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

Get the transverse spherocity scalars for hadron-colliders. More...

#include <Spherocity.hh>

Inheritance diagram for Rivet::Spherocity:
Rivet::AxesDefinition Rivet::Projection Rivet::ProjectionApplier

List of all members.

Public Member Functions

 Spherocity (const FinalState &fsp)
 Constructor.
virtual const Projectionclone () const
 Clone on the heap.
double spherocity () const
const Vector3spherocityAxis () const
const Vector3spherocityMajorAxis () const
 The spherocity major axis (axis of max spherocity perpendicular to spherocity axis).
const Vector3spherocityMinorAxis () const
 The spherocity minor axis (axis perpendicular to spherocity and spherocity major).
const Vector3axis1 () const
 AxesDefinition axis accessors.
const Vector3axis2 () const
 The 2nd most significant ("major") axis.
const Vector3axis3 () const
 The least significant ("minor") axis.
Direct methods

Ways to do the calculation directly, without engaging the caching system

void calc (const FinalState &fs)
 Manually calculate the spherocity, without engaging the caching system.
void calc (const vector< Particle > &fsparticles)
 Manually calculate the spherocity, without engaging the caching system.
void calc (const vector< FourMomentum > &fsmomenta)
 Manually calculate the spherocity, without engaging the caching system.
void calc (const vector< Vector3 > &threeMomenta)
 Manually calculate the spherocity, without engaging the caching system.

Protected Member Functions

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

Detailed Description

Get the transverse spherocity scalars for hadron-colliders.

Author:
Holger Schulz

The scalar (maximum) transverse spherocity is defined as

\[ T = \mathrm{max}_{\vec{n_\perp}} \frac{\sum_i \left|\vec{p}_{\perp,i} \cdot \vec{n} \right|}{\sum_i |\vec{p}_{\perp,i}|} \]

, with the direction of the unit vector $ \vec{n_\perp} $ which maximises $ T $ being identified as the spherocity axis. The unit vector which maximises the spherocity scalar in the plane perpendicular to $ \vec{n} $ is the "spherocity major" direction, and the vector perpendicular to both the spherocity and spherocity major directions is the spherocity minor. Both the major and minor directions have associated spherocity scalars.

Care must be taken in the case of Drell-Yan processes - there we should use the newly proposed observable $ a_T $.


Member Function Documentation

double Rivet::Spherocity::spherocity ( ) const [inline]

Spherocity scalar accessors The spherocity scalar, $ S $, (minimum spherocity).

const Vector3& Rivet::Spherocity::spherocityAxis ( ) const [inline]

Spherocity axis accessors The spherocity axis.

Referenced by axis1().


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