arXiv subjects

S. S. Afonin

Publications and source records attributed to S. S. Afonin.

At least 19 recordsLinked to original sources

arXiv2026

Advanced Statistical Analysis of Linear and Nonlinear Regge Trajectories for Light Non-strange Mesons

A rigorous statistical analysis of Regge-type trajectories for light non-strange meson mass spectra is carried out, which explicitly accounts for experimental uncertainties. We test three scenarios: a linear model with distinct radial ($n$) and orbital ($l$) slopes (Model 1), a linear model with a universal slope (Model 2), and a nonlinear model featuring a universal slope and a Dirac-Coulomb-type term $\propto (l+1)^{-1}$ (Model 3). Optimization is performed using a nonlinear $χ^2$ minimization framework, where the intrinsic theoretical model uncertainty is determined self-consistently by enforcing $χ^2/\text{dof} = 1$. To ensure robust model selection, we employ the Akaike and Bayesian information criteria alongside complementary statistical tests. Our analysis demonstrates that moderate deviations from linearity in the Regge spectrum are predominantly localized within the $S$-wave resonance sector. These distortions are successfully accommodated by the nonlinear correction in Model 3, from which an approximate Coulomb-type degeneracy, $m^2(n,l) \propto n+l$, emerges as a statistically robust feature. Furthermore, we show that the $l$-dependent correction to the principal quantum number in light non-strange mesons is consistent with the leading-order relativistic correction to the Coulomb problem.

hep-ph↗

arXiv2026

Linearity, Nonlinearity and Universality of Regge Trajectories in Light Mesons: a Statistical Approach

The masses of light non-strange mesons can be parameterized as a function of the radial quantum number $n$ and the orbital angular momentum $L$. We perform a comprehensive statistical and phenomenological comparative analysis of competing Regge-like formulas evaluated against two experimental datasets: a benchmark sample of 27 well-established states from the 2024 Particle Data Group (PDG) data, and an expanded sample of 85 states compiled within a recently proposed $(L,n)$-classification. Two linear Regge models for $M^2(L,n)$ are tested: one featuring distinct slopes for $L$ and $n$, $M^2(L,n)\propto an+bL$ (Model 1), and another assuming a universal slope, $M^2(L,n)\propto a(n+L)$ (Model 2). Model selection is conducted quantitatively using the Residual Sum of Squares (RSS), the adjusted RSS, the Akaike Information Criterion (AIC), and the Bayesian Information Criterion (BIC). Within the 27 benchmark states, Model 2 is statistically disfavored. We argue, however, that this discrepancy is driven by the specific behavior of $S$-wave ($L=0$) states. Upon their exclusion, the difference in performance between the two models becomes statistically insignificant, with information criteria selecting Model 2 as the more parsimonious description. Furthermore, we demonstrate that the masses of $S$-wave states can be successfully accommodated by a physically motivated, nonlinear $L$-dependent correction. A parallel analysis of the extended 85-state dataset, where the relative contribution of $S$-wave states is significantly smaller, reveals that Model 2 is statistically preferred, thereby restoring the Coulomb-like degeneracy in the Regge spectrum under consideration.

hep-ph↗

arXiv2026

On the hypothesis of a second Higgs boson near 0.5 TeV

Recently, a second Higgs-like boson $h'$ with the mass near 0.5~TeV was predicted from a dual holographic model describing the hypothetical strongly-coupled sector beyond the Standard Model. We analyze under what conditions this prediction can be reproduced within the framework of more traditional models for describing a strongly-coupled field theory -- the spectral sum rules and the Nambu--Jona-Lasinio model in the scalar channel. It is shown that the results of both approaches are close and lead to this prediction if the covariant four-momentum cutoff in them is identified with the unitarity bound on the Higgs boson mass, and also under the assumption that the strongly coupled sector beyond the Standard Model is described by some quantum field theory based on the $SU(2)$ gauge group. We also present additional arguments suggesting that a mass of about 0.5 TeV would be natural for a heavy analogue of the Higgs boson, if it exists.

hep-ph↗

arXiv2025

Hydrogen-like symmetry in Regge spectrum of light mesons: selection of states

We discuss the $(L,n)$-classification of excited light non-strange mesons, where $L$ and $n$ are orbital and radial quantum numbers. The selection of true non-strange quark-antiquark excited states and assigning to them definite $L$ and $n$ is a notoriously confusing problem. Three guiding principles for selection of correct observed states are formulated. They are applied for construction of a new $(L,n)$-classification. This classification is consistent both with the approximate Regge form of the spectrum and with the hydrogen-like degeneracy, i.e., the dependence of mass on the sum $L+n$.

hep-ph↗

arXiv2025

Quark model of nucleon based on an analogy with polaron

We demonstrate that the polaron theory from solid state physics can serve as an interesting analogue model for non-perturbative QCD, at least in the description of nucleons and related low-energy physics of strong interactions. By drawing explicit analogies between polaron physics, arising for an electron moving in an ionic crystal, and physics of pion-nucleon interactions, certain rules for the "polaron/QCD correspondence" are proposed. In polaron theory, the effective fermion mass as a function of the coupling constant is known both in the weak and strong coupling limits. The conjectured "polaron/QCD correspondence" translates these results into strong interactions. It is then shown how application of these rules leads to unexpectedly good quantitative predictions for the nucleon mass and the pion-nucleon sigma term. The polaron approach also predicts that the quark degrees of freedom in the form of the constituent quark account for one-third of the nucleon mass, consistent with lattice predictions. We discuss possible physical reasons underlying the observed quantitative similarity between polaron physics and non-perturbative QCD.

hep-ph↗

arXiv2025

The experimental observation of $a_0(1710)$: Long awaited from Regge approach

Recently, the BABAR (in 2021), BESIII (in 2022), and LHCb (in 2023) Collaborations reported the observation of the $a_0(1710)$ resonance. This has sparked a lively debate in the literature about the nature of this possible isospin partner of $f_0(1710)$, since the latter has long been regarded as the main candidate for the lightest glueball. We highlight the clear prediction of $a_0(1710)$ in 2007 within the Regge approach using the observed hydrogen-like degeneracy in the spectrum of light mesons. Our reanalysis of the data used shows that the prediction was reliable and thus indicates that $a_0(1710)$ and $f_0(1710)$ are conventional quark-antiquark states.

hep-ph↗

arXiv2024

The Born rule for quantum probabilities from Newton's third law

According to the Born rule, the probability density in quantum theory is determined by the square of the wave function. A generally accepted derivation of this rule has not yet been proposed. In the given work, a simple physical picture is constructed within which the Born rule arises in a natural way. In the proposed scheme, the interaction of a particle with a measuring apparatus is equivalent to creation of a "mirror image" of particle wave function in the space region of interaction. The observable quantity is the product of the particle wave function and its "image". The phase of the latter is reversed due to Newton's third law, thus leading to the Born rule.

quant-ph↗

arXiv2023

On incorporation of heavy-quark mass into soft-wall holographic models

We consider the soft-wall holographic model with the linear dilaton background. The model leads to a Hydrogen-like meson spectrum which can be interpreted as the static limit with very large quark masses when the Coulomb interaction dominates. The mass scale introduced by the linear dilaton is matched to the quark mass. The resulting model is analyzed for the scalar, vector and tensor cases. The electromagnetic coupling constants predicted by the model are decreasing with the radial number in contrast to the soft-wall model with quadratic dilaton where these couplings represent a universal constant. The given prediction is qualitatively consistent with the corresponding experimental data in vector quarkonia. The proposed model can thus be used as a constituent part of more elaborated holographic models for heavy quarkonia. A particular example of such a model is put forward.

hep-ph↗

arXiv2023

A second Higgs near 0.5 TeV from bottom-up holographic modeling of beyond the Standard Model strong sector

One of the simplest extensions of the Standard Model (SM) consists in adding a scalar singlet. This second Higgs boson is able to solve several fundamental problems of SM. Additional scalar particles arise naturally in composite Higgs scenarios in which some confining "strong sector" beyond the SM drives the electroweak symmetry breaking. The underlying strongly coupled gauge theory may be similar to QCD and could be modeled holographically. We construct a bottom-up holographic model for description of the spectrum of composite Higgs particles. The model is based on the holographic Soft Wall model and the Wilson confinement criterion. The constructed model predicts the existence of a second Higgs boson with a mass of about 515 GeV.

hep-ph↗

arXiv2023

Natural cancellation of powerlike divergences in the SM by dark matter through gauged Higgs portal

We discuss the connection between the vacuum energy problem and the number of dark matter sectors and its relation to the cancellation of quadratic divergences both in the cosmological constant and simultaneously in the polarization tensor renormalizing the Higgs meson mass. In the absence of global supersymmetry, the cancellations of quartic and quadratic divergences call for a dark Higgs scalar sector. We estimate the number of hidden(dark) gauged Higgs field sectors to be equal to five. The masses of dark bosons may be of the order of the Standard Model boson masses. Then the following picture of the Standard Model emerges: 6 leptons and 6 quarks are accompanied by 6 boson sectors, only one of the latter is realized in the conventional Standard Model.

hep-ph↗

arXiv2023

Ultraviolet regularization of energy between two static sources in the bottom-up holographic approach to strong interactions

It is well known that the potential energy between two heavy quarks carries an important information about the physics of confinement. Using the Wilson loop confinement criterion and the Nambu-Goto string action, this energy can be derived within the bottom-up holographic approach to strong interactions. We recapitulate the standard holographic derivation of the potential between two static sources with emphasis on the physical interpretation of the results. After that we consider the problem of regularization of arising ultraviolet divergence in a general case. Here the term "ultraviolet" means small values of the holographic coordinate which is related with the inverse energy scale in the holographic duality. We show that in the case of widely used Soft-Wall holographic models, in principle, many ultraviolet divergences may appear, although in practice the appearance of more than two different divergences looks somewhat exotic. Some possible subtraction schemes are discussed. Different schemes lead to a different constant shift of the potential energy and this entails a certain scheme-dependence of holographic predictions for constant term in resulting Cornell-like confinement potentials.

hep-ph↗

arXiv2022

W-boson mass anomaly as a manifestation of spontaneously broken additional SU(2) global symmetry on a new fundamental scale

Recently the CDF Collaboration has announced a new precise measurement of the $W$-boson mass $M_W$ that deviates from the Standard Model (SM) prediction by $7σ$. The discrepancy in $M_W$ is about $Δ_W\simeq70$ MeV and probably caused by a beyond the SM physics. Within a certain scenario of extension of the SM, we obtain the relation $Δ_W\simeq\frac{3α}{8π}M_W\simeq70$ MeV, where $α$ is the electromagnetic fine structure constant. The main conjecture is the appearance of longitudinal components of the $W$-bosons as the Goldstone bosons of a spontaneously broken additional $SU(2)$ global symmetry at distances much smaller than the electroweak symmetry breaking scale. We argue that within this scenario, the masses of charged Higgs scalars can get an electromagnetic radiative contribution which enhances the observed value of $M_{W^\pm}$ with respect to the usual SM prediction. Our relation for $Δ_W$ follows from the known one-loop result for the corresponding effective Coleman-Weinberg potential in combination with the Weinberg sum rules.

hep-ph↗

arXiv2022

Towards a theory of bottom-up holographic models for linear Regge trajectories of light mesons

We advance in constructing a bottom-up holographic theory of linear meson Regge trajectories that generalizes and unites into one logical framework various bottom-up holographic approaches proposed in the past and scattered in the literature. The starting point of the theory is a quadratic in fields holographic five-dimensional action in which the Poincaré invariance along the holographic coordinate is violated in the most general way compatible with the linear Regge behavior of the discrete spectrum in four dimensions. It is further demonstrated how different Soft Wall (SW) like holographic models existing in the literature plus some new ones emerge from our general setup. Various interrelations between the emerging models are studied. These models include the known SW models with different sign in the exponential background, the SW models with certain generalized backgrounds, with modified metrics, and No Wall models with 5D mass depending on the holographic coordinate in a simple polynomial way. We argue that this dependence allows to describe the effects caused by the main non-local phenomena of strongly coupled 4D gauge theory, the confinement and chiral symmetry breaking, in terms of a local 5D dual field theory in the AdS space. We provide a detailed comparison of our approach with the Light Front holographic QCD, with the spectroscopic predictions of the dual Veneziano like amplitudes, and with the experimental Regge phenomenology. We apply our general approach to a holographic study of confinement, chiral symmetry breaking, and the pion form factor.

hep-th↗

arXiv2021

The effect of higher dimensional QCD operators on the spectroscopy of bottom-up holographic models

Within the bottom-up holographic approach to QCD, the highly excited hadrons are identified with the bulk normal modes in the fifth "holographic" dimension. We show that additional states in the same mass range can appear also from taking into consideration the 5D fields dual to higher dimensional QCD operators. The possible effects of these operators were not taken into account in almost all phenomenological applications. Using the scalar case as the simplest example, we demonstrate that the additional higher dimensional operators lead to a large degeneracy of highly excited states in the Soft Wall holographic model while in the Hard Wall holographic model, they result in a proliferation of excited states. The considered model can be viewed as the first analytical toy-model predicting a one-to-one mapping of the excited meson states to definite QCD operators to which they prefer to couple.

hep-ph↗

arXiv2021

The case of equivalence of low and high energy constraints on Regge vector spectrum in AdS/QCD

The AdS/QCD models are believed to interpolate between low and high energy sectors of QCD. This belief is usually based on observations that many phenomenologically reasonable predictions follow from bounds imposed at high energies although the hypothetical range of applicability of semiclassical bottom-up holographic models is restricted by the gauge/gravity duality to low energies where QCD is strongly coupled. For testing the feasibility of high energy constraints it is interesting to calculate holographically some observable constants at low and high momenta independently and compare. We consider an AdS/QCD model describing the Regge-like linear spectrum of spin-1 mesons in a general form and show that under definite physical assumptions, the low-energy constraints on 2-point correlation functions lead to nearly the same numerical values for the parameters of linear radial spectrum as the high energy ones. The found approximate coincidence looks surprising in view of the fact that such a property for observables is natural for conformal theories while real strong interactions are not conformal.

hep-ph↗

arXiv2020

A holographic relation between the deconfinement temperature and gluon condensate

We derive a holographic prediction of the deconfinement temperature $T_c$ at vanishing chemical potential within a simplest AdS/QCD model with dynamical dilaton. Our analysis leads to a linear relation between $T_c^4$ and the gluon condensate. After normalizing this relation to the lattice data for $SU(3)$ pure gauge theory, the standard phenomenological value of gluon condensate from QCD sum rules leads to the prediction $T_c=156$ MeV which is in a perfect agreement with the modern lattice results and freeze-out temperature measured by the ALICE Collaboration.

hep-ph↗

arXiv2020

Regge trajectories in light and heavy mesons: the pattern of appearances and possible dynamical explanations

I briefly review the Regge approach to the hadron spectrum and advocate a dynamical emergence of principal quantum number in the known spectrum of light non-strange mesons. Further it is shown how the linear radial trajectories with universal slope can be extended to heavy quarkonia and a qualitative string interpretation is given. After that I discuss a recently proposed non-string model leading to a natural appearance of linear Regge trajectories and explaining many mass relations.

hep-ph↗

arXiv2020

On holographic relation between radial meson trajectories and deconfinement temperature

The interrelation between the deconfinement temperature of hadron medium and parameters of radial Regge trajectories within the bottom-up holographic models for QCD is scrutinized. We show that the lattice data on the deconfinement temperature can yield a powerful restriction on the spectrum of excited mesons and glueballs within the framework of holographic approach. The best phenomenological agreement and theoretical self-consistency are achieved if the scalar meson $f_0(1500)$ is considered as the lightest glueball.

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