Why is LaMET an effective field theory for partonic structure?

Understand

Partons are effective degrees of freedom describing the structure of hadrons involved in high-energy collisions.

• Familiar theories of partons are QCD light-front quantization and soft-collinear effective theory, both of which are intrinsically Minkowskian and appear unsuitable for classical Monte Carlo simulations.
• A ``new'' form of the parton theory has been formulated in term of the old-fashioned, Feynman's infinite momentum frame, in which the parton degrees of freedom are filtered through infinite-momentum external states.
• The partonic structure of hadrons is then related to the matrix elements of static (equal-time) correlators in the state $|P^z=\infty\rangle$.