ISSN - 03702693, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 1998, vol. 434, p. 426-436
Study of dynamics of θ → π+π- π0 decay with CMD-2 detector
A study of the θ → π+ π- π0 decay mode has been performed using a data sample of about 2.0 million θ decays collected by the CMD-2 detector at VEPP-2M collider in Novosibirsk. The following parameters of the θ-meson have been measured: Br(θ → π+ π- π0) = 0.145 ± 0.009 ± 0.003 and δθ-ω = 162 ± 17°. The analysis of the Dalitz plot showed the dominance of the θ → ρπ intermediate mechanism, the limits for the ratio of the direct amplitude of θ → 3π to that of θ → ρπ are -0.16 < a1 < 0.11 at 90% C.L. The upper limits for the probabilities of the decay modes θ → π+ π- η and direct θ → ργγ have been found for the first time: Br(θ → π+ π- η) < 3 × 10-4 and Br(θ → ργγ) < 5 × 10-4 at 90% C.L. © 1998 Published by Elsevier Science B.V. All rights reserved.