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Nuclear Theory·nucl-th

Wednesday·November 13, 2019

12 papers—6 primary·6 cross-listed

All12Primary6Cross-lists6
  1. 01

    Comparative study of the direct Li + astrophysical capture reaction in few-body models

    E.M. Tursunov · S.A. Turakulov · A.S. Kadyrov

    A comparative analysis of the astrophysical S factor and the reaction rate for the direct capture reaction, and the primordial abundance of the Li element, resulting from two-body, three-body and combined cluster models is presented. It is shown that the two-body model, based on the exact-mass prescription, can not correctly describe the dependence of the isospin-forbidden E1 S factor on energy and does not reproduce the temperature dependence of the reaction rate from the direct LUNA data. It is demonstrated that the isospin-forbidden E1 astrophysical S factor is very sensitive to the orthogonalization procedure of Pauli-forbidden states within the three-body model. On the other hand, the E2 S factor does not depend on the orthogonalization method. This insures that the orthogonolizing pseudopotentials method yields a very good description of the LUNA collaboration's low-energy direct data. At the same time, the SUSY transformation significantly underestimates the data from the LUNA collaboration. On the other hand, the energy dependence of the E1 S factor are the same in both methods. The best description of the LUNA data for the astrophysical S factor and the reaction rates is obtained within the combined E1(three-body OPP)+E2(two-body) model. It yields a value of for the Li/H primordial abundance ratio, consistent with the estimation of the LUNA collaboration. For the abundance ratio an estimation is obtained in good agreement with the Standard Model prediction.

    nucl-thastro-ph.COastro-ph.SRNPA(2020)·14 citations
  2. 02

    Production of hypernuclei and properties of hyper-nuclear matter

    Alexander Botvina🇷🇺 · Marcus Bleicher🇩🇪 · Nihal Buyukcizmeci🇹🇷

    The relativistic nucleus-nucleus collisions can produce hypernuclei and low-temperature hyper-matter as a result of hyperon capture by nuclear residues and free nucleons. We use the transport, coalescence and statistical models to describe the whole process, and point at the important advantages of such reactions: A broad variety of formed hypernuclei in masses and isospin allows for investigating properties of exotic hypernuclei, as well as the hypermatter both at high and low temperatures. The abundant production of multi-strange nuclei that can give an access to multi-hyperon systems and strange nuclear matter. The de-excitation of hot hyper-cluster will allow for the hyperon correlation studies. There is a saturation of the hypernuclei production at high energies, therefore, the optimal way to pursue this experimental study is to use the accelerator facilities of intermediate energies.

    nucl-thSpringer Proc.Phys.(2020)·0 citations
  3. 03

    Evolution of fluctuations in the initial state of heavy-ion collisions from RHIC to LHC

    Giuliano Giacalone🇫🇷 · François Gelis🇫🇷 · Pablo Guerrero-Rodríguez🇫🇮 · Matthew Luzum🇧🇷 · Cyrille Marquet🇫🇷 · Jean-Yves Ollitrault🇫🇷

    Fluctuations in the initial state of heavy-ion collisions are larger at RHIC energy than at LHC energy. This fact can be inferred from recent measurements of the fluctuations of the particle multiplicities and of elliptic flow performed at the two different energies. We show that an analytical description of the initial energy-density field and its fluctuations motivated by the color glass condensate (CGC) effective theory predicts and quantitatively captures the measured energy evolution of these observables. The crucial feature is that fluctuations in the CGC scale like the inverse of the saturation scale of the nuclei.

    nucl-thhep-exhep-phnucl-exSpringer Proc.Phys.(2020)·6 citations
  4. 04

    Extraction of the neutron charge radius from a precision calculation of the deuteron structure radius

    A.A. Filin · V. Baru · E. Epelbaum · H. Krebs · D. Möller · P. Reinert

    We present a high-accuracy calculation of the deuteron structure radius in chiral effective field theory. Our analysis employs the state-of-the-art semilocal two-nucleon potentials and takes into account two-body contributions to the charge density operators up to fifth order in the chiral expansion. The strength of the fifth-order short-range two-body contribution to the charge density operator is adjusted to the experimental data on the deuteron charge form factor. A detailed error analysis is performed by propagating the statistical uncertainties of the low-energy constants entering the two-nucleon potentials and by estimating errors from the truncation of the chiral expansion as well as from uncertainties in the nucleon form factors. Using the predicted value for the deuteron structure radius together with the very accurate atomic data for the difference of the deuteron and proton charge radii we, for the first time, extract the charge radius of the neutron from light nuclei. The extracted value reads and its magnitude is about smaller than the current value given by the Particle Data Group. In addition, given the high accuracy of the calculated deuteron charge form factor and its careful and systematic error analysis, our results open the way for an accurate determination of the nucleon form factors from elastic electron-deuteron scattering data measured at the Mainz Microtron and other experimental facilities.

    nucl-thnucl-exPRL(2020)·77 citations
  5. 05

    Excited light baryons from quark-gluon-level calculations

    J. Segovia🇪🇸 · C. Chen🇩🇪 · Z.-F. Cui🇨🇳 · Y. Lu🇨🇳 · C.D. Roberts🇨🇳

    The task of mapping and explaining the spectrum of baryons and the structure of these states in terms of quarks and gluons is a longstanding challenge in hadron physics, which is likely to persist for another decade or more. We review the progress made in this topic using a functional method based on Dyson-Schwinger equations. This framework provides a non-perturbative, Poincaré-covariant continuum formulation of Quantum Chromodynamics which is able to extract novel insight on baryon properties since the physics at the hadron level is directly related with the underlying quark-gluon substructure, via convolution of Green functions.

    nucl-thhep-lathep-ph1 citation
  6. 06

    Family of Chiral Two- plus Three-Nucleon Interactions for Accurate Nuclear Structure Studies

    Thomas Hüther🇩🇪 · Klaus Vobig🇩🇪 · Kai Hebeler🇩🇪 · Ruprecht Machleidt🇺🇸 · Robert Roth🇩🇪

    We present a family of nucleon-nucleon (NN) plus three-nucleon (3N) interactions up to N3LO in the chiral expansion that provides an accurate ab initio description of ground-state energies and charge radii up to the medium-mass regime with quantified theory uncertainties. Starting from the NN interactions proposed by Entem, Machleidt and Nosyk, we construct 3N interactions with consistent chiral order, non-local regulator, and cutoff value and explore the dependence of nuclear observables over a range of mass numbers on the 3N low-energy constants. By fixing these constants using the 3-H and 16-O ground-state energies, we obtain interactions that robustly reproduce experimental energies and radii for large range from p-shell nuclei to the nickel isotopic chain and resolve many of the deficiencies of previous interactions. Based on the order-by-order convergence and the cutoff dependence of nuclear observables, we assess the uncertainties due the interaction, which yield a significant contribution to the total theory uncertainty.

    nucl-thPLB(2020)·118 citations

Affiliations

first authorsco-authorsvia INSPIRE