2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/162224Possible influence of the weak interaction on the $μ^+ + μ^- \to μ^+ + μ^- $ scattering and the $μ^+ + μ^- \to e^+ + e^- $ reaction, both through the neutral lepton currents and the charged ones (in the second order on weak constant), are considered. The calculations show that $P$ - odd effects in the mentioned processes would prove the existence of the neutral currents which, in their turn, give the principal basis for explanation of the mass difference of a muon and an electron from the point of view of Ref. [1].20 pages, 2 tables, 4 figures. Original version in Russian is also includedHigh Energy Physics - Phenomenologytext