QCD Evolution 2024

Session

Tuesday

28 May 2024, 09:00

Aula Foscolo (University of Pavia)

Conveners

Tuesday: morning / 1

• Alexey Prokudin (JLAb)

Tuesday: morning / 2

• Alexey Prokudin (JLAb)

Tuesday: afternoon / 1

• Barbara Pasquini (Istituto Nazionale di Fisica Nucleare)

Tuesday: afternoon / 2

• Bowen Xiao (The Chinese University of Hong Kong-(Shenzhen))

46. High-Energy Behavior of pseudo- and quasi-PDFs: Implications for Lattice Calculations

Giovanni Antonio Chirilli (University of Salento)

28/05/2024, 09:00

Pseudo and quasi-PDFs are key tools to compute parton distribution functions (PDFs) directly on the lattice.
However, using the lattice to make these calculations has its challenges. To get the Bjorken-x dependence from the bi-local operator, one needs to know the behavior of these operators for large values of the momentum hadronic target.
Lattice calculation, on the other hand, can provide...

12. SIDIS at small x: Sudakov double logs from NLO corrections

Jamal Jalilian-Marian, Jamal Jalilian-Marian (Baruch College)

28/05/2024, 09:30

We calculate the next to leading order corrections to SIDIS at small Bjorken x using the color glass condensate formalism. We first show that all UV and soft divergences cancel. We then show that collinear divergences are absorbed into DGLAP evolution of quark-hadron fragmentation function while the rapidity divergences are absorbed into BK/JIMWLK evolution of dipoles. We finally show that...

27. $1/Q^2$ power corrections to TMD factorization for Drell-Yan hadronic tensor

Ian Balitsky

28/05/2024, 10:00

I present the full list of $\frac{1}{Q^2}$ power corrections to unpolarized Drell-Yan hadronic tensor for electromagnetic (EM) current at large $N_c$ and demonstrate EM gauge invariance at this level.

30. TMD factorization: Bridging large x and small x

Shaswat Tiwari (North Carolina State University)

28/05/2024, 11:00

QCD factorization takes on different forms in the large-x and the small-x regimes. In the large-x motivated collinear factorization, one gets the DGLAP evolution equation, whereas, in the small-x motivated rapidity factorization, the BFKL equation is the major player. To unify different regimes, a new TMD factorization based on the background field method is proposed, which not only reduces to...

50. Energy-Energy Correlation in the back-to-back region at N3LL+NNLO in QCD

Giancarlo Ferrera (University of Milan and INFN, Milan)

28/05/2024, 11:30

We consider the Energy-Energy Correlation function in electron-positron annihilation to hadrons. We concentrate on the back-to-back region, performing all-order resummation of the logarithmically enhanced contributions in QCD perturbation theory, up to next-to-next-to-next-to-leading logarithmic (N3LL) accuracy. Away from the back-to-back region, we consistently combine resummed predictions...

52. Parton pseudo-Distributions and their evolution

Joseph Karpie (Jefferson Lab)

28/05/2024, 12:00

The calculation of parton distributions of the nucleon is a requisite for understanding hadronic cross sections in terms of quarks and gluons. Over the last decade many calculations from first principles lattice QCD have begun through matrix elements which can be factorized similarly to cross sections. In this talk, I will highlight our calculations using the pseudo-PDF approach and its...

53. Explore Nucleon Tomography Through Correlation Measurements

Feng Yuan (Lawrence Berkeley Lab)

28/05/2024, 14:30

Correlation measurements in DIS and pp collisions provide unique opportunity to explore nucleon structure, including TMDs, GPDs, and more recently Wigner distributions. In this talk, I will review some of recent studies, which can be explored at the current and future facilities, such as JLab 12 GeV, EIC and LHC.

13. Recent progress in the determination of GPDs and TMDs in lattice QCD

Prof. Constantia Alexandrou (University of Cyprus & The Cyprus Institute)

28/05/2024, 15:00

Lattice QCD simulations are nowadays being done with physical values of the light, strange and charm quark masses. These state-of-the-art gauge ensembles are enabling precision hadron structure studies. Mellin moments are extracted at the physical point providing information of the momentum fraction and angular momentum carried by quarks and gluons in hadrons. In parallel, new theoretical...

14. Gluon TMD modeling & proton 3D imaging

Dr Francesco Giovanni Celiberto (UAH Madrid)

28/05/2024, 15:30

We present exploratory studies of the 3D gluon content of the proton, as a result of analyses on leading-twist transverse-momentum-dependent (TMD) gluon distribution functions, calculated in a spectator model for the parent proton. Our formalism embodies a fit-based parameterization for the spectator-mass density, suited to describe both the small-x and the moderate-x regime. Particular...

29. Breakdown of collinear factorisation in exclusive ${\pi }^0\gamma$ photoproduction due to Glauber pinch

Saad Nabeebaccus (IJCLab)

28/05/2024, 16:30

In this talk, I will discuss our work in 2311.09146, regarding the breakdown of collinear factorisation in the exclusive photoproduction of a ${\pi }^0\gamma$ pair. Such a process is sensitive to both quark and gluon GPD channels. In the latter case, the amplitude fails to factorise, due to the presence of a Glauber pinch, which has the same power counting as the collinear pinch. The Glauber...

4. Leading-Twist Flavor Singlet Quark TMDs at Small-x

Yossathorn Tawabutr (University of Jyväskylä)

28/05/2024, 17:00

We study the small-$x$ asymptotics of the flavor singlet, leading-twist quark transverse-momentum-dependent parton distribution functions (TMDs) via the eikonal expansion of quark propagator and the gauge link, expressing the TMD operator definitions at small-$x$ in terms of polarized dipole amplitudes, which involve an insertion of appropriate spin-dependent parton-exchange vertices into the...

23. Exclusive and semi-inclusive diffractive processes in the shockwave approach

Michael Fucilla

28/05/2024, 17:30

The center-of-mass energies available at modern accelerators, such as the Large Hadron Collider (LHC), and at forthcoming generation accelerators, such as the Electron-Ion Collider (EIC), offer us a unique opportunity to investigate hadronic matter under the most extreme conditions ever reached. In particular, they allow access to the so-called \textit{Regge-Gribov} (or \textit{semi-hard})...