Intermediate vector meson contributions to V0→P0P0γ decays

Scalar meson exchange in θ → P0P0γ decays

“…The intermediate vectors exchanged are V = V ′ = ρ for φ → π 0 π 0 γ, V = ρ and V ′ = ω for φ → π 0 ηγ, and V =K * 0 and V ′ = K * 0 for φ → K 0K 0 γ. The calculated branching ratios B VMD φ→π 0 π 0 γ = 1.2 × 10 −5 , B VMD φ→π 0 ηγ = 5.4 × 10 −6 and B VMD φ→K 0K 0 γ = 2.7 × 10 −12 [6] are found (for the first two processes) to be substantially smaller than the experimental results.…”

“…[6] using the vector me-son dominance (VMD) model. In this framework, the V → P 0 P 0 γ decays proceed through the decay chain V → V P 0 → P 0 P 0 γ.…”

Higher meson resonances inρ→π0π0γOh1, Kim2 2003Phys. Rev. D10320View full textAdd to dashboardCite

“…Since the lowest pseudoscalar mesons are not allowed in the intermediate state, an important contribution is expected to come from the vector meson channel, i.e., when M = ω or ρ. However, the estimate [8] based on the vector meson dominance, ρ → (ω)π 0 → γπ 0 π 0 and ω → (ρ)π 0 → γπ 0 π 0 , gives too small decay widths for both decays compared with the experimental data. The momentum-dependent decay width of the intermediate vector meson and the ρ-ω mixing are found to improve the situation only slightly [9].…”

“…The decay widths were estimated in the scheme of current algebra [6] or with SU(3) chiral Lagrangian [7,8]. For ρ, ω → π 0 π 0 γ decays at the tree level, one considers the two diagrams shown in Fig.…”

Finite width effects in φ radiative decays

“…As in refs. [12,16,7] we consider the K + K − meson loop contribution to the decay φ → γM 0 N 0 , fig.1, since the K + K − system strongly couples to both the φ and R resonances. In addition, since the K 0K 0 couples with the same strength as the K + K − state both to the scalar and φ resonances, we also allow for a neutral kaon loop contribution, as indicated in fig.1a, where the vertex on the left of the figure is discussed in length below.…”