Get the DIS kinematic variables and relevant boosts for an event. More...

#include <DISKinematics.hh>

Public Member Functions
	DISKinematics ()
	The default constructor.
	DEFAULT_RIVET_PROJ_CLONE (DISKinematics)
	Clone on the heap.
double	Q2 () const
	The .
double	W2 () const
	The .
double	x () const
	The Bjorken .
double	y () const
	The Inelasticity .
double	s () const
	The centre of mass energy .
const LorentzTransform &	boostHCM () const
	The LorentzRotation needed to boost a particle to the hadronic CM frame.
const LorentzTransform &	boostBreit () const
	The LorentzRotation needed to boost a particle to the hadronic Breit frame.
const Particle &	beamHadron () const
	The incoming Hadron beam particle.
bool	before (const Projection &p) const
virtual const std::set< PdgIdPair >	beamPairs () const
virtual std::string	name () const
	Get the name of the projection.
Projection &	addPdgIdPair (PdgId beam1, PdgId beam2)
	Add a colliding beam pair.
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	markAsOwned () const
Standard constructors and destructors.
virtual unique_ptr< Projection >	clone () const =0
	Clone on the heap.
Projection "getting" functions
std::set< ConstProjectionPtr >	getProjections () const
	Get the contained projections, including recursion.
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
Projection applying functions
template<typename PROJ >
const PROJ &	applyProjection (const Event &evt, const Projection &proj) const
	Apply the supplied projection on event evt.
template<typename PROJ >
const PROJ &	applyProjection (const Event &evt, const PROJ &proj) const
	Apply the supplied projection on event evt.
template<typename PROJ >
const PROJ &	applyProjection (const Event &evt, const std::string &name) const
template<typename PROJ >
const PROJ &	apply (const Event &evt, const Projection &proj) const
template<typename PROJ >
const PROJ &	apply (const Event &evt, const PROJ &proj) const
template<typename PROJ >
const PROJ &	apply (const Event &evt, const std::string &name) const
Protected Member Functions
virtual void	project (const Event &e)
	Perform the projection operation on the supplied event.
virtual int	compare (const Projection &p) const
	Compare with other projections.
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.
const Projection &	_applyProjection (const Event &evt, const std::string &name) const
const Projection &	_applyProjection (const Event &evt, const Projection &proj) const
Projection registration functions
template<typename PROJ >
const PROJ &	declareProjection (const PROJ &proj, const std::string &name)
	Register a contained projection.
template<typename PROJ >
const PROJ &	declare (const PROJ &proj, const std::string &name)
	Register a contained projection (user-facing version)
template<typename PROJ >
const PROJ &	addProjection (const PROJ &proj, const std::string &name)
	Register a contained projection (user-facing version)
const Projection &	_declareProjection (const Projection &proj, const std::string &name)
	Untemplated function to do the work...
Protected Attributes
bool	_allowProjReg
	Flag to forbid projection registration in analyses until the init phase.
Private Attributes
double	_theQ2
	The .
double	_theW2
	The .
double	_theX
	The Bjorken .
double	_theY
	The Inelasticity .
double	_theS
	The centre of mass energy .
Particle	_inHadron
LorentzTransform	_hcm
	The LorentzRotation needed to boost a particle to the hadronic CM frame.
LorentzTransform	_breit
	The LorentzRotation needed to boost a particle to the hadronic Breit frame.
Friends
class	Event
	Event is a friend.
class	Cmp< Projection >
	The Cmp specialization for Projection is a friend.

Detailed Description

Get the DIS kinematic variables and relevant boosts for an event.

Definition at line 15 of file DISKinematics.hh.

Constructor & Destructor Documentation

DISKinematics ( ) [inline]

The default constructor.

Definition at line 20 of file DISKinematics.hh.

      : _theQ2(-1.0), _theW2(-1.0), _theX(-1.0), _theY(-1.0), _theS(-1.0)
    {
      setName("DISKinematics");
      //addPdgIdPair(ANY, hadid);
      addProjection(Beam(), "Beam");
      addProjection(DISLepton(), "Lepton");
    }

Member Function Documentation

const Projection & _applyProjection	(	const Event &	evt,
		const std::string &	name
	)		const `[protected, inherited]`

Non-templated version of string-based applyProjection, to work around header dependency issue.

Definition at line 22 of file ProjectionApplier.cc.

                                                                                  {
    return evt.applyProjection(getProjection(name));
  }

const Projection & _applyProjection	(	const Event &	evt,
		const Projection &	proj
	)		const `[protected, inherited]`

Non-templated version of proj-based applyProjection, to work around header dependency issue.

Definition at line 28 of file ProjectionApplier.cc.

                                                                                      {
    return evt.applyProjection(proj);
  }

const Projection & _declareProjection	(	const Projection &	proj,
		const std::string &	name
	)		`[protected, inherited]`

Untemplated function to do the work...

Definition at line 34 of file ProjectionApplier.cc.

                                                                             {
    if (!_allowProjReg) {
      cerr << "Trying to register projection '"
           << proj.name() << "' before init phase in '" << this->name() << "'." << endl;
      exit(2);
    }
    const Projection& reg = getProjHandler().registerProjection(*this, proj, name);
    return reg;
  }

Projection& addPdgIdPair	(	PdgId	beam1,
		PdgId	beam2
	)		`[inline, inherited]`

Add a colliding beam pair.

Definition at line 108 of file Projection.hh.

                                                       {
      _beamPairs.insert(PdgIdPair(beam1, beam2));
      return *this;
    }

const PROJ& addProjection	(	const PROJ &	proj,
		const std::string &	name
	)		`[inline, protected, inherited]`

Register a contained projection (user-facing version)

Deprecated:: Use declareProjection() or declare()

Todo:: Add SFINAE to require that PROJ inherit from Projection

Definition at line 157 of file ProjectionApplier.hh.

{ return declareProjection(proj, name); }

const PROJ& apply	(	const Event &	evt,
		const Projection &	proj
	)		const `[inline, inherited]`

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

Todo:: Add SFINAE to require that PROJ inherit from Projection

Definition at line 80 of file ProjectionApplier.hh.

{ return applyProjection<PROJ>(evt, proj); }

const PROJ& apply	(	const Event &	evt,
		const PROJ &	proj
	)		const `[inline, inherited]`

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

Todo:: Add SFINAE to require that PROJ inherit from Projection

Definition at line 92 of file ProjectionApplier.hh.

{ return applyProjection<PROJ>(evt, proj); }

const PROJ& apply	(	const Event &	evt,
		const std::string &	name
	)		const `[inline, inherited]`

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

Todo:: Add SFINAE to require that PROJ inherit from Projection

Definition at line 104 of file ProjectionApplier.hh.

{ return applyProjection<PROJ>(evt, name); }

const PROJ& applyProjection	(	const Event &	evt,
		const Projection &	proj
	)		const `[inline, inherited]`

Apply the supplied projection on event evt.

Todo:: Add SFINAE to require that PROJ inherit from Projection

Definition at line 74 of file ProjectionApplier.hh.

                                                                                {
      return pcast<PROJ>(_applyProjection(evt, proj));
    }

const PROJ& applyProjection	(	const Event &	evt,
		const PROJ &	proj
	)		const `[inline, inherited]`

Apply the supplied projection on event evt.

Todo:: Add SFINAE to require that PROJ inherit from Projection

Definition at line 86 of file ProjectionApplier.hh.

                                                                          {
      return pcast<PROJ>(_applyProjection(evt, proj));
    }

const PROJ& applyProjection	(	const Event &	evt,
		const std::string &	name
	)		const `[inline, inherited]`

Apply the named projection on event evt.

Todo:: Add SFINAE to require that PROJ inherit from Projection

Definition at line 98 of file ProjectionApplier.hh.

                                                                               {
      return pcast<PROJ>(_applyProjection(evt, name));
    }

const Particle& beamHadron ( ) const [inline]

The incoming Hadron beam particle.

Definition at line 72 of file DISKinematics.hh.

                                       {
      return _inHadron;
    }

const set< PdgIdPair > beamPairs ( ) const [virtual, inherited]

Return the allowed beam pairs on which this projection can operate, not including recursion. Derived classes should ensure that all contained projections are registered in the _projections set for the beam constraint chaining to work.

Todo:: Remove the beam constraints system from projections.

Definition at line 35 of file Projection.cc.

                                                   {
    set<PdgIdPair> ret = _beamPairs;
    set<ConstProjectionPtr> projs = getProjections();
    for (set<ConstProjectionPtr>::const_iterator ip = projs.begin(); ip != projs.end(); ++ip) {
      ConstProjectionPtr p = *ip;
      getLog() << Log::TRACE << "Proj addr = " << p << endl;
      if (p) ret = intersection(ret, p->beamPairs());
    }
    return ret;
  }

bool 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.

Definition at line 24 of file Projection.cc.

                                                   {
    const std::type_info& thisid = typeid(*this);
    const std::type_info& otherid = typeid(p);
    if (thisid == otherid) {
      return compare(p) < 0;
    } else {
      return thisid.before(otherid);
    }
  }

const LorentzTransform& boostBreit ( ) const [inline]

The LorentzRotation needed to boost a particle to the hadronic Breit frame.

Definition at line 67 of file DISKinematics.hh.

                                               {
      return _breit;
    }

const LorentzTransform& boostHCM ( ) const [inline]

The LorentzRotation needed to boost a particle to the hadronic CM frame.

Definition at line 62 of file DISKinematics.hh.

                                             {
      return _hcm;
    }

virtual unique_ptr<Projection> clone ( ) const [pure virtual, inherited]

Clone on the heap.

Implemented in JetAlg, AxesDefinition, and ParticleFinder.

int compare ( const Projection & p ) const [protected, virtual]

Compare with other projections.

Implements Projection.

Definition at line 69 of file DISKinematics.cc.

                                                       {
    const DISKinematics& other = pcast<DISKinematics>(p);
    return mkNamedPCmp(other, "Lepton");
  }

const PROJ& declare	(	const PROJ &	proj,
		const std::string &	name
	)		`[inline, protected, inherited]`

Register a contained projection (user-facing version)

Todo:: Add SFINAE to require that PROJ inherit from Projection

Definition at line 151 of file ProjectionApplier.hh.

{ return declareProjection(proj, name); }

const PROJ& declareProjection	(	const PROJ &	proj,
		const std::string &	name
	)		`[inline, protected, inherited]`

Register a contained projection.

The type of the argument is used to instantiate a new projection internally: this new object is applied to events rather than the argument object. Hence you are advised to only use locally-scoped Projection objects in your Projection and Analysis constructors, and to avoid polymorphism (e.g. handling ConcreteProjection via a pointer or reference to type Projection) since this will screw up the internal type management.

Todo:: Add SFINAE to require that PROJ inherit from Projection

Definition at line 142 of file ProjectionApplier.hh.

                                                                           {
      const Projection& reg = _declareProjection(proj, name);
      const PROJ& rtn = dynamic_cast<const PROJ&>(reg);
      return rtn;
    }

DEFAULT_RIVET_PROJ_CLONE ( DISKinematics )

Clone on the heap.

const PROJ& get ( const std::string & name ) const [inline, inherited]

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

Todo:: Add SFINAE to require that PROJ inherit from Projection

Definition at line 57 of file ProjectionApplier.hh.

{ return getProjection<PROJ>(name); }

Log& getLog ( ) const [inline, inherited]

Get a Log object based on the getName() property of the calling projection object.

Reimplemented from ProjectionApplier.

Definition at line 115 of file Projection.hh.

                        {
      string logname = "Rivet.Projection." + name();
      return Log::getLog(logname);
    }

const PROJ& getProjection ( const std::string & name ) const [inline, inherited]

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

Todo:: Add SFINAE to require that PROJ inherit from Projection

Definition at line 50 of file ProjectionApplier.hh.

                                                           {
      const Projection& p = getProjHandler().getProjection(*this, name);
      return pcast<PROJ>(p);
    }

const Projection& getProjection ( const std::string & name ) const [inline, inherited]

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

Definition at line 61 of file ProjectionApplier.hh.

                                                                 {
      return getProjHandler().getProjection(*this, name);
    }

std::set<ConstProjectionPtr> getProjections ( ) const [inline, inherited]

Get the contained projections, including recursion.

Definition at line 43 of file ProjectionApplier.hh.

                                                      {
      return getProjHandler().getChildProjections(*this, ProjectionHandler::DEEP);
    }

ProjectionHandler& getProjHandler ( ) const [inline, protected, inherited]

Get a reference to the ProjectionHandler for this thread.

Definition at line 122 of file ProjectionApplier.hh.

                                              {
      return _projhandler;
    }

void markAsOwned ( ) const [inline, inherited]

Mark object as owned by the _projhandler

Todo:: Huh? What's this for?

Definition at line 111 of file ProjectionApplier.hh.

{ _owned = true; }

Cmp< Projection > mkNamedPCmp	(	const Projection &	otherparent,
		const std::string &	pname
	)		const `[protected, inherited]`

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

Definition at line 47 of file Projection.cc.

                                                                                                  {
    return pcmp(*this, otherparent, pname);
  }

Cmp< Projection > mkPCmp	(	const Projection &	otherparent,
		const std::string &	pname
	)		const `[protected, inherited]`

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

Note:: Alias for mkNamedPCmp

Definition at line 51 of file Projection.cc.

                                                                                             {
    return pcmp(*this, otherparent, pname);
  }

virtual std::string name ( ) const [inline, virtual, inherited]

Get the name of the projection.

Implements ProjectionApplier.

Definition at line 102 of file Projection.hh.

                                   {
      return _name;
    }

void project ( const Event & e ) [protected, virtual]

Perform the projection operation on the supplied event.

Implements Projection.

Definition at line 8 of file DISKinematics.cc.

                                            {
    // Identify beam hadron
    const ParticlePair& inc = applyProjection<Beam>(e, "Beam").beams();
    bool firstIsHadron  = PID::isHadron(inc.first.pid());
    bool secondIsHadron = PID::isHadron(inc.second.pid());
    if (firstIsHadron && !secondIsHadron) {
      _inHadron = inc.first;
    } else if (!firstIsHadron && secondIsHadron) {
      _inHadron = inc.second;
    } else {
      //help!
      throw Error("DISKinematics projector could not find the correct beam hadron");
    }

    // Get the DIS lepton and store some of its properties
    const DISLepton& dislep = applyProjection<DISLepton>(e, "Lepton");
    const FourMomentum pLepIn = dislep.in().momentum();
    const FourMomentum pLepOut = dislep.out().momentum();
    const FourMomentum pHad = _inHadron.momentum();
    const FourMomentum pGamma = pLepIn - pLepOut;
    const FourMomentum tothad = pGamma + pHad;
    _theQ2 = -pGamma.mass2();
    _theW2 = tothad.mass2();
    _theX = Q2()/(2.0 * pGamma * pHad);
    _theY = (pGamma * pHad) / (pLepIn * pHad);
    _theS = invariant(pLepIn + pHad);

    // Calculate boost vector for boost into HCM-system
    LorentzTransform tmp;
    tmp.setBetaVec(-tothad.boostVector());

    // Rotate so the photon is in x-z plane in HCM rest frame
    FourMomentum pGammaHCM = tmp.transform(pGamma);
    tmp.preMult(Matrix3(Vector3::mkZ(), -pGammaHCM.azimuthalAngle()));
    pGammaHCM = tmp.transform(pGamma);
    assert(isZero(dot(pGammaHCM.vector3(), Vector3::mkY())));

    // Rotate so the photon is along the positive z-axis
    const double rot_angle = pGammaHCM.polarAngle() * (pGammaHCM.px() >= 0 ? -1 : 1);
    tmp.preMult(Matrix3(Vector3::mkY(), rot_angle));
    // Check that final HCM photon lies along +ve z as expected
    pGammaHCM = tmp.transform(pGamma);
    assert(isZero(dot(pGammaHCM.vector3(), Vector3::mkX()), 1e-3));
    assert(isZero(dot(pGammaHCM.vector3(), Vector3::mkY()), 1e-3));
    assert(isZero(angle(pGammaHCM.vector3(), Vector3::mkZ()), 1e-3));

    // Finally rotate so outgoing lepton at phi = 0
    FourMomentum pLepOutHCM = tmp.transform(pLepOut);
    tmp.preMult(Matrix3(Vector3::mkZ(), -pLepOutHCM.azimuthalAngle()));
    assert(isZero(tmp.transform(pLepOut).azimuthalAngle()));
    _hcm = tmp;

    // Boost to Breit frame (use opposite convention for photon --- along *minus* z)
    tmp.preMult(Matrix3(Vector3::mkX(), PI));
    const double bz = 1 - 2*x();
    _breit = LorentzTransform::mkObjTransformFromBeta(Vector3::mkZ() * bz).combine(tmp);
    assert(isZero(angle(_breit.transform(pGamma).vector3(), -Vector3::mkZ()), 1e-3));
    assert(isZero(_breit.transform(pLepOut).azimuthalAngle(), 1e-3));
  }

double Q2 ( ) const [inline]

The $Q^2$ .

Definition at line 45 of file DISKinematics.hh.

{ return _theQ2; }

double s ( ) const [inline]

The centre of mass energy $s$ .

Definition at line 57 of file DISKinematics.hh.

{ return _theS; }

void setName ( const std::string & name ) [inline, inherited]

Used by derived classes to set their name.

Definition at line 121 of file Projection.hh.

                                        {
      _name = name;
    }

double W2 ( ) const [inline]

The $W^2$ .

Definition at line 48 of file DISKinematics.hh.

{ return _theW2; }

double x ( ) const [inline]

The Bjorken $x$ .

Definition at line 51 of file DISKinematics.hh.

{ return _theX; }

double y ( ) const [inline]

The Inelasticity $y$ .

Definition at line 54 of file DISKinematics.hh.

{ return _theY; }

Friends And Related Function Documentation

friend class Cmp< Projection > [friend, inherited]

The Cmp specialization for Projection is a friend.

Definition at line 36 of file Projection.hh.

friend class Event [friend, inherited]

Event is a friend.

Definition at line 33 of file Projection.hh.

Member Data Documentation

bool _allowProjReg [protected, inherited]

Flag to forbid projection registration in analyses until the init phase.

Definition at line 176 of file ProjectionApplier.hh.

LorentzTransform _breit [private]

The LorentzRotation needed to boost a particle to the hadronic Breit frame.

Definition at line 99 of file DISKinematics.hh.

LorentzTransform _hcm [private]

The LorentzRotation needed to boost a particle to the hadronic CM frame.

Definition at line 96 of file DISKinematics.hh.

Particle _inHadron [private]

Definition at line 93 of file DISKinematics.hh.

double _theQ2 [private]

The $Q^2$ .

Definition at line 79 of file DISKinematics.hh.

double _theS [private]

The centre of mass energy $s$ .

Definition at line 91 of file DISKinematics.hh.

double _theW2 [private]

The $W^2$ .

Definition at line 82 of file DISKinematics.hh.

double _theX [private]

The Bjorken $x$ .

Definition at line 85 of file DISKinematics.hh.

double _theY [private]

The Inelasticity $y$ .

Definition at line 88 of file DISKinematics.hh.

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

Public Member Functions

Protected Member Functions

Protected Attributes

Private Attributes

Friends

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation

Member Data Documentation