Theory and applications of parton pseudodistributions

Understand

We review the basic theory of the parton pseudodistributions approach and its applications to lattice extractions of parton distribution functions.

• The crucial idea of the approach is the realization that the correlator $M(z,p)$ of the parton fields is a function ${\cal M} (\nu, -z^2)$ of Lorentz invariants $\nu =-(zp)$, the Ioffe time, and the invariant interval $z^2$.
• This observation allows to extract the Ioffe-time distribution ${\cal M} (\nu, -z^2)$ from Euclidean separations $z$ accessible on the lattice.
• Another basic feature is the use of the ratio ${\mathfrak M} (\nu,-z^2) \equiv {\cal M} (\nu, -z^2)/{\cal M} (0, -z^2)$, that allows to eliminate artificial ultraviolet divergence generated by the gauge link for space-like intervals.