Few-Body Systems最新文献

{"title":"Channel-Dependent Color Transparency from Light Front Holographic QCD","authors":"Fidele J. Twagirayezu","doi":"10.1007/s00601-026-02090-3","DOIUrl":"10.1007/s00601-026-02090-3","url":null,"abstract":"<div><p>Color transparency begins with the production of a compact color-singlet configuration in a hard exclusive reaction. In light-front holographic QCD, the leading-twist behavior of the hadronic form factor reflects valence-Fock dominance and encodes the compact hard transverse scale of this configuration. Observable nuclear transparency additionally depends on the reaction-dependent physical-separation distribution, color screening, expansion, and propagation through nuclear matter. We formulate a framework that preserves the exact, external-scale-independent hadronic light-front wave function and distinguishes the elastic current, the exclusive production vertex, and nuclear propagation. The integer-twist form factor is obtained as a finite Regge-pole product, and its positive logarithmic profile slope and exact Beta-distribution ordering are derived analytically. For the published holographic reparametrization, the current-selected physical constituent separation approaches a nonzero endpoint value of approximately 0.457 fm even as the GPD impact profile narrows. Thus, although the form factor supplies the compact hard impact scale, it does not alone determine the reaction-dependent physical-separation distribution required for nuclear attenuation. We specify that mapping through an explicit reaction-dependent production kernel acting on the actual active-constituent/spectator separation. The resulting positive configuration distribution has a physical mean-square radius that scales as the inverse hard scale and determines a saturating color-dipole interaction without modifying the elastic form factor. Nuclear survival is averaged over configurations after exponentiation, the struck nucleon is excluded from the spectator density, the deuteron is treated as a correlated two-body state, and vector-meson decay and pion-pair attenuation are included. All experimental inputs are directly published: 29 pion transparencies, 146 pion/deuteron differential sub-bins, eight resolved proton-shell transparencies, two vector-meson slopes, and the measured vector-meson acceptance and diffraction profiles. Current-derived compact fractions require no fitted event-branch probabilities. With equal reaction-parameter priors, the acceptance-aware pion comparison gives <span>(chi ^2=19.05)</span> versus 24.07 for Glauber; withheld-target predictions give 18.91 versus 27.20. Proton electroproduction remains Glauber-like, while channel-specific vector-meson transport improves its two-slope comparison from 6.12 to 2.48. Only published experimental observables and bin boundaries are used; unpublished event populations and bin-by-bin vector-meson transparency values are not inferred or included in the analysis.</p></div>","PeriodicalId":556,"journal":{"name":"Few-Body Systems","volume":"67 4","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149189143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nonlocal Scattering Problem in Harmonic-Oscillator-Based R-matrix Approach","authors":"N. K. Timofeyuk","doi":"10.1007/s00601-026-02087-y","DOIUrl":"10.1007/s00601-026-02087-y","url":null,"abstract":"<div><p>A nonlocal two-body scattering problem for optical potentials of the Perey–Buck type is solved within a newly-developed version of the <i>R</i>-matrix approach. The approach is based on harmonic oscillator expansion of the scattering wave functions within the range of the optical potential. It results in structurally identical algebraic representations both for local and nonlocal optical potentials as well as for the kinetic energy and norm operators, which simplifies and optimizes the coding procedure. The method has been tested for proton scattering at 10, 30 and 90 MeV. With a sufficient number of harmonic oscillator basis states the new method reproduces differential cross sections obtained using available reaction codes. The nonlocal calculations were also used as a testing ground for local-equivalent models. It was found that below 30 MeV next-to-leading order models are sufficient to describe elastic scattering, while at 90 MeV this approximation works well only up to <span>(100^{circ })</span>. The method developed could be used in reaction calculations within distorted-wave models and in combining scattering calculations with various few- and many-body structure methods that use harmonic oscillator expansions.</p></div>","PeriodicalId":556,"journal":{"name":"Few-Body Systems","volume":"67 4","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00601-026-02087-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149189051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Choreographic 4-Body Orbits with Solely Attractive Linear Forces","authors":"M. Fernandez-Guasti","doi":"10.1007/s00601-026-02085-0","DOIUrl":"10.1007/s00601-026-02085-0","url":null,"abstract":"<div><p>The choreographic plane motion of four or more bodies with equal masses has been analytically described with a combination of attractive and repulsive linear forces. In this work, we describe families of choreographic solutions to the equations of motion in a plane with only attractive linear forces along the lines joining the bodies. The conditions that produce collisions between any of the four bodies can be isolated and thus avoided. The expressions of many relevant properties of the system can be obtained in closed form. The angular momentum kernel is evaluated in order to establish the set of choreographic solutions that satisfy the zero angular momentum condition. Depending on the initial parameters, there can be other symmetries and conserved quantities in addition to the energy, momentum and centre of mass. The masses and restoring force coefficients necessary conditions that allow choreographic behaviour are established. The curves admit a larger number of bodies. The analytic choreographic trajectories are similar to those obtained numerically under a Newtonian force. This all attractive forces scheme, albeit linear, moves us closer to the Newtonian gravitational paradigm.</p></div>","PeriodicalId":556,"journal":{"name":"Few-Body Systems","volume":"67 4","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00601-026-02085-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Resonant States in Light Hypernuclei","authors":"Rimantas Lazauskas","doi":"10.1007/s00601-026-02066-3","DOIUrl":"10.1007/s00601-026-02066-3","url":null,"abstract":"<div><p>Energies of strangeness <span>(S=-1)</span> three- and four-body hypernuclei are calculated employing realistic nucleon–nucleon (NN) and hyperon–nucleon (YN) interactions derived from chiral effective field theory. Both bound and resonant state positions are determined, and the impact of the three-nucleon (<span>(NNN)</span>) force on these observables is investigated.</p></div>","PeriodicalId":556,"journal":{"name":"Few-Body Systems","volume":"67 4","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analytical Solutions of the Dunkl–Schrödinger Equation for the Manning–Rosen Potential in Higher Dimensions: Bound States and Thermodynamic Properties","authors":"Fateh Merabtine","doi":"10.1007/s00601-026-02084-1","DOIUrl":"10.1007/s00601-026-02084-1","url":null,"abstract":"<div><p>The <i>d</i>-dimensional Dunkl–Schrödinger equation for the Manning–Rosen potential is solved analytically using the Greene–Aldrich approximation and a reduction to the Gauss hypergeometric equation. Closed-form bound-state energies and Jacobi-polynomial radial wave functions are obtained, recovering the standard results as <span>(nu _irightarrow 0)</span>. Thermodynamic quantities are derived via a modified Bessel-function expansion and illustrated numerically for <span>(d = 2, 3, 4)</span>. We find that the Dunkl deformation systematically controls the depth and density of the bound-state spectrum: negative deformation parameters deepen the energy levels and can stabilize states that would otherwise merge into the continuum, while positive values weaken binding and dissolve near-threshold states. The heat capacity displays a Schottky-like peak whose position and amplitude depend sensitively on both the deformation parameter and the spatial dimension.</p></div>","PeriodicalId":556,"journal":{"name":"Few-Body Systems","volume":"67 4","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149133023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spin Splitting in Dunkl Molecular Potentials Without an External Field: A Pauli–Dunkl Framework with Reflection-Induced Spin–Orbit Coupling","authors":"Amar Bouguerra,&nbsp;Boubakeur Khantoul,&nbsp;Ahmed Tedjani","doi":"10.1007/s00601-026-02083-2","DOIUrl":"10.1007/s00601-026-02083-2","url":null,"abstract":"<div><p>We propose a spin-1/2 Dunkl molecular framework in which spin splitting can arise <i>without</i> an external magnetic field, subject to two explicitly stated hypotheses concerning the spectral theory of the spin–Dunkl angular operator. All prior Dunkl–Pauli work requires an external field to lift spin degeneracy [1, 2]; the scalar Dunkl–Schrödinger equation with Kratzer–Mie and pseudoharmonic potentials has been solved but only for spinless particles [3]. We close this gap by introducing the intrinsic coupling <span>(lambda r^{-2}mathcal {S}_D)</span>, where <span>(mathcal {S}_D)</span> couples Clifford spin generators to Dunkl angular momenta through the Coxeter reflection geometry. This interaction is a phenomenologically motivated, separability-preserving field-free spin–Dunkl coupling, introduced by analogy with the standard relativistic spin–orbit term rather than derived from a Dunkl–Dirac equation (that derivation remains an open problem, Sect. 11). It can be interpreted as a reflection-induced spin–orbit term whose pattern is dictated by the Coxeter root system rather than any applied field. Using this coupling we derive closed-form radial bound-state energy spectra for spin-1/2 particles in both the Kratzer–Mie and pseudoharmonic molecular potentials within a unified Dunkl framework. These radial spectra are <i>exact for any angular eigenvalue</i> of the spin–Dunkl operator <span>(mathcal {A}_D = -Delta _{D,S} + 2Mlambda mathcal {S}_D)</span> that satisfies a stated spectral hypothesis: we prove <span>(mathcal A_D)</span> is <i>formal</i> self-adjoint, but essential self-adjointness—required for a unique self-adjoint extension with real discrete spectrum—is not proved and is adopted throughout as an explicit hypothesis. All quantitative spectral statements are conditional on this hypothesis. For the <span>(A_2)</span> Coxeter group in <span>(d=2)</span> we further propose a <i>phenomenological ansatz</i> for the angular eigenvalues. This ansatz is supported only at leading order by first-order perturbation theory and has not been derived from the exact spectrum of <span>(mathcal A_D)</span>; the full <span>(A_2)</span> angular spectrum remains an open problem. Subject to this ansatz, we illustrate numerically that the resulting spin splitting grows with <span>(lambda )</span> and, for the Kratzer–Mie potential, is asymptotically suppressed as <span>(O(k^{-3}))</span> with the Coxeter multiplicity <i>k</i>; for the pseudoharmonic potential the splitting instead saturates to a nonzero constant as <span>(krightarrow infty )</span>, reflecting the different functional dependence of the two spectra on the angular eigenvalue. We emphasize that all numerical results in this paper are illustrative consequences of an unproved ansatz, not first-principles predictions, and would need revision once the true <span>(A_2)</span> angular spectrum is known.</p></div>","PeriodicalId":556,"journal":{"name":"Few-Body Systems","volume":"67 4","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149034558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Radii of Exotic Hadrons and On Some Properties of the Exotic Particles","authors":"Aparajita Bhattacharya,&nbsp;Shukla Pal,&nbsp;Papiya Dhara,&nbsp;Ballari Chakrabarti","doi":"10.1007/s00601-026-02082-3","DOIUrl":"10.1007/s00601-026-02082-3","url":null,"abstract":"<div><p>The radii of the exotic hadrons like tetraquarks and pentaquarks are studied considering diquark-anti diquark configuration of tetraquarks and diquark-diquark-antiquark picture of pentaquarks. Diquarks are described as composite fermions. Binding energies are calculated using the ground state masses of the tetraquarks and pentaquarks, as estimated within the framework of the Flux Tube model. The leptonic decay widths for tetra quarks are studied using van-Royen Weisskoff formula. The decay widths are found to be small, ranging from <span>(10^{-3})</span> to <span>(10^{-7})</span> MeV, as expected from experimental results. The form factors of pentaquarks have been studied with the computed radii for different ranges of momentum transfer. The study is important for understanding the properties of newly discovered exotic particles.</p></div>","PeriodicalId":556,"journal":{"name":"Few-Body Systems","volume":"67 4","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148986987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of the Confinement Strength on the Energy Spectra of Two Atoms Interacting via Zero-Range or Realistic Potentials","authors":"Jakob Wulff,&nbsp;Matee ur Rehman,&nbsp;Alejandro Saenz","doi":"10.1007/s00601-026-02081-4","DOIUrl":"10.1007/s00601-026-02081-4","url":null,"abstract":"<div><p>This work analyzes the influence of an external confinement on the energy spectrum of two interacting ultracold atoms, considering either a regularized contact or a more realistic Born-Oppenheimer potential. For two harmonically confined particles with contact interaction, the known analytical solution exhibits universality in the sense that the energy spectra solely depend on the ratio of the confinement length to the scattering length. In this work it is shown that this type of universality breaks down for realistic interatomic interactions, leading to an explicit trap-size dependence of the energy spectrum. This effect is especially pronounced for very tight confinement. On the other hand, using first-order perturbation theory it is shown analytically that the here discussed universality persists for the contact interaction even in the case of anharmonic confinement, this result being also verified numerically beyond perturbation theory for a sextic trap potential. These findings demonstrate limitations of the popular contact-interaction model and highlight the necessity of considering more realistic finite-range interactions under tight trapping conditions.</p></div>","PeriodicalId":556,"journal":{"name":"Few-Body Systems","volume":"67 4","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00601-026-02081-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148986542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Flavor Decomposition of the Gravitational Form Factors and Mechanical Structure of the Proton","authors":"Hyun-Chul Kim,&nbsp;June-Young Kim,&nbsp;Ho-Yeon Won","doi":"10.1007/s00601-026-02079-y","DOIUrl":"10.1007/s00601-026-02079-y","url":null,"abstract":"<div><p>We review in the present talk a series of recent works on the flavor decomposition of the gravitational form factors of the proton and its mechanical properties within the framework of the chiral quark-soliton model. Starting from the energy-momentum tensor operator derived from the QCD instanton vacuum, we carry out the twist projection of the energy-momentum tensor operator into its twist-2 and twist-4 components, which enables us to isolate the <span>(overline{c})</span> form factor originating from the twist-4 operator. We present the flavor-decomposed mass, spin, pressure, and shear-force distributions of the proton, together with the corresponding form factors. While the up quark dominates both the mass and the spin of the proton, the strange quark is found to contribute sizably to the <i>D</i>-term form factor. We also discuss the mechanical stability of the proton governed by the pressure and shear-force distributions.</p></div>","PeriodicalId":556,"journal":{"name":"Few-Body Systems","volume":"67 4","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148927499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Radial Models of Helium and Atomic Hydrogen in Two and Three Dimensions","authors":"Dmitry Konovalov","doi":"10.1007/s00601-026-02080-5","DOIUrl":"10.1007/s00601-026-02080-5","url":null,"abstract":"<div><p>We give a uniform radial formulation of atomic hydrogen and helium in three and two dimensions, solving the 3D <i>S</i>-wave (<span>(l=0)</span>) and 2D <span>(m=0)</span> sectors with a single Laguerre-basis method. A one-parameter transcription, <span>(L=0)</span> in 3D and <span>(L=-tfrac{1}{2})</span> in 2D, reduces the dimensional change to one basis parameter, so the same validated code produces both dimensions. For helium, each electron is restricted to the matched radial sector (<span>(l_1=l_2=0)</span> in 3D, <span>(m_1=m_2=0)</span> in 2D), which separates the effects of radial measure, residual inverse-square term, and interaction law. A central observation is that dimension-matched electron–electron interactions project to pure outer-radius kernels. In 3D this gives the standard <i>S</i>-wave Coulomb kernel <span>(1/r_{12}rightarrow 1/r_&gt;)</span>; in intrinsic 2D the corresponding logarithmic interaction gives the less commonly noted kernel <span>(-2ln (r_{12}/r_0)rightarrow -2ln (r_&gt;/r_0))</span>. Each is the Coulomb Green function of its own dimension after angular projection. The planar 2D model, which keeps the 3D <span>(1/r_{12})</span> law while restricting the electrons to a plane, is therefore mixed-dimensional and yields an elliptic-integral kernel instead. Analytic log–Coulomb crossover and Rytova–Keldysh potentials are also explored as conceptually intermediate one-electron cases between the pure 3D and planar 2D Coulomb models. The method is validated against exact planar 2D hydrogen energies, published logarithmic spectra, and helium benchmarks, with the restricted radial projection recovering the full correlated energies to within about <span>(1%)</span> for the ground configuration and an order of magnitude better for the singly excited states. On this footing, radial <span>(m_1=m_2=0)</span> energies for intrinsic Gauss-law 2D helium are reported for the first time. The open-source Python code is publicly available.</p></div>","PeriodicalId":556,"journal":{"name":"Few-Body Systems","volume":"67 4","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00601-026-02080-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148909572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}