For Lambda b -> J/psi Lambda

1. Track selection of J/psi candidate:

- From jpsi Finder 

2. Jet clustering:

- Durham algorithm using pyclus subroutine from PYTHIA
- clustering parameter (PARU(45)) = 15 GeV;

3. J/psi selection( + skimming selection):

- each track have at least 3 hits in the smt
- 2.8 < Mass Jpsi< 3.35   



For Lambda selection:

 - 2 tracks of opposite charge;
 - Lambda pt > 0.4 GeV;
 - mppi > 1.105 && mppi < 1.125
 - Both track have al least 2 measurement in the SMT; 
 - l/sigma(l) > 3 , where l is the distance in xy from primary to K0s vertex

4. Lambda b->J/psi Lambda candidate selection:

 - Chi2 of B0 vertex < 25.;
 - l/sigma(l) > 3 , where l is the distance in xy between primary and B0 vertex;
 - (impact(axial)/sigma)2 + (impact(stereo)/sigma)2 < 36,
   here impact is the impact parameter of the B0 track to the primary vertex;
 - cos(alpha) > 0.9, where alpha is the angle between B0 momentum
   and the direction from primary to the B0 vertex;
 - ptotal > 5.0 GeV
 - mass constraint in both J/psi and Lambda