I will review the QCD Town Hall Meeting and White Paper, covering the achievements since the 2015 Long Range Plan and future prospects. I will discuss the recommendations and initiatives and the science behind them.
After decades of planning, the design and construction of a new Electron Ion Collider (EIC) are underway at the Brookhaven National Laboratory. This new versatile machine for studying fundamental properties of nuclear matter will map the emergence of nucleonic properties from the dynamical interactions of the dense partonic medium. In addition to flagship measurements addressing connections...
In this talk, I will review topics in heavy-ion physics at RHIC and the LHC which are related to the physics of the EIC. This includes recent work in understanding the initial state of protons and heavy nuclei, searching for saturation phenomena, and the use of ultra-peripheral collisions.
Jefferson Lab physics program ddresses important topics in nuclear, hadronic, and electroweak physics, including nuclear femtography, meson and baryon spectroscopy, quarks and gluons in nuclei, precision tests of the standard model and dark sector searches. Selected topics of the ongoing scientific program of the 12 GeV CEBAF will be presented. Also a potential energy upgrade of the...
Hadron scattering information can be accessed indirectly from lattice QCD by computing the spectrum of multi-hadron states and connecting to the infinite volume amplitudes via quantization conditions. This methodology was applied successfully for the two-hadron case to extract phase-shifts and resonance parameters. Only recently this methodology was extended to the three-hadron sector: both...
A fundamental property of the proton involves the system's response to an external electromagnetic (EM) field. It is characterized by the EM polarizabilities that describe how easily the charge and magnetization distributions inside the system are distorted by the EM field and the generalized polarizabilities that map out the resulting deformation of the densities in a proton subject to an...
The proton’s tensor charge, connected to internal quark transverse spin, is one of its fundamental properties. This quantity has garnered interest from various communities, being relevant for QCD phenomenology, ab initio studies (e.g., lattice QCD, Dyson-Schwinger), and low-energy beyond the Standard Model searches. In this talk I will review the current status of extractions of the...
The formalism of Dyson-Schwinger equations is a powerful tool to study correlation functions in quantum field theory, but has also proved to yield an outstanding framework for the evaluation of hadron properties. Starting from state of the art continuum Schwinger calculations of pion's parton distribution function, we describe its extension to off-forward hadron kinematics, yielding the pion's...
Deeply virtual exclusive reactions are theorized to be sensitive to the dynamics of bound partons in hadrons through 3D quantum mechanical phase space distributions - the generalized parton distributions; however, there are many steps in the analysis from experimental data to information on hadron structure. The FemtoNet framework was developed to analyze deeply virtual exclusive experimental...
The production of $\Sigma^{0}$ hyperons in proton proton collisions at a beam kinetic energy of 3.5 GeV impinging on a liquid hydrogen target was investigated using data collected with the HADES setup. The total production cross section is found to be $\mathrm{\sigma (pK^{+}\Sigma^{0}) [\mu b] = 17.7 \pm 1.7 (stat) \pm 1.6 (syst)}$. Differential cross section distributions of the exclusive...
We present some analytic results that describe the gluon fields at very early times after a collision of relativistic heavy ions at proper time $\tau = 0$. We use a Colour Glass Condensate approach, and perform an analytic expansion in $\tau$. We calculate the transverse and longitudinal pressures and show that they move towards their equilibrium values of one third of the energy density. We...
The grand canonical statistical ensemble is usually assumed when simulating particle emission from the Quark-Gluon Plasma fluid created in relativistic heavy-ion collisions. These simulations conserve energy and momentum on an event-average level. This talk investigates how event-by-event local energy and momentum conservation [1] introduces non-trivial multi-particle correlations in Au+Au...
We present a lattice QCD determination of the nucleon generalized parton distributions (GPDs) from an analysis of the quasi-GPD matrix element within the leading-twist framework. We preform our study on a Nf=2+1+1 twisted mass fermions ensemble with a clover improvement. The faster and more effective lattice QCD calculations of GPDs using the asymmetric frames was applied so that we can...
Understanding the internal structure and dynamics of protons and neutrons, the complex many-body systems consisting of strongly interacting quarks and gluons is at the core of exploring the visible matter universe. Gluons, which serve as mediator bosons of the strong interaction, play a key role in the nucleon’s mass and spin structures. In contrast, understanding of the gluon distributions...
Quantum Chromo Dynamics (QCD) is our current best description of interactions between quarks and gluons. It not only predicts the existence of the well understood mesons (two-quark) and baryons (three-quark) it also predicts exotic Tetra, Penta and Hexaquark states.
Experiments taking place at Thomas Jefferson Lab in Virginia, USA using the upgraded CLAS12 detector system allows a detailed...
Doubly strange, so-called cascade (𝛯) baryons, should be found in abundant numbers based on relativistic quark models yet few have been found experimentally. Finding, identifying and matching these states is one of the most important objectives in particle physics, the so-called missing resonance problem. My research centers on the 𝛯(1530), using Glue-X Phase-1 data, I was able to identify the...
The E1039/SpinQuest experiment at Fermilab will measure the transverse single spin asymmetry (TSSA) in several processes such as J/$\psi$ production and Drell-Yan di-muon pair production, exploiting the 120 GeV unpolarized proton beam from the Fermilab Main Injector on transversely polarized fixed targets of NH$_3$ and ND$_3$. Such measurements are anticipated to provide knowledge on the...
We model the evolution of the Quark-Gluon Plasma (QGP) with a multi-stage model that includes (i) geometric initial state energy deposition, (ii) viscous relativistic hydrodynamics, and (iii) hadronic transport. We perform rigorous comparison with experimental data using Bayesian inference. We go beyond previous JETSCAPE Bayesian analyses of the soft sector by studying the three-dimensional...
A series of experiments were proposed to study the fundamental structure of light nuclei, such as $^{2}{H}$ and $^{4}{He}$. The program focuses on the exploration of the nuclear Generalized Parton Distributions (GPDs), EMC effects, as well as the nature and origin of nuclear effects. The key feature of these measurements is the challenging detection of the low-momentum recoil particles in a...
In this talk, I will present results of the isoscalar quark parton distribution function (PDF) with disconnected diagrams. PDFs measure the distributions of quarks within hadrons and are used as a theoretical input to interpret results from collider experiments probing the Standard Model. These PDFs are determined by using Lattice Quantum Chromodynamics with the pseudo-PDF approach....
Generalized Parton Distributions (GPDs) have been one of the most important tools to access the nucleon 3D structure including its mass, angular momentum and mechanical properties. However, the extraction of GPDs has been challenging due to its high-dimension nature. Recent progress in lattice QCD have brought in many insights into the studies of GPDs. In this talk I will introduce the GPDs...
Spin dependent quark and gluon distributions can lead to distinctive features in the angular dependences and asymmetries from proton proton and electron proton scattering processes. Of particular interest are heavy quark production processes, wherein spin asymmetries of the heavy quarks, correlated with diquarks can reveal the underlying spin dependence. Hyperon production including heavy...
In this talk, we will present recent results from the ALICE Collaboration on ultra-peripheral heavy-ion collisions and discuss future projects.
Charged particles in heavy-ion collisions have various production mechanisms, such as thermal and associated production, and the importance of each changes with the collision energy. Studying the yields of charged particles provides a way to investigate the properties of the produced QCD matter in heavy-ion collisions and the various production mechanisms. The RHIC Beam Energy Scan (BES)...
Although significant results were obtained concerning quark transverse-momentum dependent distribution functions (TMD PDFs), the deep knowledge on their formal properties being surrounded by a rich and wealthy phenomenology, the gluon-TMD field represents an almost uncharted territory. After a brief introduction of gluon TMD PDFs and their connection with spin studies, we report progresses...
The quark model predicts a hierarchy of mesons with certain allowed $J^{PC}$, but experimental evidence has been found for several states with $J^{PC}$ that are forbidden for a pure quark anti-quark state. In the light quark sector, the most well studied of these states is the $\pi_1(1600)$. This state has several properties consistent with lattice QCD predictions for a light hybrid meson, a...
We provide the first calculation of two-gluon production at mid-rapidity in ultra-peripheral collisions in the Color Glass Condensate framework. To estimate systematic uncertainty associated with poor understanding of the wave function of the nearly real photon, we consider two diametrically different models: the dilute quark-antiquark dipole approximation and a
vector meson, in which...
We propose a new definition of unintegrated di-hadron fragmentation functions (DiFFs) which is compatible with the probability interpretation of collinear DiFFs and derive the leading-order evolution equations for these DiFFs. With these new definitions, we perform the first simultaneous extraction of DiFFs and transversity PDFs using data from semi-inclusive annihilation (SIA) in...
The (3+1)D hydrodynamics + hadronic transport hybrid models are effective quantitative tools to study the dynamics of relativistic heavy-ion collisions and to extract the transport properties of the Quark-Gluon Plasma. For collisions with $\sqrt{s_\mathrm{NN}} \sim O(10)$~GeV, the pre-equilibrium evolution before hydrodynamics plays an important role because it can reach up to 30\% of the...
A pilot calculation to extract the $a_1(1260)$ resonance from lattice QCD data is presented. Complementing calculations in the infinite volume help understand the properties of this three-body resonance, like pole position and branching ratios. The presented work is based on arXiv:2107.03973 and arXiv:2112.03355.
Many hadronic resonances, including the most intriguing ones (Roper, $\pi_1(1600)$, or $T_{cc}^+(3872)$), decay into three or more particles. To determine their masses and widths from Lattice QCD, one has to supply existing three-body formalisms with amplitude analysis techniques. In particular, one has to analytically continue reaction amplitudes extracted from the...
I will present the behavior of proton number cumulants and correlation functions in heavy-ion collisions based on relativistic hydrodynamics, incorporating essential non-critical contributions such as the exact conservation of multiple conserved charges and baryon excluded volume. I will also discuss the resulting constraints on the possible location of the QCD critical point coming from...
The baryon number is a conserved quantity in quantum chromodynamics (QCD), which is typically divided equally among the valence quarks in baryonic matter. There is an alternative theory suggesting that the baryon number is carried by a non-perturbative, Y-shaped topology of gluons called the baryon junction, which connects all three valence quarks. Neither theory has been experimentally...
We determine, from Lattice QCD, the elastic $\pi \pi$ scattering amplitudes in the three possible isospin channels and the $\sigma$ resonance. We extract its lineshape for several different quark masses corresponding with the state transitioning from bound to resonance. The extraction of the $\sigma$ pole position becomes very challenging when the state is unstable. We perform the first full...
In lattice-QCD calculations of parton distribution functions (PDFs) via large-momentum effective theory, the leading power correction appears as ${\cal O}(\Lambda_{\rm QCD}/P^z)$ in matching to the quasi distributions due to linearly-divergent self-energy in quasi-PDF operators. For lattice data with hadron momentum $P^z$ of a few GeV, this correction is important for accurate predictions of...
Numerical simulations of the (3+1)D hydrodynamic + hadronic transport hybrid model provide quantitative descriptions of the dynamics of relativistic heavy-ion collisions from a few GeV to a few TeV [1]. The net proton cumulants in the final state encode important information about the QCD phase structure. However, studying high-order cumulants of net proton fluctuations require more than...
Parton Distributions encode the universal way in which partons, ie quarks and gluons, distribute themselves within a hadron and are necessary for interpreting certain hadronic cross sections with Standard Model particles. By inverting the relationship between experimental cross sections and theoretical partonic cross sections, phenomenologists determine these parton distributions. Over the...
Nuclear matter populates a very important part of the high-energy or QCD phase diagram, where fundamental information is currently provided by theory, laboratory experiments, and astrophysics. How to translate between results obtained from different environments that produce different conditions is one of the most important open questions in nuclear physics today. I address how differences in...
Two-pion production from photon-photon fusion plays a key role in many physical processes, such as studying the substructure of the scalar mesons or constraining the hadronic contribution of the muon’s anomalous magnetic moment. A new theoretical framework has been developed which maps the $\gamma^{\star} \gamma^{\star} \to \pi\pi$ amplitude to finite-volume matrix elements that can be...
Gluons are found to become increasingly dominant constituents of nuclear matter when being probed at higher energies or smaller Bjorken-$x$ values. This has led to the question of the ultimate fate of nuclear gluonic structure and its interaction with external probes at extreme density regimes. In ultrarelativistic heavy ion collisions, the electromagnetic fields surrounding an ion, quantized...
Jets are algorithmic realizations of the fragmentation and hadronization patterns of high energy quarks and gluons liberated in relativistic hadron collisions. The last few years have witnessed an explosion of interest in jet substructure from both experimentalists and theorists. These substructure observables are derived from exploiting the information present in the clustering algorithms....
Since the first detection of gravitational waves from the coalescence of neutron stars in 2017, many new discoveries and constraints have been placed on matter at large baryon densities. The study of dense matter has also been facilitied by heavy-ion collsions at low beam energies. Heavy-ion collisions experiments from RHIC at Brookhaven National Laboratory have ran the Beam Energy Scan and...
The combination of hard probes and pioneering processes such as semi-inclusive deep inelastic scattering (SIDIS) on atomic nuclei is a powerful tool to access medium modifications of their underlying structure, explore the hadronization mechanisms, and study QCD confinement dynamics in the cold nuclear medium. Indeed, the study of the hadronization process in such a clean environment is...
I will talk about recent developments in the theory of gravitational form factors and discuss how they can be accessed in near-threshold quarkonium photo- and electro-production.
Short-Range Correlations (SRC): pairs of strongly interacting nucleons whose distance is comparable to their radii. Due to their overlapping quark distributions and strong interaction, SRC pairs serve as a bridge between nucleon interaction and partonic structure, with important consequences for strong-interaction physics, hadronic structure, and other studies. Some of the most intriguing SRCs...
We present lattice QCD results on the unpolarized and helicity GPDs for the proton using a novel method that decomposes the matrix elements into Lorentz-invariant amplitudes. This work is an extension of the proof-of-concept calculation presented in Phys.Rev.D 106 (2022) 11, 114512, which demonstrated that more optimized calculations of GPDs are applicable to any frame, with freedom in the...
We present a calculation of the scalar, vector, and tensor form factors for the pion and kaon in lattice QCD. We use two ensembles of maximally twisted mass fermions with clover improvement with two degenerate light, a strange, and a charm quark $(N_f=2+1+1)$ at lattice spacings of 0.093 fm and 0.081 fm. The pion mass of the ensembles is about 250-260 MeV. The excited-states effects are...
In the Jefferson Lab experiment, E12-06-105 performed in Hall C, we measured the inclusive scattering from a series of light to heavy nuclei at $x > 1$ in the quasielastic and deeply inelastic regimes. The measurement of quasielastic scattering from extremely high-momentum nucleons at moderate $Q^2$ but very large $x$ is a great tool to gain insight on the short-range structure and...
The feasibility of extracting generalized parton distributions (GPDs) unambiguously from deeply-virtual Compton scattering data (DVCS) has recently been questioned due to the existence of an infinite set of so-called ``shadow GPDs'' (SGPDs). These SGPDs are process-dependent, and manifest as multiple solutions---at a fixed $Q^2$---to the inverse problem in DVCS that needs to be solved to...
The charmonium photoproduction near threshold can be used to study important aspects of the gluon structure of the proton, such as the gluon Generalized Parton Distribution (GPD), the gravitational form factors, the mass radius of the proton, and the anomalous contribution to the proton mass. However, such an ambitious program requires precise measurements over the full kinematic range to...
One of the best ways to understand the spin structure of the proton is through Generalized parton distributions (GPDs) which are in principle accessible in exclusive deeply virtual photon electroproduction processes. However, in order to extract these GPDs, a proper understanding of the phase structure of the cross section is vital. In particular, the phase structure plays a key role in the...
Probing nuclear short-range correlations with real photons at Jefferson Lab
Measurement of near threshold quarkonia photoproduction cross section provides a unique tool to probe gluonic structure inside the nucleon, hence allowing extraction of gluonic form factors and mass radii. 𝐽/Ψ-007 experiment (E12-16-007) was conducted at Hall-C of the Thomas Jefferson National Accelerator Facility to measure near threshold 2-D differential 𝐽/Ψ photoproduction cross section as...
Several works have attempted to understand the pion valence partonic distribution function (PDF), both experimentally and theoretically. Questions remain, especially for the high x region. Using the recently developed Residual Field Model, we calculate the pion valence PDF in the range of 0.1<x<1. Within the model, the pion transitions into valence and residual subsystems described by their...
Evolution equations which control the scale dependence of generalized parton distributions (GPDs) are a crucial tool to extract accurately these objects from experimental data. They determine the propagation of uncertainty in the deconvolution problem of factorized observables, and offer a great opportunity to model GPDs in the small Bjorken-x limit. We use the recent momentum-space evolution...
The generalized contact formalism (GCF) is a useful model for analyzing the properties and implications of nuclear short-range correlations (SRCs). Based on an asymptotic factorization of the wave function when two-particles are found close to each other, the GCF was used to study two-body densities and momentum distributions, electron scattering reactions, and more, resulting in a consistent...
The development of the GPD formalism in the last 25 years has been a groundbreaking advance in our understanding of the structure of the nucleon. Unifying the concepts of parton distributions and of hadronic form factors, GPDs contain a wealth of new information about how quarks and gluons make up hadrons. For example, GPDs correlate different parton configurations within the hadron at the...
I Will discuss JPAC analysis of the recent results on J/psi photo production and prospects for charm studies at the next generation photo/lepton facilities.
The light-cone distribution amplitude (DA) encodes non-perturbative information of the wave function of fast moving hadrons. In particular, cross sections for high energy exclusive processes factorize into the pion DA, directly probing the internal structure of the pion, as well as providing constraints on proton structure via Deeply Virtual Meson Production. In this talk, I will present the...
Recent proposals for hadronic physics contributions to nuclear structure and dynamics in the form of diquark-based short-range correlations (SRC) and hidden color states in nuclear wavefunctions will be discussed. While hidden color states have a 40-plus year history as rigorous predictions of the SU(3) basis of QCD, future experimental developments promise unprecedented access to their study....
The EMC effect has been known for almost 40 years but it still needs to be fully understood theoretically and there are essentially no reliable experimental constraints on its flavor dependence. In order to better understand the EMC effect, We propose a clean and precise measurement of the flavor dependence of the EMC effect using parity-violating deep inelastic scattering on a 48Ca target....
Measurements of jet substructure in ultra-relativistic heavy ion collisions suggest that the jet showering process is modified by the interaction with quark gluon plasma. Modifications of the hard substructure of jets can be explored with modern data-driven techniques. In this study, we use a machine learning approach to the identify quenched jets. Jet showering processes, with and without the...
A search is reported for low-mass structures in the J/ψJ/ψ mass spectrum produced by proton-proton collisions at s√=13TeV. The data sample corresponds to an integrated luminosity of 135 fb−1 collected by the CMS experiment at the LHC. Modelling signals with relativistic Breit-Wigner shapes, and under the assumption of the absence of interference between signal components, and between signal...
We perform the first simultaneous extraction of parton collinear and transverse degrees of freedom from low-energy fixed-target Drell-Yan data in order to compare the transverse momentum dependent (TMD) parton distribution functions (PDFs) of the pion and proton. We demonstrate that the transverse separation of the quark field encoded in TMDs of the pion is more than $\sim 5 \sigma$ smaller...
Understanding the nuclear effect is critical to reduce the Parton Distribution Functions (PDFs) uncertainties at large x. Traditionally, the nuclear effect is assumed to be isoscalar. A new study within the JAM global framework by including the MARATHON He3/H3 data implements an isospin dependent off-shell correction. The results suggest an enhanced nuclear effect on the d-quark PDF in the...
In this talk, we will present the measurement of the polarization of coherent J/psi photoproduction in ultra-peripheral lead-lead collisions using Run 2 data from the ALICE experiment. We will also discuss future prospects for angular correlation studies.
For heavy ion collisions in the TeV beam energy region, the large number of initial hard scatterings create a richly "doped" hot quark-gluon plasma containing many charm quarks/anti-quarks. This provides a uniquely "charming" environment for the massive production of heavy flavor exotic hadrons, with the notable examples of X(3872) and Tcc states, and possibly helps solve puzzles about their...
There has been rapid development in direct calculations of Bjorken-x dependent structure using large‐momentum effective theory (LaMET) and similar frameworks. In this talk, I will highlight selected results in the quark and gluon parton distribution functions of the pion, kaon, and nucleon and our attempts toward precision lattice PDF calculations using multiple lattice spacings. I also...
The MUon proton Scattering Experiment (MUSE) was built to address the proton radius puzzle by simultaneously measuring the proton radius from both $e^\pm p$ and $\mu^\pm p$ elastic scattering in a momentum transfer range sensitive to the radius extraction. The experiment is carried out at the Paul Scherrer Institute (PSI) and uses a mixed e, $\mu$, and $\pi$ beam, alternating between...
Understanding the modification of quarks in nucleons within nuclei (EMC effect) is a longstanding open question in nuclear physics. Recent experimental results from electron scattering at Jefferson Lab strengthen the correlation between the EMC effect and short- range correlated pairs (SRC) of nucleons in nuclei. That means that the EMC effect is probably driven by the high-momentum...
A major objective in the field of high-energy nuclear physics is to
quantify and characterize the quark-gluon plasma formed in relativistic
heavy-ion collisions. The ϕ meson is an excellent probe for studying
this hot and dense state of nuclear matter because of its very short
lifetime. The ϕ->µ+µ- decay channel is particularly interesting because
the decay muons do not interact with its...
I will report on the Jefferson Lab(JLab) Hall C experiment E12-10-008 (EMC effect) that is currently running and will finish data taking by mid February. Multiple cryogenic and solid targets were used to measure inclusive electron scattering using a 10.5 GeV beam from the Continuous Electron Beam Accelerator Facility at JLab. In this experiment, for a series of light to heavy nuclei, we...
The effective radius of the proton varies depending on the force through which it interacts with its surroundings. While the charge radius, relevant to electromagnetic interactions, is known to within a few hundredths of a fermi, the mass radius, relevant to gravitational interactions, is still heavily disputed. Experimental measurements (e.g. from GlueX), lattice QCD calculations and various...
Investigating the modifications of jets and high-$p_T$ probes in small systems requires the integration of soft and hard physics. The recent advancements in the JETSCAPE framework have led to the development of an event generator that considers the correlations between soft and hard partons to study jet observables in small systems. This hybrid approach separates the multi-scale physics of the...
We present our results for TMD factorization at sub-leading power beyond, and leading order in the strong coupling, focusing on the matching of the large and small transverse momentum contribution in semi-inclusive deep inelastic scattering processes (SIDIS and Drell Yan). We pay special attention to azimuthal modulations of polarized and unpolarized cross sections such as the Cahn effect....
TMD observables are normally expressed in terms of their contributions coming from different regions in transverse momentum. The low transverse momentum is often ascribed to an intrinsic non perturbative property of the hadron, described by TMD factorization, while the large transverse momentum region can be computed using fixed order collinear perturbation theory. In the middle region, often...
The exploration of medium modification of unpolarized structure functions in nuclei has been underway for several decades. The theoretical descriptions of this effect, known as the “EMC effect”, are numerous and there is currently no universal community consensus about its cause, although connections to short-range correlations do appear to be plausible. In this talk I will discuss something...
sPHENIX will start data taking in Spring 2023 at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. Built around the excellent BaBar superconducting solenoid, the central detector consists of a silicon pixel vertexer adapted from the ALICE ITS design, a silicon strip detector with single event timing resolution, a compact TPC, novel EM calorimetry, and two layers of...
The forthcoming Deep Underground Neutrino Experiment aims to precisely measure all aspects of the neutrino mixing matrix across a wide range of neutrino energies. Thus, it is incumbent upon the community to deeply understand the scattering processes at play across DUNE's broadband beam, including quasielastic, meson-exchange current, resonance, and deep inelastic scattering. I'll briefly...
The Jefferson Lab Polarized Electrons for Polarized Positrons (PEPPo) experiment demonstrated that it is possible to make polarized positrons with the polarized electron beam at CEBAF. Jefferson Lab is now looking to develop a dedicated positron source that will be able to feed the CEBAF accelerator with polarized positrons and deliver up to 11 GeV positrons to the experimental halls. I...
In this talk I will focus on the asymmetry ALT involving a longitudinally polarized electron or proton colliding with a transversely polarized proton, with a single pion, photon, or jet detected in the final state. We provide rigorous numerical predictions for Jefferson Lab, COMPASS, RHIC, and the future Electron-Ion Collider using recent extractions of the parton distribution functions (PDFs)...
Hadronic and radiative decays of light mesons decays offer a privileged environment to test QCD and search for physics beyond the Standard Model.
A new generation of precision experiments in hadron physics will soon offer new data that will have an impact on determinations of fundamental QCD parameters, such as the ratio of light quark masses or the $\eta$-$\eta^{\prime}$ mixing parameters,...
One of the most puzzling aspects of the Standard Model is that the overwhelming majority of the mass of hadronic systems arises from massless and nearly massless objects. How this occurs is poorly understood, and remains a major open question of the standard model. From the little that we do understand, we know that mass generation is intricately connected to the internal structure of hadronic...
The Lorentz group of special relativity contains a Galilean subgroup, under which light front time is invariant. Using the light front time variable along with the ordinary three Cartesian spatial coordinates allows a fully relativistic spatial description of the internal structure of hadrons, specifically in the form of two-dimensional densities on the plane transverse to the observer's line...
The ability of current and next generation accelerator based neutrino oscillation measurements to reach their desired sensitivity and provide new insight into the nature of our Universe, requires a high-level of understanding of the neutrino-nucleus interactions. These include precise estimation of the relevant cross sections and the reconstruction of the incident neutrino energy from the...
ABSTRACT
This talk illustrates the chiral nature of the non-Abelian covariant derivative for SU(N) gauge groups. In the chromostatic limit, the interior volume of a hadron is filled by a single color-vortex. The Strong Conjecture for Color Confinement suggests that this volume is separated from an exterior volume by a domain wall of topological charge.
The mechanical properties of the proton, including angular momentum, mass, pressure, and shear forces, are encoded in the matrix element of the proton energy-momentum tensor and are expressed in the gravitational form factors (GFFs). Recent theoretical developments have shown that GFFs can be accessed in deeply virtual Compton scattering (DVCS) and in deeply virtual (vector) mesons production...
A quark-model treatment of hadron decays suggests that the creation of a constituent quark-antiquark pair occurs in a spin-triplet p-wave scalar configuration, 3P0 in spectroscopic Russell-Saunders notation. This chiral-symmetry breaking vertex has long been known to have to be nonperturbative since the fundamental underlying theory, chromodynamics, is to a good approximation chirally...
Current and future accelerator-based neutrino facilities utilizing intense neutrino beams and advanced neutrino detectors are focused on precisely determining neutrino oscillation properties and signals of weakly interacting Beyond the Standard Model (BSM) physics. These are subtle effects, such as extracting the CP violation phase and disentangling parameter degeneracies between oscillation...
The PANDA FAIR Phase-0 experiment at the Mainz Microtron (MAMI) accelerator facility at Mainz in Germany is set to determine the double-virtual transition form factor (TFF) of the neutral pion via single-pion electroproduction. The determination of the electroproduction cross section on a highly charged target using low momenta transfers gives access to the so-called virtual Primakoff...
The quark-gluon dynamics manifests itself in a set of non-perturbative functions describing all possible spin-spin and spin-orbit correlations. Single and Dihadron semi-inclusive and hard exclusive production, both in current and target fragmentation regions, provide a variety of spin and azimuthal angle dependent observables, sensitive to the dynamics of quark-gluon interactions. Studies...
Antineutrino scattering on free protons (or neutrino scattering off free neutrons) gives a unique measurement of neutron and proton structure and is a building block for predicting neutrino scattering on more complex nuclei. Previous measurements have had to rely on scattering neutrinos off deuterium and then correcting for poorly known nuclear effects, or by low intensity anti-neutrino...
We consider the MIT bag model of hadrons with a Tsallis statistics. In the new framework we obtain a perspective in which the bag pressure can be dismissed by using the q parameter of the non-extensive statistics. This parameter effectively describes the interactions among the components in the hadron.
Semi-inclusive deep inelastic π+ electroproduction has been studied with the CLAS12 detector at Jefferson Laboratory. Data were taken by Run Group A at Hall B of the laboratory using a polarized 10.6 GeV electron beam, interacting with an unpolarized liquid hydrogen target. The collected statistics enable a high-precision study of the Cosφ and Cos2φ azimuthal moments of the unpolarized...
Mapping the 3D structure of the proton in terms of its spinning quark and gluon constituents is one of the main goals of current hadronic physics investigations. Generalized parton distributions can provide part of the solution, connecting GPDs through Fourier transformation to the average spatial density of quarks and gluons with a given longitudinal momentum fraction, x. Notwithstanding the...
The $\eta$ and $\eta'$ mesons are almost unique in the particle universe because of their quantum numbers and the dynamics of their decay are strongly constrained. This effect increases the branching ratio of rare decays which can be studied to probe physics BSM. The integrated eta meson samples collected in earlier experiments have been about ~$10^9$ events, dominated by the WASA at Cosy...
Heavy flavor production, both open heavy flavor and quarkonium, has been studied in a variety of systems, particularly in $p+p$, $p+A$, and $A+A$ collisions at RHIC and the LHC. The new sPHENIX detector will make important contributions to $\Upsilon$ production as well as heavy flavor jets at RHIC. The LHC experiments include both collider data and fixed-target environments. Heavy flavor...
The first excited state of the nucleon dominates many nuclear phenomena at energies above the pion-production threshold and plays a prominent role in the physics of the strong interaction. The study of the N to ∆ transition form factors (TFFs) allows to shed light on key aspects of the nucleonic structure that are essential for the complete understanding of the nucleon dynamics. In this talk...
Quantum simulation has the potential to be an indispensable technique in the investigation of non-perturbative phenomena in strongly interacting quantum field theories (QFTs). A central question in the current quantum era is: what non-perturbative QFT problems can be tackled with the Noisy Intermediate Scale Quantum (NISQ) machines? In this work, we provide an explicit example to this question...
Determining the structure of protons and nuclei at high energy is one of central goals of the heavy-ion collisions and the future Electron-Ion Collider (EIC). To extract the proton shape fluctuations from HERA exclusive vector meson production data, we apply Bayesian inference and determine probabilistic constraints on the parameters describing the fluctuating structure of protons at high...
We report the observation of the existence of a possible universal limit for valence parton distributions that should exist once partonic degrees of freedom are relevant for high energy scattering from strongly interacting bound systems like a nucleon, meson or few nucleon system at very short distances. Our observation is based on the notion that the Bjorken x weighted valence parton...
Testing detailed predictions of QCD and searching for phenomena Beyond the Standard Model at the LHC and the EIC requires knowing spin dependent Parton Distribution Functions for quarks and gluons. For some observables Generalized or Transverse Momentum pdf’s are needed. Calculating these distributions from QCD, ab initio, is prohibitively resource intensive and depends on non-perturbative...
Resolution of the proton spin puzzle, which is inability of the constituent quark model to explain discrepancy between the spin-$1/2$ of the proton and the amount of spin carried by its quarks and gluons, as measured in experiment, is an outstanding problem in modern hadronic physics. One possibility is that "missing” spin of the proton may be found at small values of Bjorken-x. As a result,...
We present a model for the J/ψ Λ spectrum in B− → J/ψ Λ p ̄ decays, including the $P^\Lambda_{\psi s}(4338)$
baryon recently observed by the LHCb collaboration. We assume production via triangle diagrams
which couple to the final state via non-perturbative interactions which are constrained by heavy-
quark and SU3-flavor symmetry. The bulk of the distribution is described by a triangle...
Extending the TMD factorization to thrust-dependent observables entails difficulties ultimately associated with the behavior of soft radiation.
In this talk, the factorization properties of the thrust distribution of $e^+e^-$ annihilation into a single hadron are discussed and their peculiarities with respect to standard TMD factorization are highlighted.
I present the phenomenological...
Sokhna Bineta Lo Amar (1, 2)
Paul Gueye (2)
Oumar Ka (1)
(1) Cheikh Anta Diop University (UCAD), Dakar (Senegal)
(2) Facility For Rare Isotope Beams (FRIB), Michigan State University (USA)
Abstract. The study of unstable nuclei far from β-stability through fragmentation of heavy ion beams is one the most used approaches in low to intermediate energy nuclear physics to gain insights into...
The PrimEx eta experiment aims to extract the eta radiative decay width by measuring the cross section for eta photo-production via the Primakoff Effect. This decay width will help with the determination of the eta-eta’ mixing angle and the ratio of the light quark masses. The experiment took data in Hall D at Jefferson Lab using the GlueX detector in 2019, 2021, and just recently in fall of...
In deep-inelastic scattering, the energetic quarks liberated from hadrons travel and interact with the nuclear medium via several processes. One of these processes is the quark energy loss induced by gluon bremsstrahlung and intra-nuclear interactions of creating future hadrons. Moreover, one manifestation of these interactions is the enhanced emission of low-energy charged particles, referred...
We report the results of the test beam studies performed on a prototype for the high-granularity calorimeter insert for the ePIC detector at the EIC. The ECAL-sized prototype was constructed using layers of Fe absorber plates and scintillating tiles with silicon photomultipliers. A 4 GeV positron beam from Jefferson Laboratory's Hall D pair spectrometer was used to evaluate its performance....
Laser cooled atomic ions offer unprecedented control over both internal and external degrees of freedom at the single-particle level. They are considered among the foremost candidates for realizing quantum simulation and computation platforms that can outperform classical computers in specific tasks. Trapped ions can be used to simulate effective models of lattice gauge theories and to...
The deuteron electro-disintegration $D(e,e'p)n$ experiment aims to measure $D(e,e'p)n$ cross sections at high $Q^2$, $x_{Bj}>1$, and missing momenta $p_m>600$ MeV/c within a relative statistical error of 15%. To obtain a greater understanding of the strong nuclear force, we must probe deeper in the nucleus within ranges where nucleons overlap (sub-fermi distances). In this region, the...
Heavy quarks, like charm quarks, are produced early in the relativistic heavy-ion collisions and probe all stages of the evolution of the created medium – known as the Quark Gluons Plasma. Two-particle correlations at low relative momentum (the femtoscopic correlations) are sensitive to the interactions in the final state and the extent of the region from which correlated particles are...
Baryon anticorrelation measurements have disagreed with theory in the last few years: the number of experimental baryon pairs with small phase-space separation falls short from existing numerical Monte Carlo simulations.
We have computationally extracted baryon (anti)correlations from one of the best known Monte Carlo codes, PYTHIA, that produces them at the string-fragmentation level in...
I recount the early motivation for creating the GHP along with the subsequent maneuvering that was needed to overcome obstacles.
The leading uncertainty in obtaining precise fundamental information from particle physics experiments is often due to the difficulty of quantifying non-perturbative strong-interaction effects.
Over the last decade, Lattice QCD simulations, in which space and time are approximated by a discrete lattice of points, have improved in precision to the extent that a number of important quantities...
Mesons with heavy flavor content are a promising probe of the hot QCD phases produced in heavy-ion collisions. I will present our recent progress on the thermal modification of the properties of heavy mesons in hot mesonic matter. We use a self-consistent theoretical approach that employs an effective field theory based on chiral and heavy-quark spin-flavor symmetries. We apply the...
I will give an overview of the findings via the observation of hadronic resonances in heavy ion collisions from SPS to RHIC and LHC energies. The short-lived resonances are interacting through the full evolution of the collision and can be used to probe the dynamics of the partonic and hadronic matter. I started this topic with my PhD research topic at the SPS and continued with my work at the...
I will present a short overview of some of the important developments in lattice QCD calculations in the context of relativistic heavy-ion collision experiments at RHIC. I will outline why lattice QCD calculation will play a critical role in the scientific success of the future EIC, and present some progress along these directions.
The intrinsic spin of fundamental particles emerges naturally from relativistic quantum mechanics, implying a deep connection between spin dynamics and the forces that ultimately shape the structure of our universe. Spin is therefore an excellent probe into the nature of complex theories, such as Quantum Chromodynamics, where the manifestation of spin correlations in dynamic objects like the...
