Measurement of the quadratic slope parameter in the K_L -> 3\pi^0 decay Dalitz plot

TL;DR

This paper reports the most precise measurement to date of the quadratic slope parameter in the Dalitz plot for the decay of neutral kaons into three neutral pions, using a large dataset from the NA48 experiment.

Contribution

It provides the first highly precise measurement of the quadratic slope parameter h in K_L -> 3π^0 decay Dalitz plot, improving the understanding of kaon decay dynamics.

Findings

Quadratic slope parameter h = (-6.1 +- 0.9_stat +- 0.5_syst) x 10^{-3}

Based on 14.7 million reconstructed decays

Most precise measurement of Dalitz plot slope parameters in kaon decays

Abstract

A value of (-6.1 +- 0.9_{stat} +- 0.5_{syst})*10^{-3} is obtained for the quadratic slope parameter h in the K_L -> 3\pi^0 decay Dalitz plot at the NA48 experiment at the CERN SPS. The result is based on 14.7*10^6 fully reconstructed K_L -> 3\pi^0 -> 6\gamma decays. This is the most precise measurement of any of the Dalitz plot slope parameters in the charged and neutral kaon decays so far.