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

中性粲介子系统是独特的，混合和衰变是由上型夸克跃迁驱动的，因此是一个强大的探测器，可以寻找标准模型之外的物理学迹象，并补充美容和K介子领域正在进行的测量。考虑到非CP对称的贡献，粲系统中的混合由四个参数表征：两个混合参数x（y），与D 0介子质量本征态之间的质量（宽度）差成比例，和两个CP破坏参数|Q/p|和phi。该研究项目旨在通过拟合衰变时间和衰变D 0->K+pi+pi-pi-的五维相空间分布来测量所有四个参数。仅在2015-16年收集的运行2 LHCb数据样本，这将是一个比以往任何时候都更大的信号样本，提供世界领先的精度。主要的挑战包括选择一个振幅模型来描述Cabibbo青睐和双重Cabibbo抑制衰变的相空间依赖性;考虑衰变时间和相空间变量的非均匀效率;以及理解背景源。

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.