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Nuclear Theory·nucl-th

Tuesday·January 5, 2021

13 papers—8 primary·5 cross-listed

All13Primary8Cross-lists5
  1. 09

    The Mystery of Bloom-Gilman Duality: A Light Front Holographic QCD Perspective

    Aiden B. Sheckler🇺🇸 · Gerald A. Miller🇺🇸

    Light front wave functions motivated by holographic constructions are used to study Bloom-Gilman duality of deep inelastic scattering. Separate expressions for structure functions in terms of quark and hadronic degrees of freedom are presented, with a goal of relating the two expressions. A two-parton model is defined and resonance transition form factors are computed using previously derived light front wave functions. A new form of global duality is derived from the valence quark-number sum rule. Using a complete set of hadronic states is necessary for this new global duality to be achieved. Previous original work does not provide such a set. This is remedied by amending the model to include a longitudinal confining potential, and the resulting complete set is sufficient to carry out the study of Bloom-Gilman duality. Expressions for transition form factors are obtained and all are shown to fall asymptotically as 1/Q2. The Feynman mechanism dominates the asymptotic behavior of the model. These transition form factors are used to assess the validity of the global and local duality sum rules, with the result that both neither are satisfied. Evaluations of the hadronic expression for q(x,Q2) provide more details about this lack. This result shows that the observed validity of both global and local forms of duality for deep inelastic scattering must be related to a feature of QCD that is deeper than completeness. Our simple present model suggests a prediction that Bloom-Gilman duality would not be observed if deep inelastic scattering experiments were to be made on the pion. The underlying origin of the duality phenomenon in deep inelastic scattering is deeply buried within the confinement aspects of QCD, and remains a mystery.

    ↳ hep-phnucl-exnucl-thPRD(2021)·7 citations
  2. 10

    P-wave nucleon-pion scattering amplitude in the channel from lattice QCD

    Giorgio Silvi🇩🇪 · Srijit Paul🇩🇪 · Constantia Alexandrou🇨🇾 · Stefan Krieg🇩🇪 · Luka Leskovec🇺🇸 · Stefan Meinel🇺🇸 · John Negele🇺🇸 · Marcus Petschlies🇩🇪 · Andrew Pochinsky🇺🇸 · Gumaro Rendon🇺🇸 · Sergey Syritsyn🇺🇸 · Antonino Todaro🇩🇪

    We determine the resonance parameters using lattice QCD and the Lüscher method. The resonance occurs in elastic pion-nucleon scattering with in the isospin , -wave channel. Our calculation is performed with flavors of clover fermions on a lattice with fm. The pion and nucleon masses are MeV and MeV, and the strong decay channel is found to be above the threshold. To thoroughly map out the energy-dependence of the nucleon-pion scattering amplitude, we compute the spectra in all relevant irreducible representations of the lattice symmetry groups for total momenta up to , including irreps that mix and waves. We perform global fits of the amplitude parameters to up to 21 energy levels, using a Breit-Wigner model for the -wave phase shift and the effective-range expansion for the -wave phase shift. From the location of the pole in the -wave scattering amplitude, we obtain the resonance mass MeV and the coupling .

    ↳ hep-lathep-phnucl-thPRD(2021)·46 citations
  3. 11

    A survey of heavy-antiheavy hadronic molecules

    Xiang-Kun Dong🇨🇳 · Feng-Kun Guo🇨🇳 · Bing-Song Zou🇨🇳

    Many efforts have been made to reveal the nature of the overabundant resonant structures observed by the worldwide experiments in the last two decades. Hadronic molecules attract special attention because many of these seemingly unconventional resonances are located close to the threshold of a pair of hadrons. To give an overall feature of the spectrum of hadronic molecules composed of a pair of heavy-antiheavy hadrons, namely, which pairs are possible to form molecular states, we take charmed hadrons for example to investigate the interaction between them and search for poles by solving the Bethe-Salpeter equation. We consider all possible combinations of hadron pairs of the -wave singly-charmed mesons and baryons as well as the narrow -wave charmed mesons. The interactions, which are assumed to be meson-exchange saturated, are described by constant contact terms which are resummed to generate poles. It turns out that if a system is attractive near threshold by the light meson exchange, there is a pole close to threshold corresponding to a bound state or a virtual state, depending on the strength of interaction and the cutoff. In total, 229 molecular states are predicted. The observed near-threshold structures with hidden-charm, like the famous and states, fit into the spectrum we obtain. We also highlight a bound state that has a pole consistent with the cross section of the precisely measured by the BESIII Collaboration.

    ↳ hep-phhep-exhep-latnucl-thProgr.Phys.(2021)·240 citations
  4. 12

    Maximum entropy kinetic matching conditions for heavy-ion collisions

    Derek Everett🇺🇸 · Chandrodoy Chattopadhyay🇺🇸 · Ulrich Heinz🇺🇸

    Coupling hadronic kinetic theory models to fluid dynamics in phenomenological studies of heavy ion collisions requires a prescription for ``particlization''. Existing particlization models are based on implicit or explicit assumptions about the microscopic degrees of freedom that go beyond the information provided by the preceding fluid dynamical history. We propose an alternative prescription which uses only macroscopic information provided by the hydrodynamic output. This method follows directly from the connections between information theory and statistical mechanics.

    ↳ hep-phnucl-thPRC(2021)·24 citations
  5. 13

    Effect of nuclear magnetization distribution within the Woods-Saxon model: Hyperfine splitting in neutral Tl

    S. D. Prosnyak🇷🇺 · L. V. Skripnikov🇷🇺

    Three models of the nuclear magnetization distribution are applied to predict the hyperfine structure of the hydrogenlike heavy ions and neutral thallium atoms: the uniformly magnetized ball model and single-particle models for the valence nucleon with the uniform distribution and the distribution determined by the Woods-Saxon potential. Results for the hydrogenlike ions are in excellent agreement with previous studies. The application of the Woods-Saxon model is now extended to the neutral systems with the explicit treatment of the electron correlation effects within the relativistic coupled cluster theory using the Dirac-Coulomb Hamiltonian. We estimate the uncertainty for the ratio of magnetic anomalies and numerically confirm its near nuclear-model independence. The ratio is used as a theoretical input to predict the nuclear magnetic moments of short-lived thallium isotopes. We also show that the differential magnetic anomalies are strongly model dependent. The accuracy of the single-particle models significantly surpasses the accuracy of the simplest uniformly magnetized ball model for the prediction of this quantity. Skripnikov [Skripnikov, J. Chem. Phys. 153, 114114 (2020)] has shown that the Bohr-Weisskopf contribution to the magnetic dipole hyperfine structure constant for an atom or a molecule induced by a heavy nucleus can be factorized into the electronic part and the universal nuclear magnetization dependent part. We numerically confirm this factorization for the Woods-Saxon single-particle model with an uncertainty less than 1%.

    ↳ physics.atom-phnucl-thPRC(2021)·14 citations

Affiliations

first authorsco-authorsvia INSPIRE