[u/mrichter/AliRoot.git] / TPHIC / AliGenTPHIC.cxx

/**************************************************************************
 * Copyright(c) 1998-2003, ALICE Experiment at CERN, All rights reserved. *
 *                                                                        *
 * Author: The ALICE Off-line Project.                                    *
 * Contributors are mentioned in the code where appropriate.              *
 *                                                                        *
 * Permission to use, copy, modify and distribute this software and its   *
 * documentation strictly for non-commercial purposes is hereby granted   *
 * without fee, provided that the above copyright notice appears in all   *
 * copies and that both the copyright notice and this permission notice   *
 * appear in the supporting documentation. The authors make no claims     *
 * about the suitability of this software for any purpose. It is          *
 * provided "as is" without express or implied warranty.                  *
 *                                                                        *
 **************************************************************************/

/* $Id$ */

// Event generator of two-photon processes
// in ultra-peripheral ion collisions.
// 5 two-photon process are implemented, see comments to SetProcess().
//%
// The example of the generator initialization for the process
// gamma gamma -> X in CaCa collisions at 7000 TeV/nucleon is the following:
//%
//    AliGenTPHIC *gener = new AliGenTPHIC();
//    gener->SetProcess(1);
//    gener->SetBeamEnergy(3500.);
//    gener->SetBeamZ(20);
//    gener->SetBeamA(40);
//    gener->SetMggRange(70.,200.);
//    gener->SetYggRange(-5.,5.);
//    gener->SetLumFunName("lum_ca_70_200.dat");
//    gener->SetLumFunFlag(-1);
//    gener->Init();
//%
// The two-photon luminosity function needed for the process cross section
// calculation is time-consuming, therefore it can be calculated once for a
// selected two-photon energy and rapidity range and selected ion species,
// saved into a file and then can be reused in further calculation.
//%
// The integral cross section of the process is calculated in each event
// by the Monte Carlo integration procedure, the differential cross section
// of each thrown event is assigned as a weight to each track of the event
// which can be then used during the event analysis by retreiving this weight
// from any of the event tracks.
// 
// The manual of the fortran generator is available in
// $ALICE_ROOT/TPHIC/TPHIC_doc.ps.gz
// For the two-photon physics in heavy ion collisions see
// G.Baur et al, Phys.Rep. 364 (2002), 359.
//%
// Author: Yuri.Kharlov@cern.ch
// 15 April 2003

#include <TParticle.h>
#include <TParticlePDG.h>
#include <TDatabasePDG.h>
#include "AliPythia.h"
#include "AliRun.h"
#include <AliGenTPHIC.h>
#include <TPHICgen.h>
#include <TPHICcommon.h>

ClassImp(AliGenTPHIC)

//------------------------------------------------------------

AliGenTPHIC::AliGenTPHIC()
{
  // Constructor: create generator instance,
  // create particle array
  // Set TPHIC parameters to default values:
  // eta_b production in Ca-Ca collisions at 7 A*TeV

  SetMC(new TPHICgen());
  fPythia = AliPythia::Instance();
  fParticles = new TClonesArray("TParticle",100);

  SetProcess   ();
  SetBeamEnergy();
  SetBeamZ     ();
  SetBeamA     ();
  SetYggRange  ();
  SetMggRange  ();
  SetNgridY    ();
  SetNgridM    ();
  SetLumFunName();
  SetLumFunFlag();
  SetKfOnium   ();
}

//____________________________________________________________
AliGenTPHIC::~AliGenTPHIC()
{
  // Destroys the object, deletes and disposes all TParticles currently on list.
  if (fParticles) {
    fParticles->Delete();
    delete fParticles;
    fParticles = 0;
  }
}

//____________________________________________________________
void AliGenTPHIC::Init()
{
  // Initialize the generator TPHIC

  fTPHICgen->Initialize();
  fEvent = 0;
}

//____________________________________________________________
void AliGenTPHIC::Generate()
{
  // Generate one event of two-photon process.
  // Gaussian smearing on the vertex is done if selected. 
  // All particles from the TPHIC/PYTHIA event listing
  // are stored in TreeK, and only final-state particles are tracked.
  // The event differectial cross section is assigned as a weight
  // to each track of the event.

  Float_t polar[3]= {0,0,0};
  Float_t origin0[3],origin[3];
  Float_t p[3], tof;
  Double_t weight;

  Int_t    ks,kf,iparent,nt, trackIt;
  Float_t  random[6];
  const Float_t kconv=0.001/2.999792458e8;

  fTPHICgen->GenerateEvent();
  weight = GetXSectionCurrent();
  if (gAlice->GetEvNumber()>=fDebugEventFirst &&
      gAlice->GetEvNumber()<=fDebugEventLast) fPythia->Pylist(1);
  fPythia->ImportParticles(fParticles,"All");

  if (fDebug == 1)
    Info("Generate()","one event is produced");

  Int_t j;
  for (j=0;j<3;j++) origin[j]=fOrigin[j];
  if(fVertexSmear==kPerEvent) {
    Rndm(random,6);
    for (j=0;j<3;j++) {
      origin0[j]+=fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
	TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
    }
  }

  Int_t ip;
  Int_t np = fParticles->GetEntriesFast();
  TParticle *iparticle;
//   Int_t* pParent   = new Int_t[np];
  for (ip=0; ip<np; ip++) {
    iparticle = (TParticle *) fParticles->At(ip);
    ks = iparticle->GetStatusCode();
//     // No initial state partons
//     if (ks==21) continue;
    p[0] = iparticle->Px();
    p[1] = iparticle->Py();
    p[2] = iparticle->Pz();
    origin[0] = origin0[0]+iparticle->Vx()/10.;
    origin[1] = origin0[1]+iparticle->Vy()/10.;
    origin[2] = origin0[2]+iparticle->Vz()/10.;
    kf = CheckPDGCode(iparticle->GetPdgCode());
    iparent = -1;
    tof     = kconv*iparticle->T();
    if (ks == 1) trackIt = 1;
    else         trackIt = 0;
    PushTrack(fTrackIt*trackIt,iparent,kf,p,origin,polar,tof,kPPrimary,nt,weight,ks);
    KeepTrack(nt); 

    if (fDebug == 2)
      printf("id=%+4d, parent=%3d, ks=%d, p = (%+11.4e,%+11.4e,%+11.4e) GeV\n",
	     kf,iparent,fTrackIt*trackIt,p[0],p[1],p[2]);
  }
  fEvent++;
  fTPHICgen->SetNEVENT(fEvent);
  if (fDebug == 1 && fEvent%100 == 0) {
    Info("Generate","Event %d\n",fEvent);
    fTPHICgen->Finish();
  }
}

//____________________________________________________________
void AliGenTPHIC::SetEventListRange(Int_t eventFirst, Int_t eventLast)
{
  // Set a range of event numbers, for which a table
  // of generated particle will be printed
  fDebugEventFirst = eventFirst;
  fDebugEventLast  = eventLast;
  if (fDebugEventLast==-1) fDebugEventLast=fDebugEventFirst;
}

//____________________________________________________________
void AliGenTPHIC::SetProcess       (Int_t   proc  )
{
  // Set process number:
  // proc=1 - gamma gamma -> X
  // proc=2 - gamma gamma -> quarkonium
  // proc=3 - gamma gamma -> fermion+ fermion-
  // proc=4 - gamma gamma -> W+ W-
  // proc=5 - not implemented
  // proc=6 - gamma gamma -> V1 V2 (vector meson pair)

  fTPHICgen->SetIPROC(proc);
}
//____________________________________________________________
  void AliGenTPHIC::SetBeamEnergy  (Float_t energy)
{
  // Set energy of the beam ion per nucleon in GeV
  fTPHICgen->SetEBMN(energy);
}
//____________________________________________________________
  void AliGenTPHIC::SetBeamZ       (Int_t   z     )
{
  // Set beam ion charge
  fTPHICgen->SetIZ(z);
}
//____________________________________________________________
  void AliGenTPHIC::SetBeamA       (Int_t   a     )
{
  // Set beam ion atomic number
  fTPHICgen->SetIA(a);
}
//____________________________________________________________
  void AliGenTPHIC::SetYggRange    (Float_t ymin, Float_t ymax)
{
  // Set rapidity range of 2-photon system for the
  // luminosity function calculation
  fTPHICgen->SetYMIN(ymin);
  fTPHICgen->SetYMAX(ymax);
}
//____________________________________________________________
  void AliGenTPHIC::SetMggRange    (Float_t mmin, Float_t mmax)
{
  // Set invariant mass range of 2-photon system for the
  // luminosity function calculation
  fTPHICgen->SetAMIN(mmin);
  fTPHICgen->SetAMAX(mmax);
}
//____________________________________________________________
  void AliGenTPHIC::SetNgridY      (Int_t   ny    )
{
  // Set number of nodes on the grid along the rapidity axis
  // to calculate the 2-photon luminosity function
  fTPHICgen->SetNY(ny);
}
//____________________________________________________________
  void AliGenTPHIC::SetNgridM      (Int_t   nm    )
{
  // Set number of nodes on the grid along the mass axis
  // to calculate the 2-photon luminosity function
  fTPHICgen->SetNMAS(nm);
}
//____________________________________________________________
  void AliGenTPHIC::SetLumFunName  (TString name  )
{
  // Set filename to store the 2-photon luminosity
  // function calculated on the grid
  fTPHICgen->SetLUMFIL(name);
}
//____________________________________________________________
  void AliGenTPHIC::SetLumFunFlag  (Int_t   flag  )
{
  // Set flag to calculate the 2-photon luminosity function:
  // flag=-1 if a new lumimosity function to be calculated
  //         and stored in a file
  // flag=+1 if a previously calculated function to be read
  //         from a file
  fTPHICgen->SetILUMF(flag);
}
//____________________________________________________________
  void AliGenTPHIC::SetKfFermion   (Int_t   kf    )
{
  // Set a PDG flavour code of a fermion for the process 3,
  // gamma gamma -> fermion+ fermion-
  fTPHICgen->SetKFERM(kf);
}
//____________________________________________________________
  void AliGenTPHIC::SetKfOnium    (Int_t   kf    )
{
  // Set a PDG flavour code of a quarkonium for the process 2,
  // gamma gamma -> quarkonium
  fTPHICgen->SetKFONIUM(kf);
}
//____________________________________________________________
  void AliGenTPHIC::SetMassOnium   (Float_t mass  )
{
  // Set a quarkonium mass [GeV] for the process 2 if it
  // differes from the Pythia's particle table.
  // For the well-known quarkonia no need to set this mass
  // because it will be taken from the Pythia table
  fTPHICgen->SetXMRES(mass);
}
//____________________________________________________________
  void AliGenTPHIC::SetGGwidthOnium(Float_t width )
{
  // Set 2-photon partial width [GeV] of the quarkonium for
  // the process 2 if it differes fromthe Pythia's particle table.
  // For the well-known quarkonia no need to set this width
  // because it will be taken from the Pythia table
  fTPHICgen->SetXGGRES(width);
}
//____________________________________________________________
  void AliGenTPHIC::SetKfVmesons   (Int_t kf1, Int_t kf2)
{
  // Set PDG flavour codes of the two vector vesons
  // for the process 2:  gamma gamma -> V1 V2
  // So far this processes is implemented for the following
  // mesons and their combinations only:
  // pho0 (113), omega (223), phi (333), J/psi (443)
  fTPHICgen->SetKV1(kf1);
  fTPHICgen->SetKV2(kf2);
}
//____________________________________________________________
  Float_t AliGenTPHIC::GetGGmass    ()
{
  // Get invariant mass of generated 2-photon system
  return fTPHICgen->GetWSQ();
}
//____________________________________________________________
  Float_t AliGenTPHIC::GetGGrapidity()
{
  // Get rapidity of generated 2-photon system
  return fTPHICgen->GetYGG();
}
//____________________________________________________________
  Float_t AliGenTPHIC::GetG1mass    ()
{
  // Get a mass of the first virtual photon of
  // the 2-photon process (-sqrt(q1^2)).
  return fTPHICgen->GetXMG1();
}
//____________________________________________________________
  Float_t AliGenTPHIC::GetG2mass    ()
{
  // Get a mass of the second virtual photon of
  // the 2-photon process (-sqrt(q2^2)).
  return fTPHICgen->GetXMG2();
}
//____________________________________________________________
  TClonesArray*  AliGenTPHIC::GetParticleList ()
{
  // Get array of particles of the event listing
  return fParticles;
}
//____________________________________________________________
  TLorentzVector AliGenTPHIC::MomentumRecNucl1()
{
  // Get 4-momentum of the first recoil nucleus after
  // the 2-photon process.
  return TLorentzVector(fTPHICgen->GetPTAG1(1),
			fTPHICgen->GetPTAG1(2),
			fTPHICgen->GetPTAG1(3),
			fTPHICgen->GetPTAG1(4));
}
//____________________________________________________________
  TLorentzVector AliGenTPHIC::MomentumRecNucl2()
{
  // Get 4-momentum of the first recoil nucleus after
  // the 2-photon process.
  return TLorentzVector(fTPHICgen->GetPTAG2(1),
			fTPHICgen->GetPTAG2(2),
			fTPHICgen->GetPTAG2(3),
			fTPHICgen->GetPTAG2(4));
}
//____________________________________________________________
  Float_t AliGenTPHIC::GetXSectionCurrent()
{
  // Get the cross section of the produced event for the
  // Monte Carlo integral cross section calculation
  return fTPHICgen->GetXSCUR();
}
//____________________________________________________________
  Float_t AliGenTPHIC::GetXSection       ()
{
  // Get the integral cross section of the process
  // calculated so far
  return fTPHICgen->GetXSTOT();
}
//____________________________________________________________
  Float_t AliGenTPHIC::GetXSectionError  ()
{
  // Get the error of the integral cross section of the process
  // calculated so far
  return fTPHICgen->GetXSTOTE();
}
Commit	Line	Data
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>
	59	#include "AliPythia.h"
	60	#include "AliRun.h"
	61	#include <AliGenTPHIC.h>
	62	#include <TPHICgen.h>
	63	#include <TPHICcommon.h>
	64
	65	ClassImp(AliGenTPHIC)
	66
	67	//------------------------------------------------------------
	68
	69	AliGenTPHIC::AliGenTPHIC()
	70	{
	71	// Constructor: create generator instance,
	72	// create particle array
	73	// Set TPHIC parameters to default values:
	74	// eta_b production in Ca-Ca collisions at 7 A*TeV
	75
	76	SetMC(new TPHICgen());
	77	fPythia = AliPythia::Instance();
	78	fParticles = new TClonesArray("TParticle",100);
	79
	80	SetProcess ();
	81	SetBeamEnergy();
	82	SetBeamZ ();
83	SetBeamA ();
84	SetYggRange ();
85	SetMggRange ();
86	SetNgridY ();
87	SetNgridM ();
88	SetLumFunName();
89	SetLumFunFlag();
90	SetKfOnium ();
91	}
92
0b5dd071	93	//____________________________________________________________
	94	AliGenTPHIC::~AliGenTPHIC()
	95	{
	96	// Destroys the object, deletes and disposes all TParticles currently on list.
	97	if (fParticles) {
	98	fParticles->Delete();
	99	delete fParticles;
	100	fParticles = 0;
	101	}
	102	}
	103
	104	//____________________________________________________________
	105	void AliGenTPHIC::Init()
	106	{
	107	// Initialize the generator TPHIC
	108
	109	fTPHICgen->Initialize();
	110	fEvent = 0;
	111	}
	112
	113	//____________________________________________________________
	114	void AliGenTPHIC::Generate()
	115	{
	116	// Generate one event of two-photon process.
	117	// Gaussian smearing on the vertex is done if selected.
	118	// All particles from the TPHIC/PYTHIA event listing
	119	// are stored in TreeK, and only final-state particles are tracked.
	120	// The event differectial cross section is assigned as a weight
	121	// to each track of the event.
	122
	123	Float_t polar[3]= {0,0,0};
	124	Float_t origin0[3],origin[3];
	125	Float_t p[3], tof;
	126	Double_t weight;
	127
	128	Int_t ks,kf,iparent,nt, trackIt;
	129	Float_t random[6];
	130	const Float_t kconv=0.001/2.999792458e8;
	131
	132	fTPHICgen->GenerateEvent();
	133	weight = GetXSectionCurrent();
	134	if (gAlice->GetEvNumber()>=fDebugEventFirst &&
	135	gAlice->GetEvNumber()<=fDebugEventLast) fPythia->Pylist(1);
	136	fPythia->ImportParticles(fParticles,"All");
	137
	138	if (fDebug == 1)
	139	Info("Generate()","one event is produced");
	140
	141	Int_t j;
	142	for (j=0;j<3;j++) origin[j]=fOrigin[j];
	143	if(fVertexSmear==kPerEvent) {
	144	Rndm(random,6);
	145	for (j=0;j<3;j++) {
	146	origin0[j]+=fOsigma[j]TMath::Cos(2random[2j]TMath::Pi())*
	147	TMath::Sqrt(-2TMath::Log(random[2j+1]));
	148	}
	149	}
	150
	151	Int_t ip;
	152	Int_t np = fParticles->GetEntriesFast();
	153	TParticle *iparticle;
	154	// Int_t* pParent = new Int_t[np];
	155	for (ip=0; ip<np; ip++) {
	156	iparticle = (TParticle *) fParticles->At(ip);
157	ks = iparticle->GetStatusCode();
158	// // No initial state partons
159	// if (ks==21) continue;
160	p[0] = iparticle->Px();
161	p[1] = iparticle->Py();
162	p[2] = iparticle->Pz();
163	origin[0] = origin0[0]+iparticle->Vx()/10.;
164	origin[1] = origin0[1]+iparticle->Vy()/10.;
165	origin[2] = origin0[2]+iparticle->Vz()/10.;
166	kf = CheckPDGCode(iparticle->GetPdgCode());
167	iparent = -1;
168	tof = kconv*iparticle->T();
169	if (ks == 1) trackIt = 1;
170	else trackIt = 0;
642f15cf	171	PushTrack(fTrackIt*trackIt,iparent,kf,p,origin,polar,tof,kPPrimary,nt,weight,ks);
0b5dd071	172	KeepTrack(nt);
	173
	174	if (fDebug == 2)
	175	printf("id=%+4d, parent=%3d, ks=%d, p = (%+11.4e,%+11.4e,%+11.4e) GeV\n",
	176	kf,iparent,fTrackIt*trackIt,p[0],p[1],p[2]);
	177	}
	178	fEvent++;
	179	fTPHICgen->SetNEVENT(fEvent);
	180	if (fDebug == 1 && fEvent%100 == 0) {
	181	Info("Generate","Event %d\n",fEvent);
	182	fTPHICgen->Finish();
	183	}
	184	}
	185
	186	//____________________________________________________________
	187	void AliGenTPHIC::SetEventListRange(Int_t eventFirst, Int_t eventLast)
	188	{
	189	// Set a range of event numbers, for which a table
	190	// of generated particle will be printed
	191	fDebugEventFirst = eventFirst;
	192	fDebugEventLast = eventLast;
	193	if (fDebugEventLast==-1) fDebugEventLast=fDebugEventFirst;
	194	}
	195
	196	//____________________________________________________________
	197	void AliGenTPHIC::SetProcess (Int_t proc )
	198	{
	199	// Set process number:
	200	// proc=1 - gamma gamma -> X
	201	// proc=2 - gamma gamma -> quarkonium
	202	// proc=3 - gamma gamma -> fermion+ fermion-
	203	// proc=4 - gamma gamma -> W+ W-
	204	// proc=5 - not implemented
	205	// proc=6 - gamma gamma -> V1 V2 (vector meson pair)
	206
	207	fTPHICgen->SetIPROC(proc);
	208	}
	209	//____________________________________________________________
	210	void AliGenTPHIC::SetBeamEnergy (Float_t energy)
	211	{
	212	// Set energy of the beam ion per nucleon in GeV
	213	fTPHICgen->SetEBMN(energy);
	214	}
	215	//____________________________________________________________
	216	void AliGenTPHIC::SetBeamZ (Int_t z )
	217	{
	218	// Set beam ion charge
	219	fTPHICgen->SetIZ(z);
	220	}
	221	//____________________________________________________________
	222	void AliGenTPHIC::SetBeamA (Int_t a )
	223	{
	224	// Set beam ion atomic number
	225	fTPHICgen->SetIA(a);
	226	}
	227	//____________________________________________________________
	228	void AliGenTPHIC::SetYggRange (Float_t ymin, Float_t ymax)
	229	{
	230	// Set rapidity range of 2-photon system for the
	231	// luminosity function calculation
	232	fTPHICgen->SetYMIN(ymin);
	233	fTPHICgen->SetYMAX(ymax);
	234	}
	235	//____________________________________________________________
236	void AliGenTPHIC::SetMggRange (Float_t mmin, Float_t mmax)
237	{
238	// Set invariant mass range of 2-photon system for the
239	// luminosity function calculation
240	fTPHICgen->SetAMIN(mmin);
241	fTPHICgen->SetAMAX(mmax);
242	}
243	//____________________________________________________________
244	void AliGenTPHIC::SetNgridY (Int_t ny )
245	{
246	// Set number of nodes on the grid along the rapidity axis
247	// to calculate the 2-photon luminosity function
248	fTPHICgen->SetNY(ny);
249	}
250	//____________________________________________________________
251	void AliGenTPHIC::SetNgridM (Int_t nm )
252	{
253	// Set number of nodes on the grid along the mass axis
254	// to calculate the 2-photon luminosity function
255	fTPHICgen->SetNMAS(nm);
256	}
257	//____________________________________________________________
258	void AliGenTPHIC::SetLumFunName (TString name )
259	{
260	// Set filename to store the 2-photon luminosity
261	// function calculated on the grid
262	fTPHICgen->SetLUMFIL(name);
263	}
264	//____________________________________________________________
265	void AliGenTPHIC::SetLumFunFlag (Int_t flag )
266	{
267	// Set flag to calculate the 2-photon luminosity function:
268	// flag=-1 if a new lumimosity function to be calculated
269	// and stored in a file
270	// flag=+1 if a previously calculated function to be read
271	// from a file
272	fTPHICgen->SetILUMF(flag);
273	}
274	//____________________________________________________________
275	void AliGenTPHIC::SetKfFermion (Int_t kf )
276	{
277	// Set a PDG flavour code of a fermion for the process 3,
278	// gamma gamma -> fermion+ fermion-
279	fTPHICgen->SetKFERM(kf);
280	}
281	//____________________________________________________________
282	void AliGenTPHIC::SetKfOnium (Int_t kf )
283	{
284	// Set a PDG flavour code of a quarkonium for the process 2,
285	// gamma gamma -> quarkonium
286	fTPHICgen->SetKFONIUM(kf);
287	}
288	//____________________________________________________________
289	void AliGenTPHIC::SetMassOnium (Float_t mass )
290	{
291	// Set a quarkonium mass [GeV] for the process 2 if it
292	// differes from the Pythia's particle table.
293	// For the well-known quarkonia no need to set this mass
294	// because it will be taken from the Pythia table
295	fTPHICgen->SetXMRES(mass);
296	}
297	//____________________________________________________________
298	void AliGenTPHIC::SetGGwidthOnium(Float_t width )
299	{
300	// Set 2-photon partial width [GeV] of the quarkonium for
301	// the process 2 if it differes fromthe Pythia's particle table.
302	// For the well-known quarkonia no need to set this width
303	// because it will be taken from the Pythia table
304	fTPHICgen->SetXGGRES(width);
305	}
306	//____________________________________________________________
307	void AliGenTPHIC::SetKfVmesons (Int_t kf1, Int_t kf2)
308	{
309	// Set PDG flavour codes of the two vector vesons
310	// for the process 2: gamma gamma -> V1 V2
311	// So far this processes is implemented for the following
312	// mesons and their combinations only:
313	// pho0 (113), omega (223), phi (333), J/psi (443)
314	fTPHICgen->SetKV1(kf1);
315	fTPHICgen->SetKV2(kf2);
316	}
317	//____________________________________________________________
318	Float_t AliGenTPHIC::GetGGmass ()
319	{
320	// Get invariant mass of generated 2-photon system
321	return fTPHICgen->GetWSQ();
322	}
323	//____________________________________________________________
324	Float_t AliGenTPHIC::GetGGrapidity()
325	{
326	// Get rapidity of generated 2-photon system
327	return fTPHICgen->GetYGG();
328	}
329	//____________________________________________________________
330	Float_t AliGenTPHIC::GetG1mass ()
331	{
332	// Get a mass of the first virtual photon of
333	// the 2-photon process (-sqrt(q1^2)).
334	return fTPHICgen->GetXMG1();
335	}
336	//____________________________________________________________
337	Float_t AliGenTPHIC::GetG2mass ()
338	{
339	// Get a mass of the second virtual photon of
340	// the 2-photon process (-sqrt(q2^2)).
341	return fTPHICgen->GetXMG2();
342	}
343	//____________________________________________________________
344	TClonesArray* AliGenTPHIC::GetParticleList ()
345	{
346	// Get array of particles of the event listing
347	return fParticles;
348	}
349	//____________________________________________________________
350	TLorentzVector AliGenTPHIC::MomentumRecNucl1()
351	{
352	// Get 4-momentum of the first recoil nucleus after
353	// the 2-photon process.
354	return TLorentzVector(fTPHICgen->GetPTAG1(1),
355	fTPHICgen->GetPTAG1(2),
356	fTPHICgen->GetPTAG1(3),
357	fTPHICgen->GetPTAG1(4));
358	}
359	//____________________________________________________________
360	TLorentzVector AliGenTPHIC::MomentumRecNucl2()
361	{
362	// Get 4-momentum of the first recoil nucleus after
363	// the 2-photon process.
364	return TLorentzVector(fTPHICgen->GetPTAG2(1),
365	fTPHICgen->GetPTAG2(2),
366	fTPHICgen->GetPTAG2(3),
367	fTPHICgen->GetPTAG2(4));
368	}
369	//____________________________________________________________
370	Float_t AliGenTPHIC::GetXSectionCurrent()
371	{
372	// Get the cross section of the produced event for the
373	// Monte Carlo integral cross section calculation
374	return fTPHICgen->GetXSCUR();
375	}
376	//____________________________________________________________
377	Float_t AliGenTPHIC::GetXSection ()
378	{
379	// Get the integral cross section of the process
380	// calculated so far
381	return fTPHICgen->GetXSTOT();
382	}
383	//____________________________________________________________
384	Float_t AliGenTPHIC::GetXSectionError ()
385	{
386	// Get the error of the integral cross section of the process
387	// calculated so far
388	return fTPHICgen->GetXSTOTE();
389	}