Theory Seminar: Stella Schindler
- Theory Seminar: Stella Schindlerhttps://jlab-org.zoomgov.com/j/1611179843?pwd=M09CNTFpbFVZSW1IQlhIMGp3RUVHUT09CC F224-2252022-10-03EDT13:00:00 ~ 2022-10-03EDT14:00:0017603
Individuals joining the hybrid seminar remotely are kindly asked to provide their full names upon entering the ZoomGov event and to introduce themselves prior to asking questions of the speaker.
Speaker: Stella Schindler (MIT)
Title: Enabling lattice calculation of TMDs via factorization
Abstract: Transverse momentum distributions (TMDs) encode the three-dimensional momentum structure of quarks and gluons inside hadrons. Global fits to experimental data exhibit large uncertainties for non-perturbative parton momenta, a kinematic region where lattice QCD is typically well-positioned to provide complementary information. Unfortunately, TMD dynamics are dominated by the lightcone, which induces a so-called sign problem, an obstacle to numerics that is NP-hard in the general case. To circumvent this issue, lattice theorists typically project Wilson lines appearing in TMD matrix elements from a lightcone path onto an equal-time slice. We derive a factorization formula connecting the resulting lattice-calculable equal-time distributions (“quasi-TMDs”) to the TMDs that appear in cross-sections (Collins scheme). This formula holds at leading power to all orders in a_s, for all spins and parton flavors. This rigorously connects lattice calculations and physical TMDs for the first time, and opens the path towards computing gluon TMDs.