3,203 research outputs found
Required precision of mass and half-life measurements for r-process nuclei planned at future RI-beam facilities
In order to understand the r-process nucleosynthesis, we suggest precision
required for mass and beta-decay half-life measurements planned at future
RI-beam facilities. To satisfy a simple requirement that we put on nuclear
model predictions, it is concluded that the detectors for the mass measurements
must have a precision of 1sigma ~< 250 keV, and that the detectors for the
half-life measurements demand a precision of 1sigma ~< 0.15 ms. Both the above
precisions are required at the neutron richness of A/Z = 3.0 at the N=82 shell
closure and A/Z = 2.9 at the N=50 shell closure. For the doubly magic nuclide
78Ni, a precision of 1sigma ~< 300 keV and 1sigma ~< 5 ms are required,
respectively, for mass and half-life measurements. This analysis aims to
provide a first rough guide for ongoing detector developments.Comment: 8 pages, 2 figures. in Proceedings of Int. conf. The Future
Astronuclear Physics, From microscopic puzzles to macroscopic nightmares,
Eds. H.M.J. Boffin et al., EAS Publication Series, EDP Sciences, in press
(2004
Strangeness Enhancement in p+p, p+Pb and Pb+Pb Collisions at LHC Energies
We investigate whether the quark gluon plasma (QGP) is created in small
colliding systems from analyses of various hadron yields and their ratios in
proton-proton (p+p), proton-lead (p+Pb) and lead-lead (Pb+Pb) collisions at LHC
energies. Recently, the ALICE Collaboration reports enhancement of yield ratio
of multi-strange hadrons to charged pions as a function of multiplicity at
mid-rapidity. Motivated by these results, we develop the dynamical core-corona
initialization framework and find that our results describe tendencies of the
ALICE data especially for multi-strange hadrons. These results indicate that
the QGP is partly formed in high multiplicity events in small colliding
systems.Comment: 4 pages, 5 figures; contribution to the proceedings of the 8th
International Conference on Quarks and Nuclear Physics (QNP2018), Tsukuba,
November 13-17, 201
Intrinsic electric field effects on few-particle interactions in coupled GaN quantum dots
We study the multi-exciton optical spectrum of vertically coupled GaN/AlN
quantum dots with a realistic three-dimensional direct-diagonalization approach
for the description of few-particle Coulomb-correlated states. We present a
detailed analysis of the fundamental properties of few-particle/exciton
interactions peculiar of nitride materials. The giant intrinsic electric fields
and the high electron/hole effective masses give rise to different effects
compared to GaAs-based quantum dots: intrinsic exciton-exciton coupling,
non-molecular character of coupled dot exciton wavefunction, strong dependence
of the oscillator strength on the dot height, large ground state energy shift
for dots separated by different barriers. Some of these effects make GaN/AlN
quantum dots interesting candidates in quantum information processing.Comment: 23 pages, 8 figures, 1 tabl
Kaehler Manifolds of Quasi-Constant Holomorphic Sectional Curvatures
The Kaehler manifolds of quasi-constant holomorphic sectional curvatures are
introduced as Kaehler manifolds with complex distribution of codimension two,
whose holomorphic sectional curvature only depends on the corresponding point
and the geometric angle, associated with the section. A curvature identity
characterizing such manifolds is found. The biconformal group of
transformations whose elements transform Kaehler metrics into Kaehler ones is
introduced and biconformal tensor invariants are obtained. This makes it
possible to classify the manifolds under consideration locally. The class of
locally biconformal flat Kaehler metrics is shown to be exactly the class of
Kaehler metrics whose potential function is only a function of the distance
from the origin in complex Euclidean space. Finally we show that any rotational
even dimensional hypersurface carries locally a natural Kaehler structure,
which is of quasi-constant holomorphic sectional curvatures.Comment: 36 page
SUGGESTION TO ROWERS OBTAINED BY INVERSE DYNAMICS AND FUZZY MODELING
The aims of this study were to clarify the relationships between rowerâs partial motions and the rowing performance, i.e. boat speed and efficiency, and to suggest the rower which part of the body he/she should concentrate on. Inverse dynamics found time-series patterns of joint torque power. The power patterns were parameterized to six parameters, amounts and timings of three partial motions, i.e. leg extension, trunk swing and arm pull, during the driving phase of rowing stroke. These parameters are easy for a rower to sense and control one by one. Fuzzy modeling identified the relationship between the parameters and the performance. The obtained linguistic fuzzy rules gave effective suggestion to each rower
Modern and geohistorical tsunamiites
17th International Sedimentological Congress [ISC 2006 FUKUOKA, JAPAN] 25-27 August, 2006FE-A8: Modern and geohistorical tsunamiites in central Japan Field Excursion Guideboo
The origin of short-lived radionuclides and the astrophysical environment of solar system formation
Based on early solar system abundances of short-lived radionuclides (SRs),
such as Al (T Myr) and Fe (T Myr),
it is often asserted that the Sun was born in a large stellar cluster, where a
massive star contaminated the protoplanetary disk with freshly
nucleosynthesized isotopes from its supernova (SN) explosion. To account for
the inferred initial solar system abundances of short-lived radionuclides, this
supernova had to be close ( 0.3 pc) to the young ( 1 Myr)
protoplanetary disk.
Here we show that massive star evolution timescales are too long, compared to
typical timescales of star formation in embedded clusters, for them to explode
as supernovae within the lifetimes of nearby disks. This is especially true in
an Orion Nebular Cluster (ONC)-type of setting, where the most massive star
will explode as a supernova 5 Myr after the onset of star formation,
when nearby disks will have already suffered substantial photoevaporation
and/or formed large planetesimals.
We quantify the probability for {\it any} protoplanetary disk to receive SRs
from a nearby supernova at the level observed in the early solar system. Key
constraints on our estimate are: (1) SRs have to be injected into a newly
formed ( 1 Myr) disk, (2) the disk has to survive UV
photoevaporation, and (3) the protoplanetary disk must be situated in an
enrichment zone permitting SR injection at the solar system level without disk
disruption. The probability of protoplanetary disk contamination by a supernova
ejecta is, in the most favorable case, 3 10
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