#include <TDatabasePDG.h>
#include <TPDGCode.h>
#include <TH2F.h>
+#include <TH1F.h>
+#include <TF1.h>
#include <TCanvas.h>
#include "AliCollisionGeometry.h"
#include "AliGenSlowNucleons.h"
#include "AliSlowNucleonModel.h"
- ClassImp(AliGenSlowNucleons)
+ClassImp(AliGenSlowNucleons)
+
- AliGenSlowNucleons::AliGenSlowNucleons():AliGenerator(-1)
+AliGenSlowNucleons::AliGenSlowNucleons()
+ :AliGenerator(-1),
+ fCMS(0.),
+ fMomentum(0.),
+ fBeta(0.),
+ fPmax (0.),
+ fATarget (0.),
+ fZTarget (0.),
+ fCharge(0),
+ fProtonDirection(0.),
+ fTemperatureG(0.),
+ fBetaSourceG(0.),
+ fTemperatureB(0.),
+ fBetaSourceB(0.),
+ fNgp(0),
+ fNgn(0),
+ fNbp(0),
+ fNbn(0),
+ fDebug(0),
+ fDebugHist1(0),
+ fDebugHist2(0),
+ fThetaDistribution(),
+ fCosThetaGrayHist(),
+ fCosTheta(),
+ fSlowNucleonModel(0)
{
// Default constructor
- fSlowNucleonModel = 0;
fCollisionGeometry = 0;
}
AliGenSlowNucleons::AliGenSlowNucleons(Int_t npart)
- :AliGenerator(npart)
+ :AliGenerator(npart),
+ fCMS(14000.),
+ fMomentum(0.),
+ fBeta(0.),
+ fPmax (10.),
+ fATarget (208.),
+ fZTarget (82.),
+ fCharge(1),
+ fProtonDirection(0.),
+ fTemperatureG(0.04),
+ fBetaSourceG(0.05),
+ fTemperatureB(0.004),
+ fBetaSourceB(0.),
+ fNgp(0),
+ fNgn(0),
+ fNbp(0),
+ fNbn(0),
+ fDebug(0),
+ fDebugHist1(0),
+ fDebugHist2(0),
+ fThetaDistribution(),
+ fCosThetaGrayHist(),
+ fCosTheta(),
+ fSlowNucleonModel(new AliSlowNucleonModel())
{
// Constructor
fName = "SlowNucleons";
fTitle = "Generator for gray particles in pA collisions";
- SetPmax();
- SetTarget();
- SetNominalCmsEnergy();
- SetCharge();
- SetTemperature();
- SetBetaSource();
- fSlowNucleonModel = new AliSlowNucleonModel();
fCollisionGeometry = 0;
- fDebug = 0;
-}
-
-AliGenSlowNucleons::AliGenSlowNucleons(const AliGenSlowNucleons & sn):
- AliGenerator(sn)
-{
-// Copy constructor
- sn.Copy(*this);
}
//____________________________________________________________
delete fSlowNucleonModel;
}
+void AliGenSlowNucleons::SetProtonDirection(Float_t dir) {
+// Set direction of the proton to change between pA (1) and Ap (-1)
+ fProtonDirection = dir / TMath::Abs(dir);
+}
void AliGenSlowNucleons::Init()
{
if (fDebug) {
fDebugHist1 = new TH2F("DebugHist1", "nu vs N_slow", 100, 0., 100., 20, 0., 20.);
fDebugHist2 = new TH2F("DebugHist2", "b vs N_slow", 100, 0., 100., 15, 0., 15.);
+ fCosThetaGrayHist = new TH1F("fCosThetaGrayHist", "Gray particles angle", 100, -1., 1.);
+ }
+ //
+ // non-uniform cos(theta) distribution
+ //
+ if(fThetaDistribution != 0) {
+ fCosTheta = new TF1("fCosTheta",
+ "(2./3.14159265358979312)/(exp(2./3.14159265358979312)-exp(-2./3.14159265358979312))*exp(2.*x/3.14159265358979312)",
+ -1., 1.);
}
}
fDebugHist1->Draw();
c->cd(2);
fDebugHist2->Draw();
+ c->cd(3);
+ fCosThetaGrayHist->Draw();
}
}
}
//
- Float_t p[3];
+ Float_t p[3], theta=0;
Float_t origin[3] = {0., 0., 0.};
Float_t polar [3] = {0., 0., 0.};
Int_t nt, i, j;
fCharge = 1;
kf = kProton;
for(i = 0; i < fNgp; i++) {
- GenerateSlow(fCharge, fTemperatureG, fBetaSourceG, p);
+ GenerateSlow(fCharge, fTemperatureG, fBetaSourceG, p, theta);
+ if (fDebug) fCosThetaGrayHist->Fill(TMath::Cos(theta));
PushTrack(fTrackIt, -1, kf, p, origin, polar,
0., kPNoProcess, nt, 1.);
KeepTrack(nt);
fCharge = 0;
kf = kNeutron;
for(i = 0; i < fNgn; i++) {
- GenerateSlow(fCharge, fTemperatureG, fBetaSourceG, p);
+ GenerateSlow(fCharge, fTemperatureG, fBetaSourceG, p, theta);
+ if (fDebug) fCosThetaGrayHist->Fill(TMath::Cos(theta));
PushTrack(fTrackIt, -1, kf, p, origin, polar,
0., kPNoProcess, nt, 1.);
KeepTrack(nt);
fCharge = 1;
kf = kProton;
for(i = 0; i < fNbp; i++) {
- GenerateSlow(fCharge, fTemperatureB, fBetaSourceB, p);
+ GenerateSlow(fCharge, fTemperatureB, fBetaSourceB, p, theta);
PushTrack(fTrackIt, -1, kf, p, origin, polar,
0., kPNoProcess, nt, 1.);
KeepTrack(nt);
fCharge = 0;
kf = kNeutron;
for(i = 0; i < fNbn; i++) {
- GenerateSlow(fCharge, fTemperatureB, fBetaSourceB, p);
+ GenerateSlow(fCharge, fTemperatureB, fBetaSourceB, p, theta);
PushTrack(fTrackIt, -1, kf, p, origin, polar,
0., kPNoProcess, nt, 1.);
KeepTrack(nt);
-void AliGenSlowNucleons::GenerateSlow(Int_t charge, Double_t T, Double_t beta, Float_t* q)
+void AliGenSlowNucleons::GenerateSlow(Int_t charge, Double_t T,
+ Double_t beta, Float_t* q, Float_t &theta)
{
/*
Three-momentum [GeV/c] is given back in q[3]
*/
- Double_t m, pmax, p, f, theta, phi;
+ Double_t m, pmax, p, f, phi;
TDatabasePDG * pdg = TDatabasePDG::Instance();
const Double_t kMassProton = pdg->GetParticle(kProton) ->Mass();
const Double_t kMassNeutron = pdg->GetParticle(kNeutron)->Mass();
}
while(f < Rndm());
- /* Spherical symmetric emission */
- theta = TMath::ACos(2. * Rndm() - 1.);
+ /* Spherical symmetric emission for black particles (beta=0)*/
+ if(beta==0 || fThetaDistribution==0) theta = TMath::ACos(2. * Rndm() - 1.);
+ /* cos theta distributed according to experimental results for gray particles (beta=0.05)*/
+ else if(fThetaDistribution!=0){
+ Double_t costheta = fCosTheta->GetRandom();
+ theta = TMath::ACos(costheta);
+ }
+ //
phi = 2. * TMath::Pi() * Rndm();
/* Determine momentum components in system of the moving source */
/* Transform to laboratory system */
Lorentz(m, fBeta, q);
+ q[2] *= fProtonDirection;
}
Double_t AliGenSlowNucleons::Maxwell(Double_t m, Double_t p, Double_t T)
{
/* Lorentz transform in the direction of q[2] */
- Double_t gamma = 1/sqrt(1-beta*beta);
+ Double_t gamma = 1/sqrt((1.-beta)*(1.+beta));
Double_t energy = sqrt(m*m + q[0]*q[0] + q[1]*q[1] + q[2]*q[2]);
q[2] = gamma * (q[2] + beta*energy);
}
-
-
-AliGenSlowNucleons& AliGenSlowNucleons::operator=(const AliGenSlowNucleons& rhs)
-{
-// Assignment operator
- rhs.Copy(*this);
- return *this;
-}
-
-void AliGenSlowNucleons::Copy(TObject&) const
-{
- //
- // Copy
- //
- Fatal("Copy","Not implemented!\n");
-}
-
-
-
-
-
-
-
git://git.uio.no / u / mrichter / AliRoot.git / blobdiff