The object of our interest is few-nucleon systems. Typically, it concerns hydrogen, deuterium or tritium nuclei in the processes of their creation, decay and interaction among each other. The systems are studied by means of different approaches and methods working with nucleons as elementary objects. The processes which we dealt or which we deal now are: deuteron electro- and photodisintegration, muon capture in hydrogen, and kaon capture by baryons. In particular, our work results in two types of outputs:

• phenomenological hadron Lagrangians;
• PT-symetric Hamiltonians.