Measurement of the KL meson lifetime with the KLOE detector

TL;DR

This paper reports the most precise measurement to date of the KL meson lifetime using the KLOE detector, based on a large sample of decay events from phi meson pairs.

Contribution

It provides a highly accurate measurement of the KL lifetime, improving precision over previous results using the KLOE detector and a large data sample.

Findings

KL lifetime measured as 50.92 ± 0.17 (stat) ± 0.25 (syst) ns

Large sample of 15 million KL decays used for analysis

First measurement with this level of precision using the KLOE detector.

Abstract

We present a measurement of the KL lifetime using the KLOE detector. From a sample of 4 x 10^8 KS KL pairs following the reaction e+ e- -> phi -> KS KL we select 15 x 10^6 KL -> p0 p0 p0 decays tagged by KS -> pi+ pi- events. From a fit of the proper time distribution we find tau_L = (50.92 +- 0.17{stat} +- 0.25{syst})$ ns. This is the most precise measurement of the KL lifetime performed to date.