Search for direct CP violation in the decays K±→3π±

We report a measurement of the direct CP violation asymmetry parameter Ag in charged kaon decays K±→π±π+π− by the NA48/2 experiment at the CERN SPS. The experiment has been designed not to be limited by systematics in the asymmetry measurement. Using 1.67×109 such decays collected during the 2003 run, the charge asymmetry in the Dalitz plot linear slope parameter g has been measured to be Ag=(1.7±2.9)×10−4. The precision of the result is limited by the statistics used.