2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/122030The current results on B to pipi decays and SU2 constraints on the Unitarity Triangle angle alpha or phi_2 from the B-factories are summarised. Based on these measurements, predictions of the isospin analysis constraints at the end of the lifetime of both B-factories are given.Proceedings to the 4th International Workshop on the CKM Unitarity Triangle (CKM06)High Energy Physics - Experimenttext