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

A search for CP violation in the phase-space structures of D⁰ and D-0 decays to the final states K^-K⁺π^-π⁺ and π^-π⁺π⁺π^- is presented. The search is carried out with a data set corresponding to an integrated luminosity of 1.0 fb^-1 collected in 2011 by the LHCb experiment in pp collisions at a centre-of-mass energy of 7 TeV. For the 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^- 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.