1,299 research outputs found
New T=1 effective interactions for the f5/2 p3/2 p1/2 g9/2 model space; Implications for valence-mirror symmetry and seniority isomers
New shell model Hamiltonians are derived for the T=1 part of the residual
interaction in the f5/2 p3/2 p1/2 g9/2 model space based on the analysis and
fit of the available experimental data for 57Ni-78Ni isotopes and 77Cu-100Sn
isotones. The fit procedure, properties of the determined effective interaction
as well as new results for valence-mirror symmetry and seniority isomers for
nuclei near 78Ni and 100Sn are discussed.Comment: 4 pages, 5 figure
A Meeting of Minds: An Alternate Humor for Teaching Mathematics to non-STEM Majors
John Allen Paulos argued essentially for three forms of humor dear to mathematics: Incongruity, Gotcha, and Word Play. Unfortunately, these three are often combative forms and easily drive non-STEM majors out of mathematics and statistics.
William Dunham in The Mathematical Universe shows how a fine mathematician can use humor to draw non-specialists in. Central to Dunham’s success is his use of Sympathetic Pain humor, which creates softer synthetic Reconciler, Consoler, or Bridgebuilder humor styles
Proton-neutron pairing in the deformed BCS approach
We examine isovector and isoscalar proton-neutron pairing correlations for
the ground state of even-even Ge isotopes with mass number A=64-76 within the
deformed BCS approach. For N=Z 64Ge the BCS solution with only T=0
proton-neutron pairs is found. For other nuclear systems (N>Z) a coexistence of
a T=0 and T=1 pairs in the BCS wave function is observed. A problem of fixing
of strengths of isoscalar and isovector pairing interactions is addressed. A
dependence of number of like and unlike pairs in the BCS ground state on the
difference between number of neutrons and protons is discussed. We found that
for nuclei with N much bigger than Z the effect of proton-neutron pairing is
small but not negligible.Comment: 24 pages, 6 figure
Study of the effect of the tensor correlation in oxygen isotopes with the charge- and parity-projected Hartree-Fock method
Recently, we developed a mean-field-type framework which treats the
correlation induced by the tensor force. To exploit the tensor correlation we
introduce single-particle states with the parity and charge mixing. To make a
total wave function have a definite charge number and a good parity, the charge
number and parity projections are performed. Taking a variation of the
projected wave function with respect to single-particle states a
Hartree-Fock-like equation, the charge- and parity-projected Hartree-Fock
equation, is obtained. In the charge- and parity-projected Hartree-Fock method,
we solve the equation selfconsistently. In this paper we extend the charge- and
parity-projected Hartree-Fock method to include a three-body force, which is
important to reproduce the saturation property of nuclei in mean-field
frameworks. We apply the charge- and parity-projected Hartree-Fock method to
sub-closed-shell oxygen isotopes (14O, 16O, 22O, 24O, and 28O) to study the
effect of the tenor correlation and its dependence on neutron numbers. We
obtain reasonable binding energies and matter radii for these nuclei. It is
found that relatively large energy gains come from the tensor force in these
isotopes and there is the blocking effect by occupied neutron orbits on the
tensor correlation
Pairing-excitation versus intruder states in 68Ni and 90Zr
A discussion on the nature of the 0+ states in 68Ni (Z=28, N=40) is presented
and a comparison is made with its valence counterpart 90Zr (Z=40, N=50).
Evidence is given for a 0+ proton intruder state at only ~2.2 MeV excitation
energy in 68Ni, while the analogous neutron intruder states in 90Zr reside at
4126 keV and 5441 keV. The application of a shell-model description of 0+
intruder states reveals that many pair-scattered neutrons across N=40 have to
be involved to explain the low excitation energy of the proton-intruder
configuration in 68Ni.Comment: 10 pages, 2 figures, 1 tabl
How magic is the magic 68Ni nucleus?
We calculate the B(E2) strength in 68Ni and other nickel isotopes using
several theoretical approaches. We find that in 68Ni the gamma transition to
the first 2+ state exhausts only a fraction of the total B(E2) strength, which
is mainly collected in excited states around 5 MeV. This effect is sensitive to
the energy splitting between the fp shell and the g_{9/2}orbital. We argue that
the small experimental B(E2) value is not strong evidence for the double-magic
character of 68Ni.Comment: 4 pages, 4 figure
Dominant g(9/2)^2 neutron configuration in the 4+1 state of 68Zn based on new g factor measurements
The factor of the state in Zn has been remeasured with
improved energy resolution of the detectors used. The value obtained is
consistent with the previous result of a negative factor thus confirming
the dominant neutron nature of the state. In addition, the
accuracy of the factors of the , and states has been
improved an d their lifetimes were well reproduced. New large-scale shell model
calculations based on a Ni core and an model space
yield a theoretical value, . Although the calculated value
is small, it cannot fully explain the experimental value, . The magnitude of the deduced B(E2) of the and
transition is, however, rather well described. These results demonstrate again
the importance of factor measurements for nuclear structure determination s
due to their specific sensitivity to detailed proton and neutron components in
the nuclear wave functions.Comment: 7 pages, 3 figs, submitted to PL
First observation of γ rays emitted from excited states south-east of Sn 132: The π g9/2-1 âš - νf7/2 multiplet of In83 132
For the first time, the γ decay of excited states has been observed in a nucleus situated in the quadrant south-east of doubly magic Sn132, a region in which experimental information so far is limited to ground-state properties. Six γ rays with energies of 50, 86, 103, 227, 357, and 602 keV were observed following the β-delayed neutron emission from Cd85133, populated in the projectile fission of a U238 beam at the Radioactive Isotope Beam Factory at RIKEN within the EURICA project. The new experimental information is compared to the results of a modern realistic shell-model calculation, the first one in this region very far from stability, focusing in particular on the π0g9/2-1 - ν1f7/2 particle-hole multiplet in In83132. In addition, theoretical estimates based on a scaling of the two-body matrix elements for the πh11/2-1 - νg9/2 analog multiplet in Tl127208, one major proton and one major neutron shell above, are presented. © 2016 American Physical Society
Review of CFD Guidelines for Dispersion Modeling
This is the review of CFD (Computational Fluid Dynamics) guidelines for dispersion modeling in the USA, Japan and Germany. Most parts of this review are based on the short report of the special meeting on CFD Guidelines held at the International Symposium on Computational Wind Engineering (CWE2014), University of Hamburg, June 2014. The objective of this meeting was to introduce and discuss the action program to make worldwide guidelines of CFD gas-dispersion modeling. The following six gas-dispersion guidelines including Verification and Validation (V&V) schemes are introduced by each author; (1) US CFD guidelines; (2) COST/ES1006; (3) German VDI (Verein Deutscher Ingenieure) guidelines; (4) Atomic Energy Society of Japan; (5) Japan Society of Atmospheric Environment; (6) Architectural Institute of Japan. All guidelines were summarized in the same format table shown in the main chapters in order to compare them with each other. In addition to the summary of guidelines, the overview of V&V schemes and many guidelines of CFD modeling in the USA are explained
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