Determination of Vus at the KLOE experiment: present results and future perspectives

TL;DR

This paper reports on precise measurements of kaon decay rates at KLOE, testing CKM matrix unitarity and lepton universality, and discusses future prospects with the upgraded KLOE-2 detector.

Contribution

It presents the latest results from KLOE on Vus measurements and outlines future plans with the KLOE-2 upgrade to improve these tests.

Findings

Precise Vus measurements from KLOE data

Confirmation of CKM unitarity within current uncertainties

Future improvements expected from KLOE-2 upgrades

Abstract

Precise measurements of semileptonic kaon decay rates at KLOE provide the measurement of the CKM mixing matrix element \vus\ and information about lepton universality. Leptonic kaon decays provide an independent measurement of $\abs{\vus}^2/\abs{\vud}^2$, through the ratio $\Gamma(K\to\mu \nu)/\Gamma(\pi\to\mu \nu)$. These measurements, together with the result of $|\vud|$ from nuclear $\beta$ transitions, provide the most precise test of CKM unitarity, allowing the universality of lepton and quark weak couplings to be tested. After the completion of the KLOE data taking, the proposal of a new run with an upgraded KLOE detector, KLOE-2, at an upgraded Dafne machine has been accepted by INFN and it is now starting. Present results from KLOE and future perspectives from KLOE-2 are reported.