Acc; | |
409 | // mother | |
410 | if ((idDec[iproc] < 2 && (isMu0Acc || isMu1Acc)) || | |
411 | (idDec[iproc] == 2 && isMuFromPiKAcc)) { | |
412 | pdgPushed[npartPushed] = mother->GetPdgCode(); | |
413 | pxPushed[npartPushed] = mother->Px(); | |
414 | pyPushed[npartPushed] = mother->Py(); | |
415 | pzPushed[npartPushed] = mother->Pz(); | |
416 | ePushed[npartPushed] = mother->Energy(); | |
417 | npartPushed++; | |
418 | if (isMu0Acc && (idDec[iproc] < 2 || mother->GetPdgCode() > 0)) { | |
419 | pdgPushed[npartPushed] = fMu[0]->GetPdgCode(); | |
420 | pxPushed[npartPushed] = fMu[0]->Px(); | |
421 | pyPushed[npartPushed] = fMu[0]->Py(); | |
422 | pzPushed[npartPushed] = fMu[0]->Pz(); | |
423 | ePushed[npartPushed] = fMu[0]->Energy(); | |
424 | npartPushed++; | |
425 | nmuons++; | |
426 | } | |
427 | ||
428 | if (isMu1Acc && (idDec[iproc] < 2 || mother->GetPdgCode() < 0)) { | |
429 | pdgPushed[npartPushed] = fMu[1]->GetPdgCode(); | |
430 | pxPushed[npartPushed] = fMu[1]->Px(); | |
431 | pyPushed[npartPushed] = fMu[1]->Py(); | |
432 | pzPushed[npartPushed] = fMu[1]->Pz(); | |
433 | ePushed[npartPushed] = fMu[1]->Energy(); | |
434 | npartPushed++; | |
435 | nmuons++; | |
436 | } | |
437 | } | |
438 | } // end if BR | |
439 | } // end loop on multiplicity | |
440 | } // end loop on process | |
441 | fHMultMu->Fill(nmuons); | |
442 | } // keep on generating until at least a muon is created in the event | |
443 | ||
444 | Int_t ntmother = 0, ntchild =0; | |
445 | for (Int_t ipart = 0; ipart < npartPushed; ipart++) { | |
446 | if (TMath::Abs(pdgPushed[ipart]) != 13) { // particle is not a muon, hence it's a mother | |
447 | PushTrack(0,-1,pdgPushed[ipart], | |
448 | pxPushed[ipart],pyPushed[ipart],pzPushed[ipart],ePushed[ipart], | |
449 | origin0[0],origin0[1],origin0[2],0., | |
450 | polar[0],polar[1],polar[2], | |
451 | kPPrimary,ntmother,1,11); | |
452 | KeepTrack(ntmother); | |
453 | } | |
454 | else { | |
455 | PushTrack(1,ntmother,pdgPushed[ipart], | |
456 | pxPushed[ipart],pyPushed[ipart],pzPushed[ipart],ePushed[ipart], | |
457 | origin0[0],origin0[1],origin0[2],0., | |
458 | polar[0],polar[1],polar[2], | |
459 | kPDecay,ntchild,1,1); | |
460 | KeepTrack(ntchild); | |
461 | } | |
462 | } | |
463 | SetHighWaterMark(ntchild); | |
464 | AliGenEventHeader* header = new AliGenEventHeader("LMR"); | |
465 | header->SetPrimaryVertex(fVertex); | |
466 | header->SetNProduced(fNprimaries); | |
467 | AddHeader(header); | |
468 | } | |
469 | ||
470 | //------------------------------------------------------------------ | |
471 | ||
472 | void AliGenMUONLMR::Decay2Body(TParticle *mother){ | |
473 | // performs decay in two muons of the low mass resonances | |
474 | Double_t md1 = fMu[0]->GetMass(); | |
475 | Int_t pdg = mother->GetPdgCode(); | |
476 | Double_t mres =0; | |
477 | // if mother is a rho, extract the mass from its line shape | |
478 | // otherwise consider the resonance mass | |
479 | if (pdg == 113) mres = fRhoLineShape->GetRandom(); | |
480 | else mres = mother->GetCalcMass(); | |
481 | // while (mres < md1 + md2) mres = fDsigmaDm[res]->GetRandom(); | |
482 | // energies and momenta in rest frame | |
483 | Double_t e1 = mres / 2.; | |
484 | Double_t p1 = TMath::Sqrt((e1 + md1)*(e1 - md1)); | |
485 | // orientation in decaying particle rest frame | |
486 | Double_t costheta = gRandom->Rndm() * 2 - 1; | |
487 | Double_t sintheta = TMath::Sqrt((1. + costheta)*(1. - costheta)); | |
488 | Double_t phi = 2. * TMath::Pi() * gRandom->Rndm(); | |
489 | Double_t px1 = p1 * sintheta * TMath::Cos(phi); | |
490 | Double_t py1 = p1 * sintheta * TMath::Sin(phi); | |
491 | Double_t pz1 = p1 * costheta; | |
492 | ||
493 | // boost muons into lab frame | |
494 | ||
495 | TLorentzVector vmother, v1, v2; | |
496 | // TLorentzVector boosted1, boosted2; | |
497 | vmother.SetPxPyPzE(mother->Px(),mother->Py(),mother->Pz(),mother->Energy()); | |
498 | v1.SetPxPyPzE(px1,py1,pz1,e1); | |
499 | v2.SetPxPyPzE(-px1,-py1,-pz1,e1); | |
500 | ||
501 | TVector3 betaParent = (1./vmother.E())*vmother.Vect(); // beta = p/E | |
502 | v1.Boost(betaParent); | |
503 | v2.Boost(betaParent); | |
504 | ||
505 | // TLorentzVector vtot = v1 + v2; | |
506 | // printf ("mother: %g %g %g %g\n",vmother.Px(), vmother.Py(), vmother.Pz(), vmother.E()); | |
507 | // printf ("vtot : %g %g %g %g\n",vtot.Px(), vtot.Py(), vtot.Pz(), vtot.E()); | |
508 | ||
509 | fMu[0]->SetMomentum(v1.Px(),v1.Py(),v1.Pz(),v1.E()); | |
510 | fMu[1]->SetMomentum(v2.Px(),v2.Py(),v2.Pz(),v2.E()); | |
511 | } | |
512 | ||
513 | //------------------------------------------------------------------ | |
514 | ||
515 | void AliGenMUONLMR::DecayPiK(TParticle *mother, Bool_t &hasDecayed){ | |
516 | // performs decays of pions and kaons | |
517 | Double_t md1 = fMu[0]->GetMass(); | |
518 | // extract the mass from the resonance's line shape | |
519 | Double_t mres = mother->GetMass(); | |
520 | // choose the pi/k sign, assuming 50% probabilities for both signs | |
521 | Int_t sign = (gRandom->Rndm() > 0.5) ? 1 : -1; | |
522 | mother->SetPdgCode(sign * TMath::Abs(mother->GetPdgCode())); | |
523 | ||
524 | // energies and momenta in rest frame | |
525 | Double_t e1 = (mres*mres + md1*md1)/(2*mres); | |
526 | Double_t p1 = TMath::Sqrt((e1 + md1)*(e1 - md1)); | |
527 | // orientation in decaying particle rest frame | |
528 | Double_t costheta = gRandom->Rndm() * 2 - 1; | |
529 | Double_t sintheta = TMath::Sqrt((1. + costheta)*(1. - costheta)); | |
530 | Double_t phi = 2. * TMath::Pi() * gRandom->Rndm(); | |
531 | Double_t px1 = p1 * sintheta * TMath::Cos(phi); | |
532 | Double_t py1 = p1 * sintheta * TMath::Sin(phi); | |
533 | Double_t pz1 = p1 * costheta; | |
534 | ||
535 | // boost muons into lab frame | |
536 | TLorentzVector vmother, v1; | |
537 | vmother.SetPxPyPzE(mother->Px(),mother->Py(),mother->Pz(),mother->Energy()); | |
538 | v1.SetPxPyPzE(px1,py1,pz1,e1); | |
539 | ||
540 | TVector3 betaParent = (1./vmother.E())*vmother.Vect(); // beta = p/E | |
541 | v1.Boost(betaParent); | |
542 | if (mother->GetPdgCode()>0) fMu[0]->SetMomentum(v1.Px(),v1.Py(),v1.Pz(),v1.E()); | |
543 | else fMu[1]->SetMomentum(v1.Px(),v1.Py(),v1.Pz(),v1.E()); | |
544 | ||
545 | Int_t idmother = 0; | |
546 | if (TMath::Abs(mother->GetPdgCode())== 211) idmother = 0; | |
547 | if (TMath::Abs(mother->GetPdgCode())== 321) idmother = 1; | |
548 | Double_t gammaRes = mother->Energy()/mres; | |
549 | Double_t zResCM = fDecay[idmother]->GetRandom(); | |
550 | Double_t zResLab = gammaRes*zResCM; | |
551 | if(zResLab > 0.938) hasDecayed = 0; // 0.938: distance from IP to absorber + lambda_i | |
552 | else hasDecayed = 1; | |
553 | } | |
554 | ||
555 | //------------------------------------------------------------------- | |
556 | ||
557 | void AliGenMUONLMR::DalitzDecay(TParticle *mother){ | |
558 | // | |
559 | // perform dalitz decays of eta, omega and etaprime | |
560 | // | |
561 | //in the rest frame of the virtual photon: | |
562 | Double_t mres = mother->GetCalcMass(); | |
563 | Double_t mumass = fMu[0]->GetMass(); | |
564 | Double_t md3 = 0; // unless differently specified, third particle is a photon | |
565 | if (mother->GetPdgCode() == 223) md3 = 0.134977; // if mother is an omega, third particle is a pi0 | |
566 | Int_t index = 0; | |
567 | if (mother->GetPdgCode() == 221) index = 0; // eta | |
568 | else if (mother->GetPdgCode() == 223) index = 1; // omega | |
569 | else if (mother->GetPdgCode() == 331) index = 2; // etaPrime | |
570 | Int_t flag = 0; | |
571 | Double_t xd=0, mvirt2=0; | |
572 | Double_t countIt = 0; | |
573 | while (flag==0) { | |
574 | xd = fDalitz[index]->GetRandom(); | |
575 | mvirt2 = xd * mres * mres; // mass of virtual photon | |
576 | // check kinematics | |
577 | if (mres - md3 > TMath::Sqrt(mvirt2) && TMath::Sqrt(mvirt2)/2. > mumass) flag=1; | |
578 | if (++countIt>1E11) { | |
579 | mvirt2 = mres * mres * 0.998; | |
580 | break; | |
581 | } | |
582 | } | |
583 | ||
584 | // | |
585 | // Generate muons in virtual photon rest frame. | |
586 | // z axis is the virt. photon direction (before boost) | |
587 | // | |
588 | ||
589 | Double_t e1 = TMath::Sqrt(mvirt2)/2.; // energy of mu1 in the virtual photon frame | |
590 | Double_t psquare = (e1 + mumass)*(e1 - mumass); | |
591 | if (psquare<0) { | |
592 | printf("Error in AliGenMUONLMR::DalitzDecay: sqrt of psquare = %f put to 0\n",psquare); | |
593 | psquare = 0; | |
594 | } | |
595 | Double_t p1 = TMath::Sqrt(psquare); | |
596 | //theta angle between the pos. muon and the virtual photon | |
597 | Double_t costheta = fCosTheta->GetRandom(); | |
598 | if (costheta>1) costheta = 1; | |
599 | if (costheta<-1) costheta = -1; | |
600 | Double_t sintheta = TMath::Sqrt((1. + costheta)*(1. - costheta)); | |
601 | Double_t phi = 2 * TMath::Pi() * gRandom->Rndm(); | |
602 | Double_t sinphi = TMath::Sin(phi); | |
603 | Double_t cosphi = TMath::Cos(phi); | |
604 | ||
605 | // fill 4-vectors of leptons in the virtual photon frame | |
606 | ||
607 | Double_t px1 = p1*sintheta*cosphi; | |
608 | Double_t py1 = p1*sintheta*sinphi; | |
609 | Double_t pz1 = p1*costheta; | |
610 | Double_t px2 = -p1*sintheta*cosphi; | |
611 | Double_t py2 = -p1*sintheta*sinphi; | |
612 | Double_t pz2 = -p1*costheta; | |
613 | Double_t e2 = e1; | |
614 | ||
615 | fMu[0]->SetMomentum(px1,py1,pz1,e1); | |
616 | fMu[1]->SetMomentum(px2,py2,pz2,e2); | |
617 | ||
618 | // calculate components of non-dilepton in CMS of parent resonance | |
619 | ||
620 | Double_t e3 = (mres * mres + md3 * md3 - mvirt2) / (2.*mres); | |
621 | Double_t psquare3 = (e3 + md3)*(e3 - md3); | |
622 | if (psquare3<0) { | |
623 | printf("Error in AliGenMUONLMR::DalitzDecay: sqrt of psquare3 = %f put to 0\n",psquare3); | |
624 | psquare3 = 0; | |
625 | } | |
626 | Double_t p3 = TMath::Sqrt(psquare3); | |
627 | Double_t costheta2 = 2.* gRandom->Rndm() - 1.; // angle between virtual photon and resonance | |
628 | if (costheta2>1) costheta2 = 1; | |
629 | if (costheta2<-1) costheta2 = -1; | |
630 | Double_t sintheta2 = TMath::Sqrt((1. + costheta2)*(1. - costheta2)); | |
631 | Double_t phi2 = 2 * TMath::Pi() * gRandom->Rndm(); | |
632 | Double_t sinphi2 = TMath::Sin(phi2); | |
633 | Double_t cosphi2 = TMath::Cos(phi2); | |
634 | Double_t px3 = p3*sintheta2*cosphi2; | |
635 | Double_t py3 = p3*sintheta2*sinphi2; | |
636 | Double_t pz3 = p3*costheta2; | |
637 | TLorentzVector v3(px3,py3,pz3,e3); | |
638 | ||
639 | sintheta2 = -sintheta2; | |
640 | cosphi2 = -cosphi2; | |
641 | sinphi2 = -sinphi2; | |
642 | ||
643 | Double_t px1new = px1*costheta2*cosphi2 - py1*sinphi2 + pz1*sintheta2*cosphi2; | |
644 | Double_t py1new = px1*costheta2*sinphi2 + py1*cosphi2 + pz1*sintheta2*sinphi2; | |
645 | Double_t pz1new =-px1*sintheta2 + pz1*costheta2; | |
646 | Double_t px2new = px2*costheta2*cosphi2 - py2*sinphi2 + pz2*sintheta2*cosphi2; | |
647 | Double_t py2new = px2*costheta2*sinphi2 + py2*cosphi2 + pz2*sintheta2*sinphi2; | |
648 | Double_t pz2new =-px2*sintheta2 + pz2*costheta2; | |
649 | ||
650 | fMu[0]->SetMomentum(px1new,py1new,pz1new,e1); | |
651 | fMu[1]->SetMomentum(px2new,py2new,pz2new,e2); | |
652 | ||
653 | Double_t evirt = mres - e3; | |
654 | Double_t pxvirt = -px3; | |
655 | Double_t pyvirt = -py3; | |
656 | Double_t pzvirt = -pz3; | |
657 | TLorentzVector vvirt(pxvirt,pyvirt,pzvirt,evirt); | |
658 | TVector3 betaVirt = (1./evirt) * vvirt.Vect(); // virtual photon beta in res frame | |
659 | ||
660 | TLorentzVector v1(px1,py1,pz1,e1); | |
661 | TLorentzVector v2(px2,py2,pz2,e2); | |
662 | ||
663 | // boost the muons in the frame where the resonance is at rest | |
664 | ||
665 | v1.Boost(betaVirt); | |
666 | v2.Boost(betaVirt); | |
667 | ||
668 | // boost muons and third particle in lab frame | |
669 | ||
670 | TLorentzVector vmother(mother->Px(), mother->Py(), mother->Pz(), mother->Energy()); | |
671 | TVector3 resBetaLab = (1./vmother.E())*vmother.Vect(); // eta beta in lab frame | |
672 | v1.Boost(resBetaLab); | |
673 | v2.Boost(resBetaLab); | |
674 | v3.Boost(resBetaLab); | |
675 | vvirt.Boost(resBetaLab); | |
676 | ||
677 | fMu[0]->SetMomentum(v1.Px(),v1.Py(),v1.Pz(),v1.E()); | |
678 | fMu[1]->SetMomentum(v2.Px(),v2.Py(),v2.Pz(),v2.E()); | |
679 | // part3->SetMomentum(v3.Px(),v3.Py(),v3.Pz(),v3.E()); | |
680 | ||
681 | // TLorentzVector vtot = v1 + v2 + v3; | |
682 | // TLorentzVector vdimu = v1 + v2; | |
683 | // printf ("mother: %g %g %g %g\n",vmother.Px(), vmother.Py(), vmother.Pz(), vmother.E()); | |
684 | // printf ("vtot : %g %g %g %g\n",vtot.Px(), vtot.Py(), vtot.Pz(), vtot.E()); | |
685 | // printf ("vvirt : %g %g %g %g\n",vvirt.Px(), vvirt.Py(), vvirt.Pz(), vvirt.E()); | |
686 | // printf ("vdimu : %g %g %g %g\n",vdimu.Px(), vdimu.Py(), vdimu.Pz(), vdimu.E()); | |
687 | ||
688 | } | |
689 | ||
690 | //------------------------------------------------------------------ | |
691 | ||
692 | Double_t AliGenMUONLMR::FormFactor(Double_t q2, Int_t decay){ | |
693 | // Calculates the form factor for Dalitz decays A->B+l+l | |
694 | // Returns: |F(q^2)|^2 | |
695 | // | |
696 | // References: L.G. Landsberg, Physics Reports 128 No.6 (1985) 301-376. | |
697 | ||
698 | Double_t ff2, mass2; | |
699 | Double_t n2, n4, m2; | |
700 | // Lepton-G | |
701 | ||
702 | Double_t lambda2inv = 0; | |
703 | switch (decay) { | |
704 | case 0: // eta -> mu mu gamma | |
705 | // eta -> l+ l- gamma: pole approximation | |
706 | lambda2inv = 1.95; | |
707 | mass2 = fParticle[kEtaLMR]->GetMass() * fParticle[kEtaLMR]->GetMass(); | |
708 | if (q2 < mass2) ff2 = TMath::Power(1./(1.-lambda2inv*q2),2); | |
709 | else ff2 = 0; | |
710 | break; | |
711 | case 1: // omega -> mu mu pi0 | |
712 | // omega -> l+ l- pi0: pole approximation | |
713 | mass2 = fParticle[kOmegaLMR]->GetMass() * fParticle[kOmegaLMR]->GetMass(); | |
714 | lambda2inv = 2.26; | |
715 | if (q2 < mass2) ff2 = TMath::Power(1./(1.-lambda2inv*q2),2); | |
716 | else ff2 = 0; | |
717 | break; | |
718 | case 2: // etaPrime -> mu mu gamma | |
719 | mass2 = fParticle[kEtaPrimeLMR]->GetMass() * fParticle[kEtaPrimeLMR]->GetMass(); | |
720 | // eta' -> l+ l- gamma: Breit-Wigner fitted to data | |
721 | n2 = 0.764 * 0.764; | |
722 | n4 = n2 * n2; | |
723 | m2 = 0.1020 * 0.1020; | |
724 | if (q2 < mass2) ff2 = n4 / (TMath::Power(n2-q2,2) + m2 * n2); | |
725 | else ff2 = 0; | |
726 | break; | |
727 | default: | |
728 | printf ("FormFactor: Decay not found\n"); | |
729 | return 0; | |
730 | break; | |
731 | } | |
732 | return ff2; | |
733 | } | |
734 | ||
735 | //____________________________________________________________ | |
736 | ||
737 | Double_t AliGenMUONLMR::RhoLineShapeNew(Double_t *x, Double_t */*para*/){ | |
738 | //new parameterization implemented by Hiroyuki Sako (GSI) | |
739 | Double_t mass = *x; | |
740 | double r, GammaTot; | |
741 | Double_t mRho = TDatabasePDG::Instance()->GetParticle("rho0")->Mass(); | |
742 | Double_t mPi = TDatabasePDG::Instance()->GetParticle("pi0")->Mass(); | |
743 | Double_t mMu = TDatabasePDG::Instance()->GetParticle("mu-")->Mass(); | |
744 | Double_t Gamma0 = TDatabasePDG::Instance()->GetParticle("rho0")->Width(); | |
745 | ||
746 | const double Norm = 0.0744416*1.01; | |
747 | ||
748 | // 0.0744416 at m = 0.72297 | |
749 | // is the max number with Norm=1 (for rho) | |
750 | ||
751 | double mThreshold = 2.*mPi; | |
752 | ||
753 | const double T = 0.170; // Assumption of pi+ temperature [GeV/c^2] | |
754 | //const double T = 0.11; // Taken from fit to pi+ temperature [GeV/c^2] | |
755 | // with Reference: LEBC-EHS collab., Z. Phys. C 50 (1991) 405 | |
756 | ||
757 | if (mass < mThreshold) { | |
758 | r = 0.; | |
759 | return r; | |
760 | } | |
761 | ||
762 | double k = sqrt(0.25*mass*mass-(mThreshold/2)*(mThreshold/2)); | |
763 | double k0 = sqrt(0.25*mRho*mRho-(mThreshold/2)*(mThreshold/2)); | |
764 | ||
765 | GammaTot = (k/k0)*(k/k0)*(k/k0)*(mRho/mass)*(mRho/mass)*Gamma0; | |
766 | ||
767 | double FormFactor2 = 1/((mass*mass-mRho*mRho)*(mass*mass-mRho*mRho)+ | |
768 | mass*mass*GammaTot*GammaTot); | |
769 | ||
770 | r = pow(mass,1.5)*pow((1-mThreshold*mThreshold/(mass*mass)),1.5)* | |
771 | ((mass*mass+2*mMu*mMu)/(mass*mass))*(pow((mass*mass-4*mMu*mMu),0.5)/mass)*FormFactor2 | |
772 | *exp(-mass/T)/Norm; | |
773 | ||
774 | return r; | |
775 | } |