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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±→π±π0π0K^{\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 10−410^{-4} in the measurement of the charge asymmetry parameter Ag=(g+−g−)/(g++g−)A_g=(g^+-g^-)/(g^++g^-), where gg is the \emph{linear slope} of the Dalitz plot in the K→3πK\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 Ag=(1.8±2.6)×10−4 A_g=(1.8\pm2.6)\times 10^{-4} This result based on more than 45⋅10645\cdot10^6 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.Comment: Talk given to "Rencontres de Moriond 2006 EW" on behalf of NA48/2 collaboratio

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