Zhiquan Sun, UC Berkeley, [HET Seminar] Strongly Coupled Soft Function

Thursday 11 Jun 2026, 11:00 → 13:00 US/Eastern

Small Seminar Room

We introduce a simple observable for heavy quark transverse momentum-dependent (TMD) fragmentation which is a vacuum expectation value of a pair of Wilson lines with cusps. The renormalization of operators built out of Wilson lines that meet at an angle (cusp) involve what is known as the cusp anomalous dimension, a universal object appearing in many processes in QCD due to the divergences from gluonic interactions. In this talk, we discuss the extraction of the cusp anomalous dimension at strong coupling for the heavy quark TMD fragmentation observable, through a computation of the expectation value of the Wilson loop in a gauge theory that is tractable at strong coupling via the AdS/CFT correspondence. This approach is complementary to perturbative calculations of the cusp anomalous dimension. We give an introduction of calculating Wilson loop expectation values in AdS/CFT using the toy example of one cusp in Minkowski space, then discuss the application to our case which has two cusps separated in the transverse direction.

https://bnl.zoomgov.com/j/16010362754?pwd=Z1l1SS9JUDlyR1hSUHNyaDV1dTZHUT09