QCD Evolution Workshop 2023

Session

Small-x

23 May 2023, 14:25

Auditorium Joliot Curie (IJCLab, Orsay (FRANCE))

Conveners

Small-x

• Melih Arslan Ozcelik (KIT - Karlsruhe Institute of Technology (DE))

Small-x

• Cyrille Marquet (CPHT - Ecole Polytechnique)

Small-x

• Michael Fucilla

32. Pseudo and quasi quark PDFs at small-x

Giovanni Antonio Chirilli (University of Regensburg)

23/05/2023, 14:25

Pseudo- and quasi-parton distribution functions (PDFs) defined through space-like bilocal operators allow for direct access to the PDFs from first principles in lattice gauge theory. However, this formalism currently leaves the small Bjorken $x$ regime inaccessible. With the future Electron-Ion Collider in mind, it is timely to study the PDFs at small-$x$. In a previous calculation, we showed...

17. Next-to-Leading Order virtual correction to Higgs-induced DIS

Anna Rinaudo

23/05/2023, 14:50

We calculate the Next-to-Leading Order (NLO) virtual correction to the Higgs-induced DIS coefficient function in the infinite top-mass limit. Since we want to use this result in the framework of kt-factorization to resum small-$x$ logarithms up to Next-to-Leading-Logarithm (NLL), we work in light-cone gauge and we keep the incoming gluon off-shell. This choice raises many challenging points...

34. Longitudinal Double-Spin Asymmetry at Small x

Ming Li

23/05/2023, 15:15

Double-spin asymmetry in particle and jet productions in longitudinally polarized proton-proton collisions is one of the flagship measurements at RHIC, with the aim of determining the spin fraction of gluons within the proton. Although current next-to-leading order perturbative QCD predictions, based on collinear factorization, have been quite successful in explaining experimental data and...

19. A unified picture for dilute-dense dynamics in QCD medium

Prof. Hongxi Xing (South China Normal University)

23/05/2023, 15:40

QCD multiple scattering plays an essential role in explaining the observed nontrivial phenomena in high energy nuclear collisions. In cold nuclear medium, there are two extensively used theoretical frameworks for describing QCD multiple scatterings, i.e. the high-twist approach and the color glass condensate (gluon saturation) framework that resums multiple eikonal scattering. In this talk, we...

9. Single and double inclusive hadron production in DIS: Next to Leading Order corrections

Jamal Jalilian-Marian

26/05/2023, 09:25

We calculate the one-loop corrections to single and double inclusive hadron production in DIS at small x using the Color Glass Condensate effective theory of QCD at small x. We show that all divergences either cancel or are absorbed into DGLAP evolution of the parton-hadron fragmentation functions and JIMWLK evolution of dipoles and quadrupoles describing the dynamics of the target proton or...

33. NLO computation of diffractive di-hadron production in a saturation framework

Emilie Li (IJCLAB)

26/05/2023, 09:50

The cross-sections of diffractive double hadron photo- or electroproduction with large pT, on a nucleon or a nucleus, are calculated to NLO accuracy.
A hybrid formalism mixing collinear factorization and high energy kt factorization, more precisely the shockwave formalism, is used to derive the results.
The cancellation of divergences is explicitly shown, and the finite parts of the NLO...

59. High-energy resummation in Higgs-plus-jet production

Michael Fucilla

26/05/2023, 10:15

Precision physics in the Higgs sector has been one of the main challenges in recent years. The pure fixed-order calculations, entering the collinear factorization framework, in particular conditions, must be supplemented by all-order resummations. In this talk, we consider the production of a Higgs boson in association with a jet at large rapidity separation. When the two detected objects are...

39. Rethinking running coupling in JIMWLK/BK

Vladimir Skokov

26/05/2023, 14:10

This talk reexamines the running coupling prescription for the small x evolution equations. Our analysis is based on the NLO JIMWLK, which enabled us to identify potentially large logarithms associated with the running coupling contributions. We show that past analyses performed in the framework of BK and JIMWLK attributed several DGLAP-like logarithms to the running coupling corrections. We...

36. Small x resummation of the photon-gluon impact factor

Anna Stasto

26/05/2023, 14:35

It is well known that the evolution in the limit of small Bjorken x acquires large corrections at NLO order. These corrections needs to be resummed by taking into account kinematical constraints and the matching to the DGLAP evolution. This is known as the collinear resummation. In order for the physical cross sections to be consistent with resummation, the impact factors entering them also...

18. High-Energy factorization and matching to NLO for quarkonium production

Dr Maxim Nefedov (IJClab, Orsay)

26/05/2023, 15:00

The $p_T$-integrated cross section of inclusive hadro and photo-production of heavy quarkonia when computed up to NLO in Collinear Factorisation(CF) shows a perturbative instability at high hadronic or photon-hadron collision energies -- the cross section could turn negative for reasonable factorisation/renormalisation scale-choices. We solve this problem by resummation of the subset of LLA...

30. Probing the odderon through $\eta_c$ production in diffractive collisions at the EIC with non-linear evolution effects.

ABHIRAM KAUSHIK BADRINARAYANAN

26/05/2023, 15:25

The production of $\eta_c$ in diffractive $ep$ and $eA$ collisions has been suggested as a golden probe of the C-odd QCD interaction, the odderon. Previous studies of this process have considered a linearised Bartels-Kwiecinski-Praszalowicz odderon [1-3], which is appropriate in the dilute regime where the x region probed in the proton is not too small. In this work [4], we explore this...