#include <NNBarOscPrimaryVtxGenerator.h>

Inheritance diagram for genie::NNBarOscPrimaryVtxGenerator:

Collaboration diagram for genie::NNBarOscPrimaryVtxGenerator:

Public Member Functions
	NNBarOscPrimaryVtxGenerator ()

	NNBarOscPrimaryVtxGenerator (string config)

	~NNBarOscPrimaryVtxGenerator ()

void	ProcessEventRecord (GHepRecord *event) const

void	Configure (const Registry &config)

void	Configure (string config)

Public Member Functions inherited from genie::EventRecordVisitorI
virtual	~EventRecordVisitorI ()

Public Member Functions inherited from genie::Algorithm
virtual	~Algorithm ()

virtual void	FindConfig (void)

virtual const Registry &	GetConfig (void) const

Registry *	GetOwnedConfig (void)

virtual const AlgId &	Id (void) const
	Get algorithm ID. More...

virtual AlgStatus_t	GetStatus (void) const
	Get algorithm status. More...

virtual bool	AllowReconfig (void) const

virtual AlgCmp_t	Compare (const Algorithm *alg) const
	Compare with input algorithm. More...

virtual void	SetId (const AlgId &id)
	Set algorithm ID. More...

virtual void	SetId (string name, string config)

const Algorithm *	SubAlg (const RgKey &registry_key) const

void	AdoptConfig (void)

void	AdoptSubstructure (void)

virtual void	Print (ostream &stream) const
	Print algorithm info. More...

Private Member Functions
void	LoadConfig (void)

void	AddInitialState (GHepRecord *event) const

void	GenerateOscillatingNeutronPosition (GHepRecord *event) const

void	GenerateFermiMomentum (GHepRecord *event) const

void	GenerateDecayProducts (GHepRecord *event) const

Private Attributes
int	fCurrInitStatePdg

NNBarOscMode_t	fCurrDecayMode

bool	fNucleonIsBound

TGenPhaseSpace	fPhaseSpaceGenerator

const NuclearModelI *	fNuclModel

Additional Inherited Members
Static Public Member Functions inherited from genie::Algorithm
static string	BuildParamVectKey (const std::string &comm_name, unsigned int i)

static string	BuildParamVectSizeKey (const std::string &comm_name)

static string	BuildParamMatKey (const std::string &comm_name, unsigned int i, unsigned int j)

static string	BuildParamMatRowSizeKey (const std::string &comm_name)

static string	BuildParamMatColSizeKey (const std::string &comm_name)

Protected Member Functions inherited from genie::EventRecordVisitorI
	EventRecordVisitorI ()

	EventRecordVisitorI (string name)

	EventRecordVisitorI (string name, string config)

Protected Member Functions inherited from genie::Algorithm
	Algorithm ()

	Algorithm (string name)

	Algorithm (string name, string config)

void	Initialize (void)

void	DeleteConfig (void)

void	DeleteSubstructure (void)

Registry *	ExtractLocalConfig (const Registry &in) const

Registry *	ExtractLowerConfig (const Registry &in, const string &alg_key) const
	Split an incoming configuration Registry into a block valid for the sub-algo identified by alg_key. More...

template<class T >
bool	GetParam (const RgKey &name, T &p, bool is_top_call=true) const

template<class T >
bool	GetParamDef (const RgKey &name, T &p, const T &def) const

template<class T >
int	GetParamVect (const std::string &comm_name, std::vector< T > &v, bool is_top_call=true) const
	Handle to load vectors of parameters. More...

int	GetParamVectKeys (const std::string &comm_name, std::vector< RgKey > &k, bool is_top_call=true) const

template<class T >
int	GetParamMat (const std::string &comm_name, TMatrixT< T > &mat, bool is_top_call=true) const
	Handle to load matrix of parameters. More...

template<class T >
int	GetParamMatSym (const std::string &comm_name, TMatrixTSym< T > &mat, bool is_top_call=true) const

int	GetParamMatKeys (const std::string &comm_name, std::vector< RgKey > &k, bool is_top_call=true) const

int	AddTopRegistry (Registry *rp, bool owns=true)
	add registry with top priority, also update ownership More...

int	AddLowRegistry (Registry *rp, bool owns=true)
	add registry with lowest priority, also update ownership More...

int	MergeTopRegistry (const Registry &r)

int	AddTopRegisties (const vector< Registry * > &rs, bool owns=false)
	Add registries with top priority, also udated Ownerships. More...

Protected Attributes inherited from genie::Algorithm
bool	fAllowReconfig

bool	fOwnsSubstruc
	true if it owns its substructure (sub-algs,...) More...

AlgId	fID
	algorithm name and configuration set More...

vector< Registry * >	fConfVect

vector< bool >	fOwnerships
	ownership for every registry in fConfVect More...

AlgStatus_t	fStatus
	algorithm execution status More...

AlgMap *	fOwnedSubAlgMp
	local pool for owned sub-algs (taken out of the factory pool) More...

Detailed Description

Definition at line 35 of file NNBarOscPrimaryVtxGenerator.h.

Constructor & Destructor Documentation

NNBarOscPrimaryVtxGenerator::NNBarOscPrimaryVtxGenerator ( )

Definition at line 35 of file NNBarOscPrimaryVtxGenerator.cxx.

                                                          :
 EventRecordVisitorI("genie::NNBarOscPrimaryVtxGenerator")
 {
 
 }

NNBarOscPrimaryVtxGenerator::NNBarOscPrimaryVtxGenerator ( string config )

Definition at line 41 of file NNBarOscPrimaryVtxGenerator.cxx.

                  :
 EventRecordVisitorI("genie::NNBarOscPrimaryVtxGenerator",config)
 {
 
 }

NNBarOscPrimaryVtxGenerator::~NNBarOscPrimaryVtxGenerator ( )

Definition at line 48 of file NNBarOscPrimaryVtxGenerator.cxx.

 {
 
 }

Member Function Documentation

void NNBarOscPrimaryVtxGenerator::AddInitialState ( GHepRecord * event ) const

private

Definition at line 76 of file NNBarOscPrimaryVtxGenerator.cxx.

References genie::units::A, genie::utils::nnbar_osc::AnnihilatingNucleonPdgCode(), fCurrDecayMode, fCurrInitStatePdg, genie::PDGLibrary::Find(), genie::PDGLibrary::Instance(), genie::pdg::IonPdgCode(), genie::pdg::IonPdgCodeToA(), genie::pdg::IonPdgCodeToZ(), genie::kIStDecayedState, genie::kIStInitialState, genie::kIStStableFinalState, genie::kPdgNeutron, and genie::kPdgProton.

Referenced by ProcessEventRecord().

 {
 
 // add initial state to event record
 
 // event record looks like this:
 //    id: 0, nucleus (kIStInitialState)
 //    |
 //    |---> { id: 1, neutron         (kIStDecayedState)
 //          { id: 2, nucleon         (kIStDecayedState)
 //          { id: 3, remnant nucleus (kIStStableFinalState)
 //
 
   TLorentzVector v4(0,0,0,0);
 
   GHepStatus_t stis = kIStInitialState;
   GHepStatus_t stdc = kIStDecayedState;
   GHepStatus_t stfs = kIStStableFinalState;
 
   int ipdg = fCurrInitStatePdg;
 
   // add initial nucleus
   double Mi  = PDGLibrary::Instance()->Find(ipdg)->Mass();
   TLorentzVector p4i(0,0,0,Mi);
   event->AddParticle(ipdg,stis,-1,-1,-1,-1, p4i, v4);
 
   // add oscillating neutron
   int neutpdg = kPdgNeutron;
   double mneut = PDGLibrary::Instance()->Find(neutpdg)->Mass();
   TLorentzVector p4neut(0,0,0,mneut);
   event->AddParticle(neutpdg,stdc,0,-1,-1,-1, p4neut, v4);
 
   // add annihilation nucleon
   int dpdg = genie::utils::nnbar_osc::AnnihilatingNucleonPdgCode(fCurrDecayMode);
   double mn = PDGLibrary::Instance()->Find(dpdg)->Mass();
   TLorentzVector p4n(0,0,0,mn);
   event->AddParticle(dpdg,stdc, 0,-1,-1,-1, p4n, v4);
 
   // add nuclear remnant
   int A = pdg::IonPdgCodeToA(ipdg);
   int Z = pdg::IonPdgCodeToZ(ipdg);
   A--; A--;
   if(dpdg == kPdgProton) { Z--; }
   int rpdg = pdg::IonPdgCode(A, Z);
   double Mf  = PDGLibrary::Instance()->Find(rpdg)->Mass();
   TLorentzVector p4f(0,0,0,Mf);
   event->AddParticle(rpdg,stfs,0,-1,-1,-1, p4f, v4);
 }

void NNBarOscPrimaryVtxGenerator::Configure ( const Registry & config )

virtual

Configure the algorithm with an external registry The registry is merged with the top level registry if it is owned, Otherwise a copy of it is added with the highest priority

Reimplemented from genie::Algorithm.

Definition at line 502 of file NNBarOscPrimaryVtxGenerator.cxx.

References genie::Algorithm::Configure(), and LoadConfig().

 {
   Algorithm::Configure(config);
   this->LoadConfig();
 }

void NNBarOscPrimaryVtxGenerator::Configure ( string config )

virtual

Configure the algorithm from the AlgoConfigPool based on param_set string given in input An algorithm contains a vector of registries coming from different xml configuration files, which are loaded according a very precise prioriy This methods will load a number registries in order of priority: 1) "Tunable" parameter set from CommonParametes. This is loaded with the highest prioriry and it is designed to be used for tuning procedure Usage not expected from the user. 2) For every string defined in "CommonParame" the corresponding parameter set will be loaded from CommonParameter.xml 3) parameter set specified by the config string and defined in the xml file of the algorithm 4) if config is not "Default" also the Default parameter set from the same xml file will be loaded Effectively this avoids the repetion of a parameter when it is not changed in the requested configuration

Reimplemented from genie::Algorithm.

Definition at line 508 of file NNBarOscPrimaryVtxGenerator.cxx.

References genie::Algorithm::Configure(), and LoadConfig().

 {
   Algorithm::Configure(config);
   this->LoadConfig();
 }

void NNBarOscPrimaryVtxGenerator::GenerateDecayProducts ( GHepRecord * event ) const

private

accept_decay

Definition at line 267 of file NNBarOscPrimaryVtxGenerator.cxx.

References genie::XclsTag::DecayMode(), genie::utils::nnbar_osc::DecayProductList(), genie::utils::nnbar_osc::DecayProductStatus(), genie::Interaction::ExclTag(), fCurrDecayMode, fCurrInitStatePdg, genie::PDGLibrary::Find(), fNucleonIsBound, fPhaseSpaceGenerator, genie::GHepParticle::GetP4(), genie::GHepParticle::GetX4(), genie::RandomGen::Instance(), genie::PDGLibrary::Instance(), genie::controls::kMaxUnweightDecayIterations, genie::kPdgNeutron, LOG, genie::units::m, genie::Interaction::NOsc(), genie::utils::print::P4AsString(), genie::GHepParticle::Pdg(), pERROR, pINFO, pNOTICE, pWARN, genie::RandomGen::RndHadro(), genie::RandomGen::RndNum(), genie::Target::SetHitNucPdg(), genie::exceptions::EVGThreadException::SetReason(), genie::RandomGen::SetSeed(), and genie::exceptions::EVGThreadException::SwitchOnFastForward().

Referenced by ProcessEventRecord().

 {
   LOG("NNBarOsc", pINFO) << "Generating decay...";
 
   PDGCodeList pdgv = genie::utils::nnbar_osc::DecayProductList(fCurrDecayMode);
   LOG("NNBarOsc", pINFO) << "Decay product IDs: " << pdgv;
   assert ( pdgv.size() >  1);
 
   LOG("NNBarOsc", pINFO) << "Performing a phase space decay...";
 
   // Get the decay product masses
 
   vector<int>::const_iterator pdg_iter;
   int idx = 0;
   double * mass = new double[pdgv.size()];
   double   sum  = 0;
   for(pdg_iter = pdgv.begin(); pdg_iter != pdgv.end(); ++pdg_iter) {
     int pdgc = *pdg_iter;
     double m = PDGLibrary::Instance()->Find(pdgc)->Mass();
     mass[idx++] = m;
     sum += m;
   }
 
   LOG("NNBarOsc", pINFO)
     << "Decaying N = " << pdgv.size() << " particles / total mass = " << sum;
   int initial_nucleus_id      = 0;
   int oscillating_neutron_id  = 1;
   int annihilation_nucleon_id = 2;
 
   // get our annihilating nucleons
   GHepParticle * initial_nucleus      = event->Particle(initial_nucleus_id);
   assert(initial_nucleus);
   GHepParticle * oscillating_neutron  = event->Particle(oscillating_neutron_id);
   assert(oscillating_neutron);
   GHepParticle * annihilation_nucleon = event->Particle(annihilation_nucleon_id);
   assert(annihilation_nucleon);
 
   Target tgt(initial_nucleus->Pdg());
   tgt.SetHitNucPdg(kPdgNeutron);
 
   // get their momentum 4-vectors and boost into rest frame
   TLorentzVector * p4_1 = oscillating_neutron->GetP4();
   TLorentzVector * p4_2 = annihilation_nucleon->GetP4();
   TLorentzVector * p4d = new TLorentzVector(*p4_1 + *p4_2);
   TVector3 boost = p4d->BoostVector();
   p4d->Boost(-boost);
 
   // get decay position
   TLorentzVector * v4d = annihilation_nucleon->GetX4();
 
   delete p4_1;
   delete p4_2;
 
   LOG("NNBarOsc", pINFO)
     << "Decaying system p4 = " << utils::print::P4AsString(p4d);
 
   // Set the decay
   bool permitted = fPhaseSpaceGenerator.SetDecay(*p4d, pdgv.size(), mass);
 
   // If the decay is not energetically allowed, select a new final state
   while(!permitted) {
 
     LOG("NNBarOsc", pINFO)
       << "Not enough energy to generate decay products! Selecting a new final state.";
 
     int mode = 0;
 
     int initial_nucleus_pdg = initial_nucleus->Pdg();
 
     std::string nucleus_pdg = std::to_string(static_cast<long long>(initial_nucleus_pdg));
     if (nucleus_pdg.size() != 10) {
       LOG("NNBarOsc", pERROR)
         << "Expecting the nuclear PDG code to be a 10-digit integer, but it is " << nucleus_pdg << ", which is "
         << nucleus_pdg.size() << " digits long. Drop me an email at jezhewes@gmail.com ; exiting...";
       exit(1);
     }
 
     int n_nucleons = std::stoi(nucleus_pdg.substr(6,3)) - 1;
     int n_protons  = std::stoi(nucleus_pdg.substr(3,3));
     double proton_frac  = ((double)n_protons) / ((double) n_nucleons);
     double neutron_frac = 1 - proton_frac;
 
     // set branching ratios, taken from bubble chamber data
     const int n_modes = 16;
     double br [n_modes] = { 0.010, 0.080, 0.100, 0.220,
                             0.360, 0.160, 0.070, 0.020,
                             0.015, 0.065, 0.110, 0.280,
                             0.070, 0.240, 0.100, 0.100 };
 
     for (int i = 0; i < n_modes; i++) {
       // for first 7 branching ratios, multiply by relative proton density
       if (i < 7)
         br[i] *= proton_frac;
       // for next 9, multiply by relative neutron density
       else
         br[i] *= neutron_frac;
     }
 
     // randomly generate a number between 1 and 0
     RandomGen * rnd = RandomGen::Instance();
     rnd->SetSeed(0);
     double p = rnd->RndNum().Rndm();
 
     // loop through all modes, figure out which one our random number corresponds to
     double threshold = 0;
     for (int j = 0; j < n_modes; j++) {
       threshold += br[j];
       if (p < threshold) {
         // once we've found our mode, stop looping
         mode = j + 1;
         break;
       }
     }
 
     // create new event record with new final state
     // TODO - I don't think Jeremy meant to make a _new_ record here; it
     // shadows the one passed in...
     // EventRecord * event = new EventRecord;
     Interaction * interaction = Interaction::NOsc((int)fCurrInitStatePdg, mode);
     event->AttachSummary(interaction);
 
     fCurrDecayMode = (NNBarOscMode_t) interaction->ExclTag().DecayMode();
 
     pdgv = genie::utils::nnbar_osc::DecayProductList(fCurrDecayMode);
     LOG("NNBarOsc", pINFO) << "Decay product IDs: " << pdgv;
     assert ( pdgv.size() > 1);
 
     // get the decay particles again
     LOG("NNBarOsc", pINFO) << "Performing a phase space decay...";
     idx = 0;
     delete [] mass;
     mass = new double[pdgv.size()];
     sum = 0;
     for(pdg_iter = pdgv.begin(); pdg_iter != pdgv.end(); ++pdg_iter) {
       int pdgc = *pdg_iter;
       double m = PDGLibrary::Instance()->Find(pdgc)->Mass();
       mass[idx++] = m;
       sum += m;
     }
 
     LOG("NNBarOsc", pINFO)
       << "Decaying N = " << pdgv.size() << " particles / total mass = " << sum;
     LOG("NNBarOsc", pINFO)
       << "Decaying system p4 = " << utils::print::P4AsString(p4d);
 
     permitted = fPhaseSpaceGenerator.SetDecay(*p4d, pdgv.size(), mass);
   }
 
   if(!permitted) {
      LOG("NNBarOsc", pERROR)
        << " *** Phase space decay is not permitted \n"
        << " Total particle mass = " << sum << "\n"
        << " Decaying system p4 = " << utils::print::P4AsString(p4d);
      // clean-up
      delete [] mass;
      delete p4d;
      delete v4d;
      // throw exception
      genie::exceptions::EVGThreadException exception;
      exception.SetReason("Decay not permitted kinematically");
      exception.SwitchOnFastForward();
      throw exception;
   }
 
   // Get the maximum weight
   //double wmax = fPhaseSpaceGenerator.GetWtMax();
   double wmax = -1;
   for(int i=0; i<200; i++) {
      double w = fPhaseSpaceGenerator.Generate();
      wmax = TMath::Max(wmax,w);
   }
   assert(wmax>0);
   wmax *= 2;
 
   LOG("NNBarOsc", pNOTICE)
      << "Max phase space gen. weight @ current hadronic system: " << wmax;
 
   // Generate an unweighted decay
   RandomGen * rnd = RandomGen::Instance();
 
   bool accept_decay=false;
   unsigned int itry=0;
   while(!accept_decay)
   {
      itry++;
 
      if(itry > controls::kMaxUnweightDecayIterations) {
        // report, clean-up and return
        LOG("NNBarOsc", pWARN)
            << "Couldn't generate an unweighted phase space decay after "
            << itry << " attempts";
        // clean up
        delete [] mass;
        delete p4d;
        delete v4d;
        // throw exception
        genie::exceptions::EVGThreadException exception;
        exception.SetReason("Couldn't select decay after N attempts");
        exception.SwitchOnFastForward();
        throw exception;
      }
      double w  = fPhaseSpaceGenerator.Generate();
      if(w > wmax) {
         LOG("NNBarOsc", pWARN)
            << "Decay weight = " << w << " > max decay weight = " << wmax;
      }
      double gw = wmax * rnd->RndHadro().Rndm();
      accept_decay = (gw<=w);
 
      LOG("NNBarOsc", pINFO)
         << "Decay weight = " << w << " / R = " << gw
         << " - accepted: " << accept_decay;
 
   } //!accept_decay
 
   // Insert final state products into a TClonesArray of GHepParticle's
   TLorentzVector v4(*v4d);
   int idp = 0;
   for(pdg_iter = pdgv.begin(); pdg_iter != pdgv.end(); ++pdg_iter) {
      int pdgc = *pdg_iter;
      TLorentzVector * p4fin = fPhaseSpaceGenerator.GetDecay(idp);
      GHepStatus_t ist =
         utils::nnbar_osc::DecayProductStatus(fNucleonIsBound, pdgc);
      p4fin->Boost(boost);
      event->AddParticle(pdgc, ist, oscillating_neutron_id,-1,-1,-1, *p4fin, v4);
      idp++;
   }
 
   // Clean-up
   delete [] mass;
   delete p4d;
   delete v4d;
 }

void NNBarOscPrimaryVtxGenerator::GenerateFermiMomentum ( GHepRecord * event ) const

private

Definition at line 201 of file NNBarOscPrimaryVtxGenerator.cxx.

References genie::units::A, genie::GHepParticle::A(), fNuclModel, genie::NuclearModelI::GenerateNucleon(), genie::GHepParticle::GetP4(), genie::kPdgNeutron, LOG, genie::GHepParticle::Mass(), genie::NuclearModelI::Momentum3(), genie::GHepParticle::Pdg(), pINFO, genie::NuclearModelI::RemovalEnergy(), genie::Target::SetHitNucPdg(), and genie::GHepParticle::SetMomentum().

Referenced by ProcessEventRecord().

 {
   GHepParticle * initial_nucleus = event->Particle(0);
   int A = initial_nucleus->A();
   if(A <= 2) {
     return;
   }
 
   GHepParticle * oscillating_neutron = event->Particle(1);
   GHepParticle * annihilation_nucleon = event->Particle(2);
   GHepParticle * remnant_nucleus = event->Particle(3);
   assert(oscillating_neutron);
   assert(annihilation_nucleon);
   assert(remnant_nucleus);
 
   // generate a Fermi momentum & removal energy
   Target tgt(initial_nucleus->Pdg());
 
   // start with oscillating neutron
   tgt.SetHitNucPdg(kPdgNeutron);
   // generate nuclear model & fermi momentum
   fNuclModel->GenerateNucleon(tgt);
   TVector3 p3 = fNuclModel->Momentum3();
   double w = fNuclModel->RemovalEnergy();
 
   // use mass & momentum to calculate energy
   double mass = oscillating_neutron->Mass();
   double energy = sqrt(pow(mass,2) + p3.Mag2()) - w;
   // give new energy & momentum to particle
   TLorentzVector p4(p3, energy);
   oscillating_neutron->SetMomentum(p4);
 
   LOG("NNBarOsc", pINFO)
      << "Generated neutron momentum: ("
      << p3.Px() << ", " << p3.Py() << ", " << p3.Pz() << "), "
      << "|p| = " << p3.Mag();
 
   // then rinse repeat for the annihilation nucleon
   tgt.SetHitNucPdg(annihilation_nucleon->Pdg());
   // use nuclear model to generate fermi momentum
   fNuclModel->GenerateNucleon(tgt);
   p3 = fNuclModel->Momentum3();
   w = fNuclModel->RemovalEnergy();
   // use mass & momentum to figure out energy
   mass = annihilation_nucleon->Mass();
   energy = sqrt(pow(mass,2) + p3.Mag2()) - w;
   // give new energy & momentum to particle
   p4 = TLorentzVector(p3, energy);
   annihilation_nucleon->SetMomentum(p4);
 
   LOG("NNBarOsc", pINFO)
      << "Generated nucleon momentum: ("
      << p3.Px() << ", " << p3.Py() << ", " << p3.Pz() << "), "
      << "|p| = " << p3.Mag();
 
   // now figure out momentum for the nuclear remnant
   p3 = -1 * (oscillating_neutron->GetP4()->Vect() + annihilation_nucleon->GetP4()->Vect());
   // figure out energy from mass & momentum
   mass = remnant_nucleus->Mass();
   energy = sqrt(pow(mass,2) + p3.Mag2());
   // give new energy & momentum to remnant
   p4 = TLorentzVector(p3, energy);
   remnant_nucleus->SetMomentum(p4);
 }

void NNBarOscPrimaryVtxGenerator::GenerateOscillatingNeutronPosition ( GHepRecord * event ) const

private

Definition at line 125 of file NNBarOscPrimaryVtxGenerator.cxx.

References genie::units::A, genie::GHepParticle::A(), genie::utils::nuclear::Density(), genie::RandomGen::Instance(), genie::constants::kPi, genie::controls::kRjMaxIterations, LOG, pERROR, pINFO, pWARN, genie::RandomGen::RndFsi(), genie::GHepParticle::SetPosition(), genie::exceptions::EVGThreadException::SetReason(), and genie::exceptions::EVGThreadException::SwitchOnFastForward().

Referenced by ProcessEventRecord().

 {
   GHepParticle * initial_nucleus = event->Particle(0);
   int A = initial_nucleus->A();
   if(A <= 2) {
     return;
   }
 
   RandomGen * rnd = RandomGen::Instance();
 
   double R0 = 1.3;
   double dA = (double)A;
   double R = R0 * TMath::Power(dA, 1./3.);
 
   LOG("NNBarOsc", pINFO)
       << "Generating vertex according to a realistic nuclear density profile";
 
   // get inputs to the rejection method
   double ymax = -1;
   double rmax = 3*R;
   double dr   = R/40.;
   for(double r = 0; r < rmax; r+=dr) {
       ymax = TMath::Max(ymax, r*r * utils::nuclear::Density(r,A));
   }
   ymax *= 1.2;
 
   // select a vertex using the rejection method
   TLorentzVector vtx(0,0,0,0);
   unsigned int iter = 0;
   while(1) {
     iter++;
 
     // throw an exception if it hasn't find a solution after many attempts
     if(iter > controls::kRjMaxIterations) {
        LOG("NNBarOsc", pWARN)
            << "Couldn't generate a vertex position after " << iter << " iterations";
        genie::exceptions::EVGThreadException exception;
        exception.SetReason("Couldn't generate vertex");
        exception.SwitchOnFastForward();
        throw exception;
     }
 
     double r = rmax * rnd->RndFsi().Rndm();
     double t = ymax * rnd->RndFsi().Rndm();
     double y = r*r * utils::nuclear::Density(r,A);
     if(y > ymax) {
        LOG("NNBarOsc", pERROR)
           << "y = " << y << " > ymax = " << ymax << " for r = " << r << ", A = " << A;
     }
     bool accept = (t < y);
     if(accept) {
        double phi      = 2*constants::kPi * rnd->RndFsi().Rndm();
        double cosphi   = TMath::Cos(phi);
        double sinphi   = TMath::Sin(phi);
        double costheta = -1 + 2 * rnd->RndFsi().Rndm();
        double sintheta = TMath::Sqrt(1-costheta*costheta);
        vtx.SetX(r*sintheta*cosphi);
        vtx.SetY(r*sintheta*sinphi);
        vtx.SetZ(r*costheta);
        vtx.SetT(0.);
        break;
     }
   } // while 1
 
   // giving position to oscillating neutron
   GHepParticle * oscillating_neutron = event->Particle(1);
   assert(oscillating_neutron);
   oscillating_neutron->SetPosition(vtx);
 
   // give same position to annihilation nucleon
   GHepParticle * annihilation_nucleon = event->Particle(2);
   assert(annihilation_nucleon);
   annihilation_nucleon->SetPosition(vtx);
 }

void NNBarOscPrimaryVtxGenerator::LoadConfig ( void )

private

Definition at line 514 of file NNBarOscPrimaryVtxGenerator.cxx.

References fNuclModel, and genie::Algorithm::SubAlg().

Referenced by Configure().

 {
 //  AlgConfigPool * confp = AlgConfigPool::Instance();
 //  const Registry * gc = confp->GlobalParameterList();
 
   fNuclModel = 0;
 
   RgKey nuclkey = "NuclearModel";
   fNuclModel = dynamic_cast<const NuclearModelI *> (this->SubAlg(nuclkey));
   assert(fNuclModel);
 }

void NNBarOscPrimaryVtxGenerator::ProcessEventRecord ( GHepRecord * event ) const

virtual

Implements genie::EventRecordVisitorI.

Definition at line 53 of file NNBarOscPrimaryVtxGenerator.cxx.

References AddInitialState(), genie::utils::nnbar_osc::AsString(), genie::XclsTag::DecayMode(), genie::Interaction::ExclTag(), fCurrDecayMode, fCurrInitStatePdg, fNucleonIsBound, GenerateDecayProducts(), GenerateFermiMomentum(), GenerateOscillatingNeutronPosition(), genie::Interaction::InitState(), genie::pdg::IonPdgCodeToA(), LOG, genie::Target::Pdg(), pNOTICE, and genie::InitialState::Tgt().

 {
   // spit out some output
   Interaction * interaction = event->Summary();
   fCurrInitStatePdg = interaction->InitState().Tgt().Pdg();
   fCurrDecayMode = (NNBarOscMode_t) interaction->ExclTag().DecayMode();
 
   // spit out that info -j
   LOG("NNBarOsc", pNOTICE)
     << "Simulating decay " << genie::utils::nnbar_osc::AsString(fCurrDecayMode)
     << " for an initial state with code: " << fCurrInitStatePdg;
 
   // check if nucleon is bound
   fNucleonIsBound = (pdg::IonPdgCodeToA(fCurrInitStatePdg) > 1);
   // can take this out for nnbar, nucleon is always bound!
 
   // now call these four functions!
   this->AddInitialState(event);
   this->GenerateOscillatingNeutronPosition(event);
   this->GenerateFermiMomentum(event);
   this->GenerateDecayProducts(event);
 }