Coverity fix.
[u/mrichter/AliRoot.git] / TPHIC / AliGenTPHIC.cxx
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0b5dd071 1/**************************************************************************
2 * Copyright(c) 1998-2003, ALICE Experiment at CERN, All rights reserved. *
3 * *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
6 * *
7 * Permission to use, copy, modify and distribute this software and its *
8 * documentation strictly for non-commercial purposes is hereby granted *
9 * without fee, provided that the above copyright notice appears in all *
10 * copies and that both the copyright notice and this permission notice *
11 * appear in the supporting documentation. The authors make no claims *
12 * about the suitability of this software for any purpose. It is *
13 * provided "as is" without express or implied warranty. *
14 * *
15 **************************************************************************/
16
17/* $Id$ */
18
0b5dd071 19// Event generator of two-photon processes
20// in ultra-peripheral ion collisions.
21// 5 two-photon process are implemented, see comments to SetProcess().
22//%
23// The example of the generator initialization for the process
24// gamma gamma -> X in CaCa collisions at 7000 TeV/nucleon is the following:
25//%
26// AliGenTPHIC *gener = new AliGenTPHIC();
27// gener->SetProcess(1);
28// gener->SetBeamEnergy(3500.);
29// gener->SetBeamZ(20);
30// gener->SetBeamA(40);
31// gener->SetMggRange(70.,200.);
32// gener->SetYggRange(-5.,5.);
33// gener->SetLumFunName("lum_ca_70_200.dat");
34// gener->SetLumFunFlag(-1);
35// gener->Init();
36//%
37// The two-photon luminosity function needed for the process cross section
38// calculation is time-consuming, therefore it can be calculated once for a
39// selected two-photon energy and rapidity range and selected ion species,
40// saved into a file and then can be reused in further calculation.
41//%
42// The integral cross section of the process is calculated in each event
43// by the Monte Carlo integration procedure, the differential cross section
44// of each thrown event is assigned as a weight to each track of the event
45// which can be then used during the event analysis by retreiving this weight
46// from any of the event tracks.
47//
48// The manual of the fortran generator is available in
49// $ALICE_ROOT/TPHIC/TPHIC_doc.ps.gz
50// For the two-photon physics in heavy ion collisions see
51// G.Baur et al, Phys.Rep. 364 (2002), 359.
52//%
53// Author: Yuri.Kharlov@cern.ch
54// 15 April 2003
55
56#include <TParticle.h>
57#include <TParticlePDG.h>
58#include <TDatabasePDG.h>
37b09b91 59#include <TClonesArray.h>
60
0b5dd071 61#include "AliPythia.h"
62#include "AliRun.h"
63#include <AliGenTPHIC.h>
64#include <TPHICgen.h>
65#include <TPHICcommon.h>
66
67ClassImp(AliGenTPHIC)
68
69//------------------------------------------------------------
70
f893d4a5 71AliGenTPHIC::AliGenTPHIC() :
72 AliGenMC(),
73 fTPHICgen(0x0),
74 fPythia(0x0),
75 fParticles(0x0),
76 fEvent(-1),
77 fDebug(0),
78 fDebugEventFirst(-1),
79 fDebugEventLast(-1)
0b5dd071 80{
81 // Constructor: create generator instance,
82 // create particle array
83 // Set TPHIC parameters to default values:
84 // eta_b production in Ca-Ca collisions at 7 A*TeV
85
86 SetMC(new TPHICgen());
87 fPythia = AliPythia::Instance();
88 fParticles = new TClonesArray("TParticle",100);
89
90 SetProcess ();
91 SetBeamEnergy();
92 SetBeamZ ();
93 SetBeamA ();
94 SetYggRange ();
95 SetMggRange ();
96 SetNgridY ();
97 SetNgridM ();
98 SetLumFunName();
99 SetLumFunFlag();
100 SetKfOnium ();
101}
102
103//____________________________________________________________
0b5dd071 104AliGenTPHIC::~AliGenTPHIC()
105{
106 // Destroys the object, deletes and disposes all TParticles currently on list.
107 if (fParticles) {
108 fParticles->Delete();
109 delete fParticles;
110 fParticles = 0;
111 }
112}
113
114//____________________________________________________________
115void AliGenTPHIC::Init()
116{
117 // Initialize the generator TPHIC
118
119 fTPHICgen->Initialize();
120 fEvent = 0;
121}
122
123//____________________________________________________________
124void AliGenTPHIC::Generate()
125{
126 // Generate one event of two-photon process.
127 // Gaussian smearing on the vertex is done if selected.
128 // All particles from the TPHIC/PYTHIA event listing
129 // are stored in TreeK, and only final-state particles are tracked.
130 // The event differectial cross section is assigned as a weight
131 // to each track of the event.
132
8feee6f7 133 Float_t polar[3] = {0,0,0};
134 Float_t origin0[3] = {0,0,0};
135 Float_t origin[3] = {0,0,0};
0b5dd071 136 Float_t p[3], tof;
137 Double_t weight;
138
139 Int_t ks,kf,iparent,nt, trackIt;
140 Float_t random[6];
141 const Float_t kconv=0.001/2.999792458e8;
142
143 fTPHICgen->GenerateEvent();
144 weight = GetXSectionCurrent();
145 if (gAlice->GetEvNumber()>=fDebugEventFirst &&
146 gAlice->GetEvNumber()<=fDebugEventLast) fPythia->Pylist(1);
147 fPythia->ImportParticles(fParticles,"All");
148
149 if (fDebug == 1)
150 Info("Generate()","one event is produced");
151
152 Int_t j;
153 for (j=0;j<3;j++) origin[j]=fOrigin[j];
154 if(fVertexSmear==kPerEvent) {
155 Rndm(random,6);
156 for (j=0;j<3;j++) {
157 origin0[j]+=fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
158 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
159 }
160 }
161
162 Int_t ip;
163 Int_t np = fParticles->GetEntriesFast();
164 TParticle *iparticle;
165// Int_t* pParent = new Int_t[np];
166 for (ip=0; ip<np; ip++) {
167 iparticle = (TParticle *) fParticles->At(ip);
168 ks = iparticle->GetStatusCode();
169// // No initial state partons
170// if (ks==21) continue;
171 p[0] = iparticle->Px();
172 p[1] = iparticle->Py();
173 p[2] = iparticle->Pz();
174 origin[0] = origin0[0]+iparticle->Vx()/10.;
175 origin[1] = origin0[1]+iparticle->Vy()/10.;
176 origin[2] = origin0[2]+iparticle->Vz()/10.;
177 kf = CheckPDGCode(iparticle->GetPdgCode());
178 iparent = -1;
179 tof = kconv*iparticle->T();
180 if (ks == 1) trackIt = 1;
181 else trackIt = 0;
642f15cf 182 PushTrack(fTrackIt*trackIt,iparent,kf,p,origin,polar,tof,kPPrimary,nt,weight,ks);
0b5dd071 183 KeepTrack(nt);
184
185 if (fDebug == 2)
186 printf("id=%+4d, parent=%3d, ks=%d, p = (%+11.4e,%+11.4e,%+11.4e) GeV\n",
187 kf,iparent,fTrackIt*trackIt,p[0],p[1],p[2]);
188 }
189 fEvent++;
190 fTPHICgen->SetNEVENT(fEvent);
191 if (fDebug == 1 && fEvent%100 == 0) {
192 Info("Generate","Event %d\n",fEvent);
193 fTPHICgen->Finish();
194 }
195}
196
197//____________________________________________________________
198void AliGenTPHIC::SetEventListRange(Int_t eventFirst, Int_t eventLast)
199{
200 // Set a range of event numbers, for which a table
201 // of generated particle will be printed
202 fDebugEventFirst = eventFirst;
203 fDebugEventLast = eventLast;
204 if (fDebugEventLast==-1) fDebugEventLast=fDebugEventFirst;
205}
206
207//____________________________________________________________
208void AliGenTPHIC::SetProcess (Int_t proc )
209{
210 // Set process number:
211 // proc=1 - gamma gamma -> X
212 // proc=2 - gamma gamma -> quarkonium
213 // proc=3 - gamma gamma -> fermion+ fermion-
214 // proc=4 - gamma gamma -> W+ W-
215 // proc=5 - not implemented
216 // proc=6 - gamma gamma -> V1 V2 (vector meson pair)
217
218 fTPHICgen->SetIPROC(proc);
219}
220//____________________________________________________________
221 void AliGenTPHIC::SetBeamEnergy (Float_t energy)
222{
223 // Set energy of the beam ion per nucleon in GeV
224 fTPHICgen->SetEBMN(energy);
225}
226//____________________________________________________________
227 void AliGenTPHIC::SetBeamZ (Int_t z )
228{
229 // Set beam ion charge
230 fTPHICgen->SetIZ(z);
231}
232//____________________________________________________________
233 void AliGenTPHIC::SetBeamA (Int_t a )
234{
235 // Set beam ion atomic number
236 fTPHICgen->SetIA(a);
237}
238//____________________________________________________________
239 void AliGenTPHIC::SetYggRange (Float_t ymin, Float_t ymax)
240{
241 // Set rapidity range of 2-photon system for the
242 // luminosity function calculation
243 fTPHICgen->SetYMIN(ymin);
244 fTPHICgen->SetYMAX(ymax);
245}
246//____________________________________________________________
247 void AliGenTPHIC::SetMggRange (Float_t mmin, Float_t mmax)
248{
249 // Set invariant mass range of 2-photon system for the
250 // luminosity function calculation
251 fTPHICgen->SetAMIN(mmin);
252 fTPHICgen->SetAMAX(mmax);
253}
254//____________________________________________________________
255 void AliGenTPHIC::SetNgridY (Int_t ny )
256{
257 // Set number of nodes on the grid along the rapidity axis
258 // to calculate the 2-photon luminosity function
259 fTPHICgen->SetNY(ny);
260}
261//____________________________________________________________
262 void AliGenTPHIC::SetNgridM (Int_t nm )
263{
264 // Set number of nodes on the grid along the mass axis
265 // to calculate the 2-photon luminosity function
266 fTPHICgen->SetNMAS(nm);
267}
268//____________________________________________________________
269 void AliGenTPHIC::SetLumFunName (TString name )
270{
271 // Set filename to store the 2-photon luminosity
272 // function calculated on the grid
273 fTPHICgen->SetLUMFIL(name);
274}
275//____________________________________________________________
276 void AliGenTPHIC::SetLumFunFlag (Int_t flag )
277{
278 // Set flag to calculate the 2-photon luminosity function:
279 // flag=-1 if a new lumimosity function to be calculated
280 // and stored in a file
281 // flag=+1 if a previously calculated function to be read
282 // from a file
283 fTPHICgen->SetILUMF(flag);
284}
285//____________________________________________________________
286 void AliGenTPHIC::SetKfFermion (Int_t kf )
287{
288 // Set a PDG flavour code of a fermion for the process 3,
289 // gamma gamma -> fermion+ fermion-
290 fTPHICgen->SetKFERM(kf);
291}
292//____________________________________________________________
293 void AliGenTPHIC::SetKfOnium (Int_t kf )
294{
295 // Set a PDG flavour code of a quarkonium for the process 2,
296 // gamma gamma -> quarkonium
297 fTPHICgen->SetKFONIUM(kf);
298}
299//____________________________________________________________
300 void AliGenTPHIC::SetMassOnium (Float_t mass )
301{
302 // Set a quarkonium mass [GeV] for the process 2 if it
303 // differes from the Pythia's particle table.
304 // For the well-known quarkonia no need to set this mass
305 // because it will be taken from the Pythia table
306 fTPHICgen->SetXMRES(mass);
307}
308//____________________________________________________________
309 void AliGenTPHIC::SetGGwidthOnium(Float_t width )
310{
311 // Set 2-photon partial width [GeV] of the quarkonium for
312 // the process 2 if it differes fromthe Pythia's particle table.
313 // For the well-known quarkonia no need to set this width
314 // because it will be taken from the Pythia table
315 fTPHICgen->SetXGGRES(width);
316}
317//____________________________________________________________
318 void AliGenTPHIC::SetKfVmesons (Int_t kf1, Int_t kf2)
319{
320 // Set PDG flavour codes of the two vector vesons
321 // for the process 2: gamma gamma -> V1 V2
322 // So far this processes is implemented for the following
323 // mesons and their combinations only:
324 // pho0 (113), omega (223), phi (333), J/psi (443)
325 fTPHICgen->SetKV1(kf1);
326 fTPHICgen->SetKV2(kf2);
327}
328//____________________________________________________________
329 Float_t AliGenTPHIC::GetGGmass ()
330{
331 // Get invariant mass of generated 2-photon system
332 return fTPHICgen->GetWSQ();
333}
334//____________________________________________________________
335 Float_t AliGenTPHIC::GetGGrapidity()
336{
337 // Get rapidity of generated 2-photon system
338 return fTPHICgen->GetYGG();
339}
340//____________________________________________________________
341 Float_t AliGenTPHIC::GetG1mass ()
342{
343 // Get a mass of the first virtual photon of
344 // the 2-photon process (-sqrt(q1^2)).
345 return fTPHICgen->GetXMG1();
346}
347//____________________________________________________________
348 Float_t AliGenTPHIC::GetG2mass ()
349{
350 // Get a mass of the second virtual photon of
351 // the 2-photon process (-sqrt(q2^2)).
352 return fTPHICgen->GetXMG2();
353}
354//____________________________________________________________
355 TClonesArray* AliGenTPHIC::GetParticleList ()
356{
357 // Get array of particles of the event listing
358 return fParticles;
359}
360//____________________________________________________________
361 TLorentzVector AliGenTPHIC::MomentumRecNucl1()
362{
363 // Get 4-momentum of the first recoil nucleus after
364 // the 2-photon process.
2c23f883 365 return TLorentzVector(fTPHICgen->GetPTAG1(0),
366 fTPHICgen->GetPTAG1(1),
0b5dd071 367 fTPHICgen->GetPTAG1(2),
2c23f883 368 fTPHICgen->GetPTAG1(3));
0b5dd071 369}
370//____________________________________________________________
371 TLorentzVector AliGenTPHIC::MomentumRecNucl2()
372{
373 // Get 4-momentum of the first recoil nucleus after
374 // the 2-photon process.
2c23f883 375 return TLorentzVector(fTPHICgen->GetPTAG2(0),
376 fTPHICgen->GetPTAG2(1),
0b5dd071 377 fTPHICgen->GetPTAG2(2),
2c23f883 378 fTPHICgen->GetPTAG2(3));
0b5dd071 379}
380//____________________________________________________________
381 Float_t AliGenTPHIC::GetXSectionCurrent()
382{
383 // Get the cross section of the produced event for the
384 // Monte Carlo integral cross section calculation
385 return fTPHICgen->GetXSCUR();
386}
387//____________________________________________________________
388 Float_t AliGenTPHIC::GetXSection ()
389{
390 // Get the integral cross section of the process
391 // calculated so far
392 return fTPHICgen->GetXSTOT();
393}
394//____________________________________________________________
395 Float_t AliGenTPHIC::GetXSectionError ()
396{
397 // Get the error of the integral cross section of the process
398 // calculated so far
399 return fTPHICgen->GetXSTOTE();
400}