Measurement of neutral charm meson mixing and CP violation parameters using D0->K3Pi decays with LHCb Run 2 data

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The neutral charm meson system is unique, with mixing and decay being driven by up-type quark transitions, and so is a powerful probe to search for signs of physics beyond the standard model, and complement ongoing measurements in the beauty and kaon sectors. Allowing for non-CP-symmetric contributions, mixing in the charm system is characterised by four parameters: two mixing parameters x (y), proportional to the mass (width) difference between D0 meson mass eigenstates, and two CP violation parameters |q/p| and phi. This research project aims to measure all four parameters by a fitting to the decay time and five-dimensional phase-space distributions of the decay D0->K+pi+pi-pi-. With the Run 2 LHCb data sample collected in 2015-16 alone, this will be a far larger signal sample than ever previously analysed, giving world-leading precision. Major challenges include picking an amplitude model to describe the phase-space dependence of the Cabibbo-favoured and doubly-Cabibbo-suppressed decays; accounting for non-uniform efficiency over the decay-time and phase-space variables; and understanding the background sources.