2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/190703We consider topology changing processes in SU(2)--Higgs theory. In the Standard Model of particle physics they are accompanied by baryon--and lepton--number non--conservation. At fixed energy and multiplicity of initial state, these processes are described by classical Theta--instanton solutions. We describe these solutions and calculate the suppression exponents for the probabilities of the topology changing transitions at relatively low energies.12 pages, 5 figuresHigh Energy Physics - Theorytext