Computes the cross section for an exclusive 1pi reaction through resonance neutrinoproduction according to the Rein-Sehgal model. More...

#include <ReinSehgalSPPXSec.h>

Inheritance diagram for genie::ReinSehgalSPPXSec:

Public Member Functions
	ReinSehgalSPPXSec ()

	ReinSehgalSPPXSec (string param_set)

virtual	~ReinSehgalSPPXSec ()

double	Integrate (const XSecAlgorithmI model, const Interaction i) const

void	Configure (const Registry &config)

void	Configure (string config)

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

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)

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)

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

	ReinSehgalRESXSecWithCache (string name)

	ReinSehgalRESXSecWithCache (string name, string config)

virtual	~ReinSehgalRESXSecWithCache ()

void	CacheResExcitationXSec (const Interaction *interaction) const

string	CacheBranchName (Resonance_t r, InteractionType_t it, int nu, int nuc) const

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

	XSecIntegratorI (string name)

	XSecIntegratorI (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

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::ReinSehgalRESXSecWithCache
bool	fUsingDisResJoin

double	fWcut

double	fEMax

const XSecAlgorithmI *	fSingleResXSecModel

BaryonResList	fResList

Protected Attributes inherited from genie::XSecIntegratorI
const IntegratorI *	fIntegrator
	GENIE numerical integrator. More...

string	fGSLIntgType
	name of GSL numerical integrator More...

double	fGSLRelTol
	required relative tolerance (error) More...

int	fGSLMaxEval
	GSL max evaluations. More...

int	fGSLMinEval
	GSL min evaluations. Ignored by some integrators. More...

unsigned int	fGSLMaxSizeOfSubintervals
	GSL maximum number of sub-intervals for 1D integrator. More...

unsigned int	fGSLRule
	GSL Gauss-Kronrod integration rule (only for GSL 1D adaptive type) 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

Computes the cross section for an exclusive 1pi reaction through resonance neutrinoproduction according to the Rein-Sehgal model.

This algorithm produces in principle what you could also get from the genie::RESXSec algorithm (RES cross section integrator) by specifying the genie::ReinSehgalSPPPXSec as the differential cross section model. However, ReinSehgalSPPXSec offers a faster alternative. Before computing any SPP cross section this algorithm computes and caches splines for resonance neutrino-production cross sections. This improves the speed since it is reducing the number of calculations (the generic algorithm needs to recompute resonance production xsec for every exclusive channel).

In this algorithm we follow the non-coherent approach: we sum the weighted resonance production cross sections rather than the resonance production amplitudes.

Is a concrete implementation of the XSecAlgorithmI interface.
D.Rein and L.M.Sehgal, Neutrino Excitation of Baryon Resonances and Single Pion Production, Ann.Phys.133, 79 (1981)

Author: Costas Andreopoulos <constantinos.andreopoulos cern.ch> University of Liverpool & STFC Rutherford Appleton Laboratory

March 09, 2006

Definition at line 45 of file ReinSehgalSPPXSec.h.

Constructor & Destructor Documentation

ReinSehgalSPPXSec::ReinSehgalSPPXSec ( )

Definition at line 29 of file ReinSehgalSPPXSec.cxx.

                                      :
 ReinSehgalRESXSecWithCache("genie::ReinSehgalSPPXSec")
 {
 
 }

ReinSehgalSPPXSec::ReinSehgalSPPXSec ( string param_set )

Definition at line 35 of file ReinSehgalSPPXSec.cxx.

                                                   :
 ReinSehgalRESXSecWithCache("genie::ReinSehgalSPPXSec", config)
 {
 
 }

ReinSehgalSPPXSec::~ReinSehgalSPPXSec ( )

virtual

Definition at line 41 of file ReinSehgalSPPXSec.cxx.

 {
 
 }

Member Function Documentation

void ReinSehgalSPPXSec::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 152 of file ReinSehgalSPPXSec.cxx.

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

void ReinSehgalSPPXSec::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 158 of file ReinSehgalSPPXSec.cxx.

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

double ReinSehgalSPPXSec::Integrate	(	const XSecAlgorithmI *	model,
		const Interaction *	i
	)		const

virtual

Implements genie::XSecIntegratorI.

Definition at line 46 of file ReinSehgalSPPXSec.cxx.

 {
   if(! model->ValidProcess(interaction) ) return 0.;
 
   const KPhaseSpace & kps = interaction->PhaseSpace();
   if(!kps.IsAboveThreshold()) {
      LOG("COHXSec", pDEBUG)  << "*** Below energy threshold";
      return 0;
   }
 
   fSingleResXSecModel = model;
 
   //-- Get 1pi exclusive channel
   SppChannel_t spp_channel = SppChannel::FromInteraction(interaction);
 
   //-- Get cache
   Cache * cache = Cache::Instance();
 
   const InitialState & init_state = interaction->InitState();
   const ProcessInfo &  proc_info  = interaction->ProcInfo();
   const Target &       target     = init_state.Tgt();
 
   InteractionType_t it = proc_info.InteractionTypeId();
   int nucleon_pdgc = target.HitNucPdg();
   int nu_pdgc      = init_state.ProbePdg();
 
   // Get neutrino energy in the struck nucleon rest frame
   double Ev = init_state.ProbeE(kRfHitNucRest);
 
   double xsec = 0;
 
   unsigned int nres = fResList.NResonances();
   for(unsigned int ires = 0; ires < nres; ires++) {
 
      //-- Get next resonance from the resonance list
      Resonance_t res = fResList.ResonanceId(ires);
 
      //-- Build a unique name for the cache branch
      string key = this->CacheBranchName(res, it, nu_pdgc, nucleon_pdgc);
      LOG("ReinSehgalSpp", pINFO)
                             << "Finding cache branch with key: " << key;
      CacheBranchFx * cache_branch =
             dynamic_cast<CacheBranchFx *> (cache->FindCacheBranch(key));
 
      if(!cache_branch) {
        LOG("ReinSehgalSpp", pWARN)
          << "No cached RES v-production data for input neutrino"
          << " (pdgc: " << nu_pdgc << ")";
        LOG("ReinSehgalSpp", pWARN)
          << "Wait while computing/caching RES production xsec first...";
 
        this->CacheResExcitationXSec(interaction);
 
        LOG("ReinSehgalSpp", pINFO) << "Done caching resonance xsec data";
        LOG("ReinSehgalSpp", pINFO)
                << "Finding newly created cache branch with key: " << key;
        cache_branch =
               dynamic_cast<CacheBranchFx *> (cache->FindCacheBranch(key));
        assert(cache_branch);
      }
      const CacheBranchFx & cbranch = (*cache_branch);
 
      //-- Get cached resonance neutrinoproduction xsec
      //   (If E>Emax, assume xsec = xsec(Emax) - but do not evaluate the
      //    cross section spline at the end of its energy range-)
      double rxsec = (Ev<fEMax-1) ? cbranch(Ev) : cbranch(fEMax-1);
 
      //-- Get the BR for the (resonance) -> (exclusive final state)
      double br = SppChannel::BranchingRatio(spp_channel, res);
 
      //-- Get the Isospin Clebsch-Gordon coefficient for the given resonance
      //   and exclusive final state
      double igg = SppChannel::IsospinWeight(spp_channel, res);
 
      //-- Compute the weighted xsec
      //  (total weight = Breit-Wigner * BR * isospin Clebsch-Gordon)
      double res_xsec_contrib = rxsec*br*igg;
 
      SLOG("ReinSehgalSpp", pINFO)
        << "Contrib. from [" << utils::res::AsString(res) << "] = "
        << "<Clebsch-Gordon = " << igg
        << "> * <BR(->1pi) = " << br
        << "> * <Breit-Wigner * d^2xsec/dQ^2dW = " << rxsec
        << "> = " << res_xsec_contrib;
 
      //-- Add contribution of this resonance to the cross section
      xsec += res_xsec_contrib;
 
   }//res
 
   SLOG("ReinSehgalSpp", pNOTICE)
          << "XSec[SPP/" << SppChannel::AsString(spp_channel)
                                << "/free] (Ev = " << Ev << " GeV) = " << xsec;
 
   //-- If requested return the free nucleon xsec even for input nuclear tgt
   if( interaction->TestBit(kIAssumeFreeNucleon) ) return xsec;
 
   //-- number of scattering centers in the target
   int NNucl = (pdg::IsProton(nucleon_pdgc)) ? target.Z() : target.N();
 
   xsec*=NNucl; // nuclear xsec
 
   return xsec;
 }

void ReinSehgalSPPXSec::LoadConfig ( void )

private

Definition at line 164 of file ReinSehgalSPPXSec.cxx.

 {
   // Get GSL integration type & relative tolerance
   GetParamDef( "gsl-integration-type", fGSLIntgType, string("adaptive") ) ;
   GetParamDef( "gsl-relative-tolerance", fGSLRelTol, 0.01 ) ;
   GetParamDef( "gsl-max-eval", fGSLMaxEval, 100000 ) ;
 
   // get upper E limit on res xsec spline (=f(E)) before assuming xsec=const
   GetParamDef( "ESplineMax", fEMax, 100. ) ;
   fEMax = TMath::Max(fEMax, 20.); // don't accept user Emax if less than 20 GeV
 
   // create the baryon resonance list specified in the config.
   fResList.Clear();
   string resonances ;
   GetParam( "ResonanceNameList", resonances ) ;
   fResList.DecodeFromNameList(resonances);
 
 }

The documentation for this class was generated from the following files:

Generator/src/Physics/Resonance/XSection/ReinSehgalSPPXSec.h
Generator/src/Physics/Resonance/XSection/ReinSehgalSPPXSec.cxx

Public Member Functions

Private Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation