On the π+ π- atom properties

Properties of π+π- atom are discussed. In the framework of the virton-quark model (VQM) the principal properties of the π+π- atom are calculated, viz., the binding energy, the wave function at the origin, the 2s-2p-level difference, and the lifetime. It turned out that the binding energy and wave function in origin are determined mainly by π+, π- mesons electromagnetic interaction. The A2π atom lifetime is determined by the difference of S-wave ππ scattering lengths. The lifetime values calculated within the VQM framework as well as other approaches are given