Understanding the properties of nuclear matter and its emergence through the underlying partonic structure and dynamics of quarks and gluons requires a new experimental facility in hadronic physics known as the Electron-Ion Collider (EIC). The EIC will address some of the most profound questions concerning the emergence of nuclear properties by precisely imaging gluons and quarks inside...
Precision CP violation (CPV) measurements are widely recognized as a highly sensitive probe of the Standard Model with new sources needed to account for the mater-antimatter asymmetry observed in the Universe. There is a long-term discussion involving the source of the strong phase needed to generate direct CPV in charmless B and D decays. I will show that the final state interactions (FSI)...
I will give an outline of the evidence of the formation of a "fluid" in small systems in ultra-relativistic hadron collisions (p-p and pA), and argue that this forces us to radically rethink our view of hydrodynamics as an effective theory. I will argue that a re-derivation of hydrodynamics as a field theory can help us in understanding how a system with as few as 20 degrees of freedom can...
I discuss some of the apparent inconsistencies in canonical, covariant
and light-front formulations of quantum field theory and the
resolution of these inconsistencies. The topics that will be
discussed are (1) the problem of inequivalent representations (2) the
problem of the trivial vacuum (3) the problem of ill-posed initial
value problems (4) the problem of rotational covariance (5)...
A novel approach to the dynamical light-front (LF) zero modes is presented. It is based on quantization of the two-dimensional LF gauge field $A^\mu(x)$ in the covariant (Feynman) gauge. The $A^{\pm}$ components are obtained as a massless limit of the massive vector field and contain an infinite set of dynamical zero modes with finite LF energy. We argue that the same zero modes are present in...
We will summarize the main properties of the so called ”abnormal solutions” of the Wick-Cutkosky model [1, 2], i.e. scalar particles interacting via massless exchange, within the Bethe-Salpeter equation [3]. These solutions have the property of not existing in the non-relativistic limit, despite of having very small binding energies, and present a genuine many-body character with a vanishing...
The Bethe-Salpeter equation for system of two oppositely charged particles not only reproduces the Coulomb spectrum, but, for enough large coupling constant ${\cal C}>\frac{\pi}{4}$, predicts additional levels [1,2] not covered by the Schroedinger equation. These relativistic states (called abnormal) are dominated, for more than 90-99 percent, by the exchanged photons [3] (which are scalar...
Basis Light Front Quantization (BLFQ) provides a foundation for the development of Hamiltonians and numerical methods to solve both relativistic bound state and scattering applications in QED and QCD. For QCD applications in limited Fock spaces, one assumes a form of confinement based on light-front holography along with an additional longitudinal confinement. For applications limited to...
I will be discussing the proton gluonic gravitational form factors, in particular, those extracted from the J/$\psi$-007 performed in Hall C at Jefferson Lab. In this experiment, the elastic photoproduction of a small dipole (J/$\psi$) is used to probe the gluonic structure of the proton. The gluons' contribution to the mechanical properties of the proton (mass density, pressure, and shear...
We use the Color Glass Condensate effective theory of QCD at small x to calculate fully inclusive structure functions as well as single and double inclusive hadron production in DIS at small x at the Next to Leading Order (NLO). We show that calculations of NLO corrections in light front perturbation theory and the traditional covariant perturbation theory agree for processes that have been...
The JIMWLK Hamiltonian governs evolution of high energy collision processes. At next-to-leading order, the Hamiltonian features large logarithms, which have to be resummed. We discuss partial resummation of these logarithms into running coupling and DGLAP-like resummation.
Basis Light-Front Quantization (BLFQ) provides a nonperturbative framework to solve relativistic many-body bound state problems in quantum field theories. We report our recent progress in applying BLFQ to reveal structure of the nucleon going beyond to its leading Fock sector. We produce the light-front wave functions of the nucleon from the light-front QCD Hamiltonian, determined for its...
The effective cross section of double parton scattering in proton collisions has been measured by many experiments with rather different results. Motivated by this fact, we assumed that the parton correlations in the transverse plane are different whether we have valence or sea partons. With this simple approach, we were able to fit the available data and found that sea parton pairs are more...
I will discuss the pion structure within a dynamical model based on the solution of the Bethe-Salpeter equation in Minkowski space.
The model consider the pion as quark anti-quark bound state, interacting through a one-gluon exchange. The inputs of the model are the quark and gluon masses, and a scale parameter related to the extended quark-gluon vertex. Within this model, we obtain the full...
We study the gravitational form factors (GFFs) and the mechanical properties like the pressure and shear distribution of quarks using the light-front wave functions (LFWFs) of the nucleon from a basis light-front quantization (BLFQ) approach in the leading Fock-sector representation. Our analysis further expands to include an extra Fock sector, which integrates three quarks and an active...
We explore light mesons beyond valence structure in the Basis Light-front Quantization (BLFQ) approach, comprising the quark-gluon interactions from the light-front quantum chromodynamics (QCD) on the Hamiltonian. After fitting the light meson mass spectroscopy, the Hamiltonian eigenvectors provide a good description of the pion and the kaon Decay constants, Electromagnetic Form factor, and...
We investigate the gravitational form factors of a strongly coupled scalar theory in the light front Hamiltonian approach. The theory can be used to mimic the non-perturbative interaction between the nucleon and the pion. We renormalize the energy-momentum tensor with a Fock sector dependent scheme. We also systematically analyze the Lorentz structure of the energy-momentum tensor and identify...
I will present how perturbative evolution offers in theory the possibility of a model independent extraction of generalized parton distributions (GPDs) from exclusive processes such as deeply virtual Compton scattering (DVCS), but falls short of its promises practically at moderate skewness -- a problem illustrated through the concept of shadow GPDs. However, perturbative evolution provides...
Basis light-front quantization (BLFQ), as a fully relativistic and nonperturbative approach based on a light-front quantized Hamiltonian with Quantum Chromodynamics (QCD) input, has the potential to achieve the first principle calculation. For QCD applications in limited Fock spaces, we implement a form of confinement based on light-front holography and additional longitudinal confinement in...
The Drell-Yan process, involving the annihilation of a quark and an antiquark into a lepton-antilepton pair, provides valuable insights into the structure and dynamics of hadrons. In this study, we focus on the investigation of azimuthal angular asymmetries, specifically the cos(2ϕ) and sin(2ϕ-ϕs) asymmetries, which probe the spin and transverse momentum-dependent properties of the...
In this talk I report our recent progress on solving the postronium system in a basis light-front Hamiltonian approach with the light-front QED Hamiltonian as input. Both the leading Fock sector ($|e^+e^-\rangle$) and the higher sector containing one dynamical photon ($|e^+e^-\gamma\rangle$) are included in the basis. We found that the rotation symmetry of the positronium system provides...
We study numerically spectrum of positronium using effective
(and renormalized) Hamiltonian obtained from QED by means of
the renormalization group procedure for effective particles
(RGPEP). The basis light-front quantization (BLFQ) provides
the framework for numerical computations. Positronium is chosen
as the testing ground for our method and a stepping stone for
future studies in QCD,...
In 2004, the CLAS detector at Jefferson Lab collected experimental data on a broad range of nuclear targets, from heavy nuclei like Lead to lighter ones such as Carbon or Deuterium, employing a 6 GeV electron beam. These data enabled us to investigate various facets of nuclear phenomena, encompassing the nuclear hadronization process, nuclear color transparency, short-range nuclear collations,...
I will discuss the link between the QCD and the light-front quark model (LFQM) utilizing the interpolation between the instant form dynamics (IFD) and the light-front dynamics (LFD). In the ‘tHooft model, the mass gap solutions, vacuum condensation, spontaneous symmetry breaking of the chiral symmetry and the mass spectra of mesons bearing the feature of the Regge trajectories are found and...
We compute the pressure, chiral condensate and strange quark number susceptibility from first principles within perturbative QCD at finite temperature and very high magnetic fields up to next-to-leading order and physical quark masses. We study the convergence of the perturbative series for the pressure for different choices of renormalization scale in the running coupling. Our results for the...
The advent of the AdS/CFT correspondence led to the development of phenomenological models aimed at describing the behavior of hadrons in non-perturbative regimes of QCD. In particular, the so-called holographic models allow the description of the behavior of quarkonium in a thermal medium, such as the plasma of quarks and gluons formed in heavy ions collisions. We will discuss how...
We study the nuclear isentropic equation of state for a stellar matter composed of nucleons, hyperons, and $\Delta$-resonances. We investigate different snapshots of the evolution of a neutron star, from its birth as a lepton-rich protoneutron star in the aftermath of a supernova explosion to a lepton-poor regime when the star starts cooling to a catalyzed configuration. We use a relativistic...
We present the description of light-nuclei, in valence approximation, within a rigorous Light-Front (LF) approach. The latter, fulfills Poincaré covariance, macroscopic locality,number of particles and momentum sum rules. We applied the analysis to electron deep inelastic scattering (DIS) on $^3$He, $^3$H and $^4$He targets, in the Bjorken limit. For details about the $^3$He case, see Ref....
In this talk, I will present recent results from an AdS/QCD model, inspired by AdS/CFT correspondence. In this model, the IR mass scale is introduced in a quadratic exponential deformation of the AdS metric. In contrast with the hard and soft wall models, there is no cut in the AdS space nor any dilaton field in the action. This model proves effective for obtaining discrete spectra for hadrons...
We present a minimal holographic QCD model that allows for a description of asymptotically linear Regge trajectories for vector mesons and nucleons in a way consistent with confinement. We consider a 5d background where the dilaton is quadratic in the infrared (far from the boundary). The background is a solution of 5d Einstein-dilaton gravity and satisfies the confinement criterion. The...
The spin-1 particles is an admirable two quarks bound state
system to understand electromagnetic properties from hadronic states.
These systems are generally relativistic, and therefore,
need an approach using quantum field theory. In the present work, we will use both the
quantum field theory at the instant form, as well,
quantum field theory on the light-front~(LFQFT).
In general, it...
We investigate the structure of the spin-1 hadron system, particularly the $\rho$-meson, through the leading-twist momentum-dependent parton distribution functions. We employ the light-front wavefunctions generated from the Basis Light-Front Quantization approach to compute the quark and gluon distribution functions (PDFs), and the transverse momentum-dependent quark distribution functions...
The exclusive photo- and electroproduction of the light vector mesons $\rho, \, \omega \, \text{and } \phi$ are studied within the color dipole picture as function of the center-of-mass energy of the $\gamma p$ collision and the momentum transfer squared $|t|$. The corresponding vector meson wave functions have been computed with the relativistic AdS/QCD holographic approach. This enabled us...
Double Parton Scattering (DPS) is a important way for which we can investigate the parton distributions of the proton and the nucleus. Although, we know that such scatterings should occur in high energy collisions, the formalism to describe it lack of answers to questions like --- is there a universal effective cross section? In direction to explore such questions, we investigate DPS in...
While the Higgs mechanism might be responsible for the masses of the elementary particles, the mass-creation mechanism for hadrons is quite different. Less than 1% percent of the mass of the proton is due to the Higgs mechanism. Particles solely composed of gluons are at the center of the strong interaction. Glueballs themselves would be massless without the strong interaction and their...
In this talk, we present a short review of the emergence of a dynamical gluon mass through the action of the Schwinger mechanism. The linchpin of this mechanism is the dynamical formation of longitudinally coupled massless bound-state poles in the vertices of the theory, and especially in the three-gluon vertex. The presence of these poles, in addition to causing the infrared saturation of...
The lattice computation of multigluon correlation functions, namely two, three and four point functions, is reviewed exploring its implications to the QCD dynamics.
A nonperturbative approach to derive the dressed quark-gluon vertex is based on longitudinal and transverse Slavnov-Taylor identities, rather than on perturbative dressing or solving the inhomogeneous Bethe-Salpeter equation. The adequate manipulation of these identities with projections leads to the functional form of all form factors of the vertex.
This novel vertex is used in the...
We explore the Dirac decomposition of the gauge invariant quark propagator, shedding light on the hadronization of a quark as this interacts with the vacuum. Using the spectral representation of the quark propagator, we link the coefficients of the Dirac decomposition of the gauge invariant quark propagator to sum rules governing the chiral-odd and chiral-even quark spectral functions.
In...
We present one-loop results for corrections from Strong Interactions to the quark-photon vertex using different confining models for the exchanged gluon. This calculation allows for the prediction of confinement effects in form factors and observables like the proton anomalous magnetic moment. We show that a range of confining models with dynamical gluon masses and even complex-conjugated...
Given the well-known limitations of the perturbative approach to Yang-Mills theories in the infrared regime, it is often interesting to resort to nonperturbative methods, such as Lattice QCD, Schwinger-Dyson equations, Renormalization Group Methods, and effective models. In particular, the so-called Refined Gribov-Zwanziger (RGZ) effective model has successfully described a nontrivial infrared...
The Faddeev-Niemi representation prescription for the Yang-Mills SU(2) gauge theory is explored through a Gauge Induced Variable technique which render the topology implied both interesting and rich on new consequences: effective modes in the classical solutions of the theory emerge in the context of a generalized Klein-Gordon Equation. Traces of mass intervals and fundamental scales appears...
In the high energy regime, in light cone coordinates it is possible to calculate the probability of bosons ($\gamma, W^\pm, Z,g $) floating in a quark-antiquark pair, which in turn can be approached through of the dipole formalism in the high energy regime. In this work we present important observables that will be essential to study the background contributions of future electron-positron...
We use the framework of the Dyson Schwinger and Bethe-Salpeter equations to compute Light-Cone Distribution Amplitudes of heavy-light mesons and quarkonia. The corresponding heavy-light Bethe-Salpter amplitudes are projected onto the light front and we reconstruct the distribution amplitudes of the mesons in the full theory.
Also we calculate the strong decay couplings for ρ→ππ, ϕ→KK, K*→Kπ,...
We study the properties of the $K^{+}$-meson in nuclear medium within
the framework of light-front field theory, such as the electromagnetic form factors (EMFF), charge radius, decay constant and probability of the kaon valence component $\eta$, where the kaon ($K^{+}$-meson) structure in nuclear medium is described using the light-front $K^{+}$ meson wave function based on a Bethe-Salpeter...
