Hosted by: Andrew Hanlon

Abstract: Transverse momentum distributions (TMDs) encode the three-dimensional momentum structure of quarks and gluons inside hadrons. Despite improvements from experimental measurements, there is still large uncertainty in the global fitting of TMDs in the non-perturbative region when the parton transverse momentum is not large. Unfortunately, the physical TMDs that appear in cross-sections are inaccessible to direct lattice QCD calculations, as their lightcone-dominated dynamics induce a real-time sign problem. One may circumvent this issue by constructing a lattice-calculable distribution that shares the same IR physics as the desired physical distribution but that may differ in the UV; these distributions must be connected with a factorization relation. In this talk, I derive a formula connecting quasi (lattice) and Collins (physical) TMDs that holds at leading power to all orders in α_s, for all spins and parton flavors. This enables a connection between lattice calculations and physical TMDs for the first time, as well as opens the path towards computing gluon TMDs.