PYTHIA
8.303

#include <Analysis.h>
Public Member Functions  
Thrust (int selectIn=2)  
Constructor.  
bool  analyze (const Event &event) 
Analyze event. More...  
double  thrust () const 
Return info on results of analysis.  
double  tMajor () const 
double  tMinor () const 
double  oblateness () const 
Vec4  eventAxis (int i) const 
void  list () const 
Provide a listing of the info. More...  
int  nError () const 
Tell how many events could not be analyzed.  
Thrust class. This class performs thrust analysis on an event.
bool analyze  (  const Event &  event  ) 
Analyze event.
Initial values and counters zero.
Loop over desired particles in the event.
Store momenta. Use energy component for absolute momentum.
Very low multiplicities (0 or 1) not considered.
Try all combinations of reference vector orthogonal to two particles.
Add all momenta with sign; two choices for each reference particle.
Maximum gives thrust axis and value.
Subtract momentum along thrust axis.
Simpleminded major and minor axes if too little transverse left.
Try all reference vectors orthogonal to one particles.
Add all momenta with sign; two choices for each reference particle.
Maximum gives major axis and value.
Orthogonal direction gives minor axis, and from there value.
Done.
void list  (  )  const 
Provide a listing of the info.
Header.
The thrust, major and minor values and related event axes.
Listing finished.