We provide state-of-the art SCETlib predictions for the $W$ and $Z/\gamma^∗$ transverse-momentum ($q_T$) distributions at the LHC at complete three-loop order in resummed perturbation theory (N$^3$LL$'$) and matched to available fixed order. We compare our predictions to high-precision measurements by the ATLAS and CMS experiments. We pay particular attention to the estimation of perturbative...
Two gluon TMDs with different Wilson line configurations have been studied intensively at small-x: the Weizsacker-Williams type and the dipole type. They have different transverse momentum dependences and thus they will correspond to two different integrated gluon distributions. However, these two distributions have exactly the same expressions in light-cone gauge. In this talk, I will discuss...
We report on the first global QCD analysis of the worm gear function g_1T, based on data from COMPASS, HERMES and Jefferson Lab. The results are compared to the Wandzura-Wilczek approximation, the large-Nc approximation, and information from lattice QCD. The talk is based on the preprint arXiv:2110.10253.
I will discuss the latest results from a global analysis of single transverse-spin asymmetries that includes data from SIDIS, electron-positron annihilation, Drell-Yan, and single-inclusive proton-proton collisions as well as constraints on transversity from lattice QCD and the Soffer bound. This aligns with Milestone 6 of the TMD Collaboration.
The large-momentum effective theory (LaMET) is a systematic approach to calculate parton physics from Euclidean approaches such as lattice QCD. With major improvements in the non-perturbative renormalization and perturbative matching, the lattice calculation of PDFs with LaMET is now entering the stage of precision control. In this talk, I will present a state-of-the-art lattice QCD...
Collins-Soper (CS) evolution kernel is critical to relate transverse-momentum-dependent parton distribution functions (TMDPDFs) at different scales. When the parton transverse momentum is small, q_T \sim \Lambda_{QCD}, the CS kernel is non-perturbative; the determination of the CS kernel in the non-perturbative regime can only be done through experiment or first-principles calculations. I will...
Drell-Yan production data have been used to extract transverse momentum dependent parton distribution functions (TMDPDFs). The evolution of these non-perturbative objects is conveniently described in $b_T$ space, which is the Fourier conjugate to transverse momentum. Both perturbative QCD calculations and non-perturbative TMD functions comprise the Drell-Yan cross section at low and high...
TMD distributions depending on the azimuthal angle provide a non-trivial example of observables that start at subleading order in the power expansion. They also have a long history, for example in 1978 Cahn showed that quark transverse momentum gives rise to an azimuthal cos(phi) asymmetry of the outgoing hadrons in semi-inclusive DIS (SIDIS). Such subleading distributions also are an...
We will present our results for TMD factorization at sub-leading power and focus on the matching of the large and small transverse momentum contribution in semi-inclusive deep inelastic scattering process (SIDIS and Drell Yan). We investigate their connection, paying special attention to azimuthal distributions such as the Cahn effect. Our results have consequences for the extension of...
In this talk, I will discuss our ongoing work in establishing a factorization and resummation formalism in Drell-Yan and Semi-Inclusive DIS which takes into consideration the evolution of TMDs at sub-leading power.
I will review results for nucleon charges and moments of momentum fraction, helicity and transversity obtained from lattice QCD and discuss systematics using the results obtained by the LANL lattice QCD team as benchmarks.
