QCD Evolution 2024

Exclusive and semi-inclusive diffractive processes in the shockwave approach

28 May 2024, 17:30

30m

Aula Foscolo (University of Pavia)

Tuesday

Speaker

Michael Fucilla

Description

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}) limit of QCD, characterized by the scale hierarchy $s\gg \{Q^2\}\gg {\mathrm{\Lambda }}_{\mathrm{Q}\mathrm{C}\mathrm{D}}^2$, where $\sqrt{s}$ is the center-of-mass energy, $\{Q\}$ a set of hard scales characterizing the process and ${\mathrm{\Lambda }}_{\mathrm{Q}\mathrm{C}\mathrm{D}}$ is the QCD mass scale. This kinematic limit is the stage where some of the most intriguing phenomena of strong interactions manifest themselves, such as the formation of a state of gluonic matter that is known under the name of \textit{color glass condensate} (CGC). This state is characterized by a high-density of particles possessing a color charge (color condensate), by a slow evolution compared to the natural time of the interaction and by a disordered field distribution (properties assimilable to those of a glass). The quest for the saturation regime constitutes one of the pillars of the EIC physics program and a stimulating opportunity for the LHC experiments. In order to reveal saturation, highly accurate theoretical predictions are therefore unavoidable

In this talk, I will present the full next-to-leading order results for the cross-sections of diffractive single- or double hadron photo- or electroproduction with large $p_T$, on a nucleon or a nucleus and a pioneering calculation of the exclusive diffractive production of a transversely polarized light-meson in ${\gamma }^{(\ast )}$ p collision, obtained in a framework mixing the higher-twist formalism of exclusive processes with the Balitsky shockwave effective theory of small-$x$ physics.

Presentation materials

Fucilla.pdf