3,565 research outputs found
New effective interaction for -shell nuclei and its implications for the stability of the ==28 closed core
The effective interaction GXPF1 for shell-model calculations in the full
shell is tested in detail from various viewpoints such as binding energies,
electro-magnetic moments and transitions, and excitation spectra. The
semi-magic structure is successfully described for or Z=28 nuclei,
Mn, Fe, Co and Ni, suggesting the
existence of significant core-excitations in low-lying non-yrast states as well
as in high-spin yrast states. The results of odd-odd nuclei, Co
and Cu, also confirm the reliability of GXPF1 interaction in the isospin
dependent properties. Studies of shape coexistence suggest an advantage of
Monte Carlo Shell Model over conventional calculations in cases where
full-space calculations still remain too large to be practical.Comment: 29pages, 26figures, to be published in Physical Review
Caustic Crossing Microlensing Event by Binary MACHOs and Time Scale Bias
Caustic crossing microlensing events provide us a unique opportunity to
measure the relative proper motion of the lens to the source, and so those
caused by binary MACHOs are of great importance for understanding the structure
of the Galactic halo and the nature of MACHOs. The microlensing event
98-SMC-01, occurred in June 1998, is the first event for which the proper
motion is ever measured through the caustic crossing, and this event may be
caused by binary MACHOs as we argue in this Letter. Motivated by the possible
existence of binary MACHOs, we have performed the Monte Carlo simulations of
caustic crossing events by binary MACHOs and investigated the properties and
detectability of the events. Our calculation shows that typical caustic
crossing events have the interval between two caustic crossings ()
of about 5 days. We argue that with the current strategy of binary event search
the proper motions of these typical events are not measurable because of the
short time scale. Therefore the proper motion distribution measured from
caustic crossing events suffers significantly from {`}time scale bias{'}, which
is a bias toward finding long time scale events and hence slowly moving lenses.
We predict there are two times more short time scale events (
days) than long time scale events ( days), and propose an
hourly monitoring observation instead of the nightly monitoring currently
undertaken to detect caustic crossing events by binary MACHOs more efficiently.Comment: 8 pages and 3 figures, accepted for publication in ApJ Letter
Effective interaction for pf-shell nuclei
An effective interaction is derived for use in the full pf basis. Starting
from a realistic G-matrix interaction, 195 two-body matrix elements and 4
single-particle energies are determined by fitting to 699 energy data in the
mass range 47 to 66. The derived interaction successfully describes various
structures of pf-shell nuclei. As examples, systematics of the energies of the
first 2+ states in the Ca, Ti, Cr, Fe, and Ni isotope chains and energy levels
of 56,57,58Ni are presented. The appearance of a new magic number 34 is seen.Comment: 5 pages, 4 figures, to be published in Phys. Rev.
Ingredients of nuclear matrix element for two-neutrino double-beta decay of 48Ca
Large-scale shell model calculations including two major shells are carried
out, and the ingredients of nuclear matrix element for two-neutrino double beta
decay are investigated. Based on the comparison between the shell model
calculations accounting only for one major shell (-shell) and those for two
major shells (-shell), the effect due to the excitation across the two
major shells is quantitatively evaluated.Comment: To appear in J. Phys. Soc. Conf. Proc. (ARIS2014); for ver.2, Fig.1
is revise
CO Observations of Luminous IR Galaxies at Intermediate Redshift
We present new measurement of CO() emission from 16 luminous
infrared galaxies (LIGs) at intermediate redshift (). These new data were selected by isolated and normal
morphology. The CO observations were performed using the NRO 45-m telescope.
Comparison of the CO and dust properties of the new result with those from
other CO measurements revealed characteristics of this sample: (1) It is the
deepest CO observations of IRAS galaxies at intermediate redshift without
strong interaction features. (2) It has typical properties of normal IRAS
galaxies in terms of star-formation efficiency, color-color diagrams and
galactic nuclear activity. (3) It has smaller gas-to-dust ratio than normal
IRAS galaxies. This can be explained by two-component dust model, and our
sample consists of most of warm dust.Comment: To appear in PASJ, text 9 pages, 5 tables, and 12 figure
A Note on the Paraxial Expansion of Cylindrically Symmetric Magnetic Field
開始ページ、終了ページ: 冊子体のページ付
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