rich_select: particle selection functions
 == using RICH likelihoods from RTRA

 before using these functions you should call for each event:
       int copyRTRItoRTRA(int algorithm)
           algorithm = 0 Rise
           algorithm = 1 Riter/Rire

 selection function for each charged particle type has two parameters
             - selection level
             - arte pointer RTRA
 selection levels:
    0  maximum probable hypothesis
    1  soft likelihood cut
    2  medium likelihood cut
    3  hard likelihood cut
 return value: 1, if the track corresponds to the hypothesis at a given
               selection level
               0, otherwise 


Usage: by including the routines (which come in the ARTE package since version 
ARTE-03-08-r8) with:

#include "riter/rich_select.hh"

you get a set of routines of the type  
 int Rich_electron(int level,ArtePointer<RTRA> r)
 int Rich_muon(int level,ArtePointer<RTRA> r)
 int Rich_pion(int level,ArtePointer<RTRA> r) 
 int Rich_kaon(int level,ArtePointer<RTRA> r)
 int Rich_proton(int level,ArtePointer<RTRA> r)
 int Rich_multie(int level,ArtePointer<RTRA> r)

Recommendations:

For e/pi/mu it is advisable to use a soft cut (level 1). It discriminates against
fakes, kaons and protons.

For K and p identification note that levels 2 and 3 effectively also cut on 
momentum (level 2 from 3GeV on, level 3 from 10 GeV on). In this case only at level 
3 fakes are removed.


 M. Staric, apr-2001

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