+/**************************************************************************
+ * 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
+/*
+<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 "AliGenHIJINGpara.h"
+#include "AliRun.h"
+#include "AliConst.h"
+#include "AliPDG.h"
+
+ClassImp(AliGenHIJINGpara)
+
+AliGenHIJINGpara::AliGenHIJINGpara(const AliGenHIJINGpara & para)
+{
+// copy constructor
+}
+
+//_____________________________________________________________________________
+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;
+}
+
+//_____________________________________________________________________________
+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 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, 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;i<fNpart;i++) {
+ while(1) {
+ gMC->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==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(fTrackIt,-1,part,p,origin,polar,0,"Primary",nt,fParentWeight);
+ break;
+ }
+ }
+}
+
+AliGenHIJINGpara& AliGenHIJINGpara::operator=(const AliGenHIJINGpara& rhs)
+{
+// Assignment operator
+ return *this;
+}
+
+
git://git.uio.no / u / mrichter / AliRoot.git / commitdiff