1,197 research outputs found
Multiquark Systems in a Constituent Quark Model with Chiral Dynamics
We discuss the stability of multiquark systems within the recent model of
Glozman et al. where the chromomagnetic hyperfine interaction is replaced by
pseudoscalar-meson exchange. We find that such an interaction binds a heavy
tetraquark system ( and by GeV.
This is at variance with results of previous models where is
unstable.Comment: 6 pages, Plain Latex, Contribution to the Workshop''Quark Confinement
and the Hadron Spectrum II'', Como, Italy, June 26--29, 1996, to appear in
the Proceedings, ed. Nora Brambilla, World Scientifi
Heavy-Flavour Pentaquarks in a Chiral Constituent Quark Model
Within the chiral constituent quark model of Glozman and Riska, we discuss
the stability of heavy pentaquarks, i.e. hadrons containing four light quarks
and a heavy antiquark. The spin-dependent part of the Hamiltonian is dominated
by the short-range part of the Goldstone-boson-exchange interaction. We find
that these systems are not bound, having an energy above the lowest
dissociation threshold into a baryon and a meson.Comment: 10 pages + table
On a three-body confinement force in hadron spectroscopy
Recently it has been argued that a three-body colour confinement interaction
can affect the stability condition of a three-quark system and the spectrum of
a tetraquark described by any constituent quark model. Here we discuss the role
of a three-body colour confinement interaction in a simple quark model and
present some of its implications for the spectra of baryons, tetraquarks and
six-quark systems.Comment: 19 pages (RevTeX), addition of new material regarding the NN
interaction, more accurate discussion of the baryonic case, accepted for
publication in Phys. Rev.
Skyrme density functional description of the double magic Ni nucleus
We calculate the single particle spectrum of the double magic nucleus
Ni in a Hartree-Fock approach using the Skyrme density-dependent
effective interaction containing central, spin-orbit and tensor parts. We show
that the tensor part has an important effect on the spin-orbit splitting of the
proton orbit which may explain the survival of magicity so far from the
stability valley. We confirm the inversion of the and levels at
the neutron number 48 in the Ni isotopic chain expected from previous Monte
Carlo shell model calculations and supported by experimental observation.Comment: 14 pages, 5 figures, typos corrected. arXiv admin note: text overlap
with arXiv:nucl-th/070206
New approach to He charge distribution
We present a study of the He charge distribution based on realistic
nucleonic wave functions and incorporation of the nucleon's quark substructure.
The central depression of the proton point density seen in modern four-body
calculations is too small by itself to lead to a correct description of the
charge distribution. We utilize six-quark structures calculated in the
Chromodielectric Model for N-N interactions, and we find a swelling of the
proton charge distribution as the internucleon distance decreases. These charge
distributions are combined with the He wave function using the Independent
Pair Approximation and two-body distributions generated from Green's Function
Monte Carlo calculations. We obtain a reasonably good fit to the experimental
charge distribution without including meson exchange currents.Comment: 9 pages, LaTeX, 4 figures (Figures 1 and 2 doesn't exist as
postscript files : they are only available on request
Using XSLT transformations for CMIS eXtent
Today, the XML language is the standard data exchange format in Internet or Intranet environments and is accepted by the all higher level Frameworks. One frequently use case is when the applications communicate with each other or need to integrate the information from different heterogeneous data sources. When we consider the applications from an enterprise level, the ECM Systems are the frameworks that can meet the business needs of the today modern organizations and that can manage all the unstructured electronic information. CMIS is a XML standard that can assure interoperability between these ECM Systems. Recently, a new extension of this standard was proposed, aiming to bring the native XML databases into the same collaboration scenario. In this paper we will try to enlarge this proposal by adding a custom transformation module that will help the developers to integrate more easily new XML documents as new custom CMIS documents query able from CMIS Interface
MiniBooNE
The physics motivations, design, and status of the Booster Neutrino
Experiment at Fermilab, MiniBooNE, are briefly discussed. Particular emphasis
is given on the ongoing preparatory work that is needed for the MiniBooNE muon
neutrino to electron neutrino oscillation appearance search. This search aims
to confirm or refute in a definitive and independent way the evidence for
neutrino oscillations reported by the LSND experiment.Comment: 3 pages, no figures, to appear in the proceedings of the 9th
International Conference on Astroparticle and Underground Physics (TAUP
2005), Zaragoza, Spain, 10-14 Sep 200
NN interaction in a Goldstone boson exchange model
Adiabatic nucleon-nucleon potentials are calculated in a six-quark
nonrelativistic chiral constituent quark model where the Hamiltonian contains a
linear confinement and a pseudoscalar meson (Goldstone boson) exchange
interaction between quarks. Calculations are performed both in a cluster model
and a molecular orbital basis, through coupled channels. In both cases the
potentials present an important hard core at short distances, explained through
the dominance of the [51]_{FS} configuration, but do not exhibit an attractive
pocket. We add a scalar meson exchange interaction and show how it can account
for some middle-range attraction.Comment: 32 pages with 12 eps figures incorporated, RevTeX. Final version
published in PR
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