Rivet: Rivet::Hemispheres Class Reference

Calculate the hemisphere masses and broadenings. More...

#include <Hemispheres.hh>

Inheritance diagram for Rivet::Hemispheres:

Public Member Functions
	Hemispheres (const AxesDefinition &ax)
	Constructor.
virtual const Projection *	clone () 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:

include/Rivet/Projections/Hemispheres.hh
src/Projections/Hemispheres.cc

Public Member Functions

Protected Member Functions

Detailed Description