UPC 2023: International workshop on the physics of Ultra Peripheral Collisions

Session

UPC and saturation

13 Dec 2023, 09:00

Playa del Carmen

Conveners

UPC and saturation

• Michael Winn (Université Paris-Saclay (FR))
• Martin Hentschinski (DESY Hamburg)

UPC and saturation

• Anisa Khatun (The University of Kansas (US))
• Edmond Iancu (Université Paris-Saclay (FR))

4. Saturation effects in exclusive heavy vector meson photoproduction at the LHC

Jani Penttala (UCLA)

13/12/2023, 09:00

Session 1: Vector meson photoproduction

The gluon density has been observed to increase rapidly with energy, which would eventually violate unitarity. At high energies, however, nonlinear effects start to become important, slowing down the evolution of the gluon density and hence giving rise to gluon saturation. While there have already been strong hints of saturation in the currently available data, a definite measurement of...

1. Probing gluon saturation via diffractive jets in nucleus-nucleus UPCs

Edmond Iancu (Université Paris-Saclay (FR))

13/12/2023, 09:30

Session 3: UPC and saturation

We argue that diffractive photo-production of jets in coherent nucleus-nucleus ultra-peripheral collisions (UPCs) at high energy is a golden channel to study gluon saturation. By ``coherent'' we mean elastic processes in which both nuclei emerge unbroken after the collision and the final state exhibits large rapidity gaps. We study such processes within the colour glass condensate effective...

7. Single and double inclusive hadron production in Ultra-Peripheral Collisions: Next to Leading Order Corrections

Jamal Jalilian-Marian (Baruch College, CUNY)

13/12/2023, 10:00

Session 3: UPC and saturation

We calculate the Next to Leading Corrections to single and double inclusive hadron production in Deep Inelastic Scattering (DIS) and in Ultra-Peripheral Collisions (UPC) using the Color Glass Condensate effective theory of QCD at small x. We argue that single inclusive hadron production where momentum of the produced hadron is of the order of Saturation scale provides a sensitive probe of...

83. The Correlated Spatial Structure of the Proton: Two-body densities as a framework for dynamical imaging

Zaki Panjsheeri

13/12/2023, 11:00

The Fourier transforms of generalized parton distributions (GPDs) give single-particle spatial densities of the quarks and gluons inside the proton. The average radius of each partonic component of the nucleon as well as the charge and matter densities of the nucleons are among physical quantities to which GPDs provide insight. However, to obtain a fuller dynamical picture of the proton’s...

15. The ratio of Psi(2s) and J/Psi exclusive photoproduction cross-sections as a tool to detect non-linear QCD evolution

Martin Hentschinski (Universidad de las Americas, Puebla)

13/12/2023, 11:15

Session 1: Vector meson photoproduction

We study the proposal that the ratio of Psi(2s) and J/Psi exclusive photoproduction cross-sections might serve as an indicator of the presence of non-linear QCD evolution, related to the presence of high and potentially saturated gluon densities in both the proton and a lead nucleus. Our study employs recent fits of the GBW and BGK dipole model and provides predictions for both exclusive...

54. UPC dijets at small-x: interplay of Color Glass Condensate and Sudakov resummation

Cyrille Marquet (CPHT - Ecole Polytechnique)

13/12/2023, 11:45

Session 3: UPC and saturation

We compute the cross section for the inclusive photo-production of a pair of jets at next-to-leading order accuracy in the Color Glass Condensate framework. We study the emergence of the large Sudakov logarithms in the back-to-back limit, and show that they cannot appear consistently unless the low-x resummation is kinematically constrained.