Deeply Virtual Compton Scattering (DVCS) is the easiest reaction that accesses the Generalized Parton Distributions (GPDs) of the nucleon. GPDs offer the exciting possibility of mapping the 3-D internal structure of protons and neutrons by providing a transverse image of the constituents as a function of their longitudinal momentum. A vigorous experimental program is currently pursued at...
Transverse-Momentum dependent Distributions (TMDs) are a key tool to understand the internal partonic 3D structure of hadrons in momentum space. I will discuss some recent TMD extractions for quarks in the Nucleon, whose analyses are reaching a theoretical precision comparable to collinear Parton Distribution Functions (PDFs), and I will show the potential impact of future electron-ion...
Masses and spins of hadrons are fundamental quantities in physics; however, their origins are not understood yet and their investigations are major purposes of building electron-ion colliders in 2030's. Both of them can be investigated by generalized parton distributions (GPDs). The $t$-channel or spacelike ($s$-channel or timelike) GPDs are studied by deeply virtual Compton scattering...
We propose to detect signals from quark orbital angular momentum (OAM) through exclusive π production in electron-(longitudinally-polarized) proton collisions. Our analysis demonstrates that the sin 2ϕ azimuthal angular correlation between the transverse momentum of the scattered electron and the recoil proton serves as a sensitive probe of quark OAM. Additionally, we present a numerical...
After 60 years of quantum chromodynamics (QCD) and the quark constituent model, new experimental evidence challenges existing descriptions of hadronic states. This work introduces a holographic approach to describing exotic vector states emerging in heavy quarkonium. We propose a WKB-based approach inspired by diquark Regge trajectories to infer the structure of the holographic confining...
The light cone distribution of light mesons, encompassing both one-dimensional light cone distribution amplitudes (LCDAs) and three-dimensional transverse momentum dependent wave functions (TMDWFs), provides insight into the inner structure of hadrons. These distributions are crucial inputs for perturbative calculations in hard exclusive processes. In this talk, I will present recent...
In the instant-time formulation of quantum field theory, solitons correspond to states. We present a new formalism for treating these states. The formalism is much simpler and easier to use than previous formalisms, making many previously impractical problems now practical. We have used it to calculate soliton masses, spectra, form factors, and scattering amplitudes, as well as the decay...
We develop an new approach for calculating heavy quark effective theory (HQET) light-cone distribution amplitudes (LCDAs) by employing a sequential effective theory methodology. The theoretical foundation of the framework is established, elucidating how the quasi distribution amplitudes (quasi DAs) with three scales can be utilized to compute HQET LCDAs. We provide theoretical support for...
In this talk I will discuss some recent progress in the study of photon and flavor asymmetric pseudoscalar meson light front wave functions made within DSEs approach.
This work presents a systematic feasibility study on measuring backward deeply virtual Compton scattering (bDVCS) on the pion through Sullivan processes, within the framework of collinear QCD factorization. In this approach, pion-to-photon transition distribution amplitudes (TDAs) are used to describe the photonic structure of the pion. Using the TDA framework considering overlap of...
We employ the non-perturbative gauge/gravity duality approach to study the phase structure of Quantum Chromodynamics (QCD) under finite temperature, baryon chemical potential, and rotational effects. Our models include the SU(3) pure gluon system, 2-flavor QCD, and 2+1-flavor QCD, all calibrated with the latest lattice data to analyze their thermodynamic properties and predict the location of...
The off-shell pion electromagnetic form factors are explored
using phenomenological relativistic constituent quark models. These composite pion models feature
massive, structureless blue quark and antiquark, allowing the computation of microscopic form factors
via the Mandelstam approach. Each model relies on two parameters which are determined by closely reproducing the pion decay...
We compute holographic entanglement entropy (EE) and the renormalized EE in AdS solitons with gauge potential for various dimensions. The renormalized EE is a cutoff-independent universal component of EE. Via Kaluza-Klein compactification of S1 and considering the low-energy regime, we deduce the (d−1)-dimensional renormalized EE from the odd-dimensional counterpart. This corresponds to the...
We apply the joint threshold and transverse momentum dependent (TMD)
factorization theorem to introduce new threshold-TMD distribution functions, including threshold-TMD parton distribution functions (PDFs) and fragmentation functions (FFs). We apply Soft-Collinear Effective Theory and renormalization group methods to perform QCD evolution for both threshold-TMD PDFs and FFs. We show the...
As the simplest quark-antiquark systems, pions and kaons are pseudo Nambu-Goldstone bosons closely related to the spontaneous symmetry breaking of the strong interaction. The study of their form factors and parton distribution functions is not only key to understanding their internal structures, but also tied to the mechanism of Emergent Hadron Mass, one of the mass generation mechanisms in...
Parton fragmentation functions (FFs) are indispensable for understanding processes of hadron production ubiquitously existing in high-energy collisions, but their first principle determination has never been realized due to the insurmountable difficulties in encoding their operator definition using traditional lattice methodology. We propose a framework that makes a first step for evaluating...
Quantum nonlocality, a fundamental feature of quantum mechanics, is frequently associated with the experimental violation of Bell-Clauser-Horne (Bell-CH) inequalities. We present a set of novel methods for the rearrangement and linear inequalities to derive a broad class of Bell-CH inequalities, which can be violated by particular quantum-entangled states. The rapid advancements in Quantum...
As Fermi had realized 100 years ago (in 1924), the electromagnetic field inspired by fast moving charged particles can be treated as photon flux, i.e, equivalent photon approximation (EPA). The EPA photons are linearly polarized, which can be used to probe the nucleus 3D structure. We studied the azimuthal asymmetries induced by the linearly polarized photons in exclusive $\rho^0$ and...
We present an innovative approach to the linearly polarized gluons confined inside the unpolarized nucleon in lepton-nucleon scattering. Our method analyzes the correlation of energy flows at azimuthal separations $\phi$.
The interference of the spinning gluon with both positive and negative helicities translates into a $\cos(2\phi)$ asymmetry imprinted on the detector. Unlike the...
Using the CGC effective theory together with the hybrid factorisation in light-cone formalism, we study forward photon+jet production in proton-nucleus collisions beyond leading order. We first compute the "real" next-to-leading order (NLO) corrections, i.e. the radiative corrections associated with a three-parton final state, out of which only two are being measured. Then we move to the...
Nuclear dependence of Single Transverse Spin Asymmetry (STSA) in $p^↑ p$ and $p^↑ A$ collisions is still a standing mystery. Recent results by PHENIX ($A^{-1/3}$) [1] and STAR ($A^0$) [2] collaborations posses strikingly different nuclear scaling which suggest that the dominant underlying mechanism for STSA may vary with the kinematics of the collision. In the forward regime, where the gluon...
We fit the structure function $F_2$ data from HERA using the Balitsky-Kovchegov (BK) equation. The non-linear equation for the unintegrated gluon density is solved, also incorporating resummations due to the DGLAP evolution and kinematical constraints. Parallel computation on GPUs is employed to handle the intensive calculations, achieving a good fit to the structure function with $\chi^2 \sim...
The presence of ultra-strong electromagnetic (EM) fields can give rise to various important phenomena in heavy ion collisions (HIC). During the early stages of HI collisions an ultra-strong EM field ($B \approx 10^{18}$ Gauss) is expected to be generated, which can have profound implications for QCD phase transitions as well as chiral symmetry restoration. The charge-dependent directed flow...
Relativistic full weak-neutral axial-vector four-current distributions inside a general spin-$\frac{1}{2}$ system are systematically studied for the first time. We show in particular that the slope of the axial form factor $G_A(Q^2)$ in the forward limit -- conventionally denoted as $R^2_A$ in the literature -- does not represent the three-dimensional mean-square axial radius in the Breit...
The canonical Hamiltonian of QCD in the front form involves severe small-$x$ divergences that impede access to the logarithmically scale-dependent Hamiltonians for quarks and gluons. We propose a method for circumventing these divergences, thus opening a pathway for the systematic computation of the Hamiltonians using the renormalization group procedure for effective particles (RGPEP). Our...
Exclusive $\chi_c$ production is sensitive to the C-odd colorless tri-gluon correlation in the $t$-channel - the long sought Odderon. While a non-perturbative C-odd compound has been recently discovered through elastic $pp$ collisions [1], however, Odderon escaped the direct detections at HERA. At the EIC and the EIcC, the high luminosity can counteract the feeble Odderon amplitude. Using the...
Though the quark distributions are are studied in different models, the gluon distributions inside the proton are not studied extensively. To understand the three dimensional structure of proton and the spin and angular momentum contributions of different partons, it is important to evaluate the gluon GPDs and TMDs. We will define a simple spectator model to study the gluon distributions in...
The most challenging aspect of Quantum Chromodynamics (QCD) is perhaps the complexity of calculations required to obtain precise results. For example, ab initio Lattice QCD calculations demand expensive computations on large supercomputers. Yet, existing machines are still not sufficiently powerful to fully address many interesting problems such as structure functions of hadrons, or...
The gluon density in nucleons has been observed to increase rapidly with energy, which would eventually violate unitarity. At high energies, however, nonlinear effects in QCD start to become important, slowing down the evolution of the gluon density and hence giving rise to gluon saturation. To study this saturation region of QCD one possibility is to look at diffractive processes which are...
Glueballs are colorless bound states of gluons as they have self-couplings. The existence of glueballs are very distinctive predictions of QCD. In this talk, I will briefly review recent experimental and theoretical progresses on the researches of glueballs. Especially, I will introduce the latest QCD sum rule calculations of the mass spectroscopy for the two-gluon and three-gluon glueballs.
We investigate different decompositions of angular momentum in QCD for a relativistic spin 1/2 composite state, specifically a quark dressed with a gluon. We employ light-front Hamiltonian perturbation theory developed in the light-front gauge and utilize a two-component framework that eliminates constrained degrees of freedom. Our investigation extends to various decompositions of angular...
Using a non-perturbative light-front Hamiltonian approach, we investigate the scattering and gluon emission of dressed quark states inside a SU(3) colored background field. We consider the scenario in deep inelastic scattering and in heavy ion collisions, where the quark originates from far outside the background field and is described by the light-front wavefunction of the QCD eigenstate in...
In this talk, I will present our calculation of kinematic power corrections $t/Q^2$ and $m^2/Q^2$ to the amplitude of deeply-virtual Compton scattering to the twist-six accuracy on a nucleon target.
Phenomenologically, this result reduces an important source of uncertainties in the QCD predictions for intermediate momentum transfers $Q^2 \sim 1 - 10 ~{\rm GeV}^2$, accessible in the existing...
In this talk I will present the results of lattice calculation of the quark helicity PDFs of proton.
We compute the gravitational form factors (GFFs) and study their applications for the description of the mechanical properties such as the pressure, shear force distributions, and the mechanical radius of the proton from its light-front wave functions (LFWFs) based on basis light-front quantization (BLFQ). We find acceptable agreement between our BLFQ computations and the lattice QCD for the...
We investigate the internal stress of charmonium using the recently derived light-front wave function representation. We employ three “good components” of the energy-momentum tensor, $T^{++}$, $T^{+-}$, and $T^{12}$, to extract the gravitational form factors. The obtained form factors satisfy the known constraints and are used to derive the physical distributions of the system. We discover...
The non-diagonal hard exclusive reactions admitting a description in terms of generalized parton distributions (GPDs) with transition $N\to\Delta, N^*$ provide insight into the internal dynamics of hadron excitations. A unified description of these reactions in the complete resonance region can be performed by introducing the concept of $N \to N \pi$ transition GPDs.
In this study, we...
We propose two approaches for extracting the total gluon helicity contribution to proton spin from lattice QCD, one from local operator matrix elements in a fixed gauge accessible on lattice with feasible renormalization, and the other from gauge-invariant nonlocal gluon correlators. Neither of these approaches requires a matching procedure when converted to the MS scheme. Our proposal...
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 interaction between the nucleon and the pion. We renormalize the energy-momentum tensor with a Fock sector-dependent scheme. We futher analyze the hadron matrix elements of the energy-momentum tensor and identify three “good currents” to...
We determine the mass spectroscopy and diffractive cross-section of ρ and ϕ vector meson by solving the holographic light-front Schrodinger equation along with the ’t Hooft equation of (1+1)-dimensional QCD in the large Nc limit. In order to obtained the diffractive cross-sections, we utilized the holographic LFWFs in conjunction with the color glass condensate dipole cross-section. Our...
Within Basis light-front Quantization framework, we obtain the masses comparable to experiment and the light-front wave functions of $\Lambda_b$ and its isospin triplet baryons $\Sigma_b^+$, $\Sigma_b^0$ and $\Sigma_b^-$. Our prediction of their electromagnetic properties is in agreement with other theoretical calculations. Meanwhile their parton distribution functions (PDFs) are obtained...
Semileptonic decays involve the transition of a heavy meson (such as B or D) to a lighter meson via the exchange of a W boson. Understanding the form factors governing these transitions is essential for precision measurements of CKM matrix elements and testing the Standard Model. The form factors are manifestations of nonperturbative QCD processes, and various phenomenological models have been...
We present the first systematic investigation of the Lorentz covariance of the charge form factor for a strongly coupled scalar theory in (3+1)-dimensions. Our results are based on the non-perturbative solution of the scalar Yukawa theory with a Fock sector expansion including up to thee-particles (one mock nucleon plus two mock pions or two mock nucleons plus one mock anti-nucleon). The...
Within the basis light-front quantization framework, we systematically investigate the unpolarized and longitudinally polarized double parton distributions (DPDs) of quarks inside the proton. We utilize the light-front wave functions of the proton derived in the valence sector from a Hamiltonian quantized on the light-front. Our current analysis yields significant correlations of the quarks'...
We demonstrate, in the context of a scalar version of the chiral effective field theory, that the multi-sea quark contribution to the nucleon is significant and highly non-trivial in sharp contrast to the prediction of perturbation theory. The non-perturbative calculation is performed in the Fock sector dependent renormalization scheme on the light front, in which the non-perturbative...
We propose a method to solve for the structure of relativistic 2-body bound states from Bethe--Salpeter equations (BSEs) in Minkowski space. Particularly after introducing both the Källén--Lehmann spectral representation of dressed propagators and the Nakanishi integral representation of the Bethe--Salpeter amplitudes, the BSE for scalar bound states of scalar constituents is converted into...
The transport properties of dense nucleon matter at low temperatures are important but have rarely been studied in nuclear physics and astrophysics. In this work, we present a primary study of both bulk and shear viscosities of dense nucleon matter within the framework of the Boltzmann equation. To describe the static properties of nucleon matter, we apply the Walecka model in the mean-field...
The BESIII experiment locates at the BEPCII e^+ e^- collider in Beijing, China, running in a center-of-mass energy range from 1.8 GeV to 4.95 GeV. After 16 years of successful running of the experiment since 2009, BESIII has accumulated a large statistics of electron-positron annihilation sample, such as data set at J/ψ, ψ(2S) and ψ(3770) peaks, and fine scan data between 1.8 GeV and 4.95 GeV....
As the theory of quantum chromodynamics has unfolded, the pion has come to be understood as Nature’s most fundamental Nambu-Goldstone boson. It is attached to chiral symmetry, which is dynamically broken, quite probably as a corollary of emergence of hadron mass. Continuum Schwinger function methods are well suited to tackling the pion. This presentation describes the theoretical developments...
As the lightest and simplest hadron composited by valence quarks, pion meson and the involved channels are usually treated as the benchmarks of measurements, which requires the theoretical calculations based on the knowledge of its inner structure to achieve at a high accuracy. How precise do we know the pion meson light-cone distribution amplitudes (LCDAs) ? In this talk I will report the...
Transition GPDs describe matrix elements of nonlocal partonic QCD operators between ground and excited baryon states and provide new tools for quantifying and interpreting the structure of baryon resonances in QCD.
We consider a description of non-diagonal Deeply Virtual Compton Scattering process involving a transition between anucleon and a nucleon resonance in the pion-nucleon system...
We study the spatial distributions of the energy-momentum tensor (EMT) for transversely polarized nucleons in the elastic frame (EF), a general reference frame that bridges the Breit frame (rest frame) and the infinite momentum frame (IMF). As the longitudinal momentum, $P_{z}$, increases, the spin-dependent contributions are induced in the EF energy and EF longitudinal normal force...
The meson's boundstate equation in two dimensional QCD under large Nc limit (QCD2) are exactly solvable in both light-front quantization and equal time quantization. In the meanwhile, QCD2 captures some key features of realistic QCD in four dimension, such as color confinement, nonzero quark condensate. QCD2 become an ideal theoretical laboratory for...
In the past few years, there has been rapid progress in both theoretical developments and lattice calculations of the partonic structure of hadrons. In this talk, I will present some recent results aimed at achieving precise hadron tomography using lattice QCD.
I will present a light-front spectator model for the proton that incorporates the gluonic degree of freedom. The model is based on light-front wave functions modeled from the soft-wall anti–de Sitter/QCD prediction, which allows us to explore the gluonic structure within the proton. Using this model, we have successfully predicted key results for gluon transverse momentum distributions (TMDs)...
In this work, we demonstrate quantum advantage for simulating dynamics of multiple particles in the (3+1)-d QCD Hamiltonian on the light front, especially in the high-energy physics phenomena of an incoming quark jet or gluon jet scattered on the nuclear medium. Using quantum simulation with direct encoding, we provide an universal framework to simulate jet particles, and it is efficient in...
I will present a mass gap solution of the 1+1D QCD in the large Nc limit known as the ‘tHooft model to discuss a link between QCD and the Light-Front Quark Model (LFQM). I will illuminate the interpolation between the instant form dynamics and the light-front dynamics and discuss its utility in the computation of the parton distribution function (PDF). I will then illustrate the...
We introduce and explore a new type of $k_\perp$-dependent functions. The existence of this kind of TMDs has been stemmed from the factorization theorem and they are initiated by the interactions encoded in the corresponding correlators. In contrast to the well-known transverse momentum dependentfunction, the new functions can be associated with the collective alignment of quark spin vectors....
Light-front quantum mechanics is an alternative to light-front quantum
field theory for modeling strongly interacting systems at relativistic
energies. The advantages are that (1) rotational covariance is exact,
so there are no problems identifying states of a given spin or
applying arbitrary Poincar\'e transformations to these states (2) it
is possible to construct realistic models of...
We introduce the concept of the nucleon energy correlators, a set of novel objects that encode the microscopic details of a nucleon, such as the parton angular distribution in a nucleon, the collinear splitting to all orders, as well as the internal transverse dynamics of the nucleon.
I will review the application of few-body methods to explore the structure of light hadrons in Minkowski space. The description of the nucleon and pion are based on the solution of the Bethe-Salpeter equation in Minkowski space built with phenomenological kernels. For the proton, we will show results obtained with the projection onto the light-front of the Faddeev-Bethe-Salpeter equation,...
We report a lattice QCD calculation of the parton distribution function (PDF) of a deuteron-like dibaryon system using large-momentum effective theory. The calculation is done on three Wilson Clover ensembles with a fixed lattice spacing a=0.105 fm and two pion masses. The lattice matrix elements are computed at proton momenta up to 2.46 GeV with the signal of high momentum modes being...
I will briefly outline the current Stony Brook program to address the light mesons and hadrons on the light front, based on the current evidence of the topological nature of the QCD vacuum from lattice simulations. I will provide a detailed description of the light mesons: pions, kaons, rhos on the light front, using the instanton liquid model (ILM) of the QCD vacuum.
Light-front (LF) wave function of a three-fermion system, forming a bound state with the total angular momentum $J=\frac{1}{2}$, is determined, in general, by 16 invariant components - in coincidence with number of combinations $2\times 2\times2\times2=16$, which spin projections of three constituents and their bound state are forming. Parity conservation, in contrast to a two-fermion system,...
The energy momentum tensor (EMT) matrix elements appear in the moments of various parton distributions. The external gravity coupling to EMT provide the constraints to hadron structure due to equivalence principle, This provides the complementary aspect of Ji's sum rules and the possibility of its tests in the experiments with precise measurements of spin precession.
The notion of...
We use light-cone QCD sum rules with chiral currents to study the transition form factors in the semileptonic decay of charmed and bottom scalar mesons, $D/B \rightarrow a_{0}(980)/\, \text{Pion}/\, \rho/\, b_{1}+ l\nu_{l}$ $(l=e, \mu)$. For this, we consider various distribution amplitudes of the mesons $a_{0}(980)$, pion, $\rho$, and $b_{1}$ corresponding to different form factors. Our...
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\title{Dark Photon Sensitivity Study in an $\eta$ Factory Experiment at HIAF}
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A simulation study has been conducted on dark photon sensitivity for a proposed $\eta$ factory experiment at Huizhou using the HIAF proton beam. The experiment, with a beam kinetic energy of 1.8 GeV, is expected to produce...
We calculate the gluon gravitational form factors (GFFs) of the proton and explore their implications for the proton's mechanical properties, including pressure and shear force distributions, as well as the mechanical and mass radii, using a light-front gluon-spectator model based on soft-wall AdS/QCD. The model parameters are determined by fitting the unpolarized gluon distribution function...
The canonical Hamiltonian of QCD in the front form involves severe small-$x$ divergences that impede access to the logarithmically scale-dependent dynamics of hadronic constituents. We present a method for circumventing these divergences, thus opening a pathway for the systematic computation of the Hamiltonians for quarks and gluons using the renormalization group procedure for effective...
In our work, we develop a perturbative framework for analyzing time-dependent quantum solitons, focusing on configurations like soliton collisions and oscillons, separating classical motion from quantum aspects. The method reduces complex soliton dynamics in quantum field theory to a manageable, fully perturbative approach.
We analyze the contributions to the gravitational form factors (GFFs) arising from the photon component of the energy-momentum tensor within the framework of light-front QED. Considering a dressed electron state, we employ the light-front Hamiltonian approach in light-front gauge. Additionally, we explore the impact of the photon on the mechanical properties of the dressed electron state, like...
A new measurement of the heavy-flavor hadron double-spin asymmetry has been proposed for the future Electron-Ion Collider. Using basis light-front quantization as a non-perturbative approach, we generate the proton's PDFs. By convolving these PDFs with coefficient functions, we calculate the structure function and the heavy-flavor hadron double longitudinal spin asymmetry. These results offer...
We investigate the properties of the charged kaon in symmetric nuclear matter by employing a Bethe-Salpeter amplitude to model the quark-antiquark bound state, which is well established by prior studies of its vacuum properties. Our analysis examines the electromagnetic form factor, charge radius, decay constant, and the light-front valence component probability. To effectively describe the...
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 He3, H3 and He4 targets, in the Bjorken limit. For details about the 3He case, see Ref. [1]. Within the...
In the Hamiltonian light-front formulation of field theory the vacuum (ground state) is trivial and hence a Fock space expansion makes sense. I will discuss how this is consistent with other formulations, such as Euclidean lattice (where the vacuum is non-trivial), and how this impacts calculations of hadron spectra and structure.
Basis light-front quantization (BLFQ) is designed as a non-perturbative Hamiltonian approach to solving quantum chromodynamics (QCD) as a quantum many-body problem. In this talk, I will introduce the basic ideas of BLFQ and show how this method, starting from a semiclassical approximation to QCD, leads to a reasonable description of hadron spectrum and wave functions. The latter is used to...
Within the Basis Light-Front Quantization framework, we systematically investigate the subleading twist (twist-3) transverse-momentum-dependent parton distribution functions (TMDs) of the kaon beyond the Wandzura-Wilczek (WW) approximation. The subleading twist TMDs are not independent and can be decomposed into twist-2 and genuine twist-3 terms from the equations of motion. The latter...
