Nature has two sources of mass. One is the Higgs boson, which is responsible for every mass scale that appears explicitly in the Standard Model Lagrangian. The Higgs was discovered at CERN in 2012; and with that discovery, the Standard Model became complete.
However, in connection with everyday matter, the material which constitutes our computers and ourselves, the Higgs produces little...
With $e^-$ constituents in a classical potential atoms are at the borderline between hard processes and soft classical physics. Data and phenomenology indicate that hadrons are similar. The importance of this cannot be overemphasized: It suggests a first-principles, analytic QCD approach to strong dynamics analogous to that long developed for QED atoms.
Bound state perturbation theory is...
Originally conceived for precise luminosity measurements, the gas injection system SMOG currently allows the unique LHCb detector capabilities to be exploited for fixed-target studies in proton-gas collisions at $\sqrt{s}$ ∼ 100 GeV. The first results obtained with SMOG data are reported: antiproton production with a He target and $J/\psi$, $D^0$ productions in p-He and p-Ar collisions. The...
For a long time, lattice QCD was unable to address the x-dependence of partonic distributions, direct access to which is impossible in Euclidean spacetime. Recent years have brought a breakthrough for such calculations when it was realized that partonic light-cone correlations can be accessed through spatial correlations computable on the lattice. Appropriately devised observables can be...
We develop a procedure to renormalize the quasi parton distribution in the recently proposed hybrid scheme and match it to the $\overline{\rm MS}$ scheme light-cone parton distribution at next-to-next-to-leading-order in perturbation theory. Under this procedure we calculate the pion valence quark
distribution using two fine lattices with spacing
$a=0.04$ fm and $0.06$ fm and valence pion...
The structure of nucleons as well as nuclei at large longitudinal momenta, x, is crucial for understanding QCD confinement, the origin of non-perturbative charm and beauty in the proton, or for explaining the origins of the nuclear EMC effect. Parton distribution functions (PDFs), which describe the longitudinal structure of hadrons, are typically determined in global analysis of experimental...
We developed a non-perturbative model for valence parton distribution functions (PDFs) based on the mean field interactions of valence quarks in the nucleonic interior. The model is based on the separation of the valence three-quark cluster and residual system in the nucleon. Then the nucleon structure function is calculated within the effective light-front diagrammatic approach ...
In 2010, precise determination of the proton radius from muonic lamb shift data, a result that systematically disagreed with previous atomic lamb shift and electron scattering data, sparked what was to become known as the proton radius puzzle. Since then, there have many new measurements and new theory calculations done to understand the source of the discrepancy. A preponderance of the new...
Effective field theories are exceptionally suited to define and determine the proton radius and its relatives from low energy observables. They not only provide a unified and unambiguous definition of the low energy constants that naturally includes electromagnetic corrections, but they also yield a robust determination of the theoretical uncertainty. In this talk, I will present the...
The Generalized Polarizabilities (GPs) are fundamental properties of the
nucleon. They characterize the nucleon's response to an applied
electromagnetic field, offering access to the polarization densities inside
the nucleon, and as such they represent an essential part for a complete
understanding of the nucleon structure and dynamics. The GPs can be
explored through the measurement of...
In this talk, I will present the details of a new factorized approach to inclusive lepton-hadron scattering, in particular to semi-inclusive deep-inelastic scattering, which treats QED and QCD radiation on equal footing, and provides a systematically improvable approximation to the extraction of transverse momentum dependent parton distributions. We demonstrate how the QED contributions can be...
It has been more than 30 years since the EMC published a surprising result on the spin structure of the proton: the spins of its three quark components account for only a small part of the spin of the proton. In this talk, we discuss what has been learned so far, what is still missing and what could be learned from the upcoming experiments, including the Jefferson Lab 12 GeV upgrade and the...
The structure of hadrons depends strongly on the confinement mechanism. This talk illustrates the dynamics of confinement at the border between the interior and exterior of hadrons. The extended chiral structure is illustrated in chromostatics and amplified by a discussion of vortices and the orbital angular momentum resulting in the pion tornado.
I will report on recent developments in the extraction of the transversity distribution from various methodologies, including transverse momentum dependent (TMD) and collinear twist-3 observables, collinear dihadron fragmentation processes, and lattice QCD. Connected to this is the calculation of the tensor charges of the nucleon, which are important quantities that sit at the intersection of...
We determine approximate next-to-next-to-leading order (NNLO) corrections to unpolarized and polarized semi-inclusive DIS. They are derived using the threshold resummation formalism, which we fully develop to next-to-next-to-leading logarithmic (NNLL) accuracy, including the two-loop hard factor. In terms of the customary SIDIS variables x and z they include all double distributions in the...
We review the recent progress on the extraction of TMD PDFs and TMD FFs from global data of Semi-Inclusive Deep-Inelastic Scattering, Drell-Yan and Z boson production. In particular, we address the tension between the low-energy SIDIS data and the theory predictions.
I review the latest extractions of TMD distributions made with artemide. The main emphasis is made on the first determination of realistic uncertainty band for unpolarized TMDPDF, and on the interplay between collinear and TMD distributions.
I will give a brief overview of our current understanding of fragmentation from phenomenological analyses of (polarized) collinear and TMD fragmentation functions, including some recent extractions, formulations of new factorization theorems, and Monte Carlo studies.
COMPASS is a fixed-target experiment located at the CERN SPS, which has been collecting data since 2002. One of the key aspects of the broad COMPASS physics program is the investigation of the transverse-momentum and transverse-spin structure of the nucleon, which has been pursued via measurements of semi-inclusive deep inelastic scattering using a 160 GeV/c muon beam and transversely...
After fifty years of investigations, the nucleon structure is still far from being understood and continues to represent a unique test bench for QCD. Despite the enormous progresses achieved in five decades of deep-inelastic scattering (DIS) experiments, a number of crucial open questions are still on the carpet and subject of intense theoretical and experimental studies. In the last two...
A small-$x$ model for gluon GTMDs will be discussed. With this model a reasonable description of the H1 data on diffractive dijet production in electron-proton collisions can be obtained. Predictions for the EIC will be given for both electroproduction and photoproduction which may allow to further test the underlying GTMD description.
The SpinQuest experiment (E1039) at Fermilab aims to extract Sivers functions for the light sea-quarks in the range of 0.1 < xB < 0.5 through Transverse Single Spin Asymmetry (TSSA) measurements from the Drell-Yan (DY) process, using an unpolarized 120 GeV proton beam interacting with polarized fixed target of either NH3 or ND3. In addition to the DY TSSA measurements, J/ψ TSSAs will also be...
I give an overview of generalized parton distributions (GPDs), a vital theoretical tool for understanding the 3D partonic structure of hadrons. GPDs provide a generalization of collinear parton distributions that additionally encode the elastic form factors associated with electromagnetic, axial, and gravitational currents. They can be experimentally studied through hard inclusive reactions...
We compute the matching of TMD distributions to collinear distributions of twist-2 and twist-3 to all powers of small-$b$ (large-$p_T$).
The computation is based on the operator product expansion of the non-local TMD operators.
For the first time, a non-trivial expression for the pretzelosity distribution is derived.
Effective chiral Lagrangian of nucleons and pions in external gravitational field and the corresponding energy-momentum tensor will be considered. Gravitational form factors of the nucleon and their relation to internal forces will be discussed.
In this contribution I will revisit GPD evolution in momentum space. I will highlight some fundamental properties of the evolution kernels and present a leading-order numerical implementation that quantitatively fulfils all these properties.
Deeply virtual Compton scattering (DVCS) is a particularly promising channel to extract generalized parton distributions (GPDs) allowing the study of the three-dimensional structure and the energy-momentum tensor of the nucleon. However, the access to GPDs from DVCS experimental data is complicated by the so-called deconvolution problem and the lack of precise data in some kinematic regions....
Generalized Parton Distributions (GPDs) describe the correlations between the longitudinal momentum and the transverse position of the partons inside the nucleon. They are nowadays the subject of an intense effort of research, in the perspective of understanding nucleon spin and mechanical properties.
In this talk, we present the first measurement of the Timelike Compton Scattering (TCS)...
Following simple large Nc arguments and perturbative QCD constraints complemented with uncertainty estimates based on the idea of meson dominance and the half-width rule, we describe the pseudoscalar form factors of the nucleon. We analyze their implications in the space-like region at intermediate and low energies and compare to recent lattice QCD determinations. Our analysis allows for a...
A lattice QCD determination of the nucleon sigma terms, which are closely related to the scalar charges of the nucleons, will be presented. These sigma terms determine the strength of the spin-independent interactions of nucleons with WIMPs searched for in direct dark matter detection experiments. They are also closely related to the masses of the nucleons. The calculation presented here is...
Generalized parton distributions (GPDs) are important quantities that characterize the structure of hadrons. They provide information about the partons’ momentum distribution and also on their distribution in position space. Most of the information from lattice QCD is on the Mellin moments of GPDs, namely form factors and their generalizations. Recent developments in calculations of matrix...
In the last few years, several new techniques for quantum many-body physics based on quantum information methods and concepts have been developed and applied. In one such approach, quantum simulation, an inaccessible physical model is mapped to another quantum device which can be manipulated and measured in the lab, hence serving as its simulator. In another one, by considering the special...
We present a first attempt to design a quantum circuit for the determination of the parton content of the proton through the estimation of parton distribution functions (PDFs), in the context of high energy physics (HEP). The growing interest in quantum computing and the recent developments of new algorithms and quantum hardware devices motivates the study of methodologies applied to HEP. In...
Quantum computers can efficiently simulate quantum field theory observables. Basis light front quantized systems have been modeled for meson states using confining effective field theory. Some form factors and parton distributions were obtained from an available quantum computer not yet able to implement error correction – a NISQ device. The procedure will be outlined and some early results shown.
Double parton scattering (DPS) is the phenomenon in which, during a nucleon-nucleon scattering, two partons from each nucleon undergo two distinct hard interactions.
The cross section resulting from DPS interactions is normally power-suppressed with respect to the traditional single parton scattering (SPS) cross section. However, the two contributions can be similar in size in some...
In factorization theorems for double parton scattering (DPS) the non-perturbative parts of the cross section are encoded in universal functions, double parton distributions (DPDs) in the case of collinear factorization and double transverse momentum dependent parton distributions (dTMDs) for transverse momentum dependent (TMD) factorization.
These distributions contain a wealth of information...
In this contribution, I discuss the possibilities offered by double parton scattering (DPS) processes initiated by photon-proton interactions. In fact, the DPS cross section depends on the double parton distribution functions (dPDFs) of hadrons. These new quantities encode new informations on the 3D partonic structure of the proton, complementary to TMDs and GPDs. In fact, dPDFs are...
Understanding the structure and dynamics of the proton constitute one of the most important challenges in hadron physics. From the theoretical point of view, one of the challenges is to extract from Lattice QCD calculations, performed in Euclidean space, Minkowskian quantities such as the proton parton distribution function. Due to the inherent difficulties associated with the mapping of...
We present exploratory studies of the 3D gluon content of the proton, as a result of analyses on leading-twist transverse-momentum-dependent (TMD) gluon distribution functions, calculated in a spectator model for the parent proton. Our formalism embodies a fit-based parameterization for the spectator-mass density, suited to describe both the small- and the moderate-x regime. Particular...
In the context of a theory for only one heavy flavor in QCD, we use the renormalization group procedure for effective particles (RGPEP) to derive the effective potential for $Q\bar Q$ and $QQQ$ that arises at the energy scale at which bound states are formed. The RGPEP provides the connection between low- and high-energy interactions in QCD through the construction of effective particles....
We revisit inclusive $J/\psi$ and $\Upsilon$ photoproduction at lepton-hadron colliders, namely in the limit when the exchange photon is quasi real. Our computation includes the leading-$v$ next-to-leading order (NLO) $\alpha_s$ corrections. Similarly to the case of NLO charmonium-hadroproduction processes, the resulting cross sections obtained in the $\overline{\text{MS}}$ factorisation...
The COMPASS experiment continues the investigation of the transverse spin and transverse momentum structure of the nucleon.
Very recently, a new set of measurements has been performed in SIDIS of high energy muons off unpolarised protons. This talk will review the results on the transverse momentum distributions of the final state hadrons. A fairly complete study of the kinematic dependence...
The transverse single-spin asymmetry in inclusive electron-nucleon scattering, e + N(S_T) -> e’ + X, represents a pure two-photon exchange observable and is of fundamental interest for exploring higher-order QED effects in electron scattering. We compute this observable in the resonance region, where excitation of Delta isobars occurs in both intermediate and final states. We employ a novel...
The Relativistic Heavy Ion Collider (RHIC) is the world's only polarized proton+proton collider, capable of reaching center of mass energies up to 510 GeV. The STAR experiment at RHIC has been carrying out a cold QCD program in order to gain deeper insight into the proton's spin structure and dynamics.
Data from longitudinally polarized $p$+$p$ collisions allow one to study...
I will survey a number of new developments in hadron physics
which can be derived from the application of super-conformal quantum
mechanics and lightฉ\front holography -- its embedding in higher
dimensional gravity theory. This includes new insights into the
physics of color confinement, chiral symmetry, the spectroscopy and
dynamics of hadrons, as well as surprising supersymmetric...
Within a recently developed formalism for $e^+e^-$ one-hadron production, we present preliminary results on the extraction of unpolarized transverse momentum dependent fragmentation functions (TMDFFs). We address possible constrains at large values of impact parameter $b_T$, for the TMDFF and the Collins-Soper kernel. We outline a work plan for global extractions of fragmentation functions.
By adopting the helicity formalism within a TMD scheme, we present the complete structure of the azimuthal dependences and polarization observables for two-hadron production in $e^+e^-$ annihilation processes. The leading-twist TMD fragmentation functions (FF) for spin-1/2 hadrons, with their properties and their probabilistic interpretation, are fully accounted for.
The role of the...
In this talk I will make an overview on recent progress in the field of massive event shapes. In particular, the status of computations carried out in fixed-order QCD as well as in effective field theories (SCET and bHQET) will be reviewed. I will show how to efficiently carry out large-log resummation in the presence of heavy-quark masses and present some phenomenological studies. If time...
We consider four and five parton scattering amplitudes in QCD and analyse their high-energy limit and colour structure. On the one hand, our main tools are the Reggeization of $2\rightarrow n$ scattering amplitudes in QCD, known as the effective action that governs their behaviour in the Regge limit or multi-Regge (MR) limit in the case of five or more partons. On the other hand, we use the...
The anomalous magnetic moment of the muon, $(g-2)_{\mu}$, is an interesting quantity to search for new physics. In particular, it has attracted quite attention due to the persisting discrepancy among theory and experiment, that has been confirmed recently this year at Fermilab.
In this talk, I review the current status of its theoretical determination, with special attention to the hadronic...
Recently the first part of the proposed measurements of the AMBER collaboration
were approved as NA66 at CERN. AMBER will use the M2 beamline of the CERN SPS
with muon as well as hadron beams to perform a variety of hadron structure and
spectroscopy studies. These studies will allow to adress fundamental questions
of QCD. The talk will cover the proposed measurements and the preparation of...
Prospects for quarkonium-production studies accessible during the upcoming high-luminosity phases of the CERN Large Hadron Collider operation after 2021 are reviewed. Current experimental and theoretical open issues in the field are assessed together with the potential for future studies in quarkonium-related physics. This will be possible through the exploitation of the huge data samples to...
A polarized gaseous target, operated in combination with the high-energy, high-intensity LHC beams and a highly performing LHC particle detector, has the potential to open new physics frontiers and to deepen our understanding of the intricacies of the strong interaction in the non-perturbative regime of QCD. Specifically, the LHCspin project aims to develop, in the next few years, innovative...
I will present my thoughts about how heavy-ion physics
can profit from eA measurements, paying a particular attention to cold nuclear matter effects that can be studied at
the future Electron-Ion Collider and the implications of these measurements on the interpretation of RHIC and LHC data.
