New results on direct CP violation in charged kaon decays by NA48/2

Abstract

The NA48/2 result, based on the data collected during the 2003 run, on direct CP violation in $K^{\pm }\to {\pi }^{\pm }{\pi }^0{\pi }^0$ decay is presented. The main goal of the experiment is to reach a sensitivity at level of $10^{-4}$ in the measurement of the charge asymmetry parameter $A_g=(g^{+}-g^{-})/(g^{+}+g^{-})$, where $g$ is the \emph{linear slope} of the Dalitz plot in the $K\to 3\pi$ decay. Thanks to the simultaneous collection of the two kaon charges and to the high resolution of the main sub-detectors, the systematics uncertainties are kept under the statistical error level. The experimental procedure, the analysis technique and the main systematics are discussed to present the final result $$A_g=(1.8\pm 2.6)\times 10^{-4}$$ This result based on more than $45\cdot 10^6$ events, correspondig to one half of the whole two year data taking, is about an order of magnitude more precise with respect to the previous measurement.

Talk given to "Rencontres de Moriond 2006 EW" on behalf of NA48/2 collaboration

References in corpus (5)

• $K^{+}\to {\pi }^{+}\nu \bar{\nu }$: a rising star on the stage of flavour physics
• Search for direct CP violation in the decays K\pm \to 3π\pm
• Measurements of the Charge Asymmetry of the Dalitz Plot Parameters for $K^{\pm }\to {\pi }^{\pm }{\pi }^0{\pi }^0$ Decays
• CP violation in $K^{\pm }\to {\pi }^0{\pi }^0{\pi }^{\pm }$ decay
• Charged Kaon K -> 3 pi CP Violating Asymmetries