Conveners
Monday: morning / 1
- Alessandro Bacchetta (Istituto Nazionale di Fisica Nucleare)
Monday: morning / 2
- Alessandro Bacchetta (Istituto Nazionale di Fisica Nucleare)
Monday: afternoon / 1
- Marco Radici (Istituto Nazionale di Fisica Nucleare)
Monday: afternoon / 2
- Leonard Gamberg
Progresses related to lattice QCD calculations of the rapidity anomalous dimension of quark transverse-momentum-dependent distributions, i.e., the Collins-Soper (CS) kernel, will be presented. Methodological and numerical advances over the last year will be reviewed. Results from the state-of-the-art lattice QCD calculations will be presented and compared with the those from the...
Gravitational Form Factors (GFFs) provide an important portal for probing the energy-momentum and mass distribution of nucleons and nuclei. This work presents the study of photon and gluon momentum GFFs using the Weizsäcker-Williams method of relativistic hadrons.
First, we express the photon A-GFFs in terms of charge form factors and discuss the corresponding photon radius. Furthermore, we...
High-order behavior of the perturbative expansion for short-distance observables in QCD is intimately related to the contributions of small momenta in the corresponding Feynman diagrams and this correspondence provides one with a useful tool to investigate power-suppressed nonperturbative corrections. We use this technique to study the structure of power corrections to parton quasi- and...
I discuss the constraints that positivity of physical cross-sections impose on unpolarized and polarized collinear parton distribution functions. I explain why in a generic factorizations scheme leading-twist PDFs may turn negative beyond leading order, and show that however in the commonly used MSbar scheme this cannot happen in the perturbative regime. I then discuss the implications of this...
Semi-inclusive hadron production processes in deep-inelastic lepton-nucleon scattering (SIDIS) are important probes of the fragmentation dynamics of quarks into hadrons. Moreover, longitudinally polarized SIDIS is a powerful tool for resolving the quark flavor decomposition of the proton's spin structure. In this talk, I will present the recent calculation of the full next-to-next-to-leading...
We present an exact analytic solution of the revised large-$N_c$ small-$x$ helicity evolution equations derived recently. We find the corresponding small-$x$ asymptotics of the flavor-singlet helicity PDFs to be
\begin{align}
\Delta \Sigma (x, Q^2) \sim \Delta G (x, Q^2) \sim \left( \frac{1}{x} \right)^{\alpha_h}
\end{align}
with the intercept given by an exact analytic expression which...
I describe recent developments in Drell Yan transverse-momentum resummation, and their implications on the definition of a new observable for W-boson mass extraction from charge-current Drell Yan data.
We perform the first complete one-loop study of exclusive photoproduction of vector quarkonia off a proton, including full generalised-parton-distribution (GPD) evolution. We confirm the perturbative instability of the cross section at high photon-proton-collision energies at Next-to-Leading Order (NLO) using collinear factorisation. Such an instability is known since 20 years and has been...
I discuss ongoing progress in the understanding of heavy-quark transverse momentum-dependent (TMD) fragmentation functions (FFs). These advances include their explicit next-to-leading order calculation in massive QCD and boosted Heavy-Quark Effective Theory (bHQET), exposing a rich singularity structure that is also relevant for the extension of fixed-order subtraction schemes to...
In this presentation, I explore the connection between Transverse Momentum Dependent distributions (TMDs) and collinear distributions through the introduction and analysis of Transverse Momentum Moments (TMMs). These moments are defined as weighted integrals of TMDs over their transverse momentum with a cut-off scale. I illustrate that TMMs can be understood as equivalent to collinear...
