Search for CP violation in $D^0\to {\pi }^{-}{\pi }^{+}{\pi }^0$ decays with the energy test

Abstract

A search for time-integrated CP violation in the Cabibbo-suppressed decay $D^0\to {\pi }^{-}{\pi }^{+}{\pi }^0$ 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 $2.0{\text{fb}}^{-1}$ collected by the LHCb detector at a centre-of-mass energy of $\sqrt{s}=8\text{TeV}$, 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 $(2.6\pm 0.5)\text{\%}$.