An experimental test of the analogy between radiative pion absorption and muon capture in 12C

Abstract

Abstract The yields of the analogous reactions μ − at rest + 12 C → ν + 12 B stable and π at rest − + 12 C → γ + 12 B stable have been determined detecting the 12B activity produced in a plastic scintillator by stopping π− and μ−. Under certain assumptions about the strength of the π− absorption from the mesic 2P level and about the contribution of the particle-stable excited 12B states, the ratio of the 1S capture rates obtained is R = ( Λ π γ Λ μ )( 12 C → 12 B g.s. ) = (1.99 ± 0.53) × 10 12 . The theoretically expected value is R = (1.27 ± 0.17) × 1012.