SCET Workshop 2022

Session

TMDs and PDFs

20 Apr 2022, 14:00

University of Bern

17. Factorization connecting TMDs in SCET and lattice QCD

Stella Schindler

20/04/2022, 14:00

SCET enables the factorization of cross-sections into perturbative and non-perturbative components. The resulting non-perturbative functions are typically modeled with essentially no direct input from lattice QCD calculations. The fact that their dynamics are dominated by the lightcone typically renders them inaccessible to direct lattice QCD calculations due to a sign problem, a speculated...

9. Precision Phenomenology of Unpolarized Semi-Inclusive Deep Inelastic Scattering in Effective Field Theory

Justin Lieffers

20/04/2022, 14:30

Factorization of Semi-Inclusive Deep Inelastic Scattering (SIDIS) has been derived in multiple ways using the methods of perturbative QCD, and more recently soft collinear effective theory (SCET). In this work, we carry out precision phenomenology for Jefferson Lab experiments and possible experiments at the electron-ion collider. We work to next-to-leading order in matching, and...

6. TMD operator expansion at NLP

Ignazio Scimemi

20/04/2022, 15:00

The understanding of cross sections differential in transverse momenta are known to be factorizable with TMD in the low energy spectrum. In order achieve a complete description it is necessary to explore the power expansion that allows this factorization beyond the leading order. We have have recently considered a systematic method to perform the power expansion and the complete basis of...

3. TMD distributions at the next-to-leading power

Alexey Vladimirov

20/04/2022, 15:30

The TMD factorization at the next-to-leading power has an involved structure of singularities. I discuss the definition and properties of transverse momentum dependent (TMD) distributions of the twist-three including evolution, symmetry relations, parametrization, interpretation, and singularities. I demonstrate that the physical TMD distributions (those express cross-sections) require an...

33. Factorization for Subleading Power TMD Observables

Anjie Gao

20/04/2022, 16:30

TMD distributions depending on the azimuthal angle provide a non-trivial example of observables that start at O(lambda) 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 interesting...

18. Quasi Transverse Momentum Dependent correlator @ next-to-leading power

Simone Rodini (University of Regensburg)

20/04/2022, 17:00

The theory and phenomenology of transverse-momentum dependent parton distributions (TMDs) have seen increasing activity in the past years. Factorization theorems for both leading-power (LP) and next-to-leading power (NLP) scenario has been discussed in the context of experimental processes such as Drell-Yan (DY) or SIDIS.
However, experimental determination of all TMD distributions is an...

8. Towards lattice calculations of double parton distributions

Max Jaarsma (Universiteit van Amsterdam)

20/04/2022, 17:30

In a factorization approach to double parton scattering, the initial state is described by double parton distributions (DPDs). These functions are currently poorly constrained by experiment, but provide a view on interesting correlations between partons in the hadron. We show that DPDs can be calculated from first principles using lattice QCD via the quasi-PDF approach, opening up a new way to...

28. Rapidity evolution of TMDs with running coupling (remote)

Ian Balitsky

21/04/2022, 16:30

The scale of a coupling constant for rapidity evolution of TMD operators in the Sudakov region is calculated using BLM procedure. The effective scale for a coupling constant
is halfway in logarithmical scale between the transverse momentum and energy of TMD distribution. The resulting rapidity-only evolution equation is solved for quark and gluon TMDs.

31. Pseudo- and quasi-PDFs in the BFKL approximation (remote)

Giovanni Antonio Chirilli

21/04/2022, 17:00

To calculate the PDFs from first principles in Lattice gauge theories it is convenient to consider the Ioffe-time distribution defined through gauge-invariant bi-local operators with spacelike separation. Lattice calculations provide values for a limited range of the distance separating the bi-local operators. In order to perform the Fourier transform and obtain the pseudo- and the quasi-PDFs,...

11. TMDs in dijet and heavy hadron pair production at EIC (remote)

Rafael F. del Castillo

21/04/2022, 17:30

We discuss the measurement of gluon transverse momentum distribution (TMD) in dijet and heavy hadron pair (HHP) production in semi-inclusive deep inelastic scattering. The factorization of these processes in position space shows the appearance of a specific new soft factor matrix element on top of angular and complex valued anomalous dimensions. We show in detail how these features can be...