Line data Source code
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 : /* $Id$ */
17 :
18 : // Class to generate correlated Heavy Flavor hadron pairs (one or several pairs
19 : // per event) using paramtrized kinematics of quark pairs from some generator
20 : // and quark fragmentation functions.
21 : // Is a generalisation of AliGenParam class for correlated pairs of hadrons.
22 : // In this version quark pairs and fragmentation functions are obtained from
23 : // ~2.10^6 Pythia6.214 events generated with kCharmppMNRwmi & kBeautyppMNRwmi,
24 : // CTEQ5L PDF and Pt_hard = 2.76 GeV/c for p-p collisions at 2.76, 7, 8, 10 and 14 TeV,
25 : // and with kCharmppMNR (Pt_hard = 2.10 GeV/c) & kBeautyppMNR (Pt_hard = 2.75 GeV/c),
26 : // CTEQ4L PDF for Pb-Pb at 2.76 and 3.94 TeV, for p-Pb & Pb-p at 5 and 8.8 TeV.
27 : // Decays are performed by Pythia.
28 : // Author: S. Grigoryan, LPC Clermont-Fd & YerPhI, Smbat.Grigoryan@cern.ch
29 : // July 07: added quarks in the stack (B. Vulpescu)
30 : // April 09: added energy choice between 10 and 14 TeV (S. Grigoryan)
31 : // Sept 09: added hadron pair composition probabilities via 2D histo (X.M. Zhang)
32 : // Oct 09: added energy choice between 7, 10, 14 TeV (for p-p), 4 TeV (for Pb-Pb),
33 : // 9 TeV (for p-Pb) and -9 TeV (for Pb-p) (S. Grigoryan)
34 : // April 10: removed "static" from definition of some variables (B. Vulpescu)
35 : // May 11: added Flag for transportation of background particles while using
36 : // SetForceDecay() function (L. Manceau)
37 : // June 11: added modifications allowing the setting of cuts on HF-hadron children.
38 : // Quarks, hadrons and decay particles are loaded in the stack outside the loop
39 : // of HF-hadrons, when the cuts on their children are satisfied (L. Manceau)
40 : // Oct 11: added Pb-Pb at 2.76 TeV (S. Grigoryan)
41 : // June 12: added p-Pb & Pb-p at 5 TeV (S. Grigoryan)
42 : // April 13: added p-p at 2.76 and 8 TeV (S. Grigoryan)
43 : // March 16: added p-p at 5 and 13 TeV (S. Grigoryan)
44 : //
45 : //-------------------------------------------------------------------------
46 : // How it works (for the given flavor and p-p energy):
47 : //
48 : // 1) Reads QQbar kinematical grid (TTree) from the Input file and generates
49 : // quark pairs according to the weights of the cells.
50 : // It is a 5D grid in y1,y2,pt1,pt2 and deltaphi, with occupancy weights
51 : // of the cells obtained from Pythia (see details in GetQuarkPair).
52 : // 2) Reads "soft" and "hard" fragmentation functions (12 2D-histograms each,
53 : // for 12 pt bins) from the Input file, applies to quarks and produces hadrons
54 : // (only lower states, with proportions of species obtained from Pythia).
55 : // Fragmentation functions are the same for all hadron species and depend
56 : // on 2 variables - light cone energy-momentum fractions:
57 : // z1=(E_H + Pz_H)/(E_Q + Pz_Q), z2=(E_H - Pz_H)/(E_Q - Pz_Q).
58 : // "soft" & "hard" FFs correspond to "slower" & "faster" quark of a pair
59 : // (see details in GetHadronPair). Fragmentation does not depend on p-p energy.
60 : // 3) Decays the hadrons and saves all the particles in the event stack in the
61 : // following order: HF hadron from Q, then its decay products, then HF hadron
62 : // from Qbar, then its decay productes, then next HF hadon pair (if any)
63 : // in the same way, etc...
64 : // 4) It is fast, e.g., generates the same number of events with a beauty pair
65 : // ~15 times faster than AliGenPythia with kBeautyppMNRwmi (w/o tracking)
66 : //
67 : // An Input file for each quark flavor and p-p energy is in EVGEN/dataCorrHF/
68 : // One can use also user-defined Input files.
69 : //
70 : // More details could be found in my presentation at DiMuonNet Workshop, Dec 2006:
71 : // http://www-dapnia.cea.fr/Sphn/Alice/DiMuonNet.
72 : //
73 : //-------------------------------------------------------------------------
74 : // How to use it:
75 : //
76 : // add the following typical lines in Config.C
77 : /*
78 : // An example for correlated charm or beauty hadron pair production at 14 TeV
79 :
80 : // AliGenCorrHF *gener = new AliGenCorrHF(1, 4, 14); // for charm, 1 pair per event
81 : AliGenCorrHF *gener = new AliGenCorrHF(1, 5, 14); // for beauty, 1 pair per event
82 :
83 : gener->SetMomentumRange(0,9999);
84 : gener->SetCutOnChild(0); // 1/0 means cuts on children enable/disable
85 : gener->SetChildThetaRange(171.0,178.0);
86 : gener->SetOrigin(0,0,0); //vertex position
87 : gener->SetSigma(0,0,0); //Sigma in (X,Y,Z) (cm) on IP position
88 : gener->SetForceDecay(kSemiMuonic);
89 : gener->SetSelectAll(kTRUE); //Force the transport of all particles.
90 : //Necessary while using a different
91 : //option than kAll for SetForceDecay
92 : gener->SetTrackingFlag(1); //1: Decay during transport,
93 : //0: No Decay during transport
94 : gener->Init();
95 : */
96 : // One can include AliGenCorrHF in an AliGenCocktail generator.
97 : //--------------------------------------------------------------------------
98 :
99 : #include <Riostream.h>
100 : #include <TCanvas.h>
101 : #include <TClonesArray.h>
102 : #include <TDatabasePDG.h>
103 : #include <TFile.h>
104 : #include <TH2F.h>
105 : #include <TLorentzVector.h>
106 : #include <TMath.h>
107 : #include <TParticle.h>
108 : #include <TParticlePDG.h>
109 : #include <TROOT.h>
110 : #include <TRandom.h>
111 : #include <TTree.h>
112 : #include <TVirtualMC.h>
113 : #include <TVector3.h>
114 :
115 : #include "AliGenCorrHF.h"
116 : #include "AliLog.h"
117 : #include "AliConst.h"
118 : #include "AliDecayer.h"
119 : #include "AliMC.h"
120 : #include "AliRun.h"
121 : #include "AliGenEventHeader.h"
122 :
123 6 : ClassImp(AliGenCorrHF)
124 :
125 : //Begin_Html
126 : /*
127 : <img src="picts/AliGenCorrHF.gif">
128 : */
129 : //End_Html
130 :
131 : Double_t AliGenCorrHF::fgdph[19] = {0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180};
132 : Double_t AliGenCorrHF::fgy[31] = {-10,-7, -6.5, -6, -5.5, -5, -4.5, -4, -3.5, -3, -2.5, -2,- 1.5, -1, -0.5, 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 10};
133 : Double_t AliGenCorrHF::fgpt[51] = {0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.6, 7.2, 7.8, 8.4, 9, 9.6, 10.3, 11.1, 12, 13, 14, 15, 16, 17, 18, 19, 20.1, 21.5, 23, 24.5, 26, 27.5, 29.1, 31, 33, 35, 37, 39.2, 42, 45, 48, 51, 55.2, 60, 65, 71, 81, 100};
134 : Int_t AliGenCorrHF::fgnptbins = 12;
135 : Double_t AliGenCorrHF::fgptbmin[12] = {0, 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 9};
136 : Double_t AliGenCorrHF::fgptbmax[12] = {0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 9, 100};
137 :
138 : //____________________________________________________________
139 0 : AliGenCorrHF::AliGenCorrHF():
140 0 : fFileName(0),
141 0 : fFile(0),
142 0 : fQuark(0),
143 0 : fEnergy(0),
144 0 : fBias(0.),
145 0 : fTrials(0),
146 0 : fSelectAll(kFALSE),
147 0 : fDecayer(0),
148 0 : fgIntegral(0)
149 0 : {
150 : // Default constructor
151 0 : }
152 :
153 : //____________________________________________________________
154 : AliGenCorrHF::AliGenCorrHF(Int_t npart, Int_t idquark, Int_t energy):
155 0 : AliGenMC(npart),
156 0 : fFileName(0),
157 0 : fFile(0),
158 0 : fQuark(idquark),
159 0 : fEnergy(energy),
160 0 : fBias(0.),
161 0 : fTrials(0),
162 0 : fSelectAll(kFALSE),
163 0 : fDecayer(0),
164 0 : fgIntegral(0)
165 0 : {
166 : // Constructor using particle number, quark type, energy & default InputFile
167 : //
168 0 : if (fQuark == 5) {
169 0 : if (fEnergy == 7)
170 0 : fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/BeautyPP7PythiaMNRwmi.root";
171 0 : else if (fEnergy == 8)
172 0 : fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/BeautyPP8PythiaMNRwmi.root";
173 0 : else if (fEnergy == 10)
174 0 : fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/BeautyPP10PythiaMNRwmi.root";
175 0 : else if (fEnergy == 13)
176 0 : fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/BeautyPP13PythiaMNRwmi.root";
177 0 : else if (fEnergy == 14)
178 0 : fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/BeautyPP14PythiaMNRwmi.root";
179 0 : else if (fEnergy == 2)
180 0 : fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/BeautyPP276PythiaMNRwmi.root";
181 0 : else if (fEnergy == 50)
182 0 : fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/BeautyPP5PythiaMNRwmi.root";
183 0 : else if (fEnergy == 3)
184 0 : fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/BeautyPbPb276PythiaMNR.root";
185 0 : else if (fEnergy == 4)
186 0 : fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/BeautyPbPb394PythiaMNR.root";
187 0 : else if (fEnergy == 5 || fEnergy == -5)
188 0 : fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/BeautyPPb5PythiaMNR.root";
189 0 : else if (fEnergy == 9 || fEnergy == -9)
190 0 : fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/BeautyPPb88PythiaMNR.root";
191 0 : else fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/BeautyPbPb394PythiaMNR.root";
192 : }
193 : else {
194 0 : fQuark = 4;
195 0 : if (fEnergy == 7)
196 0 : fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/CharmPP7PythiaMNRwmi.root";
197 0 : else if (fEnergy == 8)
198 0 : fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/CharmPP8PythiaMNRwmi.root";
199 0 : else if (fEnergy == 10)
200 0 : fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/CharmPP10PythiaMNRwmi.root";
201 0 : else if (fEnergy == 13)
202 0 : fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/CharmPP13PythiaMNRwmi.root";
203 0 : else if (fEnergy == 14)
204 0 : fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/CharmPP14PythiaMNRwmi.root";
205 0 : else if (fEnergy == 2)
206 0 : fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/CharmPP276PythiaMNRwmi.root";
207 0 : else if (fEnergy == 50)
208 0 : fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/CharmPP5PythiaMNRwmi.root";
209 0 : else if (fEnergy == 3)
210 0 : fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/CharmPbPb276PythiaMNR.root";
211 0 : else if (fEnergy == 4)
212 0 : fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/CharmPbPb394PythiaMNR.root";
213 0 : else if (fEnergy == 5 || fEnergy == -5)
214 0 : fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/CharmPPb5PythiaMNR.root";
215 0 : else if (fEnergy == 9 || fEnergy == -9)
216 0 : fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/CharmPPb88PythiaMNR.root";
217 0 : else fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/CharmPbPb394PythiaMNR.root";
218 : }
219 0 : fName = "Default";
220 0 : fTitle= "Generator for correlated pairs of HF hadrons";
221 :
222 0 : fChildSelect.Set(5);
223 0 : for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
224 0 : SetForceDecay();
225 0 : SetCutOnChild();
226 0 : SetChildMomentumRange();
227 0 : SetChildPtRange();
228 0 : SetChildPhiRange();
229 0 : SetChildThetaRange();
230 0 : }
231 :
232 : //___________________________________________________________________
233 : AliGenCorrHF::AliGenCorrHF(char* tname, Int_t npart, Int_t idquark, Int_t energy):
234 0 : AliGenMC(npart),
235 0 : fFileName(tname),
236 0 : fFile(0),
237 0 : fQuark(idquark),
238 0 : fEnergy(energy),
239 0 : fBias(0.),
240 0 : fTrials(0),
241 0 : fSelectAll(kFALSE),
242 0 : fDecayer(0),
243 0 : fgIntegral(0)
244 0 : {
245 : // Constructor using particle number, quark type, energy & user-defined InputFile
246 : //
247 0 : if (fQuark != 5) fQuark = 4;
248 0 : fName = "UserDefined";
249 0 : fTitle= "Generator for correlated pairs of HF hadrons";
250 :
251 0 : fChildSelect.Set(5);
252 0 : for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
253 0 : SetForceDecay();
254 0 : SetCutOnChild();
255 0 : SetChildMomentumRange();
256 0 : SetChildPtRange();
257 0 : SetChildPhiRange();
258 0 : SetChildThetaRange();
259 0 : }
260 :
261 : //____________________________________________________________
262 0 : AliGenCorrHF::~AliGenCorrHF()
263 0 : {
264 : // Destructor
265 0 : delete fFile;
266 0 : }
267 :
268 : //____________________________________________________________
269 : void AliGenCorrHF::Init()
270 : {
271 : // Initialisation
272 0 : AliInfo(Form("Number of HF-hadron pairs = %d",fNpart));
273 0 : AliInfo(Form(" QQbar kinematics and fragm. functions from: %s",fFileName.Data() ));
274 0 : fFile = TFile::Open(fFileName.Data());
275 0 : if(!fFile->IsOpen()){
276 0 : AliError(Form("Could not open file %s",fFileName.Data() ));
277 0 : }
278 :
279 0 : ComputeIntegral(fFile);
280 :
281 0 : fParentWeight = 1./fNpart; // fNpart is number of HF-hadron pairs
282 :
283 : // particle decay related initialization
284 :
285 0 : if (TVirtualMC::GetMC()) fDecayer = TVirtualMC::GetMC()->GetDecayer();
286 0 : fDecayer->SetForceDecay(fForceDecay);
287 0 : fDecayer->Init();
288 :
289 : //
290 0 : AliGenMC::Init();
291 0 : }
292 : //____________________________________________________________
293 : void AliGenCorrHF::Generate()
294 : {
295 : //
296 : // Generate fNpart of correlated HF hadron pairs per event
297 : // in the the desired theta and momentum windows (phi = 0 - 2pi).
298 : //
299 :
300 : // Reinitialize decayer
301 :
302 0 : fDecayer->SetForceDecay(fForceDecay);
303 0 : fDecayer->Init();
304 :
305 0 : Float_t polar[2][3]; // Polarisation of the parent particle (for GEANT tracking)
306 0 : Float_t origin0[2][3]; // Origin of the generated parent particle (for GEANT tracking)
307 : Float_t pt, pl, ptot; // Transverse, logitudinal and total momenta of the parent particle
308 : Float_t phi, theta; // Phi and theta spherical angles of the parent particle momentum
309 0 : Float_t p[2][3]; // Momenta
310 0 : Int_t nt, i, j, ihad, ipa, ipa0, ipa1, ihadron[2], iquark[2];
311 0 : Float_t wgtp[2], wgtch[2], random[6];
312 0 : Float_t pq[2][3], pc[3]; // Momenta of the two quarks
313 : Double_t tanhy2, qm = 0;
314 0 : Int_t np[2];
315 0 : Double_t dphi=0, ptq[2], yq[2], pth[2], plh[2], ph[2], phih[2], phiq[2];
316 0 : Int_t ncsel[2];
317 0 : Int_t** pSelected = new Int_t* [2];
318 0 : Int_t** trackIt = new Int_t* [2];
319 :
320 0 : for (i=0; i<2; i++) {
321 0 : ptq[i] =0;
322 0 : yq[i] =0;
323 0 : pth[i] =0;
324 0 : plh[i] =0;
325 0 : phih[i] =0;
326 0 : phiq[i] =0;
327 0 : ihadron[i] =0;
328 0 : iquark[i] =0;
329 0 : for (j=0; j<3; j++) polar[i][j]=0;
330 : }
331 :
332 : // same quarks mass as in the fragmentation functions
333 0 : if (fQuark == 4) qm = 1.20;
334 : else qm = 4.75;
335 :
336 0 : TClonesArray *particleshad1 = new TClonesArray("TParticle",1000);
337 0 : TClonesArray *particleshad2 = new TClonesArray("TParticle",1000);
338 :
339 0 : TList *particleslist = new TList();
340 0 : particleslist->Add(particleshad1);
341 0 : particleslist->Add(particleshad2);
342 :
343 0 : TDatabasePDG *pDataBase = TDatabasePDG::Instance();
344 :
345 : // Calculating vertex position per event
346 0 : if (fVertexSmear==kPerEvent) {
347 0 : Vertex();
348 0 : for (i=0;i<2;i++){
349 0 : for (j=0;j<3;j++) origin0[i][j]=fVertex[j];
350 : }
351 : }
352 : else {
353 0 : for (i=0;i<2;i++){
354 0 : for (j=0;j<3;j++) origin0[i][j]=fOrigin[j];
355 : }
356 : }
357 :
358 : ipa = 0;
359 : ipa1 = 0;
360 : ipa0 = 0;
361 :
362 : // Generating fNpart HF-hadron pairs
363 0 : fNprimaries = 0;
364 :
365 0 : while (ipa<2*fNpart) {
366 :
367 0 : GetQuarkPair(fFile, fgIntegral, yq[0], yq[1], ptq[0], ptq[1], dphi);
368 :
369 0 : GetHadronPair(fFile, fQuark, yq[0], yq[1], ptq[0], ptq[1], ihadron[0], ihadron[1], plh[0], plh[1], pth[0], pth[1]);
370 :
371 : // Boost particles from c.m.s. to ALICE lab frame for p-Pb & Pb-p collisions
372 0 : if (fEnergy == 5 || fEnergy == -5 || fEnergy == 9 || fEnergy == -9) {
373 : Double_t dyBoost = 0.47;
374 0 : Double_t beta = TMath::TanH(dyBoost);
375 0 : Double_t gamma = 1./TMath::Sqrt((1.-beta)*(1.+beta));
376 0 : Double_t gb = gamma * beta;
377 0 : yq[0] += dyBoost;
378 0 : yq[1] += dyBoost;
379 0 : plh[0] = gb * TMath::Sqrt(plh[0]*plh[0] + pth[0]*pth[0]) + gamma * plh[0];
380 0 : plh[1] = gb * TMath::Sqrt(plh[1]*plh[1] + pth[1]*pth[1]) + gamma * plh[1];
381 0 : if (fEnergy == 5 || fEnergy == 9) {
382 0 : yq[0] *= -1;
383 0 : yq[1] *= -1;
384 0 : plh[0] *= -1;
385 0 : plh[1] *= -1;
386 0 : }
387 0 : }
388 :
389 : // Cuts from AliGenerator
390 :
391 : // Cut on theta
392 0 : theta=TMath::ATan2(pth[0],plh[0]);
393 0 : if (theta<fThetaMin || theta>fThetaMax) continue;
394 0 : theta=TMath::ATan2(pth[1],plh[1]);
395 0 : if (theta<fThetaMin || theta>fThetaMax) continue;
396 :
397 : // Cut on momentum
398 0 : ph[0]=TMath::Sqrt(pth[0]*pth[0]+plh[0]*plh[0]);
399 0 : if (ph[0]<fPMin || ph[0]>fPMax) continue;
400 0 : ph[1]=TMath::Sqrt(pth[1]*pth[1]+plh[1]*plh[1]);
401 0 : if (ph[1]<fPMin || ph[1]>fPMax) continue;
402 :
403 : // Add the quarks in the stack
404 :
405 0 : phiq[0] = Rndm()*k2PI;
406 0 : if (Rndm() < 0.5) {
407 0 : phiq[1] = phiq[0] + dphi*kDegrad;
408 0 : } else {
409 0 : phiq[1] = phiq[0] - dphi*kDegrad;
410 : }
411 0 : if (phiq[1] > k2PI) phiq[1] -= k2PI;
412 0 : if (phiq[1] < 0 ) phiq[1] += k2PI;
413 :
414 : // quarks pdg
415 0 : iquark[0] = +fQuark;
416 0 : iquark[1] = -fQuark;
417 :
418 : // px and py
419 0 : TVector2 qvect1 = TVector2();
420 0 : TVector2 qvect2 = TVector2();
421 0 : qvect1.SetMagPhi(ptq[0],phiq[0]);
422 0 : qvect2.SetMagPhi(ptq[1],phiq[1]);
423 0 : pq[0][0] = qvect1.Px();
424 0 : pq[0][1] = qvect1.Py();
425 0 : pq[1][0] = qvect2.Px();
426 0 : pq[1][1] = qvect2.Py();
427 :
428 : // pz
429 0 : tanhy2 = TMath::TanH(yq[0]);
430 0 : tanhy2 *= tanhy2;
431 0 : pq[0][2] = TMath::Sqrt((ptq[0]*ptq[0]+qm*qm)*tanhy2/(1-tanhy2));
432 0 : pq[0][2] = TMath::Sign((Double_t)pq[0][2],yq[0]);
433 0 : tanhy2 = TMath::TanH(yq[1]);
434 0 : tanhy2 *= tanhy2;
435 0 : pq[1][2] = TMath::Sqrt((ptq[1]*ptq[1]+qm*qm)*tanhy2/(1-tanhy2));
436 0 : pq[1][2] = TMath::Sign((Double_t)pq[1][2],yq[1]);
437 :
438 : // Here we assume that |phi_H1 - phi_H2| = |phi_Q1 - phi_Q2| = dphi
439 : // which is a good approximation for heavy flavors in Pythia
440 : // ... moreover, same phi angles as for the quarks ...
441 :
442 0 : phih[0] = phiq[0];
443 0 : phih[1] = phiq[1];
444 :
445 : ipa1 = 0;
446 :
447 0 : for (ihad = 0; ihad < 2; ihad++) {
448 : while(1) {
449 :
450 : ipa0=ipa1;
451 :
452 : // particle type
453 0 : fChildWeight=(fDecayer->GetPartialBranchingRatio(ihadron[ihad]))*fParentWeight;
454 0 : wgtp[ihad]=fParentWeight;
455 0 : wgtch[ihad]=fChildWeight;
456 0 : TParticlePDG *particle = pDataBase->GetParticle(ihadron[ihad]);
457 0 : Float_t am = particle->Mass();
458 0 : phi = phih[ihad];
459 0 : pt = pth[ihad];
460 0 : pl = plh[ihad];
461 0 : ptot=TMath::Sqrt(pt*pt+pl*pl);
462 :
463 0 : p[ihad][0]=pt*TMath::Cos(phi);
464 0 : p[ihad][1]=pt*TMath::Sin(phi);
465 0 : p[ihad][2]=pl;
466 :
467 0 : if(fVertexSmear==kPerTrack) {
468 0 : Rndm(random,6);
469 0 : for (j=0;j<3;j++) {
470 0 : origin0[ihad][j]=
471 0 : fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
472 0 : TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
473 : }
474 : }
475 :
476 : // Looking at fForceDecay :
477 : // if fForceDecay != none Primary particle decays using
478 : // AliPythia and children are tracked by GEANT
479 : //
480 : // if fForceDecay == none Primary particle is tracked by GEANT
481 : // (In the latest, make sure that GEANT actually does all the decays you want)
482 :
483 0 : if (fForceDecay != kNoDecay) {
484 : // Using lujet to decay particle
485 0 : Float_t energy=TMath::Sqrt(ptot*ptot+am*am);
486 0 : TLorentzVector pmom(p[ihad][0], p[ihad][1], p[ihad][2], energy);
487 0 : fDecayer->Decay(ihadron[ihad],&pmom);
488 :
489 : // select decay particles
490 :
491 0 : np[ihad]=fDecayer->ImportParticles((TClonesArray *)particleslist->At(ihad));
492 :
493 : // Selecting GeometryAcceptance for particles fPdgCodeParticleforAcceptanceCut;
494 :
495 0 : if (fGeometryAcceptance)
496 0 : if (!CheckAcceptanceGeometry(np[ihad],(TClonesArray*)particleslist->At(ihad))) continue;
497 :
498 0 : trackIt[ihad] = new Int_t [np[ihad]];
499 0 : pSelected[ihad] = new Int_t [np[ihad]];
500 0 : Int_t* pFlag = new Int_t [np[ihad]];
501 :
502 0 : for (i=0; i<np[ihad]; i++) {
503 0 : pFlag[i] = 0;
504 0 : pSelected[ihad][i] = 0;
505 : }
506 :
507 0 : if (np[ihad] >1) {
508 : TParticle* iparticle = 0;
509 : Int_t ipF, ipL;
510 :
511 0 : for (i = 1; i<np[ihad] ; i++) {
512 0 : trackIt[ihad][i] = 1;
513 : iparticle =
514 0 : (TParticle *) ((TClonesArray *) particleslist->At(ihad))->At(i);
515 0 : Int_t kf = iparticle->GetPdgCode();
516 0 : Int_t ks = iparticle->GetStatusCode();
517 : // flagged particle
518 0 : if (pFlag[i] == 1) {
519 0 : ipF = iparticle->GetFirstDaughter();
520 0 : ipL = iparticle->GetLastDaughter();
521 0 : if (ipF > 0) for (j=ipF-1; j<ipL; j++) pFlag[j]=1;
522 0 : continue;
523 : }
524 :
525 : // flag decay products of particles with long life-time (c tau > .3 mum)
526 0 : if (ks != 1) {
527 0 : Double_t lifeTime = fDecayer->GetLifetime(kf);
528 0 : if (lifeTime > (Double_t) fMaxLifeTime) {
529 0 : ipF = iparticle->GetFirstDaughter();
530 0 : ipL = iparticle->GetLastDaughter();
531 0 : if (ipF > 0) for (j=ipF-1; j<ipL; j++) pFlag[j]=1;
532 : } else {
533 0 : trackIt[ihad][i] = 0;
534 0 : pSelected[ihad][i] = 1;
535 : }
536 0 : } // ks==1 ?
537 : //
538 : // children
539 0 : if ((ChildSelected(TMath::Abs(kf)) || fForceDecay == kAll || fSelectAll) && trackIt[ihad][i])
540 : {
541 0 : if (fCutOnChild) {
542 0 : pc[0]=iparticle->Px();
543 0 : pc[1]=iparticle->Py();
544 0 : pc[2]=iparticle->Pz();
545 : //printf("px %f py %f pz %f\n",pc[0],pc[1],pc[2]);
546 0 : Bool_t childok = KinematicSelection(iparticle, 1);
547 0 : if(childok) {
548 0 : pSelected[ihad][i] = 1;
549 0 : ncsel[ihad]++;
550 : } else {
551 0 : ncsel[ihad]=-1;
552 0 : break;
553 : } // child kine cuts
554 0 : } else {
555 0 : pSelected[ihad][i] = 1;
556 0 : ncsel[ihad]++;
557 : } // if child selection
558 : } // select muon
559 0 : } // decay particle loop
560 0 : } // if decay products
561 :
562 0 : if ((fCutOnChild && ncsel[ihad] >0) || !fCutOnChild) ipa1++;
563 :
564 0 : if (pFlag) delete[] pFlag;
565 :
566 0 : } // kinematic selection
567 : else // nodecay option, so parent will be tracked by GEANT (pions, kaons, eta, omegas, baryons)
568 : {
569 0 : gAlice->GetMCApp()->
570 0 : PushTrack(fTrackIt,-1,ihadron[ihad],p[ihad],origin0[ihad],polar[ihad],0,kPPrimary,nt,wgtp[ihad]);
571 0 : ipa1++;
572 0 : fNprimaries++;
573 :
574 : }
575 0 : break;
576 : } // while(1) loop
577 0 : if (ipa1<ipa0+1){
578 : ipa1=0;
579 0 : if (pSelected[ihad]) delete pSelected[ihad];
580 0 : if (trackIt[ihad]) delete trackIt[ihad];
581 0 : particleshad1->Clear();
582 0 : particleshad2->Clear();
583 : break;
584 : }//go out of loop and generate new pair if at least one hadron is rejected
585 : } // hadron pair loop
586 0 : if(ipa1==2){
587 :
588 0 : ipa=ipa+ipa1;
589 :
590 0 : if(fForceDecay != kNoDecay){
591 0 : for(ihad=0;ihad<2;ihad++){
592 :
593 : //load tracks in the stack if both hadrons of the pair accepted
594 0 : LoadTracks(iquark[ihad],pq[ihad],ihadron[ihad],p[ihad],np[ihad],
595 0 : (TClonesArray *)particleslist->At(ihad),origin0[ihad],
596 0 : polar[ihad],wgtp[ihad],wgtch[ihad],nt,ncsel[ihad],
597 0 : pSelected[ihad],trackIt[ihad]);
598 :
599 0 : if (pSelected[ihad]) delete pSelected[ihad];
600 0 : if (trackIt[ihad]) delete trackIt[ihad];
601 :
602 : }
603 0 : particleshad1->Clear();
604 0 : particleshad2->Clear();
605 : }
606 : }
607 0 : } // while (ipa<2*fNpart) loop
608 :
609 0 : SetHighWaterMark(nt);
610 :
611 0 : AliGenEventHeader* header = new AliGenEventHeader("CorrHF");
612 0 : header->SetPrimaryVertex(fVertex);
613 0 : header->SetNProduced(fNprimaries);
614 0 : AddHeader(header);
615 :
616 :
617 0 : delete particleshad1;
618 0 : delete particleshad2;
619 0 : delete particleslist;
620 :
621 0 : delete[] pSelected;
622 0 : delete[] trackIt;
623 0 : }
624 : //____________________________________________________________________________________
625 : void AliGenCorrHF::IpCharm(TH2F *hProbHH, Int_t &pdg3, Int_t &pdg4)
626 : {
627 : // Composition of a lower state charm hadron pair from a ccbar quark pair
628 0 : Int_t pdgH[] = {411, 421, 431, 4122, 4132, 4232, 4332};
629 :
630 0 : Double_t id3, id4;
631 0 : hProbHH->GetRandom2(id3, id4);
632 0 : pdg3 = pdgH[(Int_t)TMath::Floor(id3)];
633 0 : pdg4 = -1*pdgH[(Int_t)TMath::Floor(id4)];
634 :
635 : return;
636 0 : }
637 :
638 : void AliGenCorrHF::IpBeauty(TH2F *hProbHH, Int_t &pdg3, Int_t &pdg4)
639 : {
640 : // Composition of a lower state beauty hadron pair from a bbbar quark pair
641 : // B-Bbar mixing will be done by Pythia at their decay point
642 0 : Int_t pdgH[] = {511, 521, 531, 5122, 5132, 5232, 5332};
643 :
644 0 : Double_t id3, id4;
645 0 : hProbHH->GetRandom2(id3, id4);
646 0 : pdg3 = pdgH[(Int_t)TMath::Floor(id3)];
647 0 : pdg4 = -1*pdgH[(Int_t)TMath::Floor(id4)];
648 :
649 0 : if ( (pdg3== 511) || (pdg3== 521) || (pdg3== 531) ) pdg3 *= -1;
650 0 : if ( (pdg4==-511) || (pdg4==-521) || (pdg4==-531) ) pdg4 *= -1;
651 :
652 : return;
653 0 : }
654 :
655 : //____________________________________________________________________________________
656 : Double_t AliGenCorrHF::ComputeIntegral(TFile* fG) // needed by GetQuarkPair
657 : {
658 : // Read QQbar kinematical 5D grid's cell occupancy weights
659 0 : Int_t cell[6]; // cell[6]={wght,iy1,iy2,ipt1,ipt2,idph}
660 0 : TTree* tG = (TTree*) fG->Get("tGqq");
661 0 : tG->GetBranch("cell")->SetAddress(&cell);
662 0 : Int_t nbins = tG->GetEntries();
663 :
664 : // delete previously computed integral (if any)
665 0 : if(fgIntegral) delete [] fgIntegral;
666 :
667 0 : fgIntegral = new Double_t[nbins+1];
668 0 : fgIntegral[0] = 0;
669 : Int_t bin;
670 0 : for(bin=0;bin<nbins;bin++) {
671 0 : tG->GetEvent(bin);
672 0 : fgIntegral[bin+1] = fgIntegral[bin] + cell[0];
673 : }
674 : // Normalize integral to 1
675 0 : if (fgIntegral[nbins] == 0 ) {
676 0 : return 0;
677 : }
678 0 : for (bin=1;bin<=nbins;bin++) fgIntegral[bin] /= fgIntegral[nbins];
679 :
680 0 : return fgIntegral[nbins];
681 0 : }
682 :
683 :
684 : //____________________________________________________________________________________
685 : void AliGenCorrHF::GetQuarkPair(TFile* fG, Double_t* fInt, Double_t &y1, Double_t &y2, Double_t &pt1, Double_t &pt2, Double_t &dphi)
686 : // modification of ROOT's TH3::GetRandom3 for 5D
687 : {
688 : // Read QQbar kinematical 5D grid's cell coordinates
689 0 : Int_t cell[6]; // cell[6]={wght,iy1,iy2,ipt1,ipt2,idph}
690 0 : TTree* tG = (TTree*) fG->Get("tGqq");
691 0 : tG->GetBranch("cell")->SetAddress(&cell);
692 0 : Int_t nbins = tG->GetEntries();
693 0 : Double_t rand[6];
694 0 : gRandom->RndmArray(6,rand);
695 0 : Int_t ibin = TMath::BinarySearch(nbins,fInt,rand[0]);
696 0 : tG->GetEvent(ibin);
697 0 : y1 = fgy[cell[1]] + (fgy[cell[1]+1]-fgy[cell[1]])*rand[1];
698 0 : y2 = fgy[cell[2]] + (fgy[cell[2]+1]-fgy[cell[2]])*rand[2];
699 0 : pt1 = fgpt[cell[3]] + (fgpt[cell[3]+1]-fgpt[cell[3]])*rand[3];
700 0 : pt2 = fgpt[cell[4]] + (fgpt[cell[4]+1]-fgpt[cell[4]])*rand[4];
701 0 : dphi = fgdph[cell[5]]+ (fgdph[cell[5]+1]-fgdph[cell[5]])*rand[5];
702 0 : }
703 :
704 : //____________________________________________________________________________________
705 : void AliGenCorrHF::GetHadronPair(TFile* fG, Int_t idq, Double_t y1, Double_t y2, Double_t pt1, Double_t pt2, Int_t &id3, Int_t &id4, Double_t &pz3, Double_t &pz4, Double_t &pt3, Double_t &pt4)
706 : {
707 : // Generate a hadron pair
708 : void (*fIpParaFunc)(TH2F *, Int_t &, Int_t &);//Pointer to hadron pair composition function
709 : fIpParaFunc = IpCharm;
710 : Double_t mq = 1.2; // c & b quark masses (used in AliPythia)
711 0 : if (idq == 5) {
712 : fIpParaFunc = IpBeauty;
713 : mq = 4.75;
714 0 : }
715 0 : Double_t z11 = 0.;
716 0 : Double_t z12 = 0.;
717 0 : Double_t z21 = 0.;
718 0 : Double_t z22 = 0.;
719 0 : Double_t pz1, pz2, e1, e2, mh, ptemp, rand[2];
720 0 : char tag[100];
721 0 : TH2F *h2h[12], *h2s[12], *hProbHH; // hard & soft fragmentation and HH-probability functions
722 0 : for (Int_t ipt = 0; ipt<fgnptbins; ipt++) {
723 0 : snprintf(tag,100, "h2h_pt%d",ipt);
724 0 : h2h[ipt] = (TH2F*) fG->Get(tag);
725 0 : snprintf(tag,100, "h2s_pt%d",ipt);
726 0 : h2s[ipt] = (TH2F*) fG->Get(tag);
727 : }
728 :
729 0 : if (y1*y2 < 0) {
730 0 : for (Int_t ipt = 0; ipt<fgnptbins; ipt++) {
731 0 : if(pt1 >= fgptbmin[ipt] && pt1 < fgptbmax[ipt])
732 0 : h2h[ipt]->GetRandom2(z11, z21);
733 0 : if(pt2 >= fgptbmin[ipt] && pt2 < fgptbmax[ipt])
734 0 : h2h[ipt]->GetRandom2(z12, z22);
735 : }
736 0 : }
737 : else {
738 0 : if (TMath::Abs(y1) > TMath::Abs(y2)) {
739 0 : for (Int_t ipt = 0; ipt<fgnptbins; ipt++) {
740 0 : if(pt1 >= fgptbmin[ipt] && pt1 < fgptbmax[ipt])
741 0 : h2h[ipt]->GetRandom2(z11, z21);
742 0 : if(pt2 >= fgptbmin[ipt] && pt2 < fgptbmax[ipt])
743 0 : h2s[ipt]->GetRandom2(z12, z22);
744 : }
745 0 : }
746 : else {
747 0 : for (Int_t ipt = 0; ipt<fgnptbins; ipt++) {
748 0 : if(pt1 >= fgptbmin[ipt] && pt1 < fgptbmax[ipt])
749 0 : h2s[ipt]->GetRandom2(z11, z21);
750 0 : if(pt2 >= fgptbmin[ipt] && pt2 < fgptbmax[ipt])
751 0 : h2h[ipt]->GetRandom2(z12, z22);
752 : }
753 : }
754 : }
755 0 : gRandom->RndmArray(2,rand);
756 0 : ptemp = TMath::Sqrt(pt1*pt1 + mq*mq);
757 0 : pz1 = ptemp*TMath::SinH(y1);
758 0 : e1 = ptemp*TMath::CosH(y1);
759 0 : ptemp = TMath::Sqrt(pt2*pt2 + mq*mq);
760 0 : pz2 = ptemp*TMath::SinH(y2);
761 0 : e2 = ptemp*TMath::CosH(y2);
762 :
763 0 : hProbHH = (TH2F*)fG->Get("hProbHH");
764 0 : fIpParaFunc(hProbHH, id3, id4);
765 0 : mh = TDatabasePDG::Instance()->GetParticle(id3)->Mass();
766 0 : ptemp = z11*z21*(e1*e1-pz1*pz1) - mh*mh;
767 0 : if (idq==5) pt3 = pt1; // an approximation at low pt, try better
768 0 : else pt3 = rand[0]; // pt3=pt1 gives less D-hadrons at low pt
769 0 : if (ptemp > 0) pt3 = TMath::Sqrt(ptemp);
770 0 : if (pz1 > 0) pz3 = (z11*(e1 + pz1) - z21*(e1 - pz1)) / 2;
771 0 : else pz3 = (z21*(e1 + pz1) - z11*(e1 - pz1)) / 2;
772 0 : e1 = TMath::Sqrt(pz3*pz3 + pt3*pt3 + mh*mh);
773 :
774 0 : mh = TDatabasePDG::Instance()->GetParticle(id4)->Mass();
775 0 : ptemp = z12*z22*(e2*e2-pz2*pz2) - mh*mh;
776 0 : if (idq==5) pt4 = pt2; // an approximation at low pt, try better
777 0 : else pt4 = rand[1];
778 0 : if (ptemp > 0) pt4 = TMath::Sqrt(ptemp);
779 0 : if (pz2 > 0) pz4 = (z12*(e2 + pz2) - z22*(e2 - pz2)) / 2;
780 0 : else pz4 = (z22*(e2 + pz2) - z12*(e2 - pz2)) / 2;
781 0 : e2 = TMath::Sqrt(pz4*pz4 + pt4*pt4 + mh*mh);
782 :
783 : // small corr. instead of using Frag. Func. depending on yQ (in addition to ptQ)
784 : Float_t ycorr = 0.2, y3, y4;
785 0 : gRandom->RndmArray(2,rand);
786 0 : y3 = 0.5 * TMath::Log((e1 + pz3 + 1.e-13)/(e1 - pz3 + 1.e-13));
787 0 : y4 = 0.5 * TMath::Log((e2 + pz4 + 1.e-13)/(e2 - pz4 + 1.e-13));
788 0 : if(TMath::Abs(y3)<ycorr && TMath::Abs(y4)<ycorr && rand[0]>0.5) {
789 0 : ptemp = TMath::Sqrt((e1-pz3)*(e1+pz3));
790 0 : y3 = 4*(1 - 2*rand[1]);
791 0 : pz3 = ptemp*TMath::SinH(y3);
792 0 : pz4 = pz3;
793 0 : }
794 0 : }
795 :
796 :
797 : //____________________________________________________________________________________
798 : void AliGenCorrHF::LoadTracks(Int_t iquark, Float_t *pq,
799 : Int_t iPart, Float_t *p,
800 : Int_t np, TClonesArray *particles,
801 : Float_t *origin0, Float_t *polar,
802 : Float_t wgtp, Float_t wgtch,
803 : Int_t &nt, Int_t ncsel, Int_t *pSelected,
804 : Int_t *trackIt){
805 : Int_t i;
806 : Int_t ntq=-1;
807 0 : Int_t* pParent = new Int_t[np];
808 0 : Float_t pc[3], och[3];
809 : Int_t iparent;
810 :
811 0 : for(i=0;i<np;i++) pParent[i]=-1;
812 :
813 0 : if ((fCutOnChild && ncsel >0) || !fCutOnChild){
814 : // Parents
815 : // quark
816 0 : PushTrack(0, -1, iquark, pq, origin0, polar, 0, kPPrimary, nt, wgtp);
817 0 : KeepTrack(nt);
818 0 : ntq = nt;
819 : // hadron
820 0 : PushTrack(0, ntq, iPart, p, origin0, polar, 0, kPDecay, nt, wgtp);
821 0 : pParent[0] = nt;
822 0 : KeepTrack(nt);
823 0 : fNprimaries++;
824 :
825 : // Decay Products
826 0 : for (i = 1; i < np; i++) {
827 0 : if (pSelected[i]) {
828 :
829 0 : TParticle* iparticle = (TParticle *) particles->At(i);
830 0 : Int_t kf = iparticle->GetPdgCode();
831 0 : Int_t jpa = iparticle->GetFirstMother()-1;
832 0 : Int_t ksc = iparticle->GetStatusCode();
833 : // RS: note, the conversion mm->cm is done now in the decayer. The time is ignored here!
834 0 : och[0] = origin0[0]+iparticle->Vx();
835 0 : och[1] = origin0[1]+iparticle->Vy();
836 0 : och[2] = origin0[2]+iparticle->Vz();
837 0 : pc[0] = iparticle->Px();
838 0 : pc[1] = iparticle->Py();
839 0 : pc[2] = iparticle->Pz();
840 :
841 0 : if (jpa > -1) {
842 0 : iparent = pParent[jpa];
843 0 : } else {
844 : iparent = -1;
845 : }
846 :
847 0 : PushTrack(fTrackIt*trackIt[i], iparent, kf,
848 0 : pc, och, polar,
849 : 0, kPDecay, nt, wgtch,ksc);
850 0 : pParent[i] = nt;
851 0 : KeepTrack(nt);
852 0 : fNprimaries++;
853 :
854 0 : } // Selected
855 : } // Particle loop
856 : }
857 0 : if (pParent) delete[] pParent;
858 :
859 : return;
860 0 : }
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