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$Υ(1s)\toγf_2(1270)$ Decay

Decay $Υ(1s)\toγf_2(1270)$ is studied by an approach in which the tensor meson, $f_2(1270)$, is strongly coupled to gluons. Besides the strong suppression of the amplitude $Υ(1s)\toγgg, gg\to f_2$ by the mass of b-quark, d-wave dominance in $Υ(1s)\toγf_2(1270)$ is revealed from this approach, which provides a large enhancement. The combination of these two factors leads to larger $B(Υ(1s)\toγf_2(1270))$. The decay rate of $Υ(1s)\toγf_2(1270)$ and the ratios of the helicity amplitudes are obtained and they are in agreement with data.