Parton Physics from Large-Momentum Effective Field Theory

Abstract

Parton physics, when formulated as light-front correlations, are difficult to study non-perturbatively, despite the promise of light-front quantization. Recently an alternative approach to partons have been proposed by re-visiting original Feynman picture of a hadron moving at asymptotically large momentum. Here I formulate the approach in the language of an effective field theory for a large hadron momentum $P$ in lattice QCD, LaMET for short. I show that using this new effective theory, parton properties, including light-front parton wave functions, can be extracted from lattice observables in a systematic expansion of $1/P$, much like that the parton distributions can be extracted from the hard scattering data at momentum scales of a few GeV.

Figures (1)

• Figure 1: The line segment in the space direction $z$ in a frame with a high-momentum hadron is transformed into a line segment along the light-cone direction in light-front coordinates of the hadron at rest, the length is increased by the boost factor $\gamma$, which goes to infinity in the IMF.