HIJING parameterisation including baryons, first commit.

diff --git a/EVGEN/AliGenHIJINGparaBa.cxx b/EVGEN/AliGenHIJINGparaBa.cxx
new file mode 100644 (file)
index 0000000..18e115c
--- /dev/null
+++ b/EVGEN/AliGenHIJINGparaBa.cxx
@@ -0,0 +1,349 @@
+/**************************************************************************
+ * 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.                  *
+ **************************************************************************/
+
+/*
+$Log$
+*/
+///////////////////////////////////////////////////////////////////
+// Parameterisation of pi, K, n and p eta and pt distributions   //
+// eta: according to HIJING (shadowing + quenching)              //
+// pT : according to CDF measurement at 1.8 TeV                  //
+// Author: andreas.morsch@cern.ch                                //
+//                                                               //
+///////////////////////////////////////////////////////////////////
+
+#include "AliGenHIJINGparaBa.h"
+#include "AliGenEventHeader.h"
+#include "AliRun.h"
+#include "AliConst.h"
+#include "AliPDG.h"
+
+#include <TF1.h>
+#include <TArrayF.h>
+
+ClassImp(AliGenHIJINGparaBa)
+
+
+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);
+}
+
+ static Double_t ptbaryon( Double_t *px, Double_t *)
+{
+// baryons
+//                pt-distribution
+//____________________________________________________________
+
+  return ptscal(*px,7);  //  7==> Baryon in the PtScal function
+}
+
+ static Double_t etabaryon( Double_t *py, Double_t *)
+{
+// eta-distribution
+//____________________________________________________________
+    const Float_t p0 =  1.10343e+02;
+    const Float_t p1 =  1.73247e+01;
+    const Float_t p2 = -7.23808e+00;
+    const Float_t p3 =  4.48334e-01;
+    const Double_t y = TMath::Abs(*py);
+//
+    return (p0+p1*y+p2*y*y+p3*y*y*y)/20.;
+}
+
+AliGenHIJINGparaBa::AliGenHIJINGparaBa()
+  :AliGenHIJINGpara()
+{
+    //
+    // Default constructor
+    //
+    fName="HIGINGparaBa";
+    fTitle="HIJING Parametrisation Particle Generator with Baryons";
+    fETAba = 0;
+    fPtba  = 0;
+}
+
+//_____________________________________________________________________________
+AliGenHIJINGparaBa::AliGenHIJINGparaBa(Int_t npart)
+  :AliGenHIJINGpara(npart)
+{
+  // 
+  // Standard constructor
+  //
+    fName="HIGINGparaBa";
+    fTitle="HIJING Parametrisation Particle Generator with Baryons";
+    fETAba = 0;
+    fPtba  = 0;
+}
+
+//_____________________________________________________________________________
+AliGenHIJINGparaBa::~AliGenHIJINGparaBa()
+{
+  //
+  // Standard destructor
+  //
+    delete fPtba;
+    delete fETAba;
+}
+
+//_____________________________________________________________________________
+void AliGenHIJINGparaBa::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);
+    fPtba   = new TF1("ptbaryon",&ptbaryon,0,20,0);
+    fETApic = new TF1("etapic",&etapic,etaMin,etaMax,0);
+    fETAkac = new TF1("etakac",&etakac,etaMin,etaMax,0);
+    fETAba  = new TF1("etabaryon",&etabaryon,etaMin,etaMax,0);
+
+    TF1 *etaPic0 = new TF1("etapic",&etapic,    -7, 7, 0);
+    TF1 *etaKac0 = new TF1("etakac",&etakac,    -7, 7, 0);
+    TF1 *etaBar0 = new TF1("etabar",&etabaryon, -7, 7, 0);
+    
+    TF1 *ptPic0  = new TF1("ptpi",  &ptpi,     0., 15., 0);
+    TF1 *ptKac0  = new TF1("ptka",  &ptka,     0., 15., 0);
+    TF1 *ptBar0  = new TF1("ptbar", &ptbaryon, 0., 15., 0);
+
+    Float_t intETApi  = etaPic0->Integral(-0.5, 0.5);
+    Float_t intETAka  = etaKac0->Integral(-0.5, 0.5);
+    Float_t intETAba  = etaBar0->Integral(-0.5, 0.5);
+
+    Float_t scalePi   = 6979./(intETApi/1.5);
+    Float_t scaleKa   =  657./(intETAka/2.0);
+    Float_t scaleBa   =  364./(intETAba/2.0);
+
+//  Fraction of events corresponding to the selected pt-range    
+    Float_t intPt    = (0.837*ptPic0->Integral(0, 15)+
+                       0.105*ptKac0->Integral(0, 15)+
+                        0.058*ptBar0->Integral(0, 15));
+    Float_t intPtSel = (0.837*ptPic0->Integral(fPtMin, fPtMax)+
+                       0.105*ptKac0->Integral(fPtMin, fPtMax)+
+                       0.058*ptBar0->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)+
+                         scaleBa*etaBar0->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 AliGenHIJINGParaBa !");
+       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);
+    }
+}
+
+//_____________________________________________________________________________
+void AliGenHIJINGparaBa::Generate()
+{
+  //
+  // Generate one trigger
+  //
+
+  
+    const Float_t kBorne1 = 0.837;
+    const Float_t kBorne2 = kBorne1+0.105;
+    
+    Float_t polar[3]= {0,0,0};
+    //
+    const Int_t kPions[3]   = {kPi0, kPiPlus, kPiMinus};
+    const Int_t kKaons[4]   = {kK0Long, kK0Short, kKPlus, kKMinus};
+    const Int_t kBaryons[4] = {kProton, kProtonBar, kNeutron, kNeutronBar};
+    //
+    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 == kPerEvent) {
+       Float_t dv[3];
+       dv[2] = 1.e10;
+       while(TMath::Abs(dv[2]) > fCutVertexZ*fOsigma[2]) {
+           Rndm(random,6);
+           for (j=0; j < 3; j++) {
+               dv[j] = fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
+                   TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
+           }
+       }
+       for (j=0; j < 3; j++) origin[j] += dv[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] < kBorne1) {
+               part  = kPions[Int_t (random[1]*3)];
+               ptf   = fPtpi;
+               etaf  = fETApic;
+           } else if (random[0] < kBorne2) {
+               part  = kKaons[Int_t (random[1]*4)];
+               ptf   = fPtka;
+               etaf  = fETAkac;
+           } else {
+               part  = kBaryons[Int_t (random[1]*4)];
+               ptf   = fPtba;
+               etaf  = fETAba;
+           }
+           
+           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]));
+               }
+           }
+           SetTrack(fTrackIt,-1,part,p,origin,polar,0,kPPrimary,nt,fParentWeight);
+           break;
+       } // while(1)
+    } // Particle loop
+// Header
+    AliGenEventHeader* header = new AliGenEventHeader("HIJINGparam");
+// Event Vertex
+    header->SetPrimaryVertex(eventVertex);
+    gAlice->SetGenEventHeader(header); 
+}
+
+
+

diff --git a/EVGEN/AliGenHIJINGparaBa.h b/EVGEN/AliGenHIJINGparaBa.h
new file mode 100644 (file)
index 0000000..267ff68
--- /dev/null
+++ b/EVGEN/AliGenHIJINGparaBa.h
@@ -0,0 +1,38 @@
+#ifndef ALIGENHIJINGPARABA_H
+#define ALIGENHIJINGPARABA_H
+/* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
+ * See cxx source for full Copyright notice                               */
+
+/* $Id$ */
+
+// Parameterisation of pi, K, n and p eta and pt distributions
+// Author: andreas.morsch@cern.ch
+
+#include "AliGenHIJINGpara.h"
+class TF1;
+
+class AliGenHIJINGparaBa : public AliGenHIJINGpara
+{
+ public:
+    AliGenHIJINGparaBa();
+    AliGenHIJINGparaBa(Int_t npart);
+    virtual ~AliGenHIJINGparaBa();
+    virtual void Generate();
+    virtual void Init();
+ protected:
+    TF1* fPtba;          //! Parametrised pt distribution for baryons
+    TF1* fETAba;         //! Parametrised eta distribution for baryons
+
+    ClassDef(AliGenHIJINGparaBa,1) // Hijing parametrisation generator with baryons
+};
+#endif
+
+
+
+
+
+
+
+
+
+