New measurements of the $\eta$ and $K^0$ masses

TL;DR

This paper reports new precise measurements of the $ ext{eta}$ and $ ext{K}^0$ meson masses using decay data from the NA48 detector at CERN, achieving improved accuracy over previous results.

Contribution

The study introduces a novel measurement approach using symmetric decays to minimize systematic uncertainties in meson mass determination.

Findings

Measured $M( ext{eta})$ as 547.843±0.051 MeV/c$^2$

Measured $M( ext{K}^0)$ as 497.625±0.031 MeV/c$^2$

Achieved improved precision in meson mass measurements.

Abstract

New measurements of the $\eta$ and $K^0$ masses have been performed using decays to 3$\pi^0$ with the NA48 detector at the CERN SPS. Using symmetric decays to reduce systematic effects, the results $M(\eta) = 547.843\pm0.051$ MeV/c$^2$ and $M(K^0) = 497.625\pm0.031$ MeV/c$^2$ were obtained.