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* Author: The ALICE Off-line Project. *
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/*
$Log$
Revision 1.8 2001/07/20 11:03:58 morsch
Issue warning message if used outside allowed eta range (-8 to 8).
Revision 1.7 2001/07/17 12:41:01 morsch
- Calculation of fraction of event corresponding to selected pt-range corrected
(R. Turrisi)
- Parent weight corrected.
Revision 1.6 2001/05/16 14:57:10 alibrary
New files for folders and Stack
Revision 1.5 2000/12/21 16:24:06 morsch
Coding convention clean-up
Revision 1.4 2000/11/30 07:12:50 alibrary
Introducing new Rndm and QA classes
Revision 1.3 2000/10/02 21:28:06 fca
Removal of useless dependecies via forward declarations
Revision 1.2 2000/07/11 18:24:55 fca
Coding convention corrections + few minor bug fixes
Revision 1.1 2000/06/09 20:20:30 morsch
Same class as previously in AliSimpleGen.cxx
All coding rule violations except RS3 corrected (AM)
*/
// 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
/*
The responsible person for this module is
Andreas Morsch.
*/ //End_Html // // /////////////////////////////////////////////////////////////////// #include "AliGenHIJINGpara.h" #include "TF1.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); TF1 *ptPic0 = new TF1("ptpi",&ptpi,0.,15.,0); TF1 *ptKac0 = new TF1("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); } } //_____________________________________________________________________________ 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==kPerEvent) { 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;iGetRandom())); if(theta fThetaMax) continue; pt=ptf->GetRandom(); pl=pt/TMath::Tan(theta); ptot=TMath::Sqrt(pt*pt+pl*pl); if(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; } } } AliGenHIJINGpara& AliGenHIJINGpara::operator=(const AliGenHIJINGpara& rhs) { // Assignment operator return *this; }