T-odd correlation in the Kl3γ decay

The dependence of the K+→π0l+νlγ decay width on the T-odd kinematical variable ξ=q(vector sign)·[p(vector sign)lxp(vector sign)π]/M3 is studied at the tree and one-loop levels of the standard model (SM). It is shown that at the tree level this decay width is an even function of ξ, while the odd contribution arises due to the electromagnetic final state interaction. This contribution is determined by the imaginary parts of the one-loop diagrams. The calculations performed show that the ξ-odd contribution to the K+→π0e+νeγ and K+→π0μ+νμγ decay widths is four orders of magnitude smaller than the even contribution coming from the tree level of the SM