Twist - 3 contribution to the γ ∗ γ → ππ amplitude in the Wandzura - Wilczek approximation ∗
نویسندگان
چکیده
We have calculated the Wandzura-Wilczek contribution to the twist-3 part of γ * γ → 2π amplitude. It describes interaction of the longitudinally polarized virtual photon with the real one, and it is suppressed by 1/Q, where Q 2 is the virtuality of the γ * , as compared to the twist-2 contribution. We have found that, in the Wandzura-Wilczek approximation, factorization applies to the twist-3 amplitude.
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