Search for C P violation and observation of P violation in Λb0→p π-π+π- decays

A search for C P violation in the Λ_b⁰→p π^-π⁺π^- decay is performed using LHCb data corresponding to an integrated luminosity of 6.6 fb^-1 collected in p p collisions at center-of-mass energies of 7, 8 and 13 TeV. The analysis uses both triple product asymmetries and the unbinned energy test method. The highest significances of C P asymmetry are 2.9 standard deviations from triple product asymmetries and 3.0 standard deviations for the energy test method. Once the global p -value is considered, all results are consistent with no C P violation. Parity violation is observed at a significance of 5.5 standard deviations for the triple product asymmetry method and 5.3 standard deviations for the energy test method. The reported deviations are given in regions of phase space.