Large-momentum effective theory for parton physics

Octubre 30, 2020
De 3:00pm hasta 4:00pm

Webinar of the series "Hadron Structure(s) from First Principles"

Specialist level
Xiangdong Ji
University of Maryland

Webinar of the series "Hadron Structure(s) from First Principles"


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 terms 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 |Pz = \infty>. This representation lays the foundation of large-momentum effective theory (LaMET) which approximates parton physics through a systematic M/Pz expansion of the lattice QCD matrix elements at a finite but large momentum Pz, and removes the residual logarithmic-Pz dependence by the standard effective-field theory matching and running.