K →πvv: New Contributions from Unit-Charged Scalars in Topcolor-Assisted Technicolor Models

We calculate the new contributions to the rare K-decays K⁺→π⁺vv and K_L →π⁰ vv from the unit-charged scalars appearing in the topcolor-assisted technicolor models. By using the square-root ansatz for the mixing matrices D_L and D_R, we find that: (a) the new contributions from top-pions π^± and b-pions H^± dominate over that from ordinary technipions π₁ and π₈; (b) for a^ts*_Ra^td_R = -1/4, the enhancements to the ratios B(K⁺→π^±vv ) and B(K_L →π⁰ vv ) from new scalars can be as large as a factor 7 and 11, respectively; (c) the theoretical predictions are still consistent with the data after including the new contributions.