Search for CP violation in D0→π−π+π0D0→π−π+π0 decays with the energy test

A search for time-integrated CP   violation in the Cabibbo-suppressed decay D0→π−π+π0D0→π−π+π0 is performed using for the first time an unbinned model-independent technique known as the energy test. Using proton–proton collision data, corresponding to an integrated luminosity of 2.0 fb−12.0 fb−1 collected by the LHCb detector at a centre-of-mass energy of s=8 TeV, the world's best sensitivity to CP violation in this decay is obtained. The data are found to be consistent with the hypothesis of CP symmetry with a p  -value of (2.6±0.5)%(2.6±0.5)%.