[u/mrichter/AliRoot.git] / EVGEN / AliGenHIJINGpara.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.                  *
 **************************************************************************/

/* $Id$ */

// Parameterisation of pi and K, eta and pt distributions
// used for the ALICE TDRs.
// eta: according to HIJING (shadowing + quenching)
// pT : according to CDF measurement at 1.8 TeV
// Author: andreas.morsch@cern.ch


//Begin_Html
/*
<img src="picts/AliGeneratorClass.gif">
</pre>
<br clear=left>
<font size=+2 color=red>
<p>The responsible person for this module is
<a href="mailto:andreas.morsch@cern.ch">Andreas Morsch</a>.
</font>
<pre>
*/
//End_Html
//                                                               //
///////////////////////////////////////////////////////////////////

#include <TArrayF.h>
#include <TClonesArray.h>
#include <TDatabasePDG.h>
#include <TF1.h>
#include <TParticle.h>
#include <TPDGCode.h>

#include "AliConst.h"
#include "AliDecayer.h"
#include "AliGenEventHeader.h"
#include "AliGenHIJINGpara.h"
#include "AliRun.h"

ClassImp(AliGenHIJINGpara)


AliGenHIJINGpara::AliGenHIJINGpara(const AliGenHIJINGpara & para):
    AliGenerator(para)
{
// Copy constructor
    para.Copy(*this);
}

//_____________________________________________________________________________
static Double_t ptpi(Double_t *px, Double_t *)
{
  //
  //     PT-PARAMETERIZATION CDF, PRL 61(88) 1819
  //     POWER LAW FOR PT > 500 MEV
  //     MT SCALING BELOW (T=160 MEV)
  //
  const Double_t kp0 = 1.3;
  const Double_t kxn = 8.28;
  const Double_t kxlim=0.5;
  const Double_t kt=0.160;
  const Double_t kxmpi=0.139;
  const Double_t kb=1.;
  Double_t y, y1, xmpi2, ynorm, a;
  Double_t x=*px;
  //
  y1=TMath::Power(kp0/(kp0+kxlim),kxn);
  xmpi2=kxmpi*kxmpi;
  ynorm=kb*(TMath::Exp(-sqrt(kxlim*kxlim+xmpi2)/kt));
  a=ynorm/y1;
  if (x > kxlim)
    y=a*TMath::Power(kp0/(kp0+x),kxn);
  else
    y=kb*TMath::Exp(-sqrt(x*x+xmpi2)/kt);
  return y*x;
}

//_____________________________________________________________________________
static Double_t ptscal(Double_t pt, Int_t np)
{
    //    SCALING EN MASSE PAR RAPPORT A PTPI
    //     MASS PI,K,ETA,RHO,OMEGA,ETA',PHI
    const Double_t khm[10] = {.13957,.493,.5488,.769,.7826,.958,1.02,0,0,0};
    //     VALUE MESON/PI AT 5 GEV
    const Double_t kfmax[10]={1.,0.3,0.55,1.0,1.0,1.0,1.0,0,0,0};
    np--;
    Double_t f5=TMath::Power(((
	sqrt(100.018215)+2.)/(sqrt(100.+khm[np]*khm[np])+2.0)),12.3);
    Double_t fmax2=f5/kfmax[np];
    // PIONS
    Double_t ptpion=100.*ptpi(&pt, (Double_t*) 0);
    Double_t fmtscal=TMath::Power(((
	sqrt(pt*pt+0.018215)+2.)/ (sqrt(pt*pt+khm[np]*khm[np])+2.0)),12.3)/ 
	fmax2;
    return fmtscal*ptpion;
}

//_____________________________________________________________________________
static Double_t ptka( Double_t *px, Double_t *)
{
    //
    // pt parametrisation for k
    //
    return ptscal(*px,2);
}


//_____________________________________________________________________________
static Double_t etapic( Double_t *py, Double_t *)
{
  //
  // eta parametrisation for pi
  //
    const Double_t ka1    = 4913.;
    const Double_t ka2    = 1819.;
    const Double_t keta1  = 0.22;
    const Double_t keta2  = 3.66;
    const Double_t kdeta1 = 1.47;
    const Double_t kdeta2 = 1.51;
    Double_t y=TMath::Abs(*py);
    //
    Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1);
    Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2);
    return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2);
}

//_____________________________________________________________________________
static Double_t etakac( Double_t *py, Double_t *)
{
    //
    // eta parametrisation for ka
    //
    const Double_t ka1    = 497.6;
    const Double_t ka2    = 215.6;
    const Double_t keta1  = 0.79;
    const Double_t keta2  = 4.09;
    const Double_t kdeta1 = 1.54;
    const Double_t kdeta2 = 1.40;
    Double_t y=TMath::Abs(*py);
    //
    Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1);
    Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2);
    return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2);
}

//_____________________________________________________________________________
AliGenHIJINGpara::AliGenHIJINGpara()
  :AliGenerator()
{
    //
    // Default constructor
    //
    fPtpi    =  0;
    fPtka    =  0;
    fETApic  =  0;
    fETAkac  =  0;
    fDecayer =  0;
    fNt      = -1;
    SetCutVertexZ();
    SetPtRange();
    SetPi0Decays();
}

//_____________________________________________________________________________
AliGenHIJINGpara::AliGenHIJINGpara(Int_t npart)
  :AliGenerator(npart)
{
  // 
  // Standard constructor
  //
    fName="HIJINGpara";
    fTitle="HIJING Parametrisation Particle Generator";
    fPtpi    =  0;
    fPtka    =  0;
    fETApic  =  0;
    fETAkac  =  0;
    fDecayer =  0;
    fNt      = -1;
    SetCutVertexZ();
    SetPtRange();
    SetPi0Decays();
}

//_____________________________________________________________________________
AliGenHIJINGpara::~AliGenHIJINGpara()
{
  //
  // Standard destructor
  //
    delete fPtpi;
    delete fPtka;
    delete fETApic;
    delete fETAkac;
}

//_____________________________________________________________________________
void AliGenHIJINGpara::Init()
{
  //
  // Initialise the HIJING parametrisation
  //
    Float_t etaMin =-TMath::Log(TMath::Tan(
	TMath::Min((Double_t)fThetaMax/2,TMath::Pi()/2-1.e-10)));
    Float_t etaMax = -TMath::Log(TMath::Tan(
	TMath::Max((Double_t)fThetaMin/2,1.e-10)));
    fPtpi   = new TF1("ptpi",&ptpi,0,20,0);
    fPtka   = new TF1("ptka",&ptka,0,20,0);
    fETApic = new TF1("etapic",&etapic,etaMin,etaMax,0);
    fETAkac = new TF1("etakac",&etakac,etaMin,etaMax,0);

    TF1 etaPic0("etapic",&etapic,-7,7,0);
    TF1 etaKac0("etakac",&etakac,-7,7,0);

    TF1 ptPic0("ptpi",&ptpi,0.,15.,0);
    TF1 ptKac0("ptka",&ptka,0.,15.,0);

    Float_t intETApi  = etaPic0.Integral(-0.5, 0.5);
    Float_t intETAka  = etaKac0.Integral(-0.5, 0.5);
    Float_t scalePi   = 7316/(intETApi/1.5);
    Float_t scaleKa   =  684/(intETAka/2.0);

//  Fraction of events corresponding to the selected pt-range    
    Float_t intPt    = (0.877*ptPic0.Integral(0, 15)+
			0.123*ptKac0.Integral(0, 15));
    Float_t intPtSel = (0.877*ptPic0.Integral(fPtMin, fPtMax)+
			0.123*ptKac0.Integral(fPtMin, fPtMax));
    Float_t ptFrac   = intPtSel/intPt;

//  Fraction of events corresponding to the selected eta-range    
    Float_t intETASel  = (scalePi*etaPic0.Integral(etaMin, etaMax)+
			  scaleKa*etaKac0.Integral(etaMin, etaMax));
//  Fraction of events corresponding to the selected phi-range    
    Float_t phiFrac    = (fPhiMax-fPhiMin)/2/TMath::Pi();

    fParentWeight = Float_t(fNpart)/(intETASel*ptFrac*phiFrac);
    
    printf("%s: The number of particles in the selected kinematic region corresponds to %f percent of a full event\n ", 
	   ClassName(),100.*fParentWeight);

// Issue warning message if etaMin or etaMax are outside the alowed range 
// of the parametrization
    if (etaMin < -8.001 || etaMax > 8.001) {
	printf("\n \n WARNING FROM AliGenHIJINGPara !");
	printf("\n YOU ARE USING THE PARAMETERISATION OUTSIDE ");	
	printf("\n THE ALLOWED PSEUDORAPIDITY RANGE (-8. - 8.)");	    
	printf("\n YOUR LIMITS: %f %f \n \n ", etaMin, etaMax);
    }
//
//
    if (fPi0Decays && gMC)
	fDecayer = gMC->GetDecayer();
}


//_____________________________________________________________________________
void AliGenHIJINGpara::Generate()
{
  //
  // Generate one trigger
  //

  
    const Float_t kRaKpic=0.14;
    const Float_t kBorne=1/(1+kRaKpic);
    Float_t polar[3]= {0,0,0};
    //
    const Int_t kPions[3] = {kPi0, kPiPlus, kPiMinus};
    const Int_t kKaons[4] = {kK0Long, kK0Short, kKPlus, kKMinus};
    //
    Float_t origin[3];
    Float_t pt, pl, ptot;
    Float_t phi, theta;
    Float_t p[3];
    Int_t i, part, j;
    //
    TF1 *ptf;
    TF1 *etaf;
    //
    Float_t random[6];
    //
    for (j=0;j<3;j++) origin[j]=fOrigin[j];

    if(fVertexSmear == kPerEvent) {
	Vertex();
	for (j=0; j < 3; j++) origin[j] = fVertex[j];
    } // if kPerEvent
    TArrayF eventVertex;
    eventVertex.Set(3);
    eventVertex[0] = origin[0];
    eventVertex[1] = origin[1];
    eventVertex[2] = origin[2];

    for(i=0;i<fNpart;i++) {
	while(1) {
	    Rndm(random,3);
	    if(random[0]<kBorne) {
		part=kPions[Int_t (random[1]*3)];
		ptf=fPtpi;
		etaf=fETApic;
	    } else {
		part=kKaons[Int_t (random[1]*4)];
		ptf=fPtka;
		etaf=fETAkac;
	    }
	    phi=fPhiMin+random[2]*(fPhiMax-fPhiMin);
	    theta=2*TMath::ATan(TMath::Exp(-etaf->GetRandom()));
	    if(theta<fThetaMin || theta>fThetaMax) continue;
	    pt=ptf->GetRandom();
	    pl=pt/TMath::Tan(theta);
	    ptot=TMath::Sqrt(pt*pt+pl*pl);
	    if(ptot<fPMin || ptot>fPMax) continue;
	    p[0]=pt*TMath::Cos(phi);
	    p[1]=pt*TMath::Sin(phi);
	    p[2]=pl;
	    if(fVertexSmear==kPerTrack) {
		Rndm(random,6);
		for (j=0;j<3;j++) {
		    origin[j]=fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
			TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
		}
	    }
	    if (part == kPi0 && fPi0Decays){
//
//          Decay pi0 if requested
		PushTrack(0,-1,part,p,origin,polar,0,kPPrimary,fNt,fParentWeight);
		KeepTrack(fNt);
		DecayPi0(origin, p);
	    } else {
		PushTrack(fTrackIt,-1,part,p,origin,polar,0,kPPrimary,fNt,fParentWeight);
		KeepTrack(fNt);
	    }

	    break;
	}
	SetHighWaterMark(fNt);
    }
//

// Header
    AliGenEventHeader* header = new AliGenEventHeader("HIJINGparam");
// Event Vertex
    header->SetPrimaryVertex(eventVertex);
    gAlice->SetGenEventHeader(header); 
}

void AliGenHIJINGpara::SetPtRange(Float_t ptmin, Float_t ptmax) {
    AliGenerator::SetPtRange(ptmin, ptmax);
}

void AliGenHIJINGpara::DecayPi0(Float_t* orig, Float_t * p) 
{
//
//    Decay the pi0
//    and put decay products on the stack
//
    static TClonesArray *particles;
    if(!particles) particles = new TClonesArray("TParticle",1000);
//    
    const Float_t kMass = TDatabasePDG::Instance()->GetParticle(kPi0)->Mass();
    Float_t       e     = TMath::Sqrt(p[0] * p[0] + p[1] * p[1] + p[2] * p[2]+ kMass * kMass);
//
//  Decay the pi0    
    TLorentzVector pmom(p[0], p[1], p[2], e);
    fDecayer->Decay(kPi0, &pmom);
    
//
// Put decay particles on the stack
//
    Float_t polar[3] = {0., 0., 0.};
    Int_t np = fDecayer->ImportParticles(particles);
    Int_t nt;    
    for (Int_t i = 1; i < np; i++)
    {
	TParticle* iParticle =  (TParticle *) particles->At(i);
	p[0] = iParticle->Px();
	p[1] = iParticle->Py();
	p[2] = iParticle->Pz();
	Int_t part = iParticle->GetPdgCode();

	PushTrack(fTrackIt, fNt, part, p, orig, polar, 0, kPDecay, nt, fParentWeight);
	KeepTrack(nt);
    }
    fNt = nt;
}

void AliGenHIJINGpara::Copy(AliGenHIJINGpara &) const
{
  Fatal("Copy","Not implemented!\n");
}
Commit	Line	Data
790bbabf	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	/* $Id$ */
675e9664	17
	18	// Parameterisation of pi and K, eta and pt distributions
	19	// used for the ALICE TDRs.
	20	// eta: according to HIJING (shadowing + quenching)
	21	// pT : according to CDF measurement at 1.8 TeV
	22	// Author: andreas.morsch@cern.ch
	23
	24
790bbabf	25	//Begin_Html
	26	/*
	27	<img src="picts/AliGeneratorClass.gif">
	28	</pre>
	29	<br clear=left>
	30	<font size=+2 color=red>
	31	<p>The responsible person for this module is
	32	<a href="mailto:andreas.morsch@cern.ch">Andreas Morsch</a>.
	33	</font>
	34	<pre>
	35	*/
	36	//End_Html
	37	// //
	38	///////////////////////////////////////////////////////////////////
	39
971816d4	40	#include <TArrayF.h>
2067f62c	41	#include <TClonesArray.h>
116cbefd	42	#include <TDatabasePDG.h>
116cbefd	43	#include <TF1.h>
2067f62c	44	#include <TParticle.h>
116cbefd	45	#include <TPDGCode.h>
	46
	47	#include "AliConst.h"
	48	#include "AliDecayer.h"
116cbefd	49	#include "AliGenEventHeader.h"
	50	#include "AliGenHIJINGpara.h"
	51	#include "AliRun.h"
971816d4	52
790bbabf	53	ClassImp(AliGenHIJINGpara)
790bbabf	54
198bb1c7	55
	56	AliGenHIJINGpara::AliGenHIJINGpara(const AliGenHIJINGpara & para):
	57	AliGenerator(para)
790bbabf	58	{
198bb1c7	59	// Copy constructor
198bb1c7	60	para.Copy(*this);
790bbabf	61	}
	62
	63	//_____________________________________________________________________________
	64	static Double_t ptpi(Double_t px, Double_t )
	65	{
	66	//
	67	// PT-PARAMETERIZATION CDF, PRL 61(88) 1819
	68	// POWER LAW FOR PT > 500 MEV
	69	// MT SCALING BELOW (T=160 MEV)
	70	//
	71	const Double_t kp0 = 1.3;
	72	const Double_t kxn = 8.28;
	73	const Double_t kxlim=0.5;
	74	const Double_t kt=0.160;
	75	const Double_t kxmpi=0.139;
	76	const Double_t kb=1.;
	77	Double_t y, y1, xmpi2, ynorm, a;
	78	Double_t x=*px;
	79	//
	80	y1=TMath::Power(kp0/(kp0+kxlim),kxn);
	81	xmpi2=kxmpi*kxmpi;
	82	ynorm=kb(TMath::Exp(-sqrt(kxlimkxlim+xmpi2)/kt));
	83	a=ynorm/y1;
	84	if (x > kxlim)
	85	y=a*TMath::Power(kp0/(kp0+x),kxn);
	86	else
	87	y=kbTMath::Exp(-sqrt(xx+xmpi2)/kt);
	88	return y*x;
	89	}
	90
	91	//_____________________________________________________________________________
	92	static Double_t ptscal(Double_t pt, Int_t np)
	93	{
	94	// SCALING EN MASSE PAR RAPPORT A PTPI
	95	// MASS PI,K,ETA,RHO,OMEGA,ETA',PHI
	96	const Double_t khm[10] = {.13957,.493,.5488,.769,.7826,.958,1.02,0,0,0};
	97	// VALUE MESON/PI AT 5 GEV
	98	const Double_t kfmax[10]={1.,0.3,0.55,1.0,1.0,1.0,1.0,0,0,0};
	99	np--;
	100	Double_t f5=TMath::Power(((
	101	sqrt(100.018215)+2.)/(sqrt(100.+khm[np]*khm[np])+2.0)),12.3);
	102	Double_t fmax2=f5/kfmax[np];
	103	// PIONS
	104	Double_t ptpion=100.ptpi(&pt, (Double_t) 0);
	105	Double_t fmtscal=TMath::Power(((
	106	sqrt(ptpt+0.018215)+2.)/ (sqrt(ptpt+khm[np]*khm[np])+2.0)),12.3)/
	107	fmax2;
	108	return fmtscal*ptpion;
	109	}
	110
	111	//_____________________________________________________________________________
	112	static Double_t ptka( Double_t px, Double_t )
	113	{
	114	//
	115	// pt parametrisation for k
	116	//
	117	return ptscal(*px,2);
	118	}
	119
	120
	121	//_____________________________________________________________________________
	122	static Double_t etapic( Double_t py, Double_t )
	123	{
	124	//
125	// eta parametrisation for pi
126	//
127	const Double_t ka1 = 4913.;
128	const Double_t ka2 = 1819.;
129	const Double_t keta1 = 0.22;
130	const Double_t keta2 = 3.66;
131	const Double_t kdeta1 = 1.47;
132	const Double_t kdeta2 = 1.51;
133	Double_t y=TMath::Abs(*py);
134	//
135	Double_t ex1 = (y-keta1)(y-keta1)/(2kdeta1*kdeta1);
136	Double_t ex2 = (y-keta2)(y-keta2)/(2kdeta2*kdeta2);
137	return ka1TMath::Exp(-ex1)+ka2TMath::Exp(-ex2);
138	}
139
140	//_____________________________________________________________________________
141	static Double_t etakac( Double_t py, Double_t )
142	{
143	//
144	// eta parametrisation for ka
145	//
146	const Double_t ka1 = 497.6;
147	const Double_t ka2 = 215.6;
148	const Double_t keta1 = 0.79;
149	const Double_t keta2 = 4.09;
150	const Double_t kdeta1 = 1.54;
151	const Double_t kdeta2 = 1.40;
152	Double_t y=TMath::Abs(*py);
153	//
154	Double_t ex1 = (y-keta1)(y-keta1)/(2kdeta1*kdeta1);
155	Double_t ex2 = (y-keta2)(y-keta2)/(2kdeta2*kdeta2);
156	return ka1TMath::Exp(-ex1)+ka2TMath::Exp(-ex2);
157	}
158
159	//_____________________________________________________________________________
160	AliGenHIJINGpara::AliGenHIJINGpara()
161	:AliGenerator()
162	{
163	//
164	// Default constructor
165	//
1e66857c	166	fPtpi = 0;
	167	fPtka = 0;
	168	fETApic = 0;
	169	fETAkac = 0;
	170	fDecayer = 0;
	171	fNt = -1;
971816d4	172	SetCutVertexZ();
6b236b6f	173	SetPtRange();
2067f62c	174	SetPi0Decays();
790bbabf	175	}
	176
	177	//_____________________________________________________________________________
	178	AliGenHIJINGpara::AliGenHIJINGpara(Int_t npart)
	179	:AliGenerator(npart)
	180	{
	181	//
	182	// Standard constructor
	183	//
edbba5db	184	fName="HIJINGpara";
790bbabf	185	fTitle="HIJING Parametrisation Particle Generator";
1e66857c	186	fPtpi = 0;
	187	fPtka = 0;
	188	fETApic = 0;
	189	fETAkac = 0;
	190	fDecayer = 0;
	191	fNt = -1;
971816d4	192	SetCutVertexZ();
6b236b6f	193	SetPtRange();
2067f62c	194	SetPi0Decays();
790bbabf	195	}
	196
	197	//_____________________________________________________________________________
	198	AliGenHIJINGpara::~AliGenHIJINGpara()
	199	{
	200	//
	201	// Standard destructor
	202	//
	203	delete fPtpi;
	204	delete fPtka;
	205	delete fETApic;
	206	delete fETAkac;
	207	}
	208
	209	//_____________________________________________________________________________
	210	void AliGenHIJINGpara::Init()
	211	{
	212	//
	213	// Initialise the HIJING parametrisation
	214	//
	215	Float_t etaMin =-TMath::Log(TMath::Tan(
	216	TMath::Min((Double_t)fThetaMax/2,TMath::Pi()/2-1.e-10)));
	217	Float_t etaMax = -TMath::Log(TMath::Tan(
	218	TMath::Max((Double_t)fThetaMin/2,1.e-10)));
f25521b2	219	fPtpi = new TF1("ptpi",&ptpi,0,20,0);
f25521b2	220	fPtka = new TF1("ptka",&ptka,0,20,0);
790bbabf	221	fETApic = new TF1("etapic",&etapic,etaMin,etaMax,0);
790bbabf	222	fETAkac = new TF1("etakac",&etakac,etaMin,etaMax,0);
f25521b2	223
aecf26a3	224	TF1 etaPic0("etapic",&etapic,-7,7,0);
aecf26a3	225	TF1 etaKac0("etakac",&etakac,-7,7,0);
f25521b2	226
aecf26a3	227	TF1 ptPic0("ptpi",&ptpi,0.,15.,0);
aecf26a3	228	TF1 ptKac0("ptka",&ptka,0.,15.,0);
f25521b2	229
aecf26a3	230	Float_t intETApi = etaPic0.Integral(-0.5, 0.5);
aecf26a3	231	Float_t intETAka = etaKac0.Integral(-0.5, 0.5);
f25521b2	232	Float_t scalePi = 7316/(intETApi/1.5);
	233	Float_t scaleKa = 684/(intETAka/2.0);
	234
	235	// Fraction of events corresponding to the selected pt-range
aecf26a3	236	Float_t intPt = (0.877*ptPic0.Integral(0, 15)+
	237	0.123*ptKac0.Integral(0, 15));
	238	Float_t intPtSel = (0.877*ptPic0.Integral(fPtMin, fPtMax)+
	239	0.123*ptKac0.Integral(fPtMin, fPtMax));
f25521b2	240	Float_t ptFrac = intPtSel/intPt;
	241
	242	// Fraction of events corresponding to the selected eta-range
aecf26a3	243	Float_t intETASel = (scalePi*etaPic0.Integral(etaMin, etaMax)+
aecf26a3	244	scaleKa*etaKac0.Integral(etaMin, etaMax));
f25521b2	245	// Fraction of events corresponding to the selected phi-range
	246	Float_t phiFrac = (fPhiMax-fPhiMin)/2/TMath::Pi();
	247
	248	fParentWeight = Float_t(fNpart)/(intETASelptFracphiFrac);
790bbabf	249
9e1a0ddb	250	printf("%s: The number of particles in the selected kinematic region corresponds to %f percent of a full event\n ",
9e1a0ddb	251	ClassName(),100.*fParentWeight);
5b0e4c0f	252
	253	// Issue warning message if etaMin or etaMax are outside the alowed range
	254	// of the parametrization
	255	if (etaMin < -8.001 \|\| etaMax > 8.001) {
	256	printf("\n \n WARNING FROM AliGenHIJINGPara !");
	257	printf("\n YOU ARE USING THE PARAMETERISATION OUTSIDE ");
	258	printf("\n THE ALLOWED PSEUDORAPIDITY RANGE (-8. - 8.)");
	259	printf("\n YOUR LIMITS: %f %f \n \n ", etaMin, etaMax);
	260	}
2067f62c	261	//
2067f62c	262	//
2904363f	263	if (fPi0Decays && gMC)
2904363f	264	fDecayer = gMC->GetDecayer();
790bbabf	265	}
790bbabf	266
2067f62c	267
790bbabf	268	//_____________________________________________________________________________
	269	void AliGenHIJINGpara::Generate()
	270	{
	271	//
	272	// Generate one trigger
	273	//
	274
	275
	276	const Float_t kRaKpic=0.14;
	277	const Float_t kBorne=1/(1+kRaKpic);
	278	Float_t polar[3]= {0,0,0};
	279	//
	280	const Int_t kPions[3] = {kPi0, kPiPlus, kPiMinus};
	281	const Int_t kKaons[4] = {kK0Long, kK0Short, kKPlus, kKMinus};
	282	//
	283	Float_t origin[3];
	284	Float_t pt, pl, ptot;
	285	Float_t phi, theta;
	286	Float_t p[3];
1e66857c	287	Int_t i, part, j;
790bbabf	288	//
	289	TF1 *ptf;
	290	TF1 *etaf;
	291	//
	292	Float_t random[6];
	293	//
	294	for (j=0;j<3;j++) origin[j]=fOrigin[j];
971816d4	295
971816d4	296	if(fVertexSmear == kPerEvent) {
c8f7f6f9	297	Vertex();
c8f7f6f9	298	for (j=0; j < 3; j++) origin[j] = fVertex[j];
971816d4	299	} // if kPerEvent
	300	TArrayF eventVertex;
	301	eventVertex.Set(3);
	302	eventVertex[0] = origin[0];
	303	eventVertex[1] = origin[1];
	304	eventVertex[2] = origin[2];
	305
790bbabf	306	for(i=0;i<fNpart;i++) {
790bbabf	307	while(1) {
65fb704d	308	Rndm(random,3);
790bbabf	309	if(random[0]<kBorne) {
	310	part=kPions[Int_t (random[1]*3)];
	311	ptf=fPtpi;
2067f62c	312	etaf=fETApic;
790bbabf	313	} else {
	314	part=kKaons[Int_t (random[1]*4)];
	315	ptf=fPtka;
	316	etaf=fETAkac;
	317	}
	318	phi=fPhiMin+random[2]*(fPhiMax-fPhiMin);
	319	theta=2*TMath::ATan(TMath::Exp(-etaf->GetRandom()));
	320	if(theta<fThetaMin \|\| theta>fThetaMax) continue;
	321	pt=ptf->GetRandom();
	322	pl=pt/TMath::Tan(theta);
	323	ptot=TMath::Sqrt(ptpt+plpl);
	324	if(ptot<fPMin \|\| ptot>fPMax) continue;
	325	p[0]=pt*TMath::Cos(phi);
	326	p[1]=pt*TMath::Sin(phi);
	327	p[2]=pl;
aee8290b	328	if(fVertexSmear==kPerTrack) {
65fb704d	329	Rndm(random,6);
790bbabf	330	for (j=0;j<3;j++) {
	331	origin[j]=fOrigin[j]+fOsigma[j]TMath::Cos(2random[2j]TMath::Pi())*
	332	TMath::Sqrt(-2TMath::Log(random[2j+1]));
	333	}
	334	}
1ef5f15d	335	if (part == kPi0 && fPi0Decays){
2067f62c	336	//
2067f62c	337	// Decay pi0 if requested
642f15cf	338	PushTrack(0,-1,part,p,origin,polar,0,kPPrimary,fNt,fParentWeight);
1e66857c	339	KeepTrack(fNt);
1ef5f15d	340	DecayPi0(origin, p);
1ef5f15d	341	} else {
642f15cf	342	PushTrack(fTrackIt,-1,part,p,origin,polar,0,kPPrimary,fNt,fParentWeight);
1e66857c	343	KeepTrack(fNt);
1ef5f15d	344	}
1ef5f15d	345
790bbabf	346	break;
790bbabf	347	}
1e66857c	348	SetHighWaterMark(fNt);
790bbabf	349	}
1e66857c	350	//
1e66857c	351
971816d4	352	// Header
	353	AliGenEventHeader* header = new AliGenEventHeader("HIJINGparam");
	354	// Event Vertex
	355	header->SetPrimaryVertex(eventVertex);
	356	gAlice->SetGenEventHeader(header);
790bbabf	357	}
790bbabf	358
6b236b6f	359	void AliGenHIJINGpara::SetPtRange(Float_t ptmin, Float_t ptmax) {
2067f62c	360	AliGenerator::SetPtRange(ptmin, ptmax);
6b236b6f	361	}
790bbabf	362
2067f62c	363	void AliGenHIJINGpara::DecayPi0(Float_t* orig, Float_t * p)
	364	{
	365	//
	366	// Decay the pi0
	367	// and put decay products on the stack
	368	//
	369	static TClonesArray *particles;
	370	if(!particles) particles = new TClonesArray("TParticle",1000);
	371	//
	372	const Float_t kMass = TDatabasePDG::Instance()->GetParticle(kPi0)->Mass();
56fcdfe6	373	Float_t e = TMath::Sqrt(p[0] * p[0] + p[1] * p[1] + p[2] * p[2]+ kMass * kMass);
2067f62c	374	//
	375	// Decay the pi0
	376	TLorentzVector pmom(p[0], p[1], p[2], e);
	377	fDecayer->Decay(kPi0, &pmom);
56fcdfe6	378
2067f62c	379	//
	380	// Put decay particles on the stack
	381	//
2067f62c	382	Float_t polar[3] = {0., 0., 0.};
2067f62c	383	Int_t np = fDecayer->ImportParticles(particles);
1e66857c	384	Int_t nt;
2067f62c	385	for (Int_t i = 1; i < np; i++)
2067f62c	386	{
7b33c00a	387	TParticle* iParticle = (TParticle *) particles->At(i);
	388	p[0] = iParticle->Px();
	389	p[1] = iParticle->Py();
	390	p[2] = iParticle->Pz();
2067f62c	391	Int_t part = iParticle->GetPdgCode();
1e66857c	392
642f15cf	393	PushTrack(fTrackIt, fNt, part, p, orig, polar, 0, kPDecay, nt, fParentWeight);
1e66857c	394	KeepTrack(nt);
2067f62c	395	}
1e66857c	396	fNt = nt;
2067f62c	397	}
198bb1c7	398
	399	void AliGenHIJINGpara::Copy(AliGenHIJINGpara &) const
	400	{
	401	Fatal("Copy","Not implemented!\n");
	402	}