1,720,966 research outputs found
Low-energy Li-7(n, gamma) Li-8 and Be-7(p, gamma)B- 8 radiative capture reactions within the Skyrme Hartree-Fock approach
No full textThe electromagnetic dipole transitions in 7Be(p, ?? ) 8B and 7Li(n, ?? ) 8Li reactions at the keV-energy region were analyzed simultaneously within the Skyrme Hartree-Fock potential model. The Skyrme Hartree-Fock calculation is adopted as a microscopic approach to obtain consistently the single-particle bound and scattering states in the calculation of the radial overlap function within the potential model. All nonresonant and resonant electromagnetic dipole transitions are taken into account. The electric dipole transitions are successfully described with the slightest adjustment. The resonant magnetic dipole transitions at 633 keV and 2184 keV of the 7Be(p, ?? ) 8B reaction, and the one at 222 keV of 7Li(n, ?? ) 8Li are also analyzed. The astrophysical S17(0) factor of the 7Be(p, ?? ) 8B reaction is found to be 22.3 eV b.11Nsciescopu
Single-particle properties of the near-threshold proton-emitting resonance in B-11
No full textThe excitation function of proton elastic scattering from Be-10 at keV energy is calculated using the method of self-consistent Skyrme Hartree-Fock in the continuum. The calculation successfully reproduces the narrow near-threshold proton-emitting resonance (E-x = 11.4 MeV, gamma = 6 keV, and quantum number J(pi) = 1/2+) in B-11 relevant to the beta-delayed proton emission of Be-11. This supports the recent experimental result of Ayyad et al. at the ReA3 reaccelerator facility of the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University. The resonance is interpreted as the s1/2 single-proton resonance state in the Skyrme Hartree-Fock mean-field theory.11Nsciescopu
Origin of octupole deformation softness in atomic nuclei
No full textRecent high-energy heavy-ion collision experiments have revealed that some atomic nuclei exhibit unusual softness and significant shape fluctuations. In this work, we use the fully self-consistent mean-field theory to identify all even-even nuclei that are unstable or soft against octupole deformation. All exceptional cases of enhanced octupole transition strengths in stable even-even nuclei throughout the nuclide chart are resolved and the origin is found in basic shell structure. The presence of atomic nuclei exhibiting significant softness to quadrupole-octupole deformation is suggested. These results represent a significant advance in our understanding of the underlying mechanisms of nuclear octupole deformation and have implications for further experimental and theoretical studies. © 2023 American Physical Society.11Nsciescopu
Proton s -resonance states of C 12 and O 14,15 within the Skyrme Hartree-Fock mean-field framework
No full textThe excitation functions of proton elastic scattering on C12 and O14,15 nuclei at the energies near the proton-emission threshold are calculated using the Skyrme Hartree-Fock (SHF) in continuum approach. For each excitation function, the first resonance is identified as the s-state resonance of the mean-field theory. For O15, whose ground-state spin is nonzero, the s-state resonance splits into two resonances via the spin-spin component of the optical potential. With a slight adjustment of the strength of the central potential, which is obtained from the SHF in continuum approach, the excitation functions of proton elastic scattering for the three nuclei can be explained with high accuracy. The proposed framework can provide a practical method to explain nuclear scattering at the energies near the proton-emission threshold with minimal experimental input. © 2023 American Physical Society.11Nsciescopu
Study of the double Gamow-Teller transitions using the shell model approach
No full textThe double Gamow-Teller strength distributions in the lightest double beta-decay candidate 48Ca and its isotope 46Ca were calculated using the nuclear shell model by applying the single Gamow-Teller operator two times sequentially on the ground state of parent nucleus. The nuclear matrix element of the double Gamow- Teller transition from the ground state to the ground state that goes into the double beta decay calculation was shown as a small fraction of the total transition
Coulomb corrections to Fermi beta decay in nuclei
Full text linkWe study the influence of the Coulomb force on the Fermi beta-decays in
nuclei. This work is composed of two main parts. In the first part, we
calculate the Coulomb corrections to super-allowed beta decay. We use the
notion of the isovector monopole state and the self-consistent charge-exchange
Random Phase Approximation to compute the correction. In the second part of
this work, we examine the influence of the anti-analog state on isospin mixing
in the isobaric analog state and the correction to the beta-decay Fermi
transition.Comment: Some numerical mistakes were corrected. The present version matches
the online version published in NP
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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