Search for Direct CP Violation in K+-->pi+-pi+pi- Decays by NA48/2

TL;DR

The NA48/2 experiment at CERN measured the direct CP-violating parameter in charged kaon decays to three pions, achieving a more precise result that constrains CP violation effects.

Contribution

First preliminary measurement of Ag in K+-->pi+-pi+pi- decays with unprecedented precision using over 1.6 billion kaon decays.

Findings

Ag measured as (0.5 ± 3.8) x 10^-4

Result significantly more precise than previous measurements

No evidence of direct CP violation observed

Abstract

First preliminary measurement of the direct CP-violating parameter Ag by the NA48/2 experiment at CERN SPS is presented. Using more than 1.6 billions of charged kaon decays into three charged pions, the charge asymmetry in the K+-->pi+-pi+pi- Dalitz plot slope, Ag, has been measured to Ag = (0.5 +- 3.8) x 10^-4. This result is more than an order of magnitude more precise than results of previous experiments.