Rivet::Sphericity Class Reference

Calculate the sphericity event shape. More...

#include <Sphericity.hh>

Inheritance diagram for Rivet::Sphericity:

Public Member Functions
void	clear ()
	Reset the projection.
Vector3	mkEigenVector (Matrix3 A, const double &lambda)
virtual unique_ptr< Projection >	clone () const =0
	Clone on the heap.
virtual std::string	name () const
	Get the name of the projection.
bool	valid () const
	Get the state of the projetion.
bool	failed () const
	Get the state of the projetion.
void	markAsOwned () const
	Mark this object as owned by a proj-handler.
Constructors etc.
	Sphericity (double rparam=2.0)
	Constructor.
	Sphericity (const FinalState &fsp, double rparam=2.0)
	RIVET_DEFAULT_PROJ_CLONE (Sphericity)
	Clone on the heap.
Access the event shapes by name
Sphericity
double	sphericity () const
double	transSphericity () const
	Transverse sphericity.
double	planarity () const
	Planarity.
double	aplanarity () const
	Aplanarity.
Access the sphericity basis vectors
Sphericity axis
const Vector3 &	sphericityAxis () const
const Vector3 &	sphericityMajorAxis () const
	Sphericity major axis.
const Vector3 &	sphericityMinorAxis () const
	Sphericity minor axis.
AxesDefinition axis accessors
const Vector3 &	axis1 () const
const Vector3 &	axis2 () const
	The 2nd most significant ("major") axis.
const Vector3 &	axis3 () const
	The least significant ("minor") axis.
Access the momentum tensor eigenvalues
double	lambda1 () const
double	lambda2 () const
double	lambda3 () const
Direct methods
Ways to do the calculation directly, without engaging the caching system
void	calc (const FinalState &fs)
	Manually calculate the sphericity, without engaging the caching system.
void	calc (const Particles &particles)
	Manually calculate the sphericity, without engaging the caching system.
void	calc (const Jets &jets)
	Manually calculate the sphericity, without engaging the caching system.
void	calc (const vector< FourMomentum > &momenta)
	Manually calculate the sphericity, without engaging the caching system.
void	calc (const vector< Vector3 > &momenta)
	Manually calculate the sphericity, without engaging the caching system.
Projection operation and comparison
bool	before (const Projection &p) const
Projection "getting" functions
std::set< ConstProjectionPtr >	getProjections () const
	Get the contained projections, including recursion.
std::set< ConstProjectionPtr >	getImmediateChildProjections () const
	Get the contained projections, excluding recursion.
bool	hasProjection (const std::string &name) const
	Does this applier have a projection registered under the name name?
template<typename PROJ>
const PROJ &	getProjection (const std::string &name) const
const Projection &	getProjection (const std::string &name) const
template<typename PROJ>
const PROJ &	get (const std::string &name) const
template<typename PROJ>
const PROJ &	getProjectionFromDeclQueue (const std::string name) const
Projection applying functions
template<typename PROJ = Projection>
std::enable_if_t< std::is_base_of< Projection, PROJ >::value, const PROJ & >	apply (const Event &evt, const Projection &proj) const
	Apply the supplied projection on event evt.
template<typename PROJ = Projection>
std::enable_if_t< std::is_base_of< Projection, PROJ >::value, const PROJ & >	apply (const Event &evt, const PROJ &proj) const
	Apply the supplied projection on event evt (user-facing alias).
template<typename PROJ = Projection>
std::enable_if_t< std::is_base_of< Projection, PROJ >::value, const PROJ & >	apply (const Event &evt, const std::string &name) const
	Apply the supplied projection on event evt (user-facing alias).
template<typename PROJ = Projection>
std::enable_if_t< std::is_base_of< Projection, PROJ >::value, const PROJ & >	apply (const std::string &name, const Event &evt) const
	Apply the supplied projection on event evt (convenience arg-reordering alias).

Protected Member Functions
void	project (const Event &e)
	Perform the projection on the Event.
CmpState	compare (const Projection &p) const
	Compare with other projections.
Log &	getLog () const
	Get a Log object based on the getName() property of the calling projection object.
void	setName (const std::string &name)
	Used by derived classes to set their name.
void	fail ()
	Set the projection in an unvalid state.
Cmp< Projection >	mkNamedPCmp (const Projection &otherparent, const std::string &pname) const
Cmp< Projection >	mkPCmp (const Projection &otherparent, const std::string &pname) const
ProjectionHandler &	getProjHandler () const
	Get a reference to the ProjectionHandler for this thread.
void	setProjectionHandler (ProjectionHandler &projectionHandler) const
Projection registration functions
template<typename PROJ>
const PROJ &	declare (const PROJ &proj, const std::string &name) const
	Register a contained projection (user-facing version).
template<typename PROJ>
const PROJ &	declare (const std::string &name, const PROJ &proj) const
	Register a contained projection (user-facing, arg-reordered version).

Detailed Description

Calculate the sphericity event shape.

The sphericity tensor (or quadratic momentum tensor) is defined as

\[S^{\alpha \beta} = \frac{\sum_i p_i^\alpha p_i^\beta}{\sum_i |\mathbf{p}_i|^2} \]

, where the Greek indices are spatial components and the Latin indices are used for sums over particles. From this, the sphericity, aplanarity and planarity can be calculated by combinations of eigenvalues.

Defining the three eigenvalues \( \lambda_1 \ge \lambda_2 \ge \lambda_3 \), with \( \lambda_1 + \lambda_2 + \lambda_3 = 1 \), the sphericity is

\[S = \frac{3}{2} (\lambda_2 + \lambda_3) \]

The aplanarity is \( A = \frac{3}{2}\lambda_3 \) and the planarity is \( P = \frac{2}{3}(S-2A) = \lambda_2 - \lambda_3 \). The eigenvectors define a set of spatial axes comparable with the thrust axes, but more sensitive to high momentum particles due to the quadratic sensitivity of the tensor to the particle momenta.

Since the sphericity is quadratic in the particle momenta, it is not an infrared safe observable in perturbative QCD. This can be fixed by adding a regularizing power of \(r\) to the definition:

\[S^{\alpha \beta} = \frac{\sum_i |\mathbf{p}_i|^{r-2} p_i^\alpha p_i^\beta} {\sum_i |\mathbf{p}_i|^r} \]

\(r\) is available as a constructor argument on this class and will be taken into account by the Cmp<Projection> operation, so a single analysis can use several sphericity projections with different \(r\) values without fear of a clash.

Member Function Documentation

apply()

template<typename PROJ = Projection>

std::enable_if_t< std::is_base_of< Projection, PROJ >::value, const PROJ & > Rivet::ProjectionApplier::apply ( const Event & evt, const Projection & proj ) const

inlineinherited

Apply the supplied projection on event evt.

Apply the supplied projection on event evt (user-facing alias).

Referenced by Rivet::SimpleAnalysis::electrons(), Rivet::SimpleAnalysis::jets(), Rivet::SimpleAnalysis::metSignf(), Rivet::SimpleAnalysis::muons(), Rivet::SimpleAnalysis::photons(), Rivet::ALICE::V0AndTrigger::project(), Rivet::ATLAS::MinBiasTrigger::project(), Rivet::ATLAS::SumET_PB_Centrality::project(), Rivet::ATLAS::SumET_PBPB_Centrality::project(), Rivet::BeamThrust::project(), Rivet::BRAHMSCentrality::project(), Rivet::CentralityEstimator::project(), Rivet::CentralityProjection::project(), Rivet::EventMixingBase::project(), Rivet::GeneratedCentrality::project(), Rivet::GeneratedPercentileProjection::project(), Rivet::ImpactParameterProjection::project(), Rivet::LossyFinalState< FILTER >::project(), Rivet::MC_pPbMinBiasTrigger::project(), Rivet::MC_SumETFwdPbCentrality::project(), Rivet::PercentileProjection::project(), Rivet::SmearedJets::project(), Rivet::SmearedMET::project(), Rivet::SmearedParticles::project(), Rivet::Spherocity::project(), Rivet::STAR_BES_Centrality::project(), Rivet::Thrust::project(), Rivet::UserCentEstimate::project(), Rivet::SimpleAnalysis::set(), Rivet::SimpleAnalysis::taus(), Rivet::SimpleAnalysis::tracks(), Rivet::SimpleAnalysis::tracks(), and Rivet::SimpleAnalysis::vmet().

axis1()

const Vector3 & Rivet::Sphericity::axis1 ( ) const

inlinevirtual

Axis accessors, in decreasing order of significance. The main axis.

Implements Rivet::AxesDefinition.

axis2()

const Vector3 & Rivet::Sphericity::axis2 ( ) const

inlinevirtual

The 2nd most significant ("major") axis.

Implements Rivet::AxesDefinition.

References sphericityMajorAxis().

axis3()

const Vector3 & Rivet::Sphericity::axis3 ( ) const

inlinevirtual

The least significant ("minor") axis.

Implements Rivet::AxesDefinition.

References sphericityMinorAxis().

before()

bool Rivet::Projection::before ( const Projection & p ) const

inherited

Determine whether this object should be ordered before the object p given as argument. If p is of a different class than this, the before() function of the corresponding type_info objects is used. Otherwise, if the objects are of the same class, the virtual compare(const Projection &) will be returned.

References Projection(), and Rivet::Kin::p().

calc()

void Rivet::Sphericity::calc

(

const vector< Vector3 > &

momenta

)

Manually calculate the sphericity, without engaging the caching system.

This one actually does the calculation

clone()

virtual unique_ptr< Projection > Rivet::AxesDefinition::clone ( ) const

pure virtualinherited

Clone on the heap.

Implements Rivet::Projection.

compare()

CmpState Rivet::Sphericity::compare ( const Projection & p ) const

protectedvirtual

Compare with other projections.

Implements Rivet::Projection.

References Rivet::Kin::p().

declare() [1/2]

template<typename PROJ>

const PROJ & Rivet::ProjectionApplier::declare ( const PROJ & proj, const std::string & name ) const

inlineprotectedinherited

Register a contained projection (user-facing version).

Todo

Add SFINAE to require that PROJ inherit from Projection

Referenced by Rivet::CentralEtHCM::CentralEtHCM(), Rivet::CentralityEstimator::CentralityEstimator(), Rivet::ChargedLeptons::ChargedLeptons(), Rivet::ALICE::CLMultiplicity< true >::CLMultiplicity(), Rivet::DISDiffHadron::DISDiffHadron(), Rivet::DISFinalState::DISFinalState(), Rivet::DISKinematics::DISKinematics(), Rivet::DISLepton::DISLepton(), Rivet::EventMixingBase::EventMixingBase(), Rivet::GammaGammaKinematics::GammaGammaKinematics(), Rivet::GammaGammaLeptons::GammaGammaLeptons(), Rivet::GammaGammaLeptons::GammaGammaLeptons(), Rivet::GeneratedCentrality::GeneratedCentrality(), Rivet::HadronicFinalState::HadronicFinalState(), Rivet::HeavyHadrons::HeavyHadrons(), Rivet::Hemispheres::Hemispheres(), Rivet::InvisibleFinalState::InvisibleFinalState(), Rivet::LeadingParticlesFinalState::LeadingParticlesFinalState(), Rivet::LossyFinalState< FILTER >::LossyFinalState(), Rivet::LossyFinalState< FILTER >::LossyFinalState(), Rivet::MC_pPbMinBiasTrigger::MC_pPbMinBiasTrigger(), Rivet::MC_SumETFwdPbCentrality::MC_SumETFwdPbCentrality(), Rivet::ATLAS::MinBiasTrigger::MinBiasTrigger(), Rivet::MissingMomentum::MissingMomentum(), Rivet::NeutralFinalState::NeutralFinalState(), Rivet::NeutralFinalState::NeutralFinalState(), Rivet::NonHadronicFinalState::NonHadronicFinalState(), Rivet::ParisiTensor::ParisiTensor(), Rivet::PercentileProjection::PercentileProjection(), Rivet::PrimaryHadrons::PrimaryHadrons(), Rivet::PrimaryHadrons::PrimaryHadrons(), Rivet::SmearedMET::SmearedMET(), Rivet::SmearedMET::SmearedMET(), Rivet::SmearedMET::SmearedMET(), Rivet::Spherocity::Spherocity(), Rivet::ATLAS::SumET_PB_Centrality::SumET_PB_Centrality(), Rivet::ATLAS::SumET_PBPB_Centrality::SumET_PBPB_Centrality(), Rivet::TriggerCDFRun0Run1::TriggerCDFRun0Run1(), Rivet::TriggerCDFRun2::TriggerCDFRun2(), Rivet::UndressBeamLeptons::UndressBeamLeptons(), Rivet::ALICE::V0AndTrigger::V0AndTrigger(), Rivet::ALICE::V0Trigger<-1 >::V0Trigger(), Rivet::VetoedFinalState::VetoedFinalState(), Rivet::VisibleFinalState::VisibleFinalState(), Rivet::VisibleFinalState::VisibleFinalState(), Rivet::CentralityProjection::add(), Rivet::SimpleAnalysis::postInit(), Rivet::CentralityBinner< T, MDist >::setProjection(), and Rivet::VetoedFinalState::vetoFinalState().

declare() [2/2]

template<typename PROJ>

const PROJ & Rivet::ProjectionApplier::declare ( const std::string & name, const PROJ & proj ) const

inlineprotectedinherited

Register a contained projection (user-facing, arg-reordered version).

Todo

Add SFINAE to require that PROJ inherit from Projection

get()

template<typename PROJ>

const PROJ & Rivet::ProjectionApplier::get ( const std::string & name ) const

inlineinherited

Get the named projection, specifying return type via a template argument (user-facing alias).

Todo

Add SFINAE to require that PROJ inherit from Projection

References getProjection().

Referenced by Rivet::FastJets::FastJets(), and Rivet::FastJets::FastJets().

getProjection() [1/2]

const Projection & Rivet::ProjectionApplier::getProjection ( const std::string & name ) const

inlineinherited

Get the named projection (non-templated, so returns as a reference to a Projection base class).

References Rivet::ProjectionHandler::getProjection(), and getProjHandler().

getProjection() [2/2]

template<typename PROJ>

const PROJ & Rivet::ProjectionApplier::getProjection ( const std::string & name ) const

inlineinherited

Get the named projection, specifying return type via a template argument.

Todo

Add SFINAE to require that PROJ inherit from Projection

References Rivet::ProjectionHandler::getProjection(), getProjectionFromDeclQueue(), getProjHandler(), and Rivet::Kin::p().

Referenced by Rivet::CentralityProjection::compare(), Rivet::SimpleAnalysis::electronsProj(), get(), Rivet::SimpleAnalysis::jetsProj(), Rivet::DISFinalState::kinematics(), Rivet::SimpleAnalysis::metProj(), Rivet::SimpleAnalysis::muonsProj(), Rivet::pcmp(), Rivet::pcmp(), Rivet::pcmp(), Rivet::pcmp(), Rivet::SimpleAnalysis::photonsProj(), Rivet::SimpleAnalysis::tausProj(), Rivet::SimpleAnalysis::tracksProj(), Rivet::SmearedJets::truthJets(), and Rivet::SmearedParticles::truthParticles().

getProjectionFromDeclQueue()

template<typename PROJ>

const PROJ & Rivet::ProjectionApplier::getProjectionFromDeclQueue ( const std::string name ) const

inlineinherited

Get a named projection from this projection appliers declqueue TODO for TP: Recursion?

References MSG_ERROR.

Referenced by getProjection().

mkNamedPCmp()

Cmp< Projection > Rivet::Projection::mkNamedPCmp ( const Projection & otherparent, const std::string & pname ) const

protectedinherited

Shortcut to make a named Cmp<Projection> comparison with the *this object automatically passed as one of the parent projections.

References Projection().

Referenced by Rivet::ATLAS::MinBiasTrigger::compare(), Rivet::ATLAS::SumET_PB_Centrality::compare(), Rivet::ATLAS::SumET_PBPB_Centrality::compare(), Rivet::BeamThrust::compare(), Rivet::BRAHMSCentrality::compare(), Rivet::CentralEtHCM::compare(), Rivet::CentralityEstimator::compare(), Rivet::DISFinalState::compare(), Rivet::EventMixingBase::compare(), Rivet::FParameter::compare(), Rivet::GammaGammaFinalState::compare(), Rivet::GeneratedCentrality::compare(), Rivet::HeavyHadrons::compare(), Rivet::Hemispheres::compare(), Rivet::LossyFinalState< FILTER >::compare(), Rivet::MC_pPbMinBiasTrigger::compare(), Rivet::MC_SumETFwdPbCentrality::compare(), Rivet::PercentileProjection::compare(), Rivet::Spherocity::compare(), Rivet::STAR_BES_Centrality::compare(), and Rivet::Thrust::compare().

mkPCmp()

Cmp< Projection > Rivet::Projection::mkPCmp ( const Projection & otherparent, const std::string & pname ) const

protectedinherited

Shortcut to make a named Cmp<Projection> comparison with the *this object automatically passed as one of the parent projections.

Note

Alias for mkNamedPCmp

References Projection().

Referenced by Rivet::ALICE::PrimaryParticles::compare(), Rivet::Correlators::compare(), Rivet::SmearedJets::compare(), and Rivet::SmearedParticles::compare().

name()

virtual std::string Rivet::Projection::name ( ) const

inlinevirtualinherited

Get the name of the projection.

Implements Rivet::ProjectionApplier.

Referenced by getLog(), setName(), and Rivet::VetoedFinalState::vetoFinalState().

project()

void Rivet::Sphericity::project ( const Event & e )

protectedvirtual

Perform the projection on the Event.

Implements Rivet::Projection.

setProjectionHandler()

void Rivet::ProjectionApplier::setProjectionHandler ( ProjectionHandler & projectionHandler ) const

protectedinherited

Todo

AB: Add Doxygen comment, follow surrounding coding style

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

• /builds/hepcedar/rivet/include/Rivet/Projections/Sphericity.hh