TMDs: Towards a Synergy between Lattice QCD and Global Analysis

Session

Session II

21 Jun 2023, 11:00

Center for Frontiers in Nuclear Science, Stony Brook University

9. Global extraction of unpolarized Transverse Momentum Distributions

Chiara Bissolotti (Argonne National Laboratory)

21/06/2023, 11:00

We present a global extraction of unpolarized Transverse Momentum Dependent (TMD) Parton Distribution Functions (PDFs) and Fragmentation Functions (FFs) from two different types of processes: Semi-Inclusive Deep Inelastic Scattering (SIDIS) and Drell–Yan (DY). The analysis is performed in the TMD factorization framework and is based on data from several experiments and kinematic ranges.
The...

26. Tomography of pions and protons via transverse momentum dependent distributions

Leonard Gamberg (Penn State)

21/06/2023, 11:30

I will present our work, https://inspirehep.net/literature/2628962, on the first simultaneous extraction of parton collinear and transverse degrees of freedom from low-energy fixed-target Drell-Yan data in order to compare the transverse momentum dependent (TMD) parton distribution functions (PDFs) of the pion and proton. We demonstrate that the transverse separation of the quark field encoded...

24. Three dimensional imaging in Nuclei

John Terry (UCLA)

21/06/2023, 12:00

In this talk, I'll discuss our recent work where we perform the first simultaneous global QCD extraction of the transverse momentum dependent (TMD) parton distribution functions and the TMD fragmentation functions in nuclei. We have considered the world set of data from semi-inclusive electron-nucleus deep inelastic scattering and Drell-Yan di-lepton production. In total, this data set...

17. Lattice QCD calculations of transverse momentum-dependent (TMD) observables

Michael Engelhardt (New Mexico State University)

22/06/2023, 11:00

The status of an ongoing program of evaluating TMD observables
within Lattice QCD is reviewed. These lattice calculations are
based on a definition of TMDs through hadronic matrix elements
of quark bilocal operators containing staple-shaped gauge
connections. A parametrization of the matrix elements in terms
of invariant amplitudes serves to cast them in the Lorentz frame
preferred for a...

3. Lattice calculation of the Collins-Soper kernel

Dr Hai-Tao Shu

22/06/2023, 11:30

The Collins-Soper (CS) kernel is a nonperturbative function that characterizes the rapidity evolution of transverse-momentum-dependent parton distribution functions and wave functions. In this talk, we show the determination of the CS kernel using lattice QCD in two different strategies. We compare the results obtained from these two methods and also those from literature using various methods.

18. Collins-Soper kernel from lattice QCD at the physical pion mass

Artur Avkhadiev (Massachusetts Institute of Technology)

22/06/2023, 12:00

This work presents a determination of the quark Collins-Soper kernel, which relates transverse-momentum-dependent parton distributions (TMDs) at different rapidity scales, using lattice Quantum Chromodynamics (QCD). This is the first lattice QCD calculation of the kernel at quark masses corresponding to a close-to-physical value of the pion mass, with next-to-next-leading order matching to...

29. Proton spin at small-x

Andrey Tarasov (North Carolina State University)

23/06/2023, 11:00

Resolution of the proton spin puzzle, which is inability of the constituent quark model to explain discrepancy between the spin-$1/2$ of the proton and the amount of spin carried by its quarks and gluons, as measured in experiment, is an outstanding problem in modern hadronic physics. One possibility is that ‘’missing” spin of the proton may be found at small values of Bjorken-x. I’ll give an...

25. TMD Factorization and Renormalization at Next-to-Leading Power

Anjie Gao (MIT)

23/06/2023, 11:30

Since shortly after the discovery of partons, people have thought about probing their transverse momentum inside hadrons. For example, in 1978 it was shown to give rise to an azimuthal cos(phi) asymmetry of the outgoing hadrons in the process of semi-inclusive DIS (SIDIS), known as the Cahn effect. The cos(phi) distribution, as well as a number of other asymmetries in both SIDIS and Drell-Yan,...

20. Transverse Momentum Distributions of Heavy Hadrons and Polarized Heavy Quarks

Johannes K. L. Michel (MIT CTP)

23/06/2023, 12:00

We initiate the study of transverse momentum-dependent (TMD) fragmentation functions for heavy quarks, demonstrate their factorization in terms of novel nonperturbative matrix elements in heavy-quark effective theory (HQET), and prove new TMD sum rules that arise from heavy-quark spin symmetry. We discuss the phenomenology of heavy-quark TMD FFs at $B$ factories and find that the Collins...