[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.                  *
 **************************************************************************/

/* $Id$ */

//////////////////////////////////////////////////////////////////////
//                                                                  //         //
//      Generator of spectator nucleons (either protons or neutrons)//
//        computes beam crossing and divergence and Fermi momentum  //
//                                                                  //
/////////////////////////////////////////////////////////////////////

#include <assert.h>

#include <TDatabasePDG.h>
#include <TLorentzVector.h>
#include <TMCProcess.h>
#include <TPDGCode.h>
#include <TRandom.h>
#include <TVector3.h>

#include "AliConst.h"
#include "AliGenZDC.h"
#include "AliRun.h"
#include "AliMC.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;
  
  Int_t i, j;
  for(i=0; i<201; i++){
     fProbintp[i] = 0;
     fProbintn[i] = 0;
  }
  for(j=0; j<3; j++) fPp[i] = 0;
  fDebugOpt = 0;
}

//_____________________________________________________________________________
void AliGenZDC::Init()
{
  //Initialize Fermi momentum distributions for Pb-Pb
  //
  printf("\n\n		AliGenZDC initialization:\n");
  printf("   Particle: %d, Track cosines: x = %f, y = %f, z = %f \n", 
  	 fIpart,fCosx,fCosy,fCosz);
  printf("   Fermi flag = %d, Beam divergence = %f, Crossing angle "
         "= %f, Crossing plane = %d\n\n", fFermiflag, fBeamDiv, fBeamCrossAngle,
	 fBeamCrossPlane);

  FermiTwoGaussian(207.,fPp,fProbintp,fProbintn);
}  
  
//_____________________________________________________________________________
void AliGenZDC::Generate()
{
  //
  // Generate one trigger (n or p)
  //
  Int_t i;

  Double_t mass, pLab[3], fP0, fP[3], fBoostP[3], ddp[3], dddp0, dddp[3]; 
  Float_t  fPTrack[3], 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++) fP[i] = pLab[i];  
  if(fDebugOpt == 1){
    printf("\n\n		Particle momentum before divergence and crossing\n");
    for(i=0; i<=2; i++)printf(" 	pLab[%d] = %f\n",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};
  gAlice->GetMCApp()->PushTrack(fTrackIt,-1,fIpart,fPTrack,fOrigin.GetArray(),polar,0,
  		   kPPrimary,nt);
  // -----------------------------------------------------------------------
  if(fDebugOpt == 1){
    printf("\n\n		Track momentum:\n");
    printf("\n	 fPTrack = %f, %f, %f \n",fPTrack[0],fPTrack[1],fPTrack[2]);
  }
  else if(fDebugOpt == 2){
    FILE *file;
    if((file = fopen("SpectMomentum.dat","a")) == NULL){
      printf("Cannot open file  SpectMomentum.dat\n");
      return;
    }
    fprintf(file," %f \t %f \t %f \n",fPTrack[0],fPTrack[1],fPTrack[2]);
    fclose(file);
  }
    
}

//_____________________________________________________________________________
void AliGenZDC::FermiTwoGaussian(Float_t A, Double_t *fPp, 
                Double_t *fProbintp, Double_t *fProbintn)
{
//
// Momenta distributions according to the "double-gaussian"
// distribution (Ilinov) - equal for protons and neutrons
//

   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];
   }
   if(fDebugOpt == 1){
     printf("\n\n		Initialization of Fermi momenta distribution \n");
     //for(Int_t i=0; i<=200; i++)
     //   printf(" fProbintp[%d] = %f, fProbintn[%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
//
  
  Int_t i;
  Float_t xx = gRandom->Rndm();
  assert ( id==kProton || id==kNeutron );
  if(id==kProton){
    for(i=1; 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;

  if(fDebugOpt == 1){
    printf("\n\n		Extraction of Fermi momentum\n");
    printf("\n 	pxFermi = %f  pyFermi = %f  pzFermi = %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)
{
  // Applying beam divergence and crossing angle
  //
  Double_t tetpart, fipart, tetdiv=0, fidiv=0, angleSum[2], tetsum, fisum;
  Double_t rvec;

  Double_t pmq = 0.;
  Int_t i;
  for(i=0; i<=2; i++) pmq = pmq+pLab[i]*pLab[i];
  Double_t pmod = TMath::Sqrt(pmq);

  if(icross==0){      // ##### Beam divergence
    rvec = gRandom->Gaus(0.0,1.0);
    tetdiv = fBeamDiv * TMath::Abs(rvec);
    fidiv = (gRandom->Rndm())*k2PI;
  }
  else if(icross==1){ // ##### Crossing angle
    if(fBeamCrossPlane==0.){
      tetdiv = 0.;
      fidiv = 0.;
    }
    else if(fBeamCrossPlane==1.){     // Horizontal crossing plane
      tetdiv = fBeamCrossAngle;
      fidiv = 0.;
    }
    else if(fBeamCrossPlane==2.){     // Vertical crossing plane
      tetdiv = fBeamCrossAngle;
      fidiv = k2PI/4.;
    }
  }

  tetpart = TMath::ATan2(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);
  if(fDebugOpt == 1){
    if(icross==0) printf("\n\n		Beam divergence \n");
    else  	  printf("\n\n		Beam crossing \n");
    for(i=0; i<=2; i++)printf(" 	pLab[%d] = %f\n",i,pLab[i]);
  }
}
  
//_____________________________________________________________________________
void  AliGenZDC::AddAngle(Double_t theta1, Double_t phi1, Double_t theta2,
  	       Double_t phi2, Double_t *angleSum)
{ 
  // Calculating the sum of 2 angles
  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
88cb7938	16	/* $Id$ */
116cbefd	17
8a2624cc	18	//////////////////////////////////////////////////////////////////////
	19	// // //
	20	// Generator of spectator nucleons (either protons or neutrons)//
	21	// computes beam crossing and divergence and Fermi momentum //
	22	// //
	23	/////////////////////////////////////////////////////////////////////
	24
94de3818	25	#include <assert.h>
94de3818	26
116cbefd	27	#include <TDatabasePDG.h>
68ca986e	28	#include <TLorentzVector.h>
116cbefd	29	#include <TMCProcess.h>
	30	#include <TPDGCode.h>
	31	#include <TRandom.h>
68ca986e	32	#include <TVector3.h>
68ca986e	33
68ca986e	34	#include "AliConst.h"
116cbefd	35	#include "AliGenZDC.h"
68ca986e	36	#include "AliRun.h"
5d12ce38	37	#include "AliMC.h"
68ca986e	38
	39	ClassImp(AliGenZDC)
	40
	41	//_____________________________________________________________________________
	42	AliGenZDC::AliGenZDC()
	43	:AliGenerator()
	44	{
	45	//
	46	// Default constructor
	47	//
	48	fIpart = 0;
	49	}
	50
	51	//_____________________________________________________________________________
	52	AliGenZDC::AliGenZDC(Int_t npart)
	53	:AliGenerator(npart)
	54	{
	55	//
	56	// Standard constructor
	57	//
	58	fName = "AliGenZDC";
	59	fTitle = "Generation of Test Particles for ZDCs";
	60	fIpart = kNeutron;
	61	fCosx = 0.;
	62	fCosy = 0.;
	63	fCosz = 1.;
	64	fPseudoRapidity = 0.;
5a881c97	65
68ca986e	66	fFermiflag = 1;
	67	// LHC values for beam divergence and crossing angle
	68	fBeamDiv = 0.000032;
	69	fBeamCrossAngle = 0.0001;
	70	fBeamCrossPlane = 2;
5a881c97	71
	72	Int_t i, j;
	73	for(i=0; i<201; i++){
	74	fProbintp[i] = 0;
	75	fProbintn[i] = 0;
	76	}
c294be39	77	for(j=0; j<3; j++) fPp[i] = 0;
5a881c97	78	fDebugOpt = 0;
68ca986e	79	}
	80
	81	//_____________________________________________________________________________
	82	void AliGenZDC::Init()
	83	{
8a2624cc	84	//Initialize Fermi momentum distributions for Pb-Pb
8a2624cc	85	//
c294be39	86	printf("\n\n AliGenZDC initialization:\n");
	87	printf(" Particle: %d, Track cosines: x = %f, y = %f, z = %f \n",
	88	fIpart,fCosx,fCosy,fCosz);
	89	printf(" Fermi flag = %d, Beam divergence = %f, Crossing angle "
	90	"= %f, Crossing plane = %d\n\n", fFermiflag, fBeamDiv, fBeamCrossAngle,
68ca986e	91	fBeamCrossPlane);
5a881c97	92
f5cb71ad	93	FermiTwoGaussian(207.,fPp,fProbintp,fProbintn);
68ca986e	94	}
	95
	96	//_____________________________________________________________________________
	97	void AliGenZDC::Generate()
	98	{
	99	//
	100	// Generate one trigger (n or p)
	101	//
c0ceba4c	102	Int_t i;
c0ceba4c	103
8a2624cc	104	Double_t mass, pLab[3], fP0, fP[3], fBoostP[3], ddp[3], dddp0, dddp[3];
5a881c97	105	Float_t fPTrack[3], ptot = fPMin;
68ca986e	106	Int_t nt;
68ca986e	107
866ab5a2	108	if(fPseudoRapidity==0.){
68ca986e	109	pLab[0] = ptot*fCosx;
	110	pLab[1] = ptot*fCosy;
	111	pLab[2] = ptot*fCosz;
	112	}
	113	else{
	114	Float_t scang = 2*TMath::ATan(TMath::Exp(-(fPseudoRapidity)));
	115	pLab[0] = -ptot*TMath::Sin(scang);
	116	pLab[1] = 0.;
	117	pLab[2] = ptot*TMath::Cos(scang);
	118	}
c294be39	119	for(i=0; i<=2; i++) fP[i] = pLab[i];
	120	if(fDebugOpt == 1){
	121	printf("\n\n Particle momentum before divergence and crossing\n");
	122	for(i=0; i<=2; i++)printf(" pLab[%d] = %f\n",i,pLab[i]);
68ca986e	123	}
	124
	125	// Beam divergence and crossing angle
866ab5a2	126	if(fBeamCrossAngle!=0.) {
866ab5a2	127	BeamDivCross(1,fBeamDiv,fBeamCrossAngle,fBeamCrossPlane,pLab);
c294be39	128	for(i=0; i<=2; i++) fP[i] = pLab[i];
866ab5a2	129	}
	130	if(fBeamDiv!=0.) {
	131	BeamDivCross(0,fBeamDiv,fBeamCrossAngle,fBeamCrossPlane,pLab);
c294be39	132	for(i=0; i<=2; i++) fP[i] = pLab[i];
866ab5a2	133	}
866ab5a2	134
68ca986e	135	// If required apply the Fermi momentum
68ca986e	136	if(fFermiflag==1){
c294be39	137	if((fIpart==kProton) \|\| (fIpart==kNeutron))
68ca986e	138	ExtractFermi(fIpart,fPp,fProbintp,fProbintn,ddp);
8a2624cc	139	mass=gAlice->PDGDB()->GetParticle(fIpart)->Mass();
8a2624cc	140	fP0 = TMath::Sqrt(fP[0]fP[0]+fP[1]fP[1]+fP[2]fP[2]+massmass);
c294be39	141	for(i=0; i<=2; i++) dddp[i] = ddp[i];
8a2624cc	142	dddp0 = TMath::Sqrt(dddp[0]dddp[0]+dddp[1]dddp[1]+dddp[2]dddp[2]+massmass);
68ca986e	143
866ab5a2	144	TVector3 b(fP[0]/fP0, fP[1]/fP0, fP[2]/fP0);
68ca986e	145	TLorentzVector pFermi(dddp[0], dddp[1], dddp[2], dddp0);
68ca986e	146
68ca986e	147	pFermi.Boost(b);
c0ceba4c	148	for(i=0; i<=2; i++){
68ca986e	149	fBoostP[i] = pFermi[i];
866ab5a2	150	fP[i] = pFermi[i];
68ca986e	151	}
	152
	153	}
866ab5a2	154
c294be39	155	for(i=0; i<=2; i++) fPTrack[i] = fP[i];
866ab5a2	156
68ca986e	157	Float_t polar[3] = {0,0,0};
5d12ce38	158	gAlice->GetMCApp()->PushTrack(fTrackIt,-1,fIpart,fPTrack,fOrigin.GetArray(),polar,0,
1de555dc	159	kPPrimary,nt);
03cc1ceb	160	// -----------------------------------------------------------------------
5a881c97	161	if(fDebugOpt == 1){
	162	printf("\n\n Track momentum:\n");
	163	printf("\n fPTrack = %f, %f, %f \n",fPTrack[0],fPTrack[1],fPTrack[2]);
	164	}
03cc1ceb	165	else if(fDebugOpt == 2){
	166	FILE *file;
	167	if((file = fopen("SpectMomentum.dat","a")) == NULL){
	168	printf("Cannot open file SpectMomentum.dat\n");
	169	return;
	170	}
	171	fprintf(file," %f \t %f \t %f \n",fPTrack[0],fPTrack[1],fPTrack[2]);
	172	fclose(file);
	173	}
	174
68ca986e	175	}
	176
	177	//_____________________________________________________________________________
f5cb71ad	178	void AliGenZDC::FermiTwoGaussian(Float_t A, Double_t *fPp,
5a881c97	179	Double_t fProbintp, Double_t fProbintn)
68ca986e	180	{
	181	//
	182	// Momenta distributions according to the "double-gaussian"
	183	// distribution (Ilinov) - equal for protons and neutrons
	184	//
5a881c97	185
68ca986e	186	fProbintp[0] = 0;
	187	fProbintn[0] = 0;
	188	Double_t sig1 = 0.113;
	189	Double_t sig2 = 0.250;
	190	Double_t alfa = 0.18*(TMath::Power((A/12.),(Float_t)1/3));
	191	Double_t xk = (2k2PI)/((1.+alfa)(TMath::Power(k2PI,1.5)));
	192
	193	for(Int_t i=1; i<=200; i++){
	194	Double_t p = i*0.005;
	195	fPp[i] = p;
68ca986e	196	Double_t e1 = (pp)/(2.sig1*sig1);
	197	Double_t e2 = (pp)/(2.sig2*sig2);
	198	Double_t f1 = TMath::Exp(-(e1));
	199	Double_t f2 = TMath::Exp(-(e2));
	200	Double_t probp = xkpp*(f1/(TMath::Power(sig1,3.))+
	201	alfaf2/(TMath::Power(sig2,3.)))0.005;
68ca986e	202	fProbintp[i] = fProbintp[i-1] + probp;
68ca986e	203	fProbintn[i] = fProbintp[i];
5a881c97	204	}
	205	if(fDebugOpt == 1){
	206	printf("\n\n Initialization of Fermi momenta distribution \n");
c294be39	207	//for(Int_t i=0; i<=200; i++)
c294be39	208	// printf(" fProbintp[%d] = %f, fProbintn[%d] = %f\n",i,fProbintp[i],i,fProbintn[i]);
68ca986e	209	}
	210	}
	211	//_____________________________________________________________________________
5a881c97	212	void AliGenZDC::ExtractFermi(Int_t id, Double_t fPp, Double_t fProbintp,
5a881c97	213	Double_t fProbintn, Double_t ddp)
68ca986e	214	{
	215	//
	216	// Compute Fermi momentum for spectator nucleons
	217	//
5a881c97	218
68ca986e	219	Int_t i;
68ca986e	220	Float_t xx = gRandom->Rndm();
699b37ac	221	assert ( id==kProton \|\| id==kNeutron );
68ca986e	222	if(id==kProton){
0ff3ad02	223	for(i=1; i<=200; i++){
68ca986e	224	if((xx>=fProbintp[i-1]) && (xx<fProbintp[i])) break;
	225	}
	226	}
94de3818	227	else {
68ca986e	228	for(i=0; i<=200; i++){
	229	if((xx>=fProbintn[i-1]) && (xx<fProbintn[i])) break;
	230	}
	231	}
	232	Float_t pext = fPp[i]+0.001;
	233	Float_t phi = k2PI*(gRandom->Rndm());
	234	Float_t cost = (1.-2.*(gRandom->Rndm()));
	235	Float_t tet = TMath::ACos(cost);
	236	ddp[0] = pextTMath::Sin(tet)TMath::Cos(phi);
	237	ddp[1] = pextTMath::Sin(tet)TMath::Sin(phi);
	238	ddp[2] = pext*cost;
5a881c97	239
	240	if(fDebugOpt == 1){
	241	printf("\n\n Extraction of Fermi momentum\n");
	242	printf("\n pxFermi = %f pyFermi = %f pzFermi = %f \n",ddp[0],ddp[1],ddp[2]);
	243	}
68ca986e	244	}
	245
	246	//_____________________________________________________________________________
	247	void AliGenZDC::BeamDivCross(Int_t icross, Float_t fBeamDiv, Float_t fBeamCrossAngle,
5a881c97	248	Int_t fBeamCrossPlane, Double_t *pLab)
68ca986e	249	{
8a2624cc	250	// Applying beam divergence and crossing angle
8a2624cc	251	//
866ab5a2	252	Double_t tetpart, fipart, tetdiv=0, fidiv=0, angleSum[2], tetsum, fisum;
68ca986e	253	Double_t rvec;
c0ceba4c	254
68ca986e	255	Double_t pmq = 0.;
c294be39	256	Int_t i;
c294be39	257	for(i=0; i<=2; i++) pmq = pmq+pLab[i]*pLab[i];
68ca986e	258	Double_t pmod = TMath::Sqrt(pmq);
68ca986e	259
03cc1ceb	260	if(icross==0){ // ##### Beam divergence
68ca986e	261	rvec = gRandom->Gaus(0.0,1.0);
	262	tetdiv = fBeamDiv * TMath::Abs(rvec);
	263	fidiv = (gRandom->Rndm())*k2PI;
	264	}
03cc1ceb	265	else if(icross==1){ // ##### Crossing angle
68ca986e	266	if(fBeamCrossPlane==0.){
	267	tetdiv = 0.;
	268	fidiv = 0.;
	269	}
03cc1ceb	270	else if(fBeamCrossPlane==1.){ // Horizontal crossing plane
68ca986e	271	tetdiv = fBeamCrossAngle;
	272	fidiv = 0.;
	273	}
03cc1ceb	274	else if(fBeamCrossPlane==2.){ // Vertical crossing plane
68ca986e	275	tetdiv = fBeamCrossAngle;
736c9b58	276	fidiv = k2PI/4.;
68ca986e	277	}
68ca986e	278	}
866ab5a2	279
03cc1ceb	280	tetpart = TMath::ATan2(TMath::Sqrt(pLab[0]pLab[0]+pLab[1]pLab[1]),pLab[2]);
c294be39	281	if(pLab[1]!=0. \|\| pLab[0]!=0.) fipart = TMath::ATan2(pLab[1],pLab[0]);
c294be39	282	else fipart = 0.;
68ca986e	283	if(fipart<0.) {fipart = fipart+k2PI;}
68ca986e	284	tetdiv = tetdiv*kRaddeg;
	285	fidiv = fidiv*kRaddeg;
	286	tetpart = tetpart*kRaddeg;
	287	fipart = fipart*kRaddeg;
	288	AddAngle(tetpart,fipart,tetdiv,fidiv,angleSum);
	289	tetsum = angleSum[0];
	290	fisum = angleSum[1];
68ca986e	291	tetsum = tetsum*kDegrad;
	292	fisum = fisum*kDegrad;
	293	pLab[0] = pmodTMath::Sin(tetsum)TMath::Cos(fisum);
	294	pLab[1] = pmodTMath::Sin(tetsum)TMath::Sin(fisum);
03cc1ceb	295	pLab[2] = pmod*TMath::Cos(tetsum);
5a881c97	296	if(fDebugOpt == 1){
03cc1ceb	297	if(icross==0) printf("\n\n Beam divergence \n");
03cc1ceb	298	else printf("\n\n Beam crossing \n");
c294be39	299	for(i=0; i<=2; i++)printf(" pLab[%d] = %f\n",i,pLab[i]);
68ca986e	300	}
	301	}
	302
	303	//_____________________________________________________________________________
	304	void AliGenZDC::AddAngle(Double_t theta1, Double_t phi1, Double_t theta2,
5a881c97	305	Double_t phi2, Double_t *angleSum)
8a2624cc	306	{
8a2624cc	307	// Calculating the sum of 2 angles
68ca986e	308	Double_t temp, conv, cx, cy, cz, ct1, st1, ct2, st2, cp1, sp1, cp2, sp2;
	309	Double_t rtetsum, tetsum, fisum;
	310
	311	temp = -1.;
	312	conv = 180./TMath::ACos(temp);
	313
	314	ct1 = TMath::Cos(theta1/conv);
	315	st1 = TMath::Sin(theta1/conv);
	316	cp1 = TMath::Cos(phi1/conv);
	317	sp1 = TMath::Sin(phi1/conv);
	318	ct2 = TMath::Cos(theta2/conv);
	319	st2 = TMath::Sin(theta2/conv);
	320	cp2 = TMath::Cos(phi2/conv);
	321	sp2 = TMath::Sin(phi2/conv);
	322	cx = ct1cp1st2cp2+st1cp1ct2-sp1st2*sp2;
	323	cy = ct1sp1st2cp2+st1sp1ct2+cp1st2*sp2;
	324	cz = ct1ct2-st1st2*cp2;
	325
	326	rtetsum = TMath::ACos(cz);
	327	tetsum = conv*rtetsum;
	328	if(tetsum==0. \|\| tetsum==180.){
	329	fisum = 0.;
	330	return;
	331	}
	332	temp = cx/TMath::Sin(rtetsum);
	333	if(temp>1.) temp=1.;
	334	if(temp<-1.) temp=-1.;
	335	fisum = conv*TMath::ACos(temp);
	336	if(cy<0) {fisum = 360.-fisum;}
68ca986e	337	angleSum[0] = tetsum;
	338	angleSum[1] = fisum;
	339	}
	340