Inheritance diagram for BeamDivergenceVtxGenerator:

Public Member Functions
	BeamDivergenceVtxGenerator (const edm::ParameterSet &)

void	produce (edm::Event &, const edm::EventSetup &) override

	~BeamDivergenceVtxGenerator () override=default

Public Member Functions inherited from edm::stream::EDProducer<>
	EDProducer ()=default

bool	hasAbilityToProduceInLumis () const final

bool	hasAbilityToProduceInRuns () const final

Static Public Member Functions
static void	fillDescriptions (edm::ConfigurationDescriptions &)

Private Attributes
bool	simulateBeamDivergence_

bool	simulateVertex_

edm::EDGetTokenT< edm::HepMCProduct >	sourceToken_

Additional Inherited Members
Public Types inherited from edm::stream::EDProducer<>
typedef CacheContexts< T... >	CacheTypes

typedef CacheTypes::GlobalCache	GlobalCache

typedef AbilityChecker< T... >	HasAbility

typedef CacheTypes::LuminosityBlockCache	LuminosityBlockCache

typedef LuminosityBlockContextT< LuminosityBlockCache, RunCache, GlobalCache >	LuminosityBlockContext

typedef CacheTypes::LuminosityBlockSummaryCache	LuminosityBlockSummaryCache

typedef CacheTypes::RunCache	RunCache

typedef RunContextT< RunCache, GlobalCache >	RunContext

typedef CacheTypes::RunSummaryCache	RunSummaryCache

Detailed Description

Definition at line 26 of file BeamDivergenceVtxGenerator.cc.

Constructor & Destructor Documentation

BeamDivergenceVtxGenerator::BeamDivergenceVtxGenerator ( const edm::ParameterSet & iConfig )

explicit

Definition at line 45 of file BeamDivergenceVtxGenerator.cc.

References edm::Service< T >::isAvailable().

                                                                                      :
   sourceToken_(consumes<edm::HepMCProduct>( iConfig.getParameter<edm::InputTag>("src"))),
   simulateVertex_        (iConfig.getParameter<bool>("simulateVertex")),
   simulateBeamDivergence_(iConfig.getParameter<bool>("simulateBeamDivergence"))
 {
   edm::Service<edm::RandomNumberGenerator> rng;
   if (!rng.isAvailable())
     throw cms::Exception("Configuration")
       << "The BeamDivergenceVtxGenerator requires the RandomNumberGeneratorService\n"
          "which is not present in the configuration file. \n"
          "You must add the service\n"
          "in the configuration file or remove the modules that require it.";
 
   produces<edm::HepMCProduct>();
 }

BeamDivergenceVtxGenerator::~BeamDivergenceVtxGenerator ( )

overridedefault

Member Function Documentation

void BeamDivergenceVtxGenerator::fillDescriptions ( edm::ConfigurationDescriptions & descriptions )

static

Definition at line 135 of file BeamDivergenceVtxGenerator.cc.

References edm::ConfigurationDescriptions::add(), edm::ParameterSetDescription::add(), and DEFINE_FWK_MODULE.

 {
   edm::ParameterSetDescription desc;
   desc.add<edm::InputTag>("src", edm::InputTag("generator", "unsmeared"))
     ->setComment("input collection where to retrieve outgoing particles kinematics to be smeared");
   desc.add<bool>("simulateBeamDivergence", true)->setComment("account for the beam angular divergence?");
   desc.add<bool>("simulateVertex", true)->setComment("account for the vertex transverse smearing?");
 
   descriptions.add("beamDivergenceVtxGenerator", desc);
 }

void BeamDivergenceVtxGenerator::produce	(	edm::Event &	iEvent,
		const edm::EventSetup &	iSetup
	)

override

Definition at line 64 of file BeamDivergenceVtxGenerator.cc.

 {
   // get random engine
   edm::Service<edm::RandomNumberGenerator> rng;
   CLHEP::HepRandomEngine* rnd = &(rng->getEngine(iEvent.streamID()));
 
   // get conditions
   edm::ESHandle<CTPPSBeamParameters> hBeamParameters;
   iSetup.get<CTPPSBeamParametersRcd>().get(hBeamParameters);
 
   // get input
   edm::Handle<edm::HepMCProduct> hepUnsmearedMCEvt;
   iEvent.getByToken(sourceToken_, hepUnsmearedMCEvt);
 
   // prepare output
   HepMC::GenEvent* genevt = new HepMC::GenEvent(*hepUnsmearedMCEvt->GetEvent());
   std::unique_ptr<edm::HepMCProduct> pEvent(new edm::HepMCProduct(genevt));
 
   // apply vertex smearing
   if (simulateVertex_) {
     // NB: the separtion between effective offsets in LHC sectors 45 and 56 cannot be applied, thus the values for 45 are used
     const double vtx_x = hBeamParameters->getVtxOffsetX45() + CLHEP::RandGauss::shoot(rnd) * hBeamParameters->getVtxStddevX();
     const double vtx_y = hBeamParameters->getVtxOffsetY45() + CLHEP::RandGauss::shoot(rnd) * hBeamParameters->getVtxStddevY();
     const double vtx_z = hBeamParameters->getVtxOffsetZ45() + CLHEP::RandGauss::shoot(rnd) * hBeamParameters->getVtxStddevZ();
 
     HepMC::FourVector shift(vtx_x*1E1, vtx_y*1E1, vtx_z*1E1, 0.);  // conversions: cm to mm
     pEvent->applyVtxGen(&shift);
   }
 
   // apply beam divergence
   if (simulateBeamDivergence_) {
     const double bd_x_45 = CLHEP::RandGauss::shoot(rnd) * hBeamParameters->getBeamDivergenceX45();
     const double bd_x_56 = CLHEP::RandGauss::shoot(rnd) * hBeamParameters->getBeamDivergenceX56();
 
     const double bd_y_45 = CLHEP::RandGauss::shoot(rnd) * hBeamParameters->getBeamDivergenceY45();
     const double bd_y_56 = CLHEP::RandGauss::shoot(rnd) * hBeamParameters->getBeamDivergenceY56();
 
     for (HepMC::GenEvent::particle_iterator part = genevt->particles_begin(); part != genevt->particles_end(); ++part) {
       const HepMC::FourVector mom = (*part)->momentum();
 
       // TODO: this is an oversimplified implemetation
       // the TOTEM smearing module should be taken as reference
 
       double th_x = mom.x() / mom.z();
       double th_y = mom.y() / mom.z();
 
       if (mom.z() > 0.)
       {
         th_x += bd_x_45;
         th_y += bd_y_45;
       } else {
         th_x += bd_x_56;
         th_y += bd_y_56;
       }
 
       // calculate consistent p_z component
       const double sign = (mom.z() > 0.) ? 1. : -1.;
       const double p_z = sign * mom.rho() / sqrt(1. + th_x*th_x + th_y*th_y);
 
       // set smeared momentum
       (*part)->set_momentum(HepMC::FourVector(p_z * th_x, p_z * th_y, p_z, mom.e()));
     }
   }
 
   // save output
   iEvent.put(std::move(pEvent));
 }