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Nuclear Theory·nucl-th

Thursday·November 17, 2022

5 papers—1 primary·4 cross-listed

All5Primary1Cross-lists4
  1. 01

    [Submitted on 16 Nov 2022]

    Electric conductivity of hot pion matter

    Joseph Atchison🇺🇸 · Ralf Rapp🇺🇸

    The determination of transport coefficients plays a central role in characterizing hot and dense nuclear matter. Currently, there are significant discrepancies between various calculations of the electric conductivity of hot hadronic matter. In the present work we calculate the electric conductivity of hot pion matter by extracting it from the electromagnetic spectral function, via its zero energy limit at vanishing 3-momentum, within the Vector Dominance Model (VDM). Since within the VDM the photon couples to the hadronic currents primarily through the meson, we use hadronic many-body theory to calculate the -meson's self-energy in hot pion matter, by dressing its pion cloud with thermal - and - loops including vertex corrections to maintain gauge invariance. In particular, we analyze the low-energy transport peak of the spectral function, extract its behavior with temperature and compare to (the results of) existing approaches in the literature.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2211.08713 [pdf]
    NPA(2023)·6 citations
  2. 02

    [Submitted on 16 Nov 2022] (cross-list from astro-ph.HE)

    Dark Matter or Regular Matter in Neutron Stars? How to tell the difference from the coalescence of compact objects

    Maurício Hippert🇺🇸 · Emily Dillingham🇺🇸 · Hung Tan🇺🇸 · David Curtin🇨🇦 · Jacquelyn Noronha-Hostler🇺🇸 · Nicolás Yunes🇺🇸

    The mirror twin Higgs model is a candidate for (strongly-interacting) complex dark matter, which mirrors SM interactions with heavier quark masses. A consequence of this model are mirror neutron stars -- exotic stars made entirely of mirror matter, which are significantly smaller than neutron stars and electromagnetically dark. This makes mergers of two mirror neutron stars detectable and distinguishable in gravitational wave observations, but can we observationally distinguish between regular neutron stars and those that may contain some mirror matter? This is the question we study in this paper, focusing on two possible realizations of mirror matter coupled to standard model matter within a compact object: (i) mirror matter captured by a neutron star and (ii) mirror neutron star-neutron star coalescences. Regarding (i), we find that (non-rotating) mirror-matter-admixed neutron stars no longer have a single mass-radius sequence, but rather exist in a two-dimensional mass-radius plane. Regarding (ii), we find that binary systems with mirror neutron stars would span a much wider range of chirp masses and completely different binary Love relations, allowing merger remnants to be very light black holes. The implications of this are that gravitational wave observations with advanced LIGO and Virgo, and X-ray observations with NICER, could detect or constrain the existence of mirror matter through searches with wider model and parameter priors.

    Comments:
    22 pages, 16 figures
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2211.08590 [pdf]
    PRD(2023)·77 citations
  3. 03

    [Submitted on 16 Nov 2022] (cross-list from hep-ph)

    Charged current (anti)neutrino induced eta production off the nucleon

    A. Fatima🇮🇳 · M. Sajjad Athar🇮🇳 · S. K. Singh🇮🇳

    The charged current (anti)neutrino induced eta production from the nucleons is studied in a model based on the effective Lagrangians to evaluate the contribution from the nonresonant and resonant diagrams. The contribution from the nonresonant background terms has been obtained using a microscopic model based on the SU(3) chiral Lagrangians. The contribution from the resonant diagrams due to the low lying , , and resonances has been evaluated using an effective phenomenological Lagrangian with its parameters determined from the experimental values of their branching ratios and decay widths to the channel. The model is first used to reproduce satisfactorily the experimental data from the MAINZ and JLab on the total cross sections for the photo- and electro- production of mesons, which fixes the model parameters in the vector current interaction. The PCAC hypothesis and generalized Goldberger-Treiman relation are used to fix the parameters of the axial vector interaction. The model is then applied to study the weak production of eta mesons induced by the neutrinos and antineutrinos, and predicts the numerical values for the -distribution, -momentum distribution, and the total cross section for the reactions and in the energy region up to 2 GeV. It is found that the photo, electro, and (anti)neutrino production of eta mesons is dominated by the contribution from the resonance. The results discussed in this work are relevant for the present and future accelerator experiments like MicroBooNE, T2K, NOvA, MINERvA, T2-HyperK and DUNE as well as for the atmospheric neutrino experiments.

    Comments:
    20 pages, 12 figures, 2 tables. arXiv admin note: substantial text overlap with arXiv:2206.13792
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    2211.08830 [pdf]
    PRD(2023)·6 citations
  4. 04

    [Submitted on 16 Nov 2022] (cross-list from hep-ph)

    Two-loop form factors for pseudo-scalar quarkonium production and decay

    Samuel Abreu🇨🇭 · Matteo Becchetti🇮🇹 · Claude Duhr🇩🇪 · Melih A. Ozcelik🇫🇷

    We present the analytic expressions for the two-loop form factors for the production or decay of pseudo-scalar quarkonia, in a scheme where the quarks are produced at threshold. We consider the two-loop amplitude for the process , that was previously known only numerically, as well as for the processes , and , which have not been computed before. The two-loop corrections to are the last missing ingredients for a full NNLO calculation of hadro-production. We discuss how the singularity structure of the amplitudes is affected by the threshold kinematics, which in particular introduces Coulomb singularities. In this context, we first show how the usual structure of the infrared singularities degenerates at threshold kinematics, and then extract the anomalous dimensions governing the Coulomb singularities for colour-singlet and octet channels, the latter being presented here for the first time. We give high-precision numerical results for the hard functions, which can be used for phenomenological studies of production and decay at NNLO.

    Comments:
    37 pages, 1 figure, v2: version published in JHEP
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2211.08838 [pdf]
    JHEP(2023)·22 citations
  5. 05

    [Submitted on 16 Nov 2022] (cross-list from hep-ph)

    Ground state baryons in the flux-tube three-body confinement model using Diffusion Monte Carlo

    Yao Ma🇨🇳 · Lu Meng🇩🇪 · Yan-Ke Chen🇨🇳 · Shi-Lin Zhu🇨🇳

    We make a systematical diffusion Monte Carlo (DMC) calculation for all ground state baryons in two confinement scenarios, the pairwise confinement and the three-body flux-tube confinement. With the baryons as an example, we illustrate a feasible procedure to investigate the few-quark states with possible few-body confinement mechanisms, which can be extended to the multiquark states easily. For each baryon, we extract the mass, mean-square radius, charge radius, and the quark distributions. We use the Jackknife resampling method to estimate the statistical uncertainties of masses to be less than 1 MeV. To determine the baryon charge radii, we include the constituent quark size effect, which is fixed by the experimental and lattice QCD results. Our results show that both two-body and three-body confinement mechanisms can give a good description of the experimental data if the parameters are chosen properly. In the flux-tube confinement, introducing different tension parameters for the baryons and mesons are necessary, specifically, . The lesson from the calculation of the nucleon mass with the DMC method is that the improper pre-assignment of the channels may prevent us from obtaining the real ground state. With this experience, we obtain the real ground state (the threshold with the di-meson configuration) of the system with starting from the diquark-antidiquark spin-color channels alone, which is hard to achieve in the variational method and was not obtained in the previous DMC calculations.

    Comments:
    24 pages, 18 figures. The Supplement material is attached in the source code of LaTeX. Comments are welcomed
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    2211.09021 [pdf]
    PRD(2023)·25 citations

Affiliations

first authorsco-authorsvia INSPIRE