Lattice QCD simulation at the physical point and calculations of the proton decay matrix element

本项目旨在模拟物理点上的2+1风味点阵QCD，并计算物理点上的可观测值。在物理点上获得结果的最常用策略是使用手性微扰理论作为指导原则的手性外推。然而，由于夸克质量的非平凡依赖性，这种策略在手性外推中存在较大的系统误差。在这项工作中，我们实现了物理点模拟，这是晶格QCD中长期存在的问题，消除了手性外推的系统误差，并更精确地计算了可观测值。

This project aims to simulate 2+1 flavor lattice QCD on the physical point and to calculate observables at the physical point. The most popular strategy to obtain the result at the physical point is chiral extrapolation with the use of chiral perturbation theory as a guiding principle. This strategy, however, has large systematic errors from chiral extrapolation due to the nontrivial quark mass dependence. In this work, we have achieved the physical point simulation, which has been the long-standing problem in lattice QCD, to remove systematic errors from chiral extrapolation and to calculate observables more precisely.