LHCb searches for the strong CP-violating decays η → ππ and η′ → ππ

Abstract

Abstract.A search for the CP-violating strong decays η → π + π − and η (958) → π + π − has been performed using approximately 2.5 × 10 7 events of each of the decays at 90% confidence level are set on the branching fractions, B(η → π + π − ) < 1.6 × 10 −5 and B(η → π + π − ) < 1.8 × 10 −5 . The limit for the η decay is comparable with the existing one, while that for the η is a factor of three smaller than the previous limit.