Model-independent search for CP   violation in D⁰→K⁻K⁺π⁻π⁺D0→K−K+π−π+ and D⁰→π⁻π⁺π⁺π⁻D0→π−π+π+π− decays

A search for CP   violation in the phase-space structures of D⁰D0 and D¯0 decays to the final states K⁻K⁺π⁻π⁺K−K+π−π+ and π⁻π⁺π⁺π⁻π−π+π+π− is presented. The search is carried out with a data set corresponding to an integrated luminosity of 1.0 fb⁻¹1.0 fb−1 collected in 2011 by the LHCb experiment in pp   collisions at a centre-of-mass energy of 7 TeV7 TeV. For the K⁻K⁺π⁻π⁺K−K+π−π+ final state, the four-body phase space is divided into 32 bins, each bin with approximately 1800 decays. The p-value under the hypothesis of no CP violation is 9.1%, and in no bin is a CP   asymmetry greater than 6.5% observed. The phase space of the π⁻π⁺π⁺π⁻π−π+π+π− final state is partitioned into 128 bins, each bin with approximately 2500 decays. The p-value under the hypothesis of no CP violation is 41%, and in no bin is a CP asymmetry greater than 5.5% observed. All results are consistent with the hypothesis of no CP violation at the current sensitivity.