/************************************************************************** * 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\$ */ /////////////////////////////////////////////////////////////////// // // // Generate the final state of the interaction as the input // // to the MonteCarlo // // //Begin_Html /*

The responsible person for this module is Andreas Morsch.

```*/
//End_Html
//                                                               //
///////////////////////////////////////////////////////////////////

#include "AliSimpleGen.h"
#include "AliRun.h"
#include "AliConst.h"

ClassImp(AliGenHIJINGpara)

//_____________________________________________________________________________
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 p0 = 1.3;
const Double_t xn = 8.28;
const Double_t xlim=0.5;
const Double_t t=0.160;
const Double_t xmpi=0.139;
const Double_t b=1.;
Double_t y, y1, xmpi2, ynorm, a;
Double_t x=*px;
//
y1=TMath::Power(p0/(p0+xlim),xn);
xmpi2=xmpi*xmpi;
ynorm=b*(TMath::Exp(-sqrt(xlim*xlim+xmpi2)/t));
a=ynorm/y1;
if (x > xlim)
y=a*TMath::Power(p0/(p0+x),xn);
else
y=b*TMath::Exp(-sqrt(x*x+xmpi2)/t);
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 hm[10] = {.13957,.493,.5488,.769,.7826,.958,1.02,0,0,0};
//     VALUE MESON/PI AT 5 GEV
const Double_t fmax[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.+hm[np]*hm[np])+2.0)),12.3);
Double_t fmax2=f5/fmax[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+hm[np]*hm[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 a1    = 4913.;
const Double_t a2    = 1819.;
const Double_t eta1  = 0.22;
const Double_t eta2  = 3.66;
const Double_t deta1 = 1.47;
const Double_t deta2 = 1.51;
Double_t y=TMath::Abs(*py);
//
Double_t ex1 = (y-eta1)*(y-eta1)/(2*deta1*deta1);
Double_t ex2 = (y-eta2)*(y-eta2)/(2*deta2*deta2);
return a1*TMath::Exp(-ex1)+a2*TMath::Exp(-ex2);
}

//_____________________________________________________________________________
static Double_t etakac( Double_t *py, Double_t *)
{
//
// eta parametrisation for ka
//
const Double_t a1    = 497.6;
const Double_t a2    = 215.6;
const Double_t eta1  = 0.79;
const Double_t eta2  = 4.09;
const Double_t deta1 = 1.54;
const Double_t deta2 = 1.40;
Double_t y=TMath::Abs(*py);
//
Double_t ex1 = (y-eta1)*(y-eta1)/(2*deta1*deta1);
Double_t ex2 = (y-eta2)*(y-eta2)/(2*deta2*deta2);
return a1*TMath::Exp(-ex1)+a2*TMath::Exp(-ex2);
}

//_____________________________________________________________________________
AliGenHIJINGpara::AliGenHIJINGpara()
:AliGenerator()
{
//
// Default constructor
//
fPtpi = 0;
fPtka = 0;
fETApic = 0;
fETAkac = 0;
}

//_____________________________________________________________________________
AliGenHIJINGpara::AliGenHIJINGpara(Int_t npart)
:AliGenerator(npart)
{
//
// Standard constructor
//
fName="HIGINGpara";
fTitle="HIJING Parametrisation Particle Generator";
fPtpi = 0;
fPtka = 0;
fETApic = 0;
fETAkac = 0;
}

//_____________________________________________________________________________
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 = new TF1("etapic",&etapic,-7,7,0);
TF1 *ETAkac0 = new TF1("etakac",&etakac,-7,7,0);
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);

Float_t IntPt  = (0.877*ETApic0->Integral(0, 15)+
0.123*ETAkac0->Integral(0, 15));
Float_t IntPtSel = (0.877*ETApic0->Integral(fPtMin, fPtMax)+
0.123*ETAkac0->Integral(fPtMin, fPtMax));
Float_t PtFrac = IntPtSel/IntPt;

Float_t IntETASel  = (scalePi*ETApic0->Integral(etaMin, etaMax)+
scaleKa*ETAkac0->Integral(etaMin, etaMax));
Float_t PhiFrac = (fPhiMax-fPhiMin)/2/TMath::Pi();
fParentWeight = Float_t(fNpart)/IntETASel*PtFrac*PhiFrac;

printf("\n The number of particles in the selected kinematic region corresponds to %f percent of a full event\n ", 100.*fParentWeight);

}

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

const Float_t raKpic=0.14;
const Float_t borne=1/(1+raKpic);
Float_t polar[3]= {0,0,0};
//
const Int_t pions[3] = {kPi0, kPiPlus, kPiMinus};
const Int_t kaons[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, nt, j;
//
TF1 *ptf;
TF1 *etaf;
//
Float_t random[6];
//
for (j=0;j<3;j++) origin[j]=fOrigin[j];
if(fVertexSmear==perEvent) {
gMC->Rndm(random,6);
for (j=0;j<3;j++) {
origin[j]+=fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
}
}
for(i=0;iRndm(random,3);
if(random[0]fPhiMax) continue;
theta=2*TMath::ATan(TMath::Exp(-etaf->GetRandom()));
if(thetafThetaMax) continue;
pt=ptf->GetRandom();
pl=pt/TMath::Tan(theta);
ptot=TMath::Sqrt(pt*pt+pl*pl);
if(ptotfPMax) continue;
p[0]=pt*TMath::Cos(phi);
p[1]=pt*TMath::Sin(phi);
p[2]=pl;
if(fVertexSmear==perTrack) {
gMC->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]));
}
}
gAlice->SetTrack(1,-1,part,p,origin,polar,0,"Primary",nt,fParentWeight);
break;
}
}
}

ClassImp(AliGenFixed)

//_____________________________________________________________________________
AliGenFixed::AliGenFixed()
:AliGenerator()
{
//
// Default constructor
//
fIpart = 0;
}

//_____________________________________________________________________________
AliGenFixed::AliGenFixed(Int_t npart)
:AliGenerator(npart)
{
//
// Standard constructor
//
fName="Fixed";
fTitle="Fixed Particle Generator";
// Generate Proton by default
fIpart=kProton;
}

//_____________________________________________________________________________
void AliGenFixed::Generate()
{
//
// Generate one trigger
//
Float_t polar[3]= {0,0,0};
Float_t p[3] = {fPMin*TMath::Cos(fPhiMin)*TMath::Sin(fThetaMin),
fPMin*TMath::Sin(fPhiMin)*TMath::Sin(fThetaMin),
fPMin*TMath::Cos(fThetaMin)};
Int_t i, nt;
//
for(i=0;iSetTrack(1,-1,fIpart,p,fOrigin.GetArray(),polar,0,"Primary",nt);
}
}

//_____________________________________________________________________________
void AliGenFixed::SetSigma(Float_t, Float_t, Float_t)
{
//
// Set the interaction point sigma
//
printf("Vertex smearing not implemented for fixed generator\n");
}

ClassImp(AliGenBox)

//_____________________________________________________________________________
AliGenBox::AliGenBox()
:AliGenerator()
{
//
// Default constructor
//
fIpart=0;
}

//_____________________________________________________________________________
AliGenBox::AliGenBox(Int_t npart)
:AliGenerator(npart)
{
//
// Standard constructor
//
fName="Box";
fTitle="Box particle generator";
// Generate Proton by default
fIpart=kProton;
}

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

Float_t polar[3]= {0,0,0};
//
Float_t origin[3];
Float_t p[3];
Int_t i, j, nt;
Float_t pmom, theta, phi;
//
Float_t random[6];
//
for (j=0;j<3;j++) origin[j]=fOrigin[j];
if(fVertexSmear==perEvent) {
gMC->Rndm(random,6);
for (j=0;j<3;j++) {
origin[j]+=fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
}
}
for(i=0;iRndm(random,3);
pmom=fPMin+random[0]*(fPMax-fPMin);
theta=fThetaMin+random[1]*(fThetaMax-fThetaMin);
phi=fPhiMin+random[2]*(fPhiMax-fPhiMin);
p[0] = pmom*TMath::Cos(phi)*TMath::Sin(theta);
p[1] = pmom*TMath::Sin(phi)*TMath::Sin(theta);
p[2] = pmom*TMath::Cos(theta);
if(fVertexSmear==perTrack) {
gMC->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]));
}
}
gAlice->SetTrack(1,-1,fIpart,p,origin,polar,0,"Primary",nt);
}
}

```