Unravelling the High-Energy Proton Structure with Lattice QCD

In high-energy scattering experiments, the proton can be approximated by the simple parton model that emerges in the infinite momentum frame. Parton distributions are the most important quantities for us to understand the proton structure at high energy, but they are difficult to calculate from first principle approaches, especially lattice QCD. Recent years has seen fast development of the large momentum effective theory (LaMET) which allows a direct calculation of parton distributions in lattice QCD. In this talk, I will describe the formalism of LaMET, and explain how we can perform a systematic calculation of the parton distributions with controlled precision.