2,572 research outputs found
Excitation Spectrum in the Friedberg-Lee Model
The excitation spectrum of the nucleon with the spin 1/2 is examined by using
the Friedberg-Lee model containing the constituent quark and the scalar meson.
An appropriate way of quantization for the non-linear meson field is employed
by taking account of the non-topological soliton existed in the classical
level.
Our model space for the nucleon resonances includes the three-quark plus
one-meson state in addition to the pure three-quark state.
The excitation spectrum in this model space shows that the positive parity
state appears as the first excited state associated with the 0s-excitation of
the scalar meson.
The meson excitation also generates the additional negative parity state
apart from the well-known 0p-excitation of the quark.Comment: 12 pages including 4 figures(eps). Prog. Theor. Phys. in pres
Towards understanding the probability of ground states in even-even many-body systems
For single- shells with and 11/2, we relate the large
probability of ground states to the largest (smallest) coefficients
, where is the particle number, is the seniority, is an
additional quantum number, and is the angular momentum of the state.
Interesting regularities of the probabilities of ground states are
noticed and discussed for 4-particle systems. Several counter examples of the
ground state (0GS) predominance are noticed for the first time.Comment: 5 pages, 1 figure. Phys. Rev. C64, in pres
Exchange Currents for Hypernuclear Magnetic Moments
The meson(K and ) exchange currents for the hypernuclear magnetic
moments are calculated using the effective Lagrangian method. The seagull
diagram, the mesonic diagram and the -excitation diagram are
considered. The -N exchange magnetic moments for the
, and are calculated
employing the harmonic oscillator shell model. It is found that the two-body
correction is about -9% of the single particle value for .
The exchange current, induced only in the -excitation diagram,
is found to give dominant contribution for the isovector magnetic moments of
hypernuclei with A=6.Comment: 11pp, LaTeX, 7 EPS figures, uses epsf.st
Classification of states of single- fermions with -pairing interaction
In this paper we show that a system of three fermions is exactly solvable for
the case of a single- in the presence of an angular momentum- pairing
interaction. On the basis of the solutions for this system, we obtain new sum
rules for six- symbols. It is also found that the "non-integer" eigenvalues
of three fermions with angular momentum around the maximum appear as
"non-integer" eigenvalues of four fermions when is around (or larger than)
and the Hamiltonian contains only an interaction between pairs of
fermions coupled to spin . This pattern is also found in
five and six fermion systems. A boson system with spin exhibits a similar
pattern.Comment: to be published in Physical Review
General pairing interactions and pair truncation approximations for fermions in a single-j shell
We investigate Hamiltonians with attractive interactions between pairs of
fermions coupled to angular momentum J. We show that pairs with spin J are
reasonable building blocks for the low-lying states. For systems with only a J
= Jmax pairing interaction, eigenvalues are found to be approximately integers
for a large array of states, in particular for those with total angular momenta
I le 2j. For I=0 eigenstates of four fermions in a single-j shell we show that
there is only one non-zero eigenvalue. We address these observations using the
nucleon pair approximation of the shell model and relate our results with a
number of currently interesting problems.Comment: a latex text file and 2 figures, to be publishe
One-pion exchange current corrections for nuclear magnetic moments in relativistic mean field theory
The one-pion exchange current corrections to isoscalar and isovector magnetic
moments of double-closed shell nuclei plus and minus one nucleon with
and 41 have been studied in the relativistic mean field (RMF)
theory and compared with previous relativistic and non-relativistic results. It
has been found that the one-pion exchange current gives a negligible
contribution to the isoscalar magnetic moments but a significant correction to
the isovector ones. However, the one-pion exchange current doesn't improve the
description of nuclear isovector magnetic moments for the concerned nuclei.Comment: 9 pages, 1 figure, 3 table
Residual proton-neutron interactions and the scheme
We investigate the correlation between integrated proton-neutron interactions
obtained by using the up-to-date experimental data of binding energies and the
, the product of valence proton number and valence neutron
number with respect to the nearest doubly closed nucleus. We make corrections
on a previously suggested formula for the integrated proton-neutron
interaction. Our results demonstrate a nice, nearly linear, correlation between
the integrated p-n interaction and , which provides us
with a firm foundation of the applicability of the scheme
to nuclei far from the stability line.Comment: four pages, three figures, Physical Review C, in pres
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