ISSN - 15507998, Physical Review D - Particles, Fields, Gravitation and Cosmology, 2013, vol. 87, p. -
Measurements of ψ′→p̄K+Σ0 and χcJ→p̄K+Λ
Using a sample of 1.06×108 ψ′ mesons collected with the BESIII detector at the BEPCII e+e- collider and χcJ mesons produced via radiative transitions from the ψ′, we report the first observation for ψ′→p̄K+Σ0+c.c. (charge conjugate), as well as improved measurements for the χcJ hyperon decays χcJ→p̄K+Λ+c.c. The branching fractions are measured to be B(ψ′→p̄K +Σ0+c.c.)=(1.67±0.13±0.12)×10-5, B(χc0→p̄K+Λ+c.c.)=(13.2±0. 3±1.0)×10-4, B(χc1→p̄K +Λ+c.c.)=(4.5±0.2±0.4)×10-4, and B(χc2→p̄K+Λ+c.c.)=(8.4±0. 3±0.6)×10-4, where the first error is statistical, and the second is systematic. In the decay of χc0→p̄K +Λ+c.c., an anomalous enhancement near threshold is observed in the invariant mass distribution of p̄Λ+c.c., which cannot be explained by phase space. © 2013 American Physical Society.