New results from KLOE

TL;DR

This paper presents the most precise measurement of Vus from kaon decays using the KLOE detector, along with new tests of CPT symmetry and quantum mechanics, achieving results with about 0.9% error.

Contribution

It provides a comprehensive set of experimental inputs for Vus and Vus/Vud, and introduces new tests of fundamental symmetries using KLOE data.

Findings

Vus determined with ~0.9% error

New measurement of Vus/Vud ratio

First measurement of charged asymmetry in KS -> pi e nu decay

Abstract

The most precise determination of Vus comes from semileptonic kaon decays. We have measured with the KLOE detector at DAFNE, the Frascati phi-factory, all the experimental inputs to Vus for both neutral and charged kaons. Using our results we extract the value of Vus with ~0.9% fractional error, which is dominated by the theoretical error on the form factor, f+(0). A new determination of the ratio Vus/Vud is also presented, based on our precise measurement of the absolute branching ratio for the decay K -> mu nu (gamma), combined with lattice results for the ratio f_K/f_pi. New results on CPT symmetry and quantum mechanics test have also been achieved, which are based on the first measurement of the charged asymmetry for KS -> pi e nu decay and on interferometry studies using the phi -> KL KS -> pi+ pi- pi+ pi-.