class HPidSingleLeptonEff: public HReconstructor

 All the lepton pairs contained in the GeantKine container are formed
 The yield is stored in a ntuple (simYieldN) as a function of the pair mass
 rapidity and transverse momentum. Moreover the lepton pairs in the acceptance
 are stored in a ntuple (accept).
 The HPidDilepton class contains all the pairs that have been reconstructed.
 For each of the GeantKine pair in the acceptance we checked if this pair
 has been properly
 recontructed and is contained in the HPidDilepton Container.
 For the first correctly recontructed pair a second ntuple (eff) will
 be filled with weight 1, for each additional reconstructed pair
 that dont correpond to any Geant pair, a third ntuple (fake) will be filled
 with weight 1.
 All these informations will be stored in Ntuples  to allow
 later on the user to create of efficiency matrixes with different bining.

 all the tracks coming fomr the white generator that
 has a neighbour also coming from the white generator
 that is closer than 9 deg are tagged if they
 are inside the same sector

input 2 kine objects
output opening angle of trajectories

 checks
 1. if GEANT track is in acceptance ==> fills the acceptance ntuple.
 2. loops over HPairSim category and counts number of reconstructed pairs
    which found the fully correlated track in a pair containing hadron or leptons.
    checks the direct cut flag for the pair.
 3. loops again over HPairSim and tries to find the searched track in a pair
 4. if track has not been found in a pair we do loop over HPidParticle category
    and try to find the corresponding single track.
 5. lepton ntuple are filled in case 3 and 4.

 Checks if the track euqal to the GEANT track, is primary, has lepton PID
 and PID == GEANT PID. Return the most common detector correlation if successfull
 or 0 if not. If the most common correlation misses the META ( < 76) and the
 track was going to system 0 (SHOWER), we try to find if the lepton track
 was hidden by a secondary. If so, the in commonCorrelation the META bit is set
 and the isHiddenLepton flag becomes true.

 check if the searched track is contained in the pair
 allow pairs with geant hadrons or geant secondary leptons
 pairs with embedded leptons are rejected. Checks the
 reconstructed PID for leptons and check reconstructed PID == GEANT PID
 Int_t whichPart will be -1 if no track was accepted and 1
 or 2 if particle 1 or 2 of the pair was accepted.

 calculates the pair theta, phi (in deg!!!)
 Close pair candidates the angles to the closest
 neighbours are stored separately

 checks if thw Gent track is inside the Hades acceptance.
 The acceptance is defined by a hit in the 4 MDCs and TOF
 or SHOWER. Since Drift chambers can be taken out of the
 HGeant geometry, for the outer drift chambers a hit in
 MDC3 or MDC4 is required.