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Hemispheres Class Reference

Calculate the hemisphere masses and broadenings. More...

#include <Hemispheres.hh>

List of all members.

Public Member Functions

 Hemispheres (const AxesDefinition &ax)
 Constructor.
 DEFAULT_RIVET_PROJ_CLONE (Hemispheres)
 Clone on the heap.
void clear ()
 Reset the projection.
void calc (const Vector3 &n, const std::vector< FourMomentum > &p4s)
 Use the projection manually (i.e. outside the projection mechanism) with raw 4-momentum inputs.
void calc (const Vector3 &n, const Particles &particles)
 Use the projection manually (i.e. outside the projection mechanism) with particle inputs.
void calc (const Vector3 &n, const Jets &jets)
 Use the projection manually (i.e. outside the projection mechanism) with jet inputs.
bool massMatchesBroadening ()
 Is the hemisphere with the max mass the same as the one with the max broadening?
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
Hemisphere masses (scaled by \f$ 1 / E^2_\mathrm{vis} \f$).
double E2vis () const
double Evis () const
double M2high () const
double Mhigh () const
double M2low () const
double Mlow () const
double M2diff () const
double Mdiff () const
double M2sum () const
double Msum () const
double scaledM2high () const
double scaledMhigh () const
double scaledM2low () const
double scaledMlow () const
double scaledM2diff () const
double scaledMdiff () const
Hemisphere broadenings.
double Bmax () const
double Bmin () const
double Bsum () const
double Bdiff () 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

void project (const Event &e)
 Perform the projection on the Event.
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 _E2vis
 Visible energy-squared, $ E^2_\mathrm{vis} $.
double _M2high
 Hemisphere mass variables.
double _M2low
double _Bmax
 Hemisphere broadening variables.
double _Bmin
bool _highMassEqMaxBroad
 Is the hemisphere with the max mass the same as the one with the max broadening?

Friends

class Event
 Event is a friend.
class Cmp< Projection >
 The Cmp specialization for Projection is a friend.

Detailed Description

Calculate the hemisphere masses and broadenings.

Calculate the hemisphere masses and broadenings, with event hemispheres defined by the plane normal to the thrust vector, $ \vec{n}_\mathrm{T} $.

The "high" hemisphere mass, $ M^2_\mathrm{high} / E^2_\mathrm{vis} $, is defined as

\[ \frac{M^2_\mathrm{high}}{E^2_\mathrm{vis}} = \frac{1}{E^2_\mathrm{vis}} \max \left( \left| \sum_{\vec{p}_k \cdot \vec{n}_\mathrm{T} > 0} p_k \right|^2 , \left| \sum_{\vec{p}_k \cdot \vec{n}_\mathrm{T} < 0} p_k \right|^2 \right) \]

and the corresponding "low" hemisphere mass, $ M^2_\mathrm{low} / E^2_\mathrm{vis} $, is the sum of momentum vectors in the opposite hemisphere, i.e. $ \max \rightarrow \min $ in the formula above.

Finally, we define a hemisphere mass difference:

\[ \frac{M^2_\mathrm{diff} }{ E^2_\mathrm{vis}} = \frac{ M^2_\mathrm{high} - M^2_\mathrm{low} }{ E^2_\mathrm{vis}} . \]

Similarly to the masses, we also define hemisphere broadenings, using the momenta transverse to the thrust axis:

\[ B_\pm = \frac{ \sum{\pm \vec{p}_i \cdot \vec{n}_\mathrm{T} > 0} |\vec{p}_i \times \vec{n}_\mathrm{T} | }{ 2 \sum_i | \vec{p}_i | } \]

and then a set of the broadening maximum, minimum, sum and difference as follows:

\[ B_\mathrm{max} = \max(B_+, B_-) \]

\[ B_\mathrm{min} = \min(B_+, B_-) \]

\[ B_\mathrm{sum} = B_+ + B_- \]

\[ B_\mathrm{diff} = |B_+ - B_-| \]

Internally, this projection uses a Thrust or Sphericity projection to determine the hemisphere orientation.

Definition at line 56 of file Hemispheres.hh.

Constructor & Destructor Documentation

Hemispheres ( const AxesDefinition &  ax) [inline]

Constructor.

Definition at line 60 of file Hemispheres.hh.

                                          {
      setName("Hemispheres");
      addProjection(ax, "Axes");
      clear();
    }

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));
    }
double Bdiff ( ) const [inline]

Definition at line 146 of file Hemispheres.hh.

{ return fabs(_Bmax - _Bmin); } // <- fabs(), just in case...
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);
    }
  }
double Bmax ( ) const [inline]

Definition at line 143 of file Hemispheres.hh.

{ return _Bmax; }
double Bmin ( ) const [inline]

Definition at line 144 of file Hemispheres.hh.

{ return _Bmin; }
double Bsum ( ) const [inline]

Definition at line 145 of file Hemispheres.hh.

{ return _Bmax + _Bmin; }
void calc ( const Vector3 &  n,
const std::vector< FourMomentum > &  p4s 
)

Use the projection manually (i.e. outside the projection mechanism) with raw 4-momentum inputs.

Definition at line 34 of file Hemispheres.cc.

                                                                          {
    MSG_DEBUG("Hemisphere axis = " << n);
    MSG_DEBUG("Number of constituents = " << p4s.size());

    FourMomentum p4With, p4Against;
    double Evis(0), broadWith(0), broadAgainst(0), broadDenom(0);
    foreach (const FourMomentum& p4, p4s) {
      const Vector3 p3 = p4.vector3();
      const double p3Para = dot(p3, n);
      const double p3Trans = (p3 - p3Para * n).mod();

      // Update normalisations
      Evis += p4.E();
      broadDenom += 2.0 * p3.mod();

      // Update the mass and broadening variables
      if (p3Para > 0) {
        p4With += p4;
        broadWith += p3Trans;
      } else if (p3Para < 0) {
        p4Against += p4;
        broadAgainst += p3Trans;
      } else {
        // In the incredibly unlikely event that a particle goes exactly along the
        // thrust plane, add half to each hemisphere.
        MSG_WARNING("Particle split between hemispheres");
        p4With += 0.5 * p4;
        p4Against += 0.5 * p4;
        broadWith += 0.5 * p3Trans;
        broadAgainst += 0.5 * p3Trans;
      }
    }

    // Visible energy squared.
    _E2vis = sqr(Evis);

    // Calculate masses.
    const double mass2With = p4With.mass2();
    const double mass2Against = p4Against.mass2();
    _M2high = max(mass2With, mass2Against);
    _M2low = min(mass2With, mass2Against);

    // Calculate broadenings.
    broadWith /= broadDenom;
    broadAgainst /= broadDenom;
    _Bmax = max(broadWith, broadAgainst);
    _Bmin = min(broadWith, broadAgainst);

    // Calculate high-max correlation flag.
    const int maxMassID = (mass2With >= mass2Against);
    const int maxBroadID = (broadWith >= broadAgainst);
    _highMassEqMaxBroad = (maxMassID == maxBroadID);
  }
void calc ( const Vector3 &  n,
const Particles &  particles 
)

Use the projection manually (i.e. outside the projection mechanism) with particle inputs.

Definition at line 20 of file Hemispheres.cc.

                                                                     {
    vector<FourMomentum> p4s; p4s.reserve(particles.size());
    foreach (const Particle& p, particles) p4s.push_back(p.mom());
    calc(n, p4s);
  }
void calc ( const Vector3 &  n,
const Jets &  jets 
)

Use the projection manually (i.e. outside the projection mechanism) with jet inputs.

Definition at line 27 of file Hemispheres.cc.

                                                           {
    vector<FourMomentum> p4s; p4s.reserve(jets.size());
    foreach (const Jet& j, jets) p4s.push_back(j.mom());
    calc(n, p4s);
  }
void clear ( ) [inline]

Reset the projection.

Definition at line 70 of file Hemispheres.hh.

                 {
      _E2vis = -1;
      _M2high = -1;
      _M2low = -1;
      _Bmax = -1;
      _Bmin = -1;
      _highMassEqMaxBroad = true;
    }
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 [inline, protected, virtual]

Compare with other projections.

Implements Projection.

Definition at line 93 of file Hemispheres.hh.

                                           {
      return mkNamedPCmp(p, "Axes");
    }
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 ( Hemispheres  )

Clone on the heap.

double E2vis ( ) const [inline]

Definition at line 103 of file Hemispheres.hh.

{ return _E2vis; }
double Evis ( ) const [inline]

Definition at line 104 of file Hemispheres.hh.

{ return sqrt(_E2vis); }
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;
    }
double M2diff ( ) const [inline]

Definition at line 112 of file Hemispheres.hh.

{ return _M2high -_M2low; }
double M2high ( ) const [inline]

Definition at line 106 of file Hemispheres.hh.

{ return _M2high; }
double M2low ( ) const [inline]

Definition at line 109 of file Hemispheres.hh.

{ return _M2low; }
double M2sum ( ) const [inline]

Definition at line 115 of file Hemispheres.hh.

{ return _M2high +_M2low; }
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; }
bool massMatchesBroadening ( ) [inline]

Is the hemisphere with the max mass the same as the one with the max broadening?

Definition at line 151 of file Hemispheres.hh.

                                 {
      return _highMassEqMaxBroad;
    }
double Mdiff ( ) const [inline]

Definition at line 113 of file Hemispheres.hh.

{ return sqrt(M2diff()); }
double Mhigh ( ) const [inline]

Definition at line 107 of file Hemispheres.hh.

{ return sqrt(M2high()); }
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);
  }
double Mlow ( ) const [inline]

Definition at line 110 of file Hemispheres.hh.

{ return sqrt(M2low()); }
double Msum ( ) const [inline]

Definition at line 116 of file Hemispheres.hh.

{ return sqrt(M2sum()); }
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 on the Event.

Implements Projection.

Definition at line 8 of file Hemispheres.cc.

                                          {
    clear();

    // Get thrust axes.
    const AxesDefinition& ax = applyProjection<AxesDefinition>(e, "Axes");
    const Vector3 n = ax.axis1();
    const FinalState& fs = applyProjection<FinalState>(e, ax.getProjection("FS"));
    const Particles& particles = fs.particles();
    calc(n, particles);
  }
double scaledM2diff ( ) const [inline]

Definition at line 132 of file Hemispheres.hh.

                                {
      if (M2diff() == 0.0) return 0.0;
      if (_E2vis != 0.0) return M2diff()/_E2vis;
      else return std::numeric_limits<double>::max();
    }
double scaledM2high ( ) const [inline]

Definition at line 118 of file Hemispheres.hh.

                                {
      if (isZero(_M2high)) return 0.0;
      if (!isZero(_E2vis)) return _M2high/_E2vis;
      else return std::numeric_limits<double>::max();
    }
double scaledM2low ( ) const [inline]

Definition at line 125 of file Hemispheres.hh.

                               {
      if (isZero(_M2low)) return 0.0;
      if (!isZero(_E2vis)) return _M2low/_E2vis;
      else return std::numeric_limits<double>::max();
    }
double scaledMdiff ( ) const [inline]

Definition at line 137 of file Hemispheres.hh.

{ return sqrt(scaledM2diff()); }
double scaledMhigh ( ) const [inline]

Definition at line 123 of file Hemispheres.hh.

{ return sqrt(scaledM2high()); }
double scaledMlow ( ) const [inline]

Definition at line 130 of file Hemispheres.hh.

{ return sqrt(scaledM2low()); }
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;
    }

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.

double _Bmax [private]

Hemisphere broadening variables.

Definition at line 165 of file Hemispheres.hh.

double _Bmin [private]

Definition at line 165 of file Hemispheres.hh.

double _E2vis [private]

Visible energy-squared, $ E^2_\mathrm{vis} $.

Definition at line 159 of file Hemispheres.hh.

bool _highMassEqMaxBroad [private]

Is the hemisphere with the max mass the same as the one with the max broadening?

Definition at line 168 of file Hemispheres.hh.

double _M2high [private]

Hemisphere mass variables.

Definition at line 162 of file Hemispheres.hh.

double _M2low [private]

Definition at line 162 of file Hemispheres.hh.

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