41 research outputs found
Octupole deformation instability in atomic nuclei
Recent high-energy heavy-ion collision experiments have revealed that some
atomic nuclei exhibit unusual softness and significant shape fluctuations. In
this Letter, 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. 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.Comment: New references [3,4] were added. Thank Prof. Jiangyong Jia for the
discussion
Comparative analysis of formalisms and performances of three different beyond mean-field approaches
We investigate the differences and analogies between the equation of motion
phonon method (EMPM) and second Tamm-Dancoff and random-phase approximations
(STDA and SRPA) paying special attention to the problem of spurious
center-of-mass (c.m.) admixtures. In order to compare them on an equal footing,
we perform self-consistent calculations of the multipole strength distributions
in selected doubly magic nuclei within a space including up to
two-particle-two-hole (2p-2h) basis states using the UCOM two-body intrinsic
Hamiltonian and we explore the tools each approach supplies for removing the
spurious c.m. admixtures. We find that the EMPM and STDA yield exactly the same
results when the same intrinsic Hamiltonian is used and the coupling of the
Hartree-Fock state with the 2p-2h space is neglected, but, unlike STDA and
SRPA, the EMPM offers the possibility to completely remove c.m. admixtures.Comment: 13 pages, 17 figure
The role of the continuum and the spurious 1⁻ transitions in incoherent μ⁻ - e⁻ conversion rate calculations
By using the Continuum RPA (CRPA) method, the incoherent transition strength of the exotic μ⁻ - e⁻ conversion in nuclei is investigated. The question whether excited nuclear states lying high in the continuum give an important contribution to the incoherent rate is addressed. Results for ⁴⁰Ca are compared with those obtained previously for ²⁰⁸Pb. For both nuclei we then investigate in detail the admixture of spurious components in the rate coming from 1⁻ excitations, within the self-consistent CRPA with Skyrme interactions as well as within a less consistent version. We employ and compare two methods for removing the spurious strength: the use of effective operators, as done in a previous work for ²⁰⁸Pb, or simply the exclusion of the spurious state appearing close to zero energy. In all cases, the correction achieved is quite large.Facultad de Ciencias Exacta
Women Scientists Who Made Nuclear Astrophysics
Female role models reduce the impact on women of stereotype threat, i.e., of being at risk of conforming to a negative stereotype about one's social, gender, or racial group [1,2]. This can lead women scientists to underperform or to leave their scientific career because of negative stereotypes such as, not being as talented or as interested in science as men. Sadly, history rarely provides role models for women scientists; instead, it often renders these women invisible [3]. In response to this situation, we present a selection of twelve outstanding women who helped to develop nuclear astrophysics