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Edward Shuryak

Publications and source records attributed to Edward Shuryak.

At least 19 recordsLinked to original sources
arXiv2026

Chiral Structure and Selection Rules in Light-Front Nucleon-Pentaquark Mixing

We present a light-front Hamiltonian analysis of nucleon-pentaquark mixing induced by $\sigma$- and $\pi$-type transition operators in a fully Pauli-consistent five-quark basis. The pentaquark configurations are constructed using a systematic permutation-group classification of orbital, spin-flavor, and color degrees of freedom, and the hyperfine interaction is diagonalized to obtain orthonormal eigenchannels with definite quantum numbers. We compute the mixing coefficients for all 27 positive-parity $P$-wave pentastates and find a highly sparse structure: only 6 channels contribute to the nucleon wave function, while the remaining 21 vanish due to symmetry selection rules. The nonzero contributions are concentrated in a small set of hyperfine eigenchannels, demonstrating a strong dominance pattern. The $\sigma$- and $\pi$-induced amplitudes populate the same subset of states and are related by a fixed phase, reflecting their common chiral structure, which eliminates interference in the normalization. As a result, their contributions add incoherently, yielding a total five-quark probability of about $29\%$, with the remaining $71\%$ residing in the three-quark core. These results show that nucleon-pentaquark mixing is governed primarily by symmetry selection rules and chiral structure, and that the five-quark content is dominated by a small number of dynamically selected channels.

hep-ph↗
arXiv2026

Hybrid hadrons at rest and on the light front

We present a unified description of heavy hybrid hadrons based on a constituent-gluon picture embedded in the Born-Oppenheimer (BO) framework. In this approach, the gluonic excitation is treated as a dynamical quasiparticle with a mass generated by instanton-induced interactions. We propose a simple variational derivation of the BO potentials. The main focus of the paper is the derivation of light-front wave functions for hybrid systems, specifically for the $ccg$ and $qqqg$ cases. We employ both variational methods and numerical solutions of the Schr\"odinger equation in momentum representation. Using the resulting wave functions, we compute the gluon PDFs for these systems.

hep-ph↗
arXiv2026

Glueballs, Constituent Gluons and Instantons

We present a constituent two-gluon description of the lowest-lying glueball states in pure Yang--Mills theory, calibrated against quenched lattice results. The framework incorporates an instanton-induced dynamical gluon mass, Casimir-scaled adjoint confinement, the short-distance adjoint Coulomb interaction, and instanton-induced central and tensor forces. The scalar $0^{++}$ glueball is found to be exceptionally compact, with a radius of order the instanton size, $\rho \sim \frac 13\,\mathrm{fm}$, consistent with lattice indications. By contrast, the tensor $2^{++}$ state remains spatially extended due to the centrifugal barrier. We also discuss the role of $S$-$D$ mixing. A semiclassical analysis further supports Regge behavior for excited states, in agreement with lattice results.

hep-ph↗
arXiv2026

Quantum potential with no perturbative series, and nonperturbative vacuum dominated by complex classical paths

Spectra of standard 1d potentials (double-well, sin-Gordon etc) are given by trans-series in coupling, including (badly divergent) perturbative series (PS), and nonperturbative terms. All of them are badly defined (e.g. PS are badly divergent) but in sum supposed to be good. In this paper we discuss an example of a potential with specially defined couplings making PS completely absent. We calculate its nonperturbative vacuum energy and show that they are reproduced by the action of certain complex solutions to holomorphic Newton equation.

hep-th↗
arXiv2026

The Hadron-Parton Bridge, From the QCD Vacuum to Partons

Quantum Chromodynamics (QCD) exhibits complementary descriptions of hadrons: a rest-frame picture based on confinement, chiral symmetry breaking and interquark forces, and a high-energy light-front picture expressed through parton distributions (PDFs,TMDs,GPDs) and form factors. This review develops a unified framework that connects these two domains. It is based mostly on multiple studies by the authors in the past few years. Using the Instanton Liquid Model (ILM) to capture essential nonperturbative features of the QCD vacuum, we derive effective interactions for mesons, baryons, and multiquark states, construct their wave functions in hyperspherical coordinates, and boost them to the light front. The resulting light-front Hamiltonians, incorporating both perturbative and instanton-induced dynamics in the Wilsonian spirit, provide realistic nonperturbative inputs for computing PDFs, DAs, GPDs, quasi-distributions, and gravitational form factors at a well-defined low scale. The connection to perturbative QCD is then established by matching gradient-flow-renormalized operators and LF wave functions to the standard $\overline{\rm MS}$ scheme. Perturbative DGLAP and ERBL evolution then connects these predictions to experimentally accessible regimes. % This approach is applied to quarkonia, glueballs, light mesons, baryons, tetraquarks, pentaquarks, and higher multiquark hadrons, yielding consistent descriptions of both their spectra and partonic structure. Special emphasis is placed on the energy-momentum tensor and the mechanical properties of hadrons, which emerge naturally from the same dynamical ingredients. Overall, the framework demonstrates a clear continuity between hadronic spectroscopy and partonic observables, offering a coherent multiscale picture of hadron structure rooted in the underlying dynamics of QCD.

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arXiv2025

The color force acting on a quark in the pion and nucleon

In the Operator Product Expansion (OPE) of hard scattering amplitudes, the twist-3 operators describe local colored Lorentz forces acting on a quark, thereby providing a measure of the strength of the gluon fields. Its value is directly accessible from the nucleon twist-3 polarized $g_2$-parton distribution function. In the semiclassical (instanton-based) QCD vacuum models, the leading non-perturbative contribution stems from correlated instanton-anti-instanton pairs, or molecules. We analyze the magnitude of the color force on a struck quark in light hadrons (pion and nucleon), in the context of the instanton liquid model (ILM). We derive explicitly the pertinent form factors associated with the color Lorentz force and show that they are intimately related to the pertinent hadronic gravitational and transversity form factors. Using the ILM enhanced by molecules, we detail the ensuing colored force distribution in the transverse plane for the luminal pions and nucleons. The results for the nucleons are in good agreement with those recently reported from a lattice collaboration.

hep-ph↗
arXiv2025

Pentaquarks on the light front, and their mixture with baryons

In previous papers we developed the light front formulation for Hamiltonians and wave functions (WFs) for mesons and baryons, with both confinement and chiral symmetry breaking. For baryons limited to the lowest Fock component with three quarks, the longitudinal WF is valued in an equilateral triangle with momentum fractions $x_i,i=1,2,3$. The WF was developed both numerically and using a basis function that diagonalizes the Laplacian with Dirichlet boundary conditions. In this paper we extend this analysis to $n$ quark states, and specialize to pentaquarks ($n=5$). We determine their masses and WFs, and address the mixing between baryons and pentaquarks, the issue central to understanding the observed antiquark sea of baryons.

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arXiv2025

Light S-wave pentaquarks on the light front

We construct an explicit basis set for pentaquark states on a regular 4-simplex, that diagonalizes the Hamiltonian for light pentaquarks with confinement on the light front (LF). The ensuing eigenstates are free of the center of mass motion and satisfy exact Dirichlet boundary conditions. Hyperfine interactions in the form of color-spin or flavor-spin are shown to lift the degeneracy of the 16 pentastates, with a spectrum that compares fairly with some of the empirical nucleon excited states. The quark PDF for the light pentastates is discussed.

hep-ph↗
arXiv2025

The quest for a Quark-Gluon Plasma

A chapter in a book"50 years of QGP" An extended summary of the field can be found in large books and reviews, e.g., my take in Ref.~\cite{Shuryak:2024zrh}. It is hard to compress its 600+ pages and 50+ years of research to a few given below. Those include only recollection of few episodes, from early days to now, showing how vague dreams were eventually turning into solid and detailed scientific facts.

hep-ph↗
arXiv2025

Pentaquarks made of light quarks and their admixture to baryons

This paper is a continuation of our studies of multiquark hadrons. The anti-symmetrization of their wavefunctions required by Fermi statistics is nontivial, as it mixes orbital, color, spin and flavor structures. In our previous papers we developed a method to find them based on the representations of the permutation group, and derived the explicit wave functions for baryons excited to the first and second shells $(L=1,2)$, tetraquarks $qq\bar q\bar q$ and hexaquarks ($6q$). Now we apply it to light pentaquarks ($qqqq\bar q$), in the S- and P-shells ($L=0,1$). Using Jacobi coordinates, one can use the hyperdistance approximation in 12-dimensional space. We further address the issue of ``unquenching" of baryons, by considering their mixing with pentaquarks, via two channels, through the addition of $\sigma$-like or $\pi$-like $\bar q q$ pairs. This mixing is central for understanding of the observed flavor asymmetry of the antiquark sea, the amount of orbital motion issue as well as other nucleon properties.

hep-ph↗
arXiv2025

D-shell mixing in light baryons and its effect on the orbital motion

The standard description of the nucleon in the non-relativistic quark model is an $1S,L=0$ state without orbital motion. Yet, there are several indications from phenomenology that an admixture of states with nonzero orbital motion maybe substantial. In this paper we focus on the ``second shell" of the nucleon excitations (D-shell), for which we give a modern description of the wave functions. We follow it by investigating what we call a ``maximal mixing" scenario, assuming a hypothetical long-range tensor force. We give the explicit wave functions for all states, before and after mixing, and re-assess many predictions such as the magnetic moments, the standard and transitional form-factors from the nucleon to $N^*$. Unexpectedly, in this scenario we can reproduce the long-puzzling features of the Roper resonance $N^*( 1440)$. But even in this extreme case, the admixture of the $1D,L=2$ state to a nucleon remains significantly smaller than expected from phenomenology.

hep-ph↗
arXiv2024

Glue in hadrons at medium resolution and the QCD instanton vacuum

We discuss a general framework for the evaluation of the gluonic form factors in light hadrons at low momentum transfer, in the QCD instanton vacuum. At medium resolution of the order of the inverse mean instanton size, the glue is mostly localized in single or pair of pseudoparticles, and globally constrained by the fluctuations of their topological charges. These pseudoparticles trap light quarks, giving rise to emerging multiflavor 't Hooft interactions. We explicitly evaluate the gluonic scalar, pseudoscalar, energy-momentum tensor (EMT), and the leading C-odd and C-even three gluons hadronic form factors, at next to leading order (NLO) in the instanton density, including molecular clusters of like and unlike instantons. We use the results for the EMT to address the contribution of the gluons in Ji$^\prime$s mass and spin sum rules, at low resolution. When evolved, our results for the mass and spin composition of the nucleon, are shown to be in good agreement with the recently reported lattice results at higher resolution.

hep-ph↗
arXiv2024

Wave functions of multiquark hadrons from representations of the symmetry groups $S_n$

Construction of the wave functions of multiquark hadrons by traditional method based on tensor products of colors, flavors, spins (and orbital) parts becomes quite complex when quark numbers grow $n=5,6...12$, as it gets difficult to satisfy requirements of Fermi statistics. Our novel approach is focused directly on representations of the permutation symmetry generators. After showing how $C_3$ is manifested in the wave functions of (excited) baryons, we use it to construct the wave functions for a set of pentaquarks and hexaquarks (n=5,6). We also have some partial results for larger systems, with $n=9$ and 12, and even beyond that as far as $n=24$.

hep-ph↗
arXiv2024

A cosmological "Big Storm Scenario" following the QCD phase transition

It was proposed that acoustic perturbations generated by the QCD phase transition could create an inverse turbulent cascade \cite{Kalaydzhyan:2014wca}. An assumption was that propagation toward smaller momenta could reach the wavelength of a few km, the Universe's size at the time. Such acoustic waves were proposed to be the source of gravity waves. The kilometer wavelength corresponds to year-long gravity wave today, which were recently discovered using pulsar correlations. This paper argues further that an acoustic turbulence must be an ensemble of shocks. This brings two consequences: First, shocks generate gravity waves much more efficiently than sound waves due to the intermittency of matter distribution. We reconsider gravity wave radiation, using universal emission theory for soft radiation, and argue that soft-momenta plateau should reach wavelengths of the order of shock mean free paths. Second, collisions of shock waves create local density excess, which may create primordial black holes. A good tool to settle this issue can be an evaluation of the {\em trapped surfaces} like it was done in studies of heavy ion collisions using AdS/CFT correspondence

hep-ph↗
arXiv2024

Pion gravitational form factors in the QCD instanton vacuum II

We revisit the hard QCD contributions to the pion gravitational form factors (GFFs), in terms of the twist-2,3 pion distribution amplitudes (DA), including novel semi-hard contributions from the instantons. The pion DAs are evaluated in the QCD instanton vacuum, and then properly evolved to higher resolution. The results are compared to our recent results from the QCD instanton vacuum, as well as Bethe-Salpeter calculations and recent lattice data. The interpolated hard and soft contributions to the pion D-form-factor, are used to derive the (gravitational) pressure and shear within the pion, with a clear delineation of their range.

hep-ph↗
arXiv2024

Pion gravitational form factors in the QCD instanton vacuum I

The pion form factors of the QCD energy-momentum tensor (EMT) are studied in the instanton liquid model (ILM) of the QCD vacuum. In this approach the breaking of conformal symmetry is encoded in the form of stronger-than-Poisson fluctuations in the number of instantons. For the trace of the EMT, it is shown that the gluonic trace anomaly term contributes half the pion mass, with the other half coming from the quark-mass-dependent sigma term. The $Q^2$ dependence of the form factors is governed by glueball and scalar meson exchanges. For the traceless EMT, the spin-0 and 2 form factors are computed at next-to-leading order in the instanton density using effective quark operators. Relations between the gluon and quark contributions to the EMT form factors are derived. The form factors are also expressed in terms of the pion light-front wave functions in the ILM. The results at the low resolution scale of the inverse instanton size are evolved to higher scales using the renormalization group equation. The ILM results compare well with those of recent lattice QCD calculations.

hep-ph↗
arXiv2024

Bridging hadronic and vacuum structure by heavy quarkonia

We discuss the central and, mostly, spin-dependent potentials in heavy quarkonia $\bar b b, \bar c c$, with two goals in mind. The first is phenomenological: using the splitting between the 1S and 2S pairs, as well as the 1P and 2P quartet masses, we obtain very accurate values of all matrix elements of the spin-depepdent potentials. The second is theoretical: using standard wave functions, we compute these matrix elements, from perturbative, nonperturbative and ``string" contributions. The model for nonperturbative effects is a ``dense instanton liquid model", in which the QCD vacuum is made of (strongly color correlated) instanton-antiinstanton pairs or "molecules". We calcuate their effect via standard Wilson lines, with or without extra powers of gauge fields. We find that this model provides a reasonable description of all central, spin-spin and spin-orbit forces at distances $r= 0-0.7 \, fm $, relevant for $\bar b b $ and $\bar c c$ quarkonia.

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