[u/mrichter/AliRoot.git] / ZDC / AliGenZDC.cxx

/**************************************************************************
 * Copyright(c) 1998-1999, 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.                  *
 **************************************************************************/

/*
$Log$
Revision 1.4  2000/10/05 08:02:47  fca
Correction of the generator direction

Revision 1.3  2000/10/02 21:28:20  fca
Removal of useless dependecies via forward declarations

Revision 1.2  2000/07/11 11:12:34  fca
Some syntax corrections for non standard HP aCC

Revision 1.1  2000/07/10 13:58:01  fca
New version of ZDC from E.Scomparin & C.Oppedisano

Revision 1.7  2000/01/19 17:17:40  fca

Revision 1.6  1999/09/29 09:24:35  fca
Introduction of the Copyright and cvs Log

*/
#include <assert.h>

#include <TRandom.h>
#include <TLorentzVector.h>
#include <TVector3.h>
#include "TDatabasePDG.h"

#include "AliGenZDC.h"
#include "AliConst.h"
#include "AliPDG.h"
#include "AliRun.h"
 
ClassImp(AliGenZDC)
 
//_____________________________________________________________________________
AliGenZDC::AliGenZDC()
   :AliGenerator()
{
  //
  // Default constructor
  //
  fIpart = 0;
}

//_____________________________________________________________________________
AliGenZDC::AliGenZDC(Int_t npart)
   :AliGenerator(npart)
{
  //
  // Standard constructor
  //
  fName = "AliGenZDC";
  fTitle = "Generation of Test Particles for ZDCs";
  fIpart = kNeutron;
  fCosx  = 0.;
  fCosy  = 0.;
  fCosz  = 1.;
  fPseudoRapidity = 0.;
  fFermiflag = 1;
  // LHC values for beam divergence and crossing angle
  fBeamDiv = 0.000032;
  fBeamCrossAngle = 0.0001;
  fBeamCrossPlane = 2;
}

//_____________________________________________________________________________
void AliGenZDC::Init()
{
  printf("		AliGenZDC initialized with:\n");
  printf("   Fermi flag = %d, Beam Divergence = %f, Crossing Angle "
         "= %f, Crossing Plane = %d\n\n", fFermiflag, fBeamDiv, fBeamCrossAngle,
	 fBeamCrossPlane);
  //Initialize Fermi momentum distributions for Pb-Pb
  FermiTwoGaussian(207.,82.,fPp,fProbintp,fProbintn);
}  
  
//_____________________________________________________________________________
void AliGenZDC::Generate()
{
  //
  // Generate one trigger (n or p)
  //
  Int_t i;

  Double_t mass, pLab[3], fP0, ddp[3], dddp0, dddp[3];
  Float_t ptot = fPMin;
  Int_t nt;
  
  if(fPseudoRapidity==0.){ 
    pLab[0] = ptot*fCosx;
    pLab[1] = ptot*fCosy;
    pLab[2] = ptot*fCosz;
  }
  else{
    Float_t scang = 2*TMath::ATan(TMath::Exp(-(fPseudoRapidity)));
    pLab[0] = -ptot*TMath::Sin(scang);
    pLab[1] = 0.;
    pLab[2] = ptot*TMath::Cos(scang);
  }
  for(i=0; i<=2; i++){
     fPInit[i] = pLab[i];
     fP[i] = pLab[i];
  }
  
  // Beam divergence and crossing angle
  if(fBeamCrossAngle!=0.) {
    BeamDivCross(1,fBeamDiv,fBeamCrossAngle,fBeamCrossPlane,pLab);
    for(i=0; i<=2; i++){
       fP[i] = pLab[i];
    }
  }
  if(fBeamDiv!=0.) {
    BeamDivCross(0,fBeamDiv,fBeamCrossAngle,fBeamCrossPlane,pLab);
    for(i=0; i<=2; i++){
       fP[i] = pLab[i];
    }
  }

  // If required apply the Fermi momentum
  if(fFermiflag==1){
    if((fIpart==kProton) || (fIpart==kNeutron)){
      ExtractFermi(fIpart,fPp,fProbintp,fProbintn,ddp);
    }
    mass=gAlice->PDGDB()->GetParticle(fIpart)->Mass();
    fP0 = TMath::Sqrt(fP[0]*fP[0]+fP[1]*fP[1]+fP[2]*fP[2]+mass*mass);
    for(i=0; i<=2; i++){
       dddp[i] = ddp[i];
    }
    dddp0 = TMath::Sqrt(dddp[0]*dddp[0]+dddp[1]*dddp[1]+dddp[2]*dddp[2]+mass*mass);
    
    TVector3 b(fP[0]/fP0, fP[1]/fP0, fP[2]/fP0);
    TLorentzVector pFermi(dddp[0], dddp[1], dddp[2], dddp0);

    
    pFermi.Boost(b);

    for(i=0; i<=2; i++){
       fBoostP[i] = pFermi[i];
       fP[i] = pFermi[i];
    }

  }
  
  for(i=0; i<=2; i++){
     fPTrack[i] = fP[i];
  }
      
  Float_t polar[3] = {0,0,0};
//  printf("fPTrack = %f, %f, %f \n",fPTrack[0],fPTrack[1],fPTrack[2]);
  gAlice->SetTrack(fTrackIt,-1,fIpart,fPTrack,fOrigin.GetArray(),polar,0,
  		   "Primary",nt);
}

//_____________________________________________________________________________
void AliGenZDC::FermiTwoGaussian(Double_t A, Float_t Z, Double_t* fPp, Double_t*
  		fProbintp, Double_t* fProbintn)
{
//
// Momenta distributions according to the "double-gaussian"
// distribution (Ilinov) - equal for protons and neutrons
//
//   printf("		Initialization of Fermi momenta distribution\n");
   fProbintp[0] = 0;
   fProbintn[0] = 0;
   Double_t sig1 = 0.113;
   Double_t sig2 = 0.250;
   Double_t alfa = 0.18*(TMath::Power((A/12.),(Float_t)1/3));
   Double_t xk = (2*k2PI)/((1.+alfa)*(TMath::Power(k2PI,1.5)));
   
   for(Int_t i=1; i<=200; i++){
      Double_t p = i*0.005;
      fPp[i] = p;
      Double_t e1 = (p*p)/(2.*sig1*sig1);
      Double_t e2 = (p*p)/(2.*sig2*sig2);
      Double_t f1 = TMath::Exp(-(e1));
      Double_t f2 = TMath::Exp(-(e2));
      Double_t probp = xk*p*p*(f1/(TMath::Power(sig1,3.))+
                      alfa*f2/(TMath::Power(sig2,3.)))*0.005;
      fProbintp[i] = fProbintp[i-1] + probp;
      fProbintn[i] = fProbintp[i];
//      printf(" fProbintp[%d] = %f, fProbintp[%d] = %f\n",i,fProbintp[i],i,fProbintn[i]);
   }
} 
//_____________________________________________________________________________
void AliGenZDC::ExtractFermi(Int_t id, Double_t* fPp, Double_t* fProbintp,
                Double_t* fProbintn, Double_t* ddp)
{
//
// Compute Fermi momentum for spectator nucleons
//
//  printf("		Extraction of Fermi momentum\n");

  Int_t i;
  Float_t xx = gRandom->Rndm();
  assert ( id==kProton || id==kNeutron );
  if(id==kProton){
    for(i=0; i<=200; i++){
       if((xx>=fProbintp[i-1]) && (xx<fProbintp[i])) break;
       }
  }
  else {
    for(i=0; i<=200; i++){
       if((xx>=fProbintn[i-1]) && (xx<fProbintn[i])) break;
       }
   }
         Float_t pext = fPp[i]+0.001;
	 Float_t phi = k2PI*(gRandom->Rndm());
	 Float_t cost = (1.-2.*(gRandom->Rndm()));
	 Float_t tet = TMath::ACos(cost);
	 ddp[0] = pext*TMath::Sin(tet)*TMath::Cos(phi);
	 ddp[1] = pext*TMath::Sin(tet)*TMath::Sin(phi);
	 ddp[2] = pext*cost;
//  printf(" pFx = %f  pFy = %f  pFz = %f \n",ddp[0],ddp[1],ddp[2]); 
}

//_____________________________________________________________________________
void AliGenZDC::BeamDivCross(Int_t icross, Float_t fBeamDiv, Float_t fBeamCrossAngle, 
                Int_t fBeamCrossPlane, Double_t* pLab)
{
  Double_t tetpart, fipart, tetdiv=0, fidiv=0, angleSum[2], tetsum, fisum;
  Double_t rvec;

//  printf("		Beam divergence and crossing angle\n");
  Int_t i;
  Double_t pmq = 0.;
  for(i=0; i<=2; i++){
     pmq = pmq+pLab[i]*pLab[i];
  }
  Double_t pmod = TMath::Sqrt(pmq);

  if(icross==0){
    rvec = gRandom->Gaus(0.0,1.0);
    tetdiv = fBeamDiv * TMath::Abs(rvec);
    fidiv = (gRandom->Rndm())*k2PI;
  }
  else if(icross==1){
    if(fBeamCrossPlane==0.){
      tetdiv = 0.;
      fidiv = 0.;
    }
    else if(fBeamCrossPlane==1.){
      tetdiv = fBeamCrossAngle;
      fidiv = 0.;
    }
    else if(fBeamCrossPlane==2.){
      tetdiv = fBeamCrossAngle;
      fidiv = k2PI/4.;
    }
  }

  tetpart = TMath::ATan(TMath::Sqrt(pLab[0]*pLab[0]+pLab[1]*pLab[1])/pLab[2]);
  if(pLab[1]!=0. || pLab[0]!=0.){
    fipart = TMath::ATan2(pLab[1],pLab[0]);
  }
  else{
    fipart = 0.;
  }
  if(fipart<0.) {fipart = fipart+k2PI;}
  tetdiv = tetdiv*kRaddeg;
  fidiv = fidiv*kRaddeg;
  tetpart = tetpart*kRaddeg;
  fipart = fipart*kRaddeg;
  AddAngle(tetpart,fipart,tetdiv,fidiv,angleSum);
  tetsum = angleSum[0];
  fisum  = angleSum[1];
  tetsum = tetsum*kDegrad;
  fisum = fisum*kDegrad;
  pLab[0] = pmod*TMath::Sin(tetsum)*TMath::Cos(fisum);
  pLab[1] = pmod*TMath::Sin(tetsum)*TMath::Sin(fisum);
  pLab[2] = pmod*TMath::Cos(tetsum);
  for(i=0; i<=2; i++){
     fDivP[i] = pLab[i];
  }
}
  
//_____________________________________________________________________________
void  AliGenZDC::AddAngle(Double_t theta1, Double_t phi1, Double_t theta2,
  	       Double_t phi2, Double_t* angleSum)
{
  Double_t temp, conv, cx, cy, cz, ct1, st1, ct2, st2, cp1, sp1, cp2, sp2;
  Double_t rtetsum, tetsum, fisum;
  
  temp = -1.;
  conv = 180./TMath::ACos(temp);
  
  ct1 = TMath::Cos(theta1/conv);
  st1 = TMath::Sin(theta1/conv);
  cp1 = TMath::Cos(phi1/conv);
  sp1 = TMath::Sin(phi1/conv);
  ct2 = TMath::Cos(theta2/conv);
  st2 = TMath::Sin(theta2/conv);
  cp2 = TMath::Cos(phi2/conv);
  sp2 = TMath::Sin(phi2/conv);
  cx = ct1*cp1*st2*cp2+st1*cp1*ct2-sp1*st2*sp2;
  cy = ct1*sp1*st2*cp2+st1*sp1*ct2+cp1*st2*sp2;
  cz = ct1*ct2-st1*st2*cp2;
  
  rtetsum = TMath::ACos(cz);
  tetsum = conv*rtetsum;
  if(tetsum==0. || tetsum==180.){
    fisum = 0.;
    return;
  }
  temp = cx/TMath::Sin(rtetsum);
  if(temp>1.) temp=1.;
  if(temp<-1.) temp=-1.;
  fisum = conv*TMath::ACos(temp);
  if(cy<0) {fisum = 360.-fisum;}
  angleSum[0] = tetsum;
  angleSum[1] = fisum;
}
Commit	Line	Data
68ca986e	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	/*
	17	$Log$
866ab5a2	18	Revision 1.4 2000/10/05 08:02:47 fca
	19	Correction of the generator direction
	20
699b37ac	21	Revision 1.3 2000/10/02 21:28:20 fca
	22	Removal of useless dependecies via forward declarations
	23
94de3818	24	Revision 1.2 2000/07/11 11:12:34 fca
	25	Some syntax corrections for non standard HP aCC
	26
c0ceba4c	27	Revision 1.1 2000/07/10 13:58:01 fca
	28	New version of ZDC from E.Scomparin & C.Oppedisano
	29
68ca986e	30	Revision 1.7 2000/01/19 17:17:40 fca
	31
	32	Revision 1.6 1999/09/29 09:24:35 fca
	33	Introduction of the Copyright and cvs Log
	34
	35	*/
94de3818	36	#include <assert.h>
94de3818	37
68ca986e	38	#include <TRandom.h>
	39	#include <TLorentzVector.h>
	40	#include <TVector3.h>
94de3818	41	#include "TDatabasePDG.h"
68ca986e	42
	43	#include "AliGenZDC.h"
	44	#include "AliConst.h"
	45	#include "AliPDG.h"
	46	#include "AliRun.h"
	47
	48	ClassImp(AliGenZDC)
	49
	50	//_____________________________________________________________________________
	51	AliGenZDC::AliGenZDC()
	52	:AliGenerator()
	53	{
	54	//
	55	// Default constructor
	56	//
	57	fIpart = 0;
	58	}
	59
	60	//_____________________________________________________________________________
	61	AliGenZDC::AliGenZDC(Int_t npart)
	62	:AliGenerator(npart)
	63	{
	64	//
	65	// Standard constructor
	66	//
	67	fName = "AliGenZDC";
	68	fTitle = "Generation of Test Particles for ZDCs";
	69	fIpart = kNeutron;
	70	fCosx = 0.;
	71	fCosy = 0.;
	72	fCosz = 1.;
	73	fPseudoRapidity = 0.;
	74	fFermiflag = 1;
	75	// LHC values for beam divergence and crossing angle
	76	fBeamDiv = 0.000032;
	77	fBeamCrossAngle = 0.0001;
	78	fBeamCrossPlane = 2;
	79	}
	80
	81	//_____________________________________________________________________________
	82	void AliGenZDC::Init()
	83	{
866ab5a2	84	printf(" AliGenZDC initialized with:\n");
866ab5a2	85	printf(" Fermi flag = %d, Beam Divergence = %f, Crossing Angle "
68ca986e	86	"= %f, Crossing Plane = %d\n\n", fFermiflag, fBeamDiv, fBeamCrossAngle,
	87	fBeamCrossPlane);
	88	//Initialize Fermi momentum distributions for Pb-Pb
	89	FermiTwoGaussian(207.,82.,fPp,fProbintp,fProbintn);
	90	}
	91
	92	//_____________________________________________________________________________
	93	void AliGenZDC::Generate()
	94	{
	95	//
	96	// Generate one trigger (n or p)
	97	//
c0ceba4c	98	Int_t i;
c0ceba4c	99
866ab5a2	100	Double_t mass, pLab[3], fP0, ddp[3], dddp0, dddp[3];
68ca986e	101	Float_t ptot = fPMin;
	102	Int_t nt;
	103
866ab5a2	104	if(fPseudoRapidity==0.){
68ca986e	105	pLab[0] = ptot*fCosx;
	106	pLab[1] = ptot*fCosy;
	107	pLab[2] = ptot*fCosz;
	108	}
	109	else{
	110	Float_t scang = 2*TMath::ATan(TMath::Exp(-(fPseudoRapidity)));
	111	pLab[0] = -ptot*TMath::Sin(scang);
	112	pLab[1] = 0.;
	113	pLab[2] = ptot*TMath::Cos(scang);
	114	}
c0ceba4c	115	for(i=0; i<=2; i++){
866ab5a2	116	fPInit[i] = pLab[i];
68ca986e	117	fP[i] = pLab[i];
	118	}
	119
	120	// Beam divergence and crossing angle
866ab5a2	121	if(fBeamCrossAngle!=0.) {
	122	BeamDivCross(1,fBeamDiv,fBeamCrossAngle,fBeamCrossPlane,pLab);
	123	for(i=0; i<=2; i++){
	124	fP[i] = pLab[i];
	125	}
	126	}
	127	if(fBeamDiv!=0.) {
	128	BeamDivCross(0,fBeamDiv,fBeamCrossAngle,fBeamCrossPlane,pLab);
	129	for(i=0; i<=2; i++){
	130	fP[i] = pLab[i];
	131	}
	132	}
	133
68ca986e	134	// If required apply the Fermi momentum
	135	if(fFermiflag==1){
	136	if((fIpart==kProton) \|\| (fIpart==kNeutron)){
	137	ExtractFermi(fIpart,fPp,fProbintp,fProbintn,ddp);
	138	}
94de3818	139	mass=gAlice->PDGDB()->GetParticle(fIpart)->Mass();
866ab5a2	140	fP0 = TMath::Sqrt(fP[0]fP[0]+fP[1]fP[1]+fP[2]fP[2]+massmass);
c0ceba4c	141	for(i=0; i<=2; i++){
68ca986e	142	dddp[i] = ddp[i];
	143	}
	144	dddp0 = TMath::Sqrt(dddp[0]dddp[0]+dddp[1]dddp[1]+dddp[2]dddp[2]+massmass);
	145
866ab5a2	146	TVector3 b(fP[0]/fP0, fP[1]/fP0, fP[2]/fP0);
68ca986e	147	TLorentzVector pFermi(dddp[0], dddp[1], dddp[2], dddp0);
68ca986e	148
68ca986e	149
	150	pFermi.Boost(b);
	151
c0ceba4c	152	for(i=0; i<=2; i++){
68ca986e	153	fBoostP[i] = pFermi[i];
866ab5a2	154	fP[i] = pFermi[i];
68ca986e	155	}
	156
	157	}
866ab5a2	158
	159	for(i=0; i<=2; i++){
	160	fPTrack[i] = fP[i];
	161	}
	162
68ca986e	163	Float_t polar[3] = {0,0,0};
866ab5a2	164	// printf("fPTrack = %f, %f, %f \n",fPTrack[0],fPTrack[1],fPTrack[2]);
866ab5a2	165	gAlice->SetTrack(fTrackIt,-1,fIpart,fPTrack,fOrigin.GetArray(),polar,0,
68ca986e	166	"Primary",nt);
	167	}
	168
	169	//_____________________________________________________________________________
	170	void AliGenZDC::FermiTwoGaussian(Double_t A, Float_t Z, Double_t* fPp, Double_t*
	171	fProbintp, Double_t* fProbintn)
	172	{
	173	//
	174	// Momenta distributions according to the "double-gaussian"
	175	// distribution (Ilinov) - equal for protons and neutrons
	176	//
	177	// printf(" Initialization of Fermi momenta distribution\n");
	178	fProbintp[0] = 0;
	179	fProbintn[0] = 0;
	180	Double_t sig1 = 0.113;
	181	Double_t sig2 = 0.250;
	182	Double_t alfa = 0.18*(TMath::Power((A/12.),(Float_t)1/3));
	183	Double_t xk = (2k2PI)/((1.+alfa)(TMath::Power(k2PI,1.5)));
	184
	185	for(Int_t i=1; i<=200; i++){
	186	Double_t p = i*0.005;
	187	fPp[i] = p;
68ca986e	188	Double_t e1 = (pp)/(2.sig1*sig1);
	189	Double_t e2 = (pp)/(2.sig2*sig2);
	190	Double_t f1 = TMath::Exp(-(e1));
	191	Double_t f2 = TMath::Exp(-(e2));
	192	Double_t probp = xkpp*(f1/(TMath::Power(sig1,3.))+
	193	alfaf2/(TMath::Power(sig2,3.)))0.005;
68ca986e	194	fProbintp[i] = fProbintp[i-1] + probp;
	195	fProbintn[i] = fProbintp[i];
	196	// printf(" fProbintp[%d] = %f, fProbintp[%d] = %f\n",i,fProbintp[i],i,fProbintn[i]);
	197	}
	198	}
	199	//_____________________________________________________________________________
	200	void AliGenZDC::ExtractFermi(Int_t id, Double_t* fPp, Double_t* fProbintp,
	201	Double_t* fProbintn, Double_t* ddp)
	202	{
	203	//
	204	// Compute Fermi momentum for spectator nucleons
	205	//
866ab5a2	206	// printf(" Extraction of Fermi momentum\n");
866ab5a2	207
68ca986e	208	Int_t i;
68ca986e	209	Float_t xx = gRandom->Rndm();
699b37ac	210	assert ( id==kProton \|\| id==kNeutron );
68ca986e	211	if(id==kProton){
	212	for(i=0; i<=200; i++){
	213	if((xx>=fProbintp[i-1]) && (xx<fProbintp[i])) break;
	214	}
	215	}
94de3818	216	else {
68ca986e	217	for(i=0; i<=200; i++){
	218	if((xx>=fProbintn[i-1]) && (xx<fProbintn[i])) break;
	219	}
	220	}
	221	Float_t pext = fPp[i]+0.001;
	222	Float_t phi = k2PI*(gRandom->Rndm());
	223	Float_t cost = (1.-2.*(gRandom->Rndm()));
	224	Float_t tet = TMath::ACos(cost);
	225	ddp[0] = pextTMath::Sin(tet)TMath::Cos(phi);
	226	ddp[1] = pextTMath::Sin(tet)TMath::Sin(phi);
	227	ddp[2] = pext*cost;
866ab5a2	228	// printf(" pFx = %f pFy = %f pFz = %f \n",ddp[0],ddp[1],ddp[2]);
68ca986e	229	}
	230
	231	//_____________________________________________________________________________
	232	void AliGenZDC::BeamDivCross(Int_t icross, Float_t fBeamDiv, Float_t fBeamCrossAngle,
	233	Int_t fBeamCrossPlane, Double_t* pLab)
	234	{
866ab5a2	235	Double_t tetpart, fipart, tetdiv=0, fidiv=0, angleSum[2], tetsum, fisum;
68ca986e	236	Double_t rvec;
c0ceba4c	237
866ab5a2	238	// printf(" Beam divergence and crossing angle\n");
c0ceba4c	239	Int_t i;
68ca986e	240	Double_t pmq = 0.;
c0ceba4c	241	for(i=0; i<=2; i++){
68ca986e	242	pmq = pmq+pLab[i]*pLab[i];
	243	}
	244	Double_t pmod = TMath::Sqrt(pmq);
68ca986e	245
68ca986e	246	if(icross==0){
	247	rvec = gRandom->Gaus(0.0,1.0);
	248	tetdiv = fBeamDiv * TMath::Abs(rvec);
	249	fidiv = (gRandom->Rndm())*k2PI;
	250	}
	251	else if(icross==1){
	252	if(fBeamCrossPlane==0.){
	253	tetdiv = 0.;
	254	fidiv = 0.;
	255	}
	256	else if(fBeamCrossPlane==1.){
	257	tetdiv = fBeamCrossAngle;
	258	fidiv = 0.;
	259	}
	260	else if(fBeamCrossPlane==2.){
	261	tetdiv = fBeamCrossAngle;
	262	fidiv = k2PI/4.;
	263	}
	264	}
866ab5a2	265
	266	tetpart = TMath::ATan(TMath::Sqrt(pLab[0]pLab[0]+pLab[1]pLab[1])/pLab[2]);
	267	if(pLab[1]!=0. \|\| pLab[0]!=0.){
	268	fipart = TMath::ATan2(pLab[1],pLab[0]);
68ca986e	269	}
	270	else{
	271	fipart = 0.;
	272	}
	273	if(fipart<0.) {fipart = fipart+k2PI;}
68ca986e	274	tetdiv = tetdiv*kRaddeg;
	275	fidiv = fidiv*kRaddeg;
	276	tetpart = tetpart*kRaddeg;
	277	fipart = fipart*kRaddeg;
	278	AddAngle(tetpart,fipart,tetdiv,fidiv,angleSum);
	279	tetsum = angleSum[0];
	280	fisum = angleSum[1];
68ca986e	281	tetsum = tetsum*kDegrad;
	282	fisum = fisum*kDegrad;
	283	pLab[0] = pmodTMath::Sin(tetsum)TMath::Cos(fisum);
	284	pLab[1] = pmodTMath::Sin(tetsum)TMath::Sin(fisum);
	285	pLab[2] = pmod*TMath::Cos(tetsum);
c0ceba4c	286	for(i=0; i<=2; i++){
68ca986e	287	fDivP[i] = pLab[i];
	288	}
	289	}
	290
	291	//_____________________________________________________________________________
	292	void AliGenZDC::AddAngle(Double_t theta1, Double_t phi1, Double_t theta2,
	293	Double_t phi2, Double_t* angleSum)
	294	{
	295	Double_t temp, conv, cx, cy, cz, ct1, st1, ct2, st2, cp1, sp1, cp2, sp2;
	296	Double_t rtetsum, tetsum, fisum;
	297
	298	temp = -1.;
	299	conv = 180./TMath::ACos(temp);
	300
	301	ct1 = TMath::Cos(theta1/conv);
	302	st1 = TMath::Sin(theta1/conv);
	303	cp1 = TMath::Cos(phi1/conv);
	304	sp1 = TMath::Sin(phi1/conv);
	305	ct2 = TMath::Cos(theta2/conv);
	306	st2 = TMath::Sin(theta2/conv);
	307	cp2 = TMath::Cos(phi2/conv);
	308	sp2 = TMath::Sin(phi2/conv);
	309	cx = ct1cp1st2cp2+st1cp1ct2-sp1st2*sp2;
	310	cy = ct1sp1st2cp2+st1sp1ct2+cp1st2*sp2;
	311	cz = ct1ct2-st1st2*cp2;
	312
	313	rtetsum = TMath::ACos(cz);
	314	tetsum = conv*rtetsum;
	315	if(tetsum==0. \|\| tetsum==180.){
	316	fisum = 0.;
	317	return;
	318	}
	319	temp = cx/TMath::Sin(rtetsum);
	320	if(temp>1.) temp=1.;
	321	if(temp<-1.) temp=-1.;
	322	fisum = conv*TMath::ACos(temp);
	323	if(cy<0) {fisum = 360.-fisum;}
68ca986e	324	angleSum[0] = tetsum;
	325	angleSum[1] = fisum;
	326	}
	327