Rivet  1.8.0
Public Member Functions | Protected Member Functions
Rivet::Hemispheres Class Reference

Calculate the hemisphere masses and broadenings. More...

#include <Hemispheres.hh>

Inheritance diagram for Rivet::Hemispheres:
Rivet::Projection Rivet::ProjectionApplier

List of all members.

Public Member Functions

 Hemispheres (const AxesDefinition &ax)
 Constructor.
virtual const Projectionclone () const
 Clone on the heap.
void clear ()
bool massMatchesBroadening ()
 Is the hemisphere with the max mass the same as the one with the max broadening?
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 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

Protected Member Functions

void project (const Event &e)
 Perform the projection on the Event.
int compare (const Projection &p) const
 Compare with other projections.

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.


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