$K\to 3 \pi$ decay results by NA48/2 at CERN SPS

TL;DR

The NA48/2 experiment at CERN SPS measured the charge asymmetry in $K o 3\pi$ decays with high precision, providing insights into CP violation and pion rescattering effects through Dalitz plot analysis.

Contribution

This work presents the most precise measurements of the charge asymmetry parameter $A_g$ in $K o 3\pi$ decays and analyzes Dalitz plot structures for the first time in these modes.

Findings

Charge asymmetry parameter $A_g$ measured with $10^{-4}$ precision.

Dalitz plot analysis reveals effects of charged pion rescattering.

New Dalitz plot parameters determined for charged mode.

Abstract

The NA48/2 has collected the largest amount of $K\to3 \pi$. The charge asymmetry parameter $A_g$, sensitive to CP violation effects, has been measured with a precision of $10^{-4}$ (preliminary) both in the three charged pion mode ("charged" mode) and in the mode with two neutral pions in the final state ("neutral" mode). The Dalitz plot structure in the "neutral" mode will be discussed to point out the effects of the charged pion rescattering. The new preliminary measurement of the Dalitz plot parameters in the charged mode will be presented