// Abstract interfaces
  virtual BtaCandidate* recoFromMC(BtaCandidate const *mc, int which = 0, bool checkMassHypo=false) const = 0 ;

 virtual BtaCandidate* mcFromRecoComposite(BtaCandidate const *reco, int which =0, bool checkMassHypo=false, bool FSR=false) const;