Search for direct CP violation in $K^{\pm} \to \pi^{\pm}\pi^{+}\pi^{-}$ decays by NA48/2

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 $K^{\pm} \to \pi^{\pm}\pi^{+}\pi^{-}$ Dalitz plot slope, Ag, has been measured to Ag = $(0.5 \pm 3.8) \times 10^{-4}$. This result is more than an order of magnitude more precise than results of previous experiments.