I will present an overview of recent advances in the nucleon-structure study with electromagnetic probes from the low- to the high-energy domain.
In particular, I will focus on the partonic structure of the nucleon and highlight the opportunities for future experiments in the physics of hadron tomography, nucleon spin and mass decomposition.
The Electron-Ion Collider (EIC) will be a powerful new high-luminosity facility in the United States with the capability to collide high-energy electron beams with high-energy proton and ion beams, providing access to those regions in the nucleon and nuclei where their structure is dominated by gluons. Electron and light ion beams will be polarized allowing unprecedented access to the spatial...
The goal of LHCspin is to develop innovative solutions and cutting-edge technologies to access the field of spin physics over the next few years by exploring a unique kinematic regime and exploiting new reaction processes.
To this end, a polarized gaseous target, operated in combination with high-energy, high-intensity LHC beams and the highly performing LHCb particle detector, has the...
We present exploratory analyses of the 3D proton tomography via polarized time-reversal odd gluon TMD PDFs at twist-2, obtained in a spectator-model framework. We embody in our approach a flexible parameterization for the spectator-mass spectral function, suited to catch both small- and moderate-x effects. All these studies are relevant to unveil the gluon dynamics inside hadrons, which...
Using the light-front wave functions (LFWFs) overlap representation, we built a theoretical model for the pion state, that parametrizes different pion parton distribution functions. The model is constructed with two sets of parameters, that can be fitted separately by performing two independent fits: one for the collinear, and one for the transverse direction.
At present, we have been able to...
Fragmentation functions, describing the formation of hadrons from partons, are an indispensable tool in the interpretation of hadron-production data, e.g., in the investigation of nucleon structure via semi-inclusive deep-inelastic scattering. The cleanest process to access fragmentation functions is hadron production in electron-positron annihilation. However, little information can be...
Accessing TMD Fragmentation Functions through the phenomenological analysis of SIDIS data requires a non-trivial disentangling from the TMD Parton Distribution Function, that appear as convolutions in the factorized cross section. Difficulties in this kind of analyses can partly be overcome by exploiting the thrust distribution of $e^+e^-$ annihilation into one single hadron, for which we now...
In this talk, we will present a recent re-analysis of Belle data for the transverse $\Lambda$ and $\bar{\Lambda}$ polarization in $e^+e^-$ annihilation processes within a TMD factorization approach and adopting the CSS framework.
We will also discuss the issue of isospin symmetry and the role of the charm quark contribution, with their impact on the description of the experimental data as...
We present a study of strong parity-violating contributions that can be included in inclusive Deep Inelastic Scattering (DIS) off an unpolarized proton target. We show that a non vanishing parity-violating structure function arise even in the case of pure photon exchange, in contrast with standard results.
The size of the additional strong parity-violating term is estimated by fitting...
In 2015 and 2018 the COMPASS experiment at the M2 beamline of the CERN SPS performed measurements of the Drell-Yan process, using a 190 GeV/c negative pion beam impinging on aluminium and tungsten targets and on transversely polarized ammonia target. The goal was investigating the nucleon and the pion structure. AMBER, the newly approved fixed target facility, successor of COMPASS in the same...
Pion TMDs are not as well defined as their proton counterparts, due to a
smaller amount of data collected from high energy scattering processes involving pions.
The recent measurements of unpolarized DY cross section taken at COMPASS with different targets could improve the current understanding of pion structures.
We have been investigating, together with the Pavia group and some members...
I present a preliminary determination of the collinear helicity parton distribution functions (PDFs) of the proton. The determination is performed from a set of inclusive and semi-inclusive deep-inelastic scattering data, it includes next-to-next-to-leading order QCD corrections to both processes for the first time, and it is carried out in a framework that combines a neural-network...
In this talk I will present the latest results and updates of the MAP Collaboration about the Transverse Momentum Dependent (TMD) distributions. We discuss the extraction of unpolarized quark TMD Parton Distribution Functions (TMD PDFs) and Fragmentation Functions (TMD FFs) from global fits of Drell-Yan and Semi-Inclusive Deep-Inelastic Scattering (SIDIS) data sets.
In this talk I will report the recent extraction of TMD from data using the perturbative information up to N4LL. I will discuss extraction methods and error analysis.
The transversity and the nucleon tensor charge are fundamental quantities in hadron physics as well as for our comprehension of the nucleon structure. Some tension between the values of the tensor charge, as computed on the basis of phenomenological extractions and lattice QCD simulations, has been observed.
By means of an explicit example, we present how relaxing some onstraints in...
Some transverse single-nucleon spin asymmetries in inclusive reactions in electron-nucleon reactions are discussed within a collinear twist-3 approach. The focus will be in particular on the processes eN->gammaX and eN->piX, which may be accessible at the future Electron-Ion Collider. A report on recent, ongoing efforts to understand these observables is presented.
Quarkonia are very important tools to probe gluon transverse momentum dependent (TMD) distributions at lower energies as compared, for instance, to Higgs production. Among them, the 𝐽/𝜓 meson is one of the most studied, since it frequently decays into lepton pairs, making its detection easier with respect to other quarkonia. Thus, describing observables that involve 𝐽/𝜓 production within a...
J/ψ production at the future EIC has been proposed as a tool to probe gluon TMDs. Until recently, a common assumption was to decouple the J/ψ hadronization from other soft mechanisms, even at low transverse momentum. However, at leading order in the TMD factorized expression and within NRQCD, J/ψ is produced via a color-octet state. So, soft gluon emission to become a color-singlet state...
