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Nuclear Theory·nucl-th

Tuesday·May 3, 2022

15 papers—9 primary·6 cross-listed

All15Primary9Cross-lists6
  1. 10

    [Submitted on 27 Feb 2021] (cross-list from hep-ph)

    Hybrid model of proton structure functions

    S. A. Kulagin🇷🇺 · V. V. Barinov🇷🇺

    We develop a "hybrid" model of the proton inelastic structure functions applicable in a wide region of invariant mass of produced states and invariant momentum transfer including deep inelastic scattering (DIS), nucleon resonance production as well as the region close to inelastic threshold. DIS is described in terms of the parton distributions together with higher-twist corrections from an available global QCD fit. The resonant part is addressed in terms of the Breit-Wiegner contributions from five states including the resonance, the Roper resonance, and three effective resonances describing the second and third resonance regions. The couplings of the nucleon resonances to photon are described in terms of helicity amplitudes. The nonresonant background is addressed in terms of DIS structure functions smoothly extrapolated to low- and low- values with the proper behavior at the real photon limit as well as near the inelastic threshold. We independently treat the transverse and the longitudinal structure function and fix the model parameters from a global analysis of the world hydrogen electroproduction and photoproduction cross-section data. We demonstrate a very good performance of the model by comparing our predictions with data on differential cross sections and the structure functions and .

    Comments:
    54 pages, 42 figures. Final version published in Phys. Rev. C including Supplemental Material
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2103.00158 [pdf]
    PRC(2022)·4 citations
  2. 11

    [Submitted on 1 May 2022] (cross-list from hep-ph)

    QCD at finite temperature and density within the fRG approach: An overview

    Wei-jie Fu🇨🇳

    In this paper we present an overview on recent progress in studies of QCD at finite temperature and densities within the functional renormalization group (fRG) approach. The fRG is a nonperturbative continuum field approach, in which quantum, thermal and density fluctuations are integrated in successively with the evolution of the renormalization group (RG) scale. The fRG results for the QCD phase structure and the location of the critical end point (CEP), the QCD equation of state (EoS), the magnetic EoS, baryon number fluctuations confronted with recent experimental measurements, various critical exponents, spectral functions in the critical region, the dynamical critical exponent, etc., are presented. Recent estimates of the location of the CEP from first-principle QCD calculations within fRG and Dyson-Schwinger Equations, which passes through lattice benchmark tests at small baryon chemical potentials, converge in a rather small region at baryon chemical potentials of about 600 MeV. A region of inhomogeneous instability indicated by a negative wave function renormalization is found with MeV. It is found that the non-monotonic dependence of the kurtosis of the net-proton number distributions on the beam collision energy observed in experiments, could arise from the increasingly sharp crossover in the regime of low collision energy.

    Comments:
    68 pages, 59 figures, 3 tables
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2205.00468 [pdf]
    Commun.Theor.Phys.(2022)·126 citations
  3. 12

    [Submitted on 1 May 2022] (cross-list from astro-ph.HE)

    Hybrid Equations of State for Neutron Stars with Hyperons and Deltas

    A. Clevinger🇺🇸 · J. Corkish🇺🇸 · K. Aryal🇺🇸 · V. Dexheimer🇺🇸

    In this contribution, we describe new chemically-equilibrated charge-neutral hybrid equations of state for neutron stars. They present a first-order phase transition to quark matter and differentiate by the particle population considered and how these particles interact. While some equations of state contain just nucleons and up, down-quarks, others also contain hyperons, Delta baryons, and strange quarks. The hybrid equations of state, together with corresponding hadronic ones, are available on the CompOSE repository and can be used for different astrophysical applications.

    Comments:
    Invited contribution to Special Issue on "CompOSE: a repository for Neutron Star Equations of State and Transport Properties"
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
    arXiv:
    2205.00559 [pdf]
    EPJA(2022)·22 citations
  4. 13

    [Submitted on 2 May 2022] (cross-list from hep-ph)

    Regarding the possibility to observe the LHCb hidden-charm strange pentaquark in antikaon-induced meson production on protons and nuclei near the production threshold

    E. Ya. Paryev🇷🇺

    We study the near-threshold meson production on protons and nuclei by considering incoherent direct non-resonant and two-step resonant charmonium production processes. We calculate the absolute excitation functions, energy and momentum distributions for the non-resonant, resonant and for the combined (non-resonant plus resonant) production of mesons off protons as well as off carbon and tungsten target nuclei at near-threshold incident antikaon energies by considering these elementary production channels as well as by assuming the spin-parity assignment of the hidden-charm resonance with strangeness as within six different scenarios for the branching ratio of the decay . We show that the combined observables considered reveal definite sensitivity to these scenarios, which means that they may be an important tool to provide further evidence for the existence of the pentaquark resonance and to get valuable information on its decay rate to the final state. Their measurements could be performed in the future at the J-PARC Hadron Experimental Facility.

    Comments:
    30 pages, 9 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2205.00728 [pdf]
    NPA(2022)·6 citations
  5. 14

    [Submitted on 2 May 2022] (cross-list from hep-ph)

    The electromagnetic Sigma-to-Lambda transition form factors with coupled-channel effects in the space-like region

    Yong-Hui Lin🇩🇪 · Hans-Werner Hammer🇩🇪 · Ulf-G. Meißner🇩🇪

    Using dispersion theory, the electromagnetic Sigma-to-Lambda transition form factors are expressed as the product of the pion electromagnetic form factor and the scattering amplitudes with the latter estimated from SU(3) chiral perturbation theory including the baryon decuplet as explicit degrees of freedom. The contribution of the channel is also taken into account and the - coupled-channel effect is included by means of a two-channel Muskhelishvili-Omnès representation. It is found that the electric transition form factor shows a significant shift after the inclusion of the channel, while the magnetic transition form factor is only weakly affected. However, the effect on the electric form factor is obscured by the undetermined coupling in the three-flavor chiral Lagrangian. The error bands of the Sigma-to-Lambda transition form factors from the uncertainties of the couplings and low-energy constant in three-flavor chiral perturbation theory are estimated by a bootstrap sampling method.

    Comments:
    16 pages, 10 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2205.00850 [pdf]
    EPJA(2023)·11 citations
  6. 15

    [Submitted on 2 May 2022] (cross-list from hep-ph)

    Updated QCD global analysis of single transverse-spin asymmetries I: Extracting , and the role of the Soffer bound and lattice QCD

    Leonard Gamberg🇺🇸 · Michel Malda🇺🇸 · Joshua A. Miller🇺🇸 · Daniel Pitonyak🇺🇸 · Alexei Prokudin🇺🇸 · Nobuo Sato🇺🇸

    We present an update to the QCD global analysis of single transverse-spin asymmetries presented in Cammarota, et al., PRD 102, 054002 (2020) (JAM3D-20). JAM3D-20 simultaneously included transverse momentum dependent and collinear twist-3 observables, both of which are sensitive to quark-gluon-quark correlations in hadrons. In this study we extract for the first time the twist-3 chiral odd fragmentation function by incorporating the modulation data from SIDIS along with its contribution to the single transverse-spin asymmetry in pion production from proton-proton collisions. We also explore the impact of lattice QCD tensor charge calculations and the Soffer bound on our global analysis. We find that both constraints can be accommodated within our results, with playing a key role in maintaining agreement with the data from proton-proton collisions.

    Comments:
    27 pages, 19 figures, 1 table; content added on uncertainties of non-perturbative functions, new section on the role of antiquarks, version to appear in PRD
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2205.00999 [pdf]
    PRD(2022)·80 citations

Affiliations

first authorsco-authorsvia INSPIRE