COUPLING gϕa0γ AND gϕσγ IN LIGHT-CONE SUM-RULES

Abstract

In this paper, we calculate the coupling constants gϕa0γ and gϕσγ by utilizing ω–ϕ mixing scheme and taking into account the contributions of the three-particle twist-4 distribution amplitudes of the photon in the light-cone sum-rule approach. Our results: (1) 0.130 ≤ gϕa0γ ≤ 0.194 is in agreement with the previous estimations of these coupling constants which obtained from phenomenological considerations but less than the experimental value gϕa0γ = 1.64±0.05; (2) 0.055 ≤ gϕσγ ≤ 0.076 is consistent with the phenomenological value and the experimental value gϕσγ = 0.060±0.008.