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Nuclear Theory·nucl-th

Monday·November 7, 2022

7 papers—4 primary·3 cross-listed

All7Primary4Cross-lists3
  1. 01

    Review of Gamow-Teller and Fermi Transition Strength Functions

    Muna Al-Harby · Bassam A. Shehadeh

    We studied the temperature effect in isospin-singlet pairings in Gamow-Teller excitations. We use theories of a hole-particle in the mean field shell model studied decay transition using the one-particle-one-hole model for the -decay of odd-even isotopes and the two-particle-hole models for the -decay of even-even and/or odd-odd isotopes. Our reference isotopes for the one-particle-one-hole model are \ce{^{15}O}, \ce{^{15}N}, \ce{^{17}F}, and \ce{^{41}Sc}, whereas for the two-particle-hole model we use \ce{^{16}N} (for -decay) and \ce{^{56}Ni} and \ce{^{40}Sc} (for /EC). The calculations involve evaluating the matrix elements of Gamow -Teller and Fermi transitions, then calculate the reduced transition probabilities of Gamow-Teller and Fermi, from which we evaluate the half-lives and the strength function . The results are compared with the available experimental data. For one-particle-one-hole model we found there is a deviation from experimental values which indicates that the model is not valid for beta decay for the even-even nuclei in the ground state due to the residual nucleon-nucleon interaction. As for a two-particle-hole model, we calculated the transition amplitude, from which we calculated the strength of the transition values. We found an excellent agreement between experimental and theoretical results. By drawing the relationship between temperature versus values, we found the general trend is that the strength function values slowly decrease as temperatures increases. There are fluctuations due to the strongly dependent of on the shell configuration of the valence nucleons.

    nucl-th0 citations
  2. 02

    Long Range Plan: Dense matter theory for heavy-ion collisions and neutron stars

    Alessandro Lovato🇺🇸 · Travis Dore🇩🇪 · Robert D. Pisarski🇺🇸 · Bjoern Schenke🇺🇸 · Katerina Chatziioannou🇺🇸 · Jocelyn S. Read🇺🇸 · Philippe Landry🇨🇦 · Pawel Danielewicz🇺🇸 · Dean Lee🇺🇸 · Scott Pratt🇺🇸 · Fabian Rennecke🇩🇪 · Hannah Elfner🇩🇪 and 52 other authors

    Since the release of the 2015 Long Range Plan in Nuclear Physics, major events have occurred that reshaped our understanding of quantum chromodynamics (QCD) and nuclear matter at large densities, in and out of equilibrium. The US nuclear community has an opportunity to capitalize on advances in astrophysical observations and nuclear experiments and engage in an interdisciplinary effort in the theory of dense baryonic matter that connects low- and high-energy nuclear physics, astrophysics, gravitational waves physics, and data science

    nucl-thastro-ph.HEhep-ph114 citations
  3. 03

    Relativistic resistive magneto-hydrodynamics code for high-energy heavy-ion collisions

    Kouki Nakamura🇯🇵 · Takahiro Miyoshi🇯🇵 · Chiho Nonaka🇯🇵 · Hiroyuki R. Takahashi🇯🇵

    We construct a relativistic resistive magneto-hydrodynamic (RRMHD) numerical simulation code for high-energy heavy-ion collisions. We split the system of differential equations into two parts, a non-stiff and a stiff part. For the non-stiff part, we evaluate the numerical flux using HLL approximated Riemann solver and execute the time integration by the second-order of Runge-Kutta algorithm. For the stiff part, which appears in Ampere's law, we integrate the equations using semi-analytic solutions of the electric field. We employ the generalized Lagrange multiplier method to ensure the divergence-free constraint for the magnetic field and Gauss's law. We confirm that our code reproduces well the results of standard RRMHD tests in the Cartesian coordinates. In the Milne coordinates, the code with high conductivity is validated against relativistic ideal MHD tests. We also verify the semi-analytic solutions of the accelerating longitudinal expansion of relativistic resistive magneto-hydrodynamics in high-energy heavy-ion collisions in a comparison with our numerical result. Our numerical code reproduces these solutions.

    nucl-thhep-phnucl-exEPJC(2023)·22 citations
  4. 04

    Near-threshold resonances in 11C and the 10B(p,{\alpha})7Be aneutronic reaction cross section

    J. Okołowicz🇵🇱 · M. Płoszajczak🇫🇷 · W. Nazarewicz🇺🇸

    The nucleus 11C plays an important role in the boron-proton fusion reactor environment as a catalyzer of the 10B(p,{\alpha})7Be reaction which, by producing a long-lived isotope of 7Be, poisons the aneutronic fusion process 11B(p,2{\alpha})4He. The low-energy cross section of 10B(p,{\alpha})7Be depends on the near-threshold states 7/2+1 , 5/2+2 , 5/2+3 in 11C whose properties are primarily known from the indirect measurements. We investigate the continuum-coupling induced collectivization of these resonances in the shell model embedded in the continuum. We predict a significant enhancement of the 10B(p,{\alpha})7Be cross section at energies accessible to the laser-driven hot plasma facilities.

    nucl-thPRC(2023)·8 citations
  5. 05

    Methods on compositeness and related aspects

    J.A. Oller🇪🇸

    In many physical applications, bound states and/or resonances are observed, which raises the question whether these states are elementary or composite. Here we elaborate on several methods for calculating the compositeness of bound states and resonances in Quantum Mechanics, and in Quantum Field Theory by introducing particle number operators. For resonances is typically complex and we discuss how to get meaningful results by using certain phase transformations in the matrix.

    ↳ quant-phhep-phnucl-thEPJ Web Conf.(2022)·2 citations
  6. 06

    Compositeness and several applications to exotic hadronic states with heavy quarks

    J.A. Oller🇪🇸 · Z.-H. Guo🇨🇳

    Several methods for studying the nature of a resonance are applied to resonances recently discovered in the bottonomium and charmonium sectors. We employ the effective-range expansion, the saturation of the width and compositeness of a resonance, as well as direct fits to data. The latter stem from generic -matrix parameterization that account for relevant dynamical features associated to channels that couple strongly in an energy region around the resonance masses, in which their thresholds also lie. We report on results obtained with these methods for the resonances , , , , , , , and .

    ↳ hep-phnucl-thEPJ Web Conf.(2022)·0 citations
  7. 07

    Multi-output Gaussian processes for inverse uncertainty quantification in neutron noise analysis

    Paul Lartaud🇫🇷 · Philippe Humbert🇫🇷 · Josselin Garnier🇫🇷

    In a fissile material, the inherent multiplicity of neutrons born through induced fissions leads to correlations in their detection statistics. The correlations between neutrons can be used to trace back some characteristics of the fissile material. This technique known as neutron noise analysis has applications in nuclear safeguards or waste identification. It provides a non-destructive examination method for an unknown fissile material. This is an example of an inverse problem where the cause is inferred from observations of the consequences. However, neutron correlation measurements are often noisy because of the stochastic nature of the underlying processes. This makes the resolution of the inverse problem more complex since the measurements are strongly dependent on the material characteristics. A minor change in the material properties can lead to very different outputs. Such an inverse problem is said to be ill-posed. For an ill-posed inverse problem the inverse uncertainty quantification is crucial. Indeed, seemingly low noise in the data can lead to strong uncertainties in the estimation of the material properties. Moreover, the analytical framework commonly used to describe neutron correlations relies on strong physical assumptions and is thus inherently biased. This paper addresses dual goals. Firstly, surrogate models are used to improve neutron correlations predictions and quantify the errors on those predictions. Then, the inverse uncertainty quantification is performed to include the impact of measurement error alongside the residual model bias.

    ↳ stat.COnucl-thstat.APstat.MLNucl.Sci.Eng.(2023)·1 citation

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first authorsco-authorsvia INSPIRE