Semileptonic Kaon Decays

TL;DR

This paper provides detailed theoretical calculations of various semileptonic kaon decay processes using Chiral Perturbation Theory, compares predictions with experimental data, and discusses implications for understanding the Standard Model.

Contribution

It offers next-to-leading order matrix elements for multiple kaon decay modes and estimates higher-order effects for $K_{l4}$ decays, enhancing theoretical precision.

Findings

Predictions align with experimental data within uncertainties.

Higher-order effects are estimated to reduce theoretical uncertainties.

Monte Carlo simulations are used for decay rate calculations.

Abstract

We present the matrix elements for the semileptonic kaon decays $K_{l2\gamma}$ , $K_{l2l^+l^-}$, $K_{l2l'^+l'^-}$,$K_{l3}$, $K_{l3\gamma}$ and $K_{l4}$ at next-to-leading order, and $K_{e5}$ at leading order in Chiral Perturbation Theory and compare the predictions with experimental data. For $K_{l4}$ decays we estimate yet higher orders in order to reduce theoretical uncertainties in the comparison with the data. Monte Carlo event generators are used to calculate the corresponding rates at DA$\Phi$NE. We discuss the possibilities to improve our knowledge of the low-energy structure of the Standard Model at this and similar machines.