2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/111302From the history of the $θ$-$τ$ puzzle and the discovery of parity non-conservation in 1956, we review the current status of discrete symmetry violations in the weak interaction. Possible origin of these symmetry violations are discussed.16 pages, 3 figuresHigh Energy Physics - Phenomenologytext