109 research outputs found
Neutrino Interactions in Octet Baryon Matter
Neutrino processes caused by the neutral current are studied in octet baryon
matter. Previous confusion about the baryonic matrix elements of the neutral
current interaction is excluded, and a correct table for them improved by
consideration of the proton spin problem is presented instead.Comment: 6 page
Quark description of the Nambu-Goldstone bosons in the color-flavor locked phase
We investigate the color-singlet order parameters and the quark description
of the Nambu-Goldstone (NG) bosons in the color-flavor locked (CFL) phase. We
put emphasis on the NG boson (phason) called ``H'' associated with the
symmetry breaking. We qualitatively argue the nature of H as
the second sound in the hydrodynamic regime. We articulate, based on a diquark
picture, how the structural change of the condensates and the associated NG
bosons occurs continuously from hadronic to CFL quark matter if the
quark-hadron continuity is realized. We sharpen the qualitative difference
between the flavor octet pions and the singlet phason. We propose a conjecture
that superfluid H matter undergoes a crossover to a superconductor with
tightly-bound diquarks, and then a crossover to superconducting matter with
diquarks dissociated.Comment: 14 pages, 1 table, 1 figure and confusing statements are correcte
Confronting Neutron Star Cooling Theories with New Observations
With the successful launch of Chandra and XMM/Newton X-ray space missions
combined with the lower-energy band observations, we are in the position where
careful comparison of neutron star cooling theories with observations will make
it possible to distinguish among various competing theories. For instance, the
latest theoretical and observational developments already exclude both nucleon
and kaon direct URCA cooling. In this way we can now have realistic hope for
determining various important properties, such as the composition, degree of
superfluidity, the equation of state and steller radius. These developments
should help us obtain better insight into the properties of dense matter.Comment: 11 pages, 1 figur
Kaonic nuclei studied based on a new framework of Antisymmetric Molecular Dynamics
We have developed a new framework of Antisymmetrized Molecular Dynamics
(AMD), to adequately treat the I=0 \={K}N interaction, which is essential to
study kaonic nuclei. The improved points are 1) pK/n\={K} mixing and 2)
total spin and isospin projections. These improvements enable us to investigate
various kaonic nuclei (ppnK, pppK, pppnK, BeK and
BK) systematically. We have found that they are deeply bound and
extremely dense with a variety of shapes.Comment: 10 pages, 5 figure
Dipole resonances in light neutron-rich nuclei studied with time-dependent calculations of antisymmetrized molecular dynamics
In order to study isovector dipole response of neutron-rich nuclei, we have
applied a time-dependent method of antisymmetrized molecular dynamics. The
dipole resonances in Be, B and C isotopes have been investigated. In Be,
B, C, collective modes of the vibration between a core and
valence neutrons cause soft resonances at the excitation energy MeV
below the giant dipole resonance(GDR). In C, we found that a remarkable
peak at MeV corresponds to coherent motion of four valence neutrons
against a C core, while the GDR arises from the core vibration in the
MeV region. In B and C, the dipole strengths in the low
energy region decline compared with those in B and C. We also
discuss the energy weighted sum rule for the transitions.Comment: 12 figures, submitted to Phys. Rev.
Deformations in N=14 isotones
Systematic analysis of deformations in neutron-rich N=14 isotones was done
based on the method of antisymmetrized molecular dynamics. The property of the
shape coexistence in Si, which is known to have the oblate ground state
and the prolate excited states, was successfully described. The results suggest
that the shape coexistence may occur also in neutron-rich N=14 nuclei as well
as Si. It was found that the oblate neutron shapes are favored because
of the spin-orbit force in most of N=14 isotones. moments and
transition strengths in the neutron-rich nuclei were discussed in relation to
the intrinsic deformations, and a possible difference between the proton and
neutron deformations in Ne was proposed.Comment: 13 pages, 7 figures, sumitted to Phys.Rev.
Nucleon-nucleon interactions via Lattice QCD: Methodology --HAL QCD approach to extract hadronic interactions in lattice QCD--
We review the potential method in lattice QCD, which has recently been
proposed to extract nucleon-nucleon interactions via numerical simulations. We
focus on the methodology of this approach by emphasizing the strategy of the
potential method, the theoretical foundation behind it, and special numerical
techniques. We compare the potential method with the standard finite volume
method in lattice QCD, in order to make pros and cons of the approach clear. We
also present several numerical results for the nucleon-nucleon potentials.Comment: 12 pages, 10 figure
Structure of Excited States of 10Be studied with Antisymmetrized Molecular Dynamics
We study structure of excited states of 10Be with the method of variation
after spin parity projection in the framework of antisymmetrized molecular
dynamics. Present calculations describe many excited states and reproduce the
experimental data of E2 and E1 transitions and the new data of the
transition strength successfully. We make systematic discussions on the
molecule-like structures of light unstable nuclei and the important role of the
valence neutrons based on the results obtained with the framework which is free
from such model assumptions as the existence of inert cores and clusters.Comment: 15 pages, RevTex, seven postscript figures (using epsf.sty
Structure of excited states of Be-11 studied with Antisymmetrized Molecular Dynamics
The structures of the ground and excited states of Be-11 were studied with a
microscopic method of antisymmetrized molecular dynamics. The theoretical
results reproduce the abnormal parity of the ground state and predict various
kinds of excited states. We suggest a new negative-parity band with a
well-developed clustering structure which reaches high-spin states. Focusing on
a clustering structure, we investigated structure of the ground and
excited states. We point out that molecular orbits play important roles for the
intruder ground state and the low-lying states. The features of
the breaking of clusters were also studied with the help of data for
Gamow-Teller transitions.Comment: 24 pages, 7 figures, to be submitted to Phys.Rev.
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