On K → ππ Decays in Quenched and Unquenched Chiral Perturbation Theory
نویسندگان
چکیده
We calculate the logarithmic corrections to the matrix elements for K → π and K → vacuum (which are used on the lattice to determine K → ππ amplitudes), in one-loop quenched and unquenched Chiral Perturbation Theory. We find that these corrections can be large. We also discuss, and present some results for, the direct determination of K → ππ amplitudes. In particular, we address effects from choosing ms = md and vanishing external spatial momenta, finite volume and quenching. In the quenched octet case, we find enhanced finite-volume contributions which may make numerical estimates of this matrix element unreliable for large volumes.
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