[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 <TCanvas.h>
#include <TClonesArray.h>
#include <TDatabasePDG.h>
#include <TF1.h>
#include <TH1.h>
#include <TPDGCode.h>
#include <TParticle.h>
#include <TROOT.h>
#include <TVirtualMC.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);
    gROOT->GetListOfFunctions()->Remove(fPtpi);
    fPtka   = new TF1("ptka",&ptka,0,20,0);
    gROOT->GetListOfFunctions()->Remove(fPtka);
    fPtpi->SetNpx(1000);
    fPtka->SetNpx(1000);
    fETApic = new TF1("etapic",&etapic,etaMin,etaMax,0);
    gROOT->GetListOfFunctions()->Remove(fETApic);
    fETAkac = new TF1("etakac",&etakac,etaMin,etaMax,0);
    gROOT->GetListOfFunctions()->Remove(fETAkac);

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

    TF1 ptPic0("ptPic0",&ptpi,0.,15.,0);
    TF1 ptKac0("ptKac0",&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);
    
    if (fAnalog != 0) {
	fPtWgtPi = (fPtMax - fPtMin) / fPtpi->Integral(0., 20.);
	fPtWgtKa = (fPtMax - fPtMin) / fPtka->Integral(0., 20.);
	fParentWeight = Float_t(fNpart)/(intETASel*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, wgt;
    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,4);
	    if(random[0]<kBorne) {
		part=kPions[Int_t (random[1]*3)];
		ptf=fPtpi;
		etaf=fETApic;
		wgt = fPtWgtPi;
	    } else {
		part=kKaons[Int_t (random[1]*4)];
		ptf=fPtka;
		etaf=fETAkac;
		wgt = fPtWgtKa;
	    }
	    phi=fPhiMin+random[2]*(fPhiMax-fPhiMin);
	    theta=2*TMath::ATan(TMath::Exp(-etaf->GetRandom()));
	    if(theta<fThetaMin || theta>fThetaMax) continue;
	 
	    if (fAnalog == 0) { 
		pt = ptf->GetRandom();
	    } else {
		pt = fPtMin + random[3] * (fPtMax - fPtMin);
	    }
	    
	    
	    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 (fAnalog == 0) { 
		wgt = fParentWeight;
	    } else {
		wgt *= (fParentWeight * ptf->Eval(pt));
	    }
	    
	    
	    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(TObject &) const
{
  Fatal("Copy","Not implemented!\n");
}


void AliGenHIJINGpara::Draw( const char * /*opt*/)
{
    //
    // Draw the pT and y Distributions
    //
     TCanvas *c0 = new TCanvas("c0","Canvas 0",400,10,600,700);
     c0->Divide(2,1);
     c0->cd(1);
     fPtpi->Draw();
     fPtpi->GetHistogram()->SetXTitle("p_{T} (GeV)");     
     c0->cd(2);
     fPtka->Draw();
     fPtka->GetHistogram()->SetXTitle("p_{T} (GeV)");     

}
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>
ac3faee4	41	#include <TCanvas.h>
2067f62c	42	#include <TClonesArray.h>
116cbefd	43	#include <TDatabasePDG.h>
116cbefd	44	#include <TF1.h>
cc692c80	45	#include <TH1.h>
116cbefd	46	#include <TPDGCode.h>
ac3faee4	47	#include <TParticle.h>
828fff0d	48	#include <TROOT.h>
ac3faee4	49	#include <TVirtualMC.h>
116cbefd	50
	51	#include "AliConst.h"
	52	#include "AliDecayer.h"
116cbefd	53	#include "AliGenEventHeader.h"
	54	#include "AliGenHIJINGpara.h"
	55	#include "AliRun.h"
971816d4	56
790bbabf	57	ClassImp(AliGenHIJINGpara)
790bbabf	58
198bb1c7	59
	60	AliGenHIJINGpara::AliGenHIJINGpara(const AliGenHIJINGpara & para):
	61	AliGenerator(para)
790bbabf	62	{
198bb1c7	63	// Copy constructor
198bb1c7	64	para.Copy(*this);
790bbabf	65	}
	66
	67	//_____________________________________________________________________________
	68	static Double_t ptpi(Double_t px, Double_t )
	69	{
	70	//
	71	// PT-PARAMETERIZATION CDF, PRL 61(88) 1819
	72	// POWER LAW FOR PT > 500 MEV
	73	// MT SCALING BELOW (T=160 MEV)
	74	//
cc692c80	75	const Double_t kp0 = 1.3;
	76	const Double_t kxn = 8.28;
	77	const Double_t kxlim = 0.5;
	78	const Double_t kt = 0.160;
	79	const Double_t kxmpi = 0.139;
	80	const Double_t kb = 1.;
790bbabf	81	Double_t y, y1, xmpi2, ynorm, a;
cc692c80	82	Double_t x = *px;
790bbabf	83	//
cc692c80	84	y1 = TMath::Power(kp0 / (kp0 + kxlim), kxn);
	85	xmpi2 = kxmpi * kxmpi;
	86	ynorm = kb * (TMath::Exp(-sqrt(kxlim * kxlim + xmpi2) / kt ));
	87	a = ynorm / y1;
790bbabf	88	if (x > kxlim)
cc692c80	89	y = a * TMath::Power(kp0 / (kp0 + x), kxn);
790bbabf	90	else
cc692c80	91	y = kb* TMath::Exp(-sqrt(x * x + xmpi2) / kt);
cc692c80	92
790bbabf	93	return y*x;
	94	}
	95
	96	//_____________________________________________________________________________
	97	static Double_t ptscal(Double_t pt, Int_t np)
	98	{
	99	// SCALING EN MASSE PAR RAPPORT A PTPI
	100	// MASS PI,K,ETA,RHO,OMEGA,ETA',PHI
	101	const Double_t khm[10] = {.13957,.493,.5488,.769,.7826,.958,1.02,0,0,0};
	102	// VALUE MESON/PI AT 5 GEV
	103	const Double_t kfmax[10]={1.,0.3,0.55,1.0,1.0,1.0,1.0,0,0,0};
	104	np--;
	105	Double_t f5=TMath::Power(((
	106	sqrt(100.018215)+2.)/(sqrt(100.+khm[np]*khm[np])+2.0)),12.3);
	107	Double_t fmax2=f5/kfmax[np];
	108	// PIONS
	109	Double_t ptpion=100.ptpi(&pt, (Double_t) 0);
	110	Double_t fmtscal=TMath::Power(((
	111	sqrt(ptpt+0.018215)+2.)/ (sqrt(ptpt+khm[np]*khm[np])+2.0)),12.3)/
	112	fmax2;
	113	return fmtscal*ptpion;
	114	}
	115
	116	//_____________________________________________________________________________
	117	static Double_t ptka( Double_t px, Double_t )
	118	{
	119	//
	120	// pt parametrisation for k
	121	//
	122	return ptscal(*px,2);
	123	}
	124
	125
	126	//_____________________________________________________________________________
	127	static Double_t etapic( Double_t py, Double_t )
	128	{
	129	//
	130	// eta parametrisation for pi
	131	//
	132	const Double_t ka1 = 4913.;
	133	const Double_t ka2 = 1819.;
	134	const Double_t keta1 = 0.22;
	135	const Double_t keta2 = 3.66;
	136	const Double_t kdeta1 = 1.47;
	137	const Double_t kdeta2 = 1.51;
	138	Double_t y=TMath::Abs(*py);
	139	//
	140	Double_t ex1 = (y-keta1)(y-keta1)/(2kdeta1*kdeta1);
	141	Double_t ex2 = (y-keta2)(y-keta2)/(2kdeta2*kdeta2);
	142	return ka1TMath::Exp(-ex1)+ka2TMath::Exp(-ex2);
	143	}
	144
	145	//_____________________________________________________________________________
	146	static Double_t etakac( Double_t py, Double_t )
	147	{
	148	//
	149	// eta parametrisation for ka
	150	//
	151	const Double_t ka1 = 497.6;
	152	const Double_t ka2 = 215.6;
	153	const Double_t keta1 = 0.79;
	154	const Double_t keta2 = 4.09;
	155	const Double_t kdeta1 = 1.54;
	156	const Double_t kdeta2 = 1.40;
157	Double_t y=TMath::Abs(*py);
158	//
159	Double_t ex1 = (y-keta1)(y-keta1)/(2kdeta1*kdeta1);
160	Double_t ex2 = (y-keta2)(y-keta2)/(2kdeta2*kdeta2);
161	return ka1TMath::Exp(-ex1)+ka2TMath::Exp(-ex2);
162	}
163
164	//_____________________________________________________________________________
165	AliGenHIJINGpara::AliGenHIJINGpara()
166	:AliGenerator()
167	{
168	//
169	// Default constructor
170	//
1e66857c	171	fPtpi = 0;
	172	fPtka = 0;
	173	fETApic = 0;
	174	fETAkac = 0;
	175	fDecayer = 0;
	176	fNt = -1;
971816d4	177	SetCutVertexZ();
6b236b6f	178	SetPtRange();
2067f62c	179	SetPi0Decays();
790bbabf	180	}
	181
	182	//_____________________________________________________________________________
	183	AliGenHIJINGpara::AliGenHIJINGpara(Int_t npart)
	184	:AliGenerator(npart)
	185	{
	186	//
	187	// Standard constructor
	188	//
edbba5db	189	fName="HIJINGpara";
790bbabf	190	fTitle="HIJING Parametrisation Particle Generator";
1e66857c	191	fPtpi = 0;
	192	fPtka = 0;
	193	fETApic = 0;
	194	fETAkac = 0;
	195	fDecayer = 0;
	196	fNt = -1;
971816d4	197	SetCutVertexZ();
6b236b6f	198	SetPtRange();
2067f62c	199	SetPi0Decays();
790bbabf	200	}
	201
	202	//_____________________________________________________________________________
	203	AliGenHIJINGpara::~AliGenHIJINGpara()
	204	{
	205	//
	206	// Standard destructor
	207	//
	208	delete fPtpi;
	209	delete fPtka;
	210	delete fETApic;
	211	delete fETAkac;
	212	}
	213
	214	//_____________________________________________________________________________
	215	void AliGenHIJINGpara::Init()
	216	{
	217	//
	218	// Initialise the HIJING parametrisation
	219	//
	220	Float_t etaMin =-TMath::Log(TMath::Tan(
	221	TMath::Min((Double_t)fThetaMax/2,TMath::Pi()/2-1.e-10)));
	222	Float_t etaMax = -TMath::Log(TMath::Tan(
	223	TMath::Max((Double_t)fThetaMin/2,1.e-10)));
f25521b2	224	fPtpi = new TF1("ptpi",&ptpi,0,20,0);
828fff0d	225	gROOT->GetListOfFunctions()->Remove(fPtpi);
f25521b2	226	fPtka = new TF1("ptka",&ptka,0,20,0);
828fff0d	227	gROOT->GetListOfFunctions()->Remove(fPtka);
cc692c80	228	fPtpi->SetNpx(1000);
cc692c80	229	fPtka->SetNpx(1000);
790bbabf	230	fETApic = new TF1("etapic",&etapic,etaMin,etaMax,0);
828fff0d	231	gROOT->GetListOfFunctions()->Remove(fETApic);
790bbabf	232	fETAkac = new TF1("etakac",&etakac,etaMin,etaMax,0);
828fff0d	233	gROOT->GetListOfFunctions()->Remove(fETAkac);
f25521b2	234
bbbc190a	235	TF1 etaPic0("etaPic0",&etapic,-7,7,0);
bbbc190a	236	TF1 etaKac0("etaKac0",&etakac,-7,7,0);
f25521b2	237
bbbc190a	238	TF1 ptPic0("ptPic0",&ptpi,0.,15.,0);
bbbc190a	239	TF1 ptKac0("ptKac0",&ptka,0.,15.,0);
f25521b2	240
aecf26a3	241	Float_t intETApi = etaPic0.Integral(-0.5, 0.5);
aecf26a3	242	Float_t intETAka = etaKac0.Integral(-0.5, 0.5);
f25521b2	243	Float_t scalePi = 7316/(intETApi/1.5);
	244	Float_t scaleKa = 684/(intETAka/2.0);
	245
	246	// Fraction of events corresponding to the selected pt-range
aecf26a3	247	Float_t intPt = (0.877*ptPic0.Integral(0, 15)+
	248	0.123*ptKac0.Integral(0, 15));
	249	Float_t intPtSel = (0.877*ptPic0.Integral(fPtMin, fPtMax)+
	250	0.123*ptKac0.Integral(fPtMin, fPtMax));
f25521b2	251	Float_t ptFrac = intPtSel/intPt;
	252
	253	// Fraction of events corresponding to the selected eta-range
aecf26a3	254	Float_t intETASel = (scalePi*etaPic0.Integral(etaMin, etaMax)+
aecf26a3	255	scaleKa*etaKac0.Integral(etaMin, etaMax));
f25521b2	256	// Fraction of events corresponding to the selected phi-range
	257	Float_t phiFrac = (fPhiMax-fPhiMin)/2/TMath::Pi();
	258
0af12c00	259
f25521b2	260	fParentWeight = Float_t(fNpart)/(intETASelptFracphiFrac);
790bbabf	261
0af12c00	262	if (fAnalog != 0) {
	263	fPtWgtPi = (fPtMax - fPtMin) / fPtpi->Integral(0., 20.);
	264	fPtWgtKa = (fPtMax - fPtMin) / fPtka->Integral(0., 20.);
	265	fParentWeight = Float_t(fNpart)/(intETASel*phiFrac);
	266	}
	267
	268
9e1a0ddb	269	printf("%s: The number of particles in the selected kinematic region corresponds to %f percent of a full event\n ",
9e1a0ddb	270	ClassName(),100.*fParentWeight);
5b0e4c0f	271
	272	// Issue warning message if etaMin or etaMax are outside the alowed range
	273	// of the parametrization
	274	if (etaMin < -8.001 \|\| etaMax > 8.001) {
	275	printf("\n \n WARNING FROM AliGenHIJINGPara !");
	276	printf("\n YOU ARE USING THE PARAMETERISATION OUTSIDE ");
	277	printf("\n THE ALLOWED PSEUDORAPIDITY RANGE (-8. - 8.)");
	278	printf("\n YOUR LIMITS: %f %f \n \n ", etaMin, etaMax);
	279	}
2067f62c	280	//
2067f62c	281	//
2904363f	282	if (fPi0Decays && gMC)
2904363f	283	fDecayer = gMC->GetDecayer();
790bbabf	284	}
790bbabf	285
2067f62c	286
790bbabf	287	//_____________________________________________________________________________
	288	void AliGenHIJINGpara::Generate()
	289	{
	290	//
	291	// Generate one trigger
	292	//
	293
	294
	295	const Float_t kRaKpic=0.14;
	296	const Float_t kBorne=1/(1+kRaKpic);
	297	Float_t polar[3]= {0,0,0};
	298	//
	299	const Int_t kPions[3] = {kPi0, kPiPlus, kPiMinus};
	300	const Int_t kKaons[4] = {kK0Long, kK0Short, kKPlus, kKMinus};
	301	//
	302	Float_t origin[3];
0af12c00	303	Float_t pt, pl, ptot, wgt;
790bbabf	304	Float_t phi, theta;
790bbabf	305	Float_t p[3];
1e66857c	306	Int_t i, part, j;
790bbabf	307	//
	308	TF1 *ptf;
	309	TF1 *etaf;
	310	//
	311	Float_t random[6];
	312	//
	313	for (j=0;j<3;j++) origin[j]=fOrigin[j];
971816d4	314
971816d4	315	if(fVertexSmear == kPerEvent) {
c8f7f6f9	316	Vertex();
c8f7f6f9	317	for (j=0; j < 3; j++) origin[j] = fVertex[j];
971816d4	318	} // if kPerEvent
	319	TArrayF eventVertex;
	320	eventVertex.Set(3);
	321	eventVertex[0] = origin[0];
	322	eventVertex[1] = origin[1];
	323	eventVertex[2] = origin[2];
0af12c00	324
790bbabf	325	for(i=0;i<fNpart;i++) {
790bbabf	326	while(1) {
0af12c00	327	Rndm(random,4);
790bbabf	328	if(random[0]<kBorne) {
	329	part=kPions[Int_t (random[1]*3)];
	330	ptf=fPtpi;
2067f62c	331	etaf=fETApic;
0af12c00	332	wgt = fPtWgtPi;
790bbabf	333	} else {
	334	part=kKaons[Int_t (random[1]*4)];
	335	ptf=fPtka;
	336	etaf=fETAkac;
0af12c00	337	wgt = fPtWgtKa;
790bbabf	338	}
	339	phi=fPhiMin+random[2]*(fPhiMax-fPhiMin);
	340	theta=2*TMath::ATan(TMath::Exp(-etaf->GetRandom()));
	341	if(theta<fThetaMin \|\| theta>fThetaMax) continue;
0af12c00	342
	343	if (fAnalog == 0) {
	344	pt = ptf->GetRandom();
	345	} else {
	346	pt = fPtMin + random[3] * (fPtMax - fPtMin);
	347	}
	348
	349
790bbabf	350	pl=pt/TMath::Tan(theta);
	351	ptot=TMath::Sqrt(ptpt+plpl);
	352	if(ptot<fPMin \|\| ptot>fPMax) continue;
	353	p[0]=pt*TMath::Cos(phi);
	354	p[1]=pt*TMath::Sin(phi);
	355	p[2]=pl;
aee8290b	356	if(fVertexSmear==kPerTrack) {
65fb704d	357	Rndm(random,6);
790bbabf	358	for (j=0;j<3;j++) {
	359	origin[j]=fOrigin[j]+fOsigma[j]TMath::Cos(2random[2j]TMath::Pi())*
	360	TMath::Sqrt(-2TMath::Log(random[2j+1]));
	361	}
	362	}
0af12c00	363
	364	if (fAnalog == 0) {
	365	wgt = fParentWeight;
	366	} else {
	367	wgt = (fParentWeight ptf->Eval(pt));
	368	}
	369
	370
1ef5f15d	371	if (part == kPi0 && fPi0Decays){
2067f62c	372	//
2067f62c	373	// Decay pi0 if requested
642f15cf	374	PushTrack(0,-1,part,p,origin,polar,0,kPPrimary,fNt,fParentWeight);
1e66857c	375	KeepTrack(fNt);
1ef5f15d	376	DecayPi0(origin, p);
1ef5f15d	377	} else {
642f15cf	378	PushTrack(fTrackIt,-1,part,p,origin,polar,0,kPPrimary,fNt,fParentWeight);
1e66857c	379	KeepTrack(fNt);
1ef5f15d	380	}
1ef5f15d	381
790bbabf	382	break;
790bbabf	383	}
1e66857c	384	SetHighWaterMark(fNt);
790bbabf	385	}
1e66857c	386	//
1e66857c	387
971816d4	388	// Header
	389	AliGenEventHeader* header = new AliGenEventHeader("HIJINGparam");
	390	// Event Vertex
	391	header->SetPrimaryVertex(eventVertex);
	392	gAlice->SetGenEventHeader(header);
790bbabf	393	}
790bbabf	394
6b236b6f	395	void AliGenHIJINGpara::SetPtRange(Float_t ptmin, Float_t ptmax) {
2067f62c	396	AliGenerator::SetPtRange(ptmin, ptmax);
6b236b6f	397	}
790bbabf	398
2067f62c	399	void AliGenHIJINGpara::DecayPi0(Float_t* orig, Float_t * p)
	400	{
	401	//
	402	// Decay the pi0
	403	// and put decay products on the stack
	404	//
	405	static TClonesArray *particles;
	406	if(!particles) particles = new TClonesArray("TParticle",1000);
	407	//
	408	const Float_t kMass = TDatabasePDG::Instance()->GetParticle(kPi0)->Mass();
56fcdfe6	409	Float_t e = TMath::Sqrt(p[0] * p[0] + p[1] * p[1] + p[2] * p[2]+ kMass * kMass);
2067f62c	410	//
	411	// Decay the pi0
	412	TLorentzVector pmom(p[0], p[1], p[2], e);
	413	fDecayer->Decay(kPi0, &pmom);
56fcdfe6	414
2067f62c	415	//
	416	// Put decay particles on the stack
	417	//
2067f62c	418	Float_t polar[3] = {0., 0., 0.};
2067f62c	419	Int_t np = fDecayer->ImportParticles(particles);
1e66857c	420	Int_t nt;
2067f62c	421	for (Int_t i = 1; i < np; i++)
2067f62c	422	{
7b33c00a	423	TParticle* iParticle = (TParticle *) particles->At(i);
	424	p[0] = iParticle->Px();
	425	p[1] = iParticle->Py();
	426	p[2] = iParticle->Pz();
2067f62c	427	Int_t part = iParticle->GetPdgCode();
1e66857c	428
642f15cf	429	PushTrack(fTrackIt, fNt, part, p, orig, polar, 0, kPDecay, nt, fParentWeight);
1e66857c	430	KeepTrack(nt);
2067f62c	431	}
1e66857c	432	fNt = nt;
2067f62c	433	}
198bb1c7	434
dc1d768c	435	void AliGenHIJINGpara::Copy(TObject &) const
198bb1c7	436	{
	437	Fatal("Copy","Not implemented!\n");
	438	}
cc692c80	439
	440
	441	void AliGenHIJINGpara::Draw( const char * /opt/)
	442	{
	443	//
	444	// Draw the pT and y Distributions
	445	//
	446	TCanvas *c0 = new TCanvas("c0","Canvas 0",400,10,600,700);
	447	c0->Divide(2,1);
	448	c0->cd(1);
	449	fPtpi->Draw();
	450	fPtpi->GetHistogram()->SetXTitle("p_{T} (GeV)");
	451	c0->cd(2);
	452	fPtka->Draw();
	453	fPtka->GetHistogram()->SetXTitle("p_{T} (GeV)");
	454
	455	}