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...
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...
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...
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...
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...
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...
