Recent measurements of branching fractions and $CP$ asymmetries of charmless hadronic $B$ meson decays at Belle

Abstract

Hadronic B decays without a charm quark constitute a powerful probe to search for physics beyond the standard model as well as to provide constraints on CP violation parameters. We report final measurements from Belle of the branching fractions and CP asymmetries for the decays B 0 → π 0 π 0 and B ± → K + K − π ± . The B 0 → π 0 π 0 measurements enable us to improve constraints on the angle φ 2 of the CKM unitarity triangle. For B ± → K + K − π ± we measure CP asymmetry as a function of the invariant mass of the K + K − system, where we find a strong evidence for large CP violation and a large increase in yield at low mass region. This result challenges conventional theoretical approaches as it requires a large enhancement in both tree and loop level diagrams in the same small region of phase-space.