3,050 research outputs found
The unitary-model-operator approach to nuclear many-body problems
Microscopic nuclear structure calculations have been performed within the
framework of the unitary-model-operator approach. Ground-state and
single-particle energies are calculated for nuclei around ^{14}C, ^{16}O and
^{40}Ca with modern nucleon-nucleon interactions.Comment: 6 pages, 4 figures, Talk presented at the International Symposium on
Correlation Dynamics in Nuclei (CDN05), Jan. 1 - Feb. 4, 2005, Tokyo, Japa
The unitary-model-operator approach to nuclear many-body problems
Microscopic nuclear structure calculations have been performed within the
framework of the unitary-model-operator approach. Ground-state and
single-particle energies are calculated for nuclei around ^{14}C, ^{16}O and
^{40}Ca with modern nucleon-nucleon interactions.Comment: 6 pages, 4 figures, Talk presented at the International Symposium on
Correlation Dynamics in Nuclei (CDN05), Jan. 1 - Feb. 4, 2005, Tokyo, Japa
The unitary-model-operator approach to nuclear many-body problems
Microscopic nuclear structure calculations have been performed within the
framework of the unitary-model-operator approach. Ground-state and
single-particle energies are calculated for nuclei around ^{14}C, ^{16}O and
^{40}Ca with modern nucleon-nucleon interactions.Comment: 6 pages, 4 figures, Talk presented at the International Symposium on
Correlation Dynamics in Nuclei (CDN05), Jan. 1 - Feb. 4, 2005, Tokyo, Japa
Rational Terms in Theories with Matter
We study rational remainders associated with gluon amplitudes in gauge
theories coupled to matter in arbitrary representations. We find that these
terms depend on only a small number of invariants of the matter-representation
called indices. In particular, rational remainders can depend on the second and
fourth order indices only. Using this, we find an infinite class of
non-supersymmetric theories in which rational remainders vanish for gluon
amplitudes. This class includes all the "next-to-simplest" quantum field
theories of arXiv:0910.0930. This provides new examples of amplitudes in which
rational remainders vanish even though naive power counting would suggest their
presence.Comment: 10+4 pages. (v2) typos corrected, references adde
Quasi-classical Lie algebras and their contractions
After classifying indecomposable quasi-classical Lie algebras in low
dimension, and showing the existence of non-reductive stable quasi-classical
Lie algebras, we focus on the problem of obtaining sufficient conditions for a
quasi-classical Lie algebras to be the contraction of another quasi-classical
algebra. It is illustrated how this allows to recover the Yang-Mills equations
of a contraction by a limiting process, and how the contractions of an algebra
may generate a parameterized families of Lagrangians for pairwise
non-isomorphic Lie algebras.Comment: 17 pages, 2 Table
Hermitian versus holomorphic complex and quaternionic generalized supersymmetries of the M-theory. A classification
Relying upon the division-algebra classification of Clifford algebras and
spinors, a classification of generalized supersymmetries (or, with a slight
abuse of language,"generalized supertranslations") is provided. In each given
space-time the maximal, saturated, generalized supersymmetry, compatible with
the division-algebra constraint that can be consistently imposed on spinors and
on superalgebra generators, is furnished. Constraining the superalgebra
generators in both the complex and the quaternionic cases gives rise to the two
classes of constrained hermitian and holomorphic generalized supersymmetries.
In the complex case these two classes of generalized supersymmetries can be
regarded as complementary. The quaternionic holomorphic supersymmetry only
exists in certain space-time dimensions and can admit at most a single bosonic
scalar central charge.
The results here presented pave the way for a better understanding of the
various algebra-type of structures which can be introduced in different
space-time signatures and in association with different division algebras, as
well as their mutual relations. In a previous work, e.g., the introduction of a
complex holomorphic generalized supersymmetry was shown to be necessary in
order to perform the analytic continuation of the standard -theory to the
11-dimensional Euclidean space. As an application of the present results, it is
shown that the above algebra also admits a 12-dimensional, Euclidean,
-algebra presentation.Comment: 25 pages, LaTe
Quadratic momentum dependence in the nucleon-nucleon interaction
We investigate different choices for the quadratic momentum dependence
required in nucleon-nucleon potentials to fit phase shifts in high
partial-waves. In the Argonne v18 potential L**2 and (L.S)**2 operators are
used to represent this dependence. The v18 potential is simple to use in
many-body calculations since it has no quadratic momentum-dependent terms in
S-waves. However, p**2 rather than L**2 dependence occurs naturally in
meson-exchange models of nuclear forces. We construct an alternate version of
the Argonne potential, designated Argonne v18pq, in which the L**2 and (L.S)**2
operators are replaced by p**2 and Qij operators, respectively. The quadratic
momentum-dependent terms are smaller in the v18pq than in the v18 interaction.
Results for the ground state binding energies of 3H, 3He, and 4He, obtained
with the variational Monte Carlo method, are presented for both the models with
and without three-nucleon interactions. We find that the nuclear wave functions
obtained with the v18pq are slightly larger than those with v18 at
interparticle distances < 1 fm. The two models provide essentially the same
binding in the light nuclei, although the v18pq gains less attraction when a
fixed three-nucleon potential is added.Comment: v.2 important corrections in tables and minor revisions in text;
reference for web-posted subroutine adde
Glueball enhancements in p(gamma,VV)p through vector meson dominance
Double vector meson photoproduction, p(gamma, G -> VV)p, mediated by a scalar
glueball G is investigated. Using vector meson dominance (VMD) and
Regge/pomeron phenomenology, a measureable glueball enhancement is predicted in
the invariant VV = rho rho and omega omega mass spectra. The scalar glueball is
assumed to be the lightest physical state on the daughter pomeron trajectory
governing diffractive vector meson photoproduction. In addition to cross
sections, calculations for hadronic and electromagnetic glueball decays, G -> V
V' (V,V'= rho, omega, phi, gamma), and gamma_v V -> G transition form factors
are presented based upon flavor universality, VMD and phenomenological
couplings from phi photoproduction analyses. The predicted glueball decay
widths are similar to an independent theoretical study. A novel signature for
glueball detection is also discussed
Chiral Lagrangian Parameters for Scalar and Pseudoscalar Mesons
The results of a high-statistics study of scalar and pseudoscalar meson
propagators in quenched lattice QCD are presented. For two values of lattice
spacing, ( fm) and 5.9 ( fm), we
probe the light quark mass region using clover improved Wilson fermions with
the MQA pole-shifting ansatz to treat the exceptional configuration problem.
The quenched chiral loop parameters and are determined
from a study of the pseudoscalar hairpin correlator. From a global fit to the
meson correlators, estimates are obtained for the relevant chiral Lagrangian
parameters, including the Leutwyler parameters and . Using the
parameters obtained from the singlet and nonsinglet pseudoscalar correlators,
the quenched chiral loop effect in the nonsinglet scalar meson correlator is
studied. By removing this QCL effect from the lattice correlator, we obtain the
mass and decay constant of the ground state scalar, isovector meson .Comment: 36 pages, 12 figures, LaTe
Algebraic and geometric aspects of generalized quantum dynamics
\noindent We briefly discuss some algebraic and geometric aspects of the
generalized Poisson bracket and non--commutative phase space for generalized
quantum dynamics, which are analogous to properties of the classical Poisson
bracket and ordinary symplectic structure.Comment: 10pages,revtex, IASSNSHEP-93/5
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