Radiative decays of ρ and ω mesons

Abstract

The results of the measurements of radiative decays of ρ and ω mesons with the Neutral Detector at thee ⁺ e ⁻ collider VEPP-2M are presented. The branching ratio of the decay ω→π ⁰γ was measured with higher than in previous experiments accuracy:

$${\rm B}(\omega \to \pi ^0 \gamma ) = 0.0888 \pm 0.0062$$

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The ρ⁰→π ⁰ γ branching ratio was measured for the first time:

$$B(\rho ^0 \to \pi ^0 \gamma ) = (7.9 \pm 2.0) \cdot 10^{ - 4} $$

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The decays ρ, ω→ηγ were studied. Their branching ratios with the assumption of constructive ρ−ω interference are:

$$\begin{gathered} B(\omega \to \eta \gamma ) = (7.3 \pm 2.9) \cdot 10^{ - 4} , \hfill \\ B(\rho \to \eta \gamma ) = (4.0 \pm 1.1) \cdot 10^{ - 4} \hfill \\ \end{gathered} $$

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The branching ratios of ρ, ω→ηγ and ω→e ⁺ e ⁻ decays were also measured:

$$\begin{gathered} B(\omega \to \pi ^ + \pi ^ - \pi ^0 ) = 0.8942 \pm 0.0062, \hfill \\ B(\omega \to e^ + e^ - ) = (7.14 \pm 0.36) \cdot 10^{ - 5} \hfill \\ \end{gathered} $$

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The upper limit for the ω→π ⁰ π ⁰ γ branching ratio was placed:

B(ω→π ⁰ π ⁰ γ)<4·10⁻⁴ at 90% confidence level.