28,040 research outputs found
Hybrid Baryon Signatures
We discuss whether a low-lying hybrid baryon should be defined as a three
quark - gluon bound state or as three quarks moving on an excited adiabatic
potential. We show that the latter definition becomes exact, not only for very
heavy quarks, but also for specific dynamics. We review the literature on the
signatures of hybrid baryons, with specific reference to strong hadronic
decays, electromagnetic couplings, diffractive production and production in psi
decay.Comment: Talk at ``The Physics of Excited Nucleons'' (NSTAR2000), Newport
News, VA, 16-19 Feb. 2000. 8 pages, LaTe
Multi-GeV Gluonic Mesons
Lattice QCD gives reliable predictions for hybrid charmonium and multi-GeV
glueball masses. Proton-antiproton annihilation may offer an excellent
opportunity for the first observation of these states. There are two distinct
possible programs: The search for J^PC-exotic and non-J^PC-exotic states. The
latter program represents substantially higher cross sections and does not
absolutely require partial wave analysis, two very attractive features. The
program can be performed with a varying pbar energy <10 GeV and a fixed target.Comment: Invited talk given at The pbar2000 Workshop, Chicago, IL, August 3-5,
2000. 10 pages, LaTe
Hadron Structure and Modern Spectroscopy
The colour, flavour, spin and J^PC of glueballs and hybrid mesons and baryons
are constructed in an intuitive manner in both the gluon counting and adiabatic
definitions. Glueball decay, production and mixing and hybrid meson decay
selection rules and production are clarified.Comment: Invited Lectures at the Advanced School on Quantum Chromodynamics
2000 (QCD2000), Benasque, Huesca, Spain, 3 - 6 July 2000. 26 pages, LaTeX, 4
(encapsulated) postscript figure
Strong Decays of Hybrid Mesons from the Heavy Quark Expansion of QCD
We calculate the strong decays of hybrid mesons to conventional mesons for
all the lowest lying J^PC hybrids of flavour uu, dd, ss, cc and bb. A decay
operator developed from the heavy quark expansion of quantum chromodynamics is
employed. We show that the selection rule that hybrid mesons do not decay to
identical S-wave mesons, found in other models, is preserved. We predict decays
of charmonium hybrids, discuss decays of J^PC=1^-+ exotic isovector hybrids of
various masses, and interpret the \pi(1800) as a hybrid meson.Comment: 5 pages, LaTeX, 2 eps figures. Contribution to the Seventh
International Conference on Hadron Spectroscopy (HADRON '97), Brookhaven,
August 1997. In collaboration with Eric S. Swanson and Adam P. Szczepania
Hybrid Baryons
We review the status of hybrid baryons. The only known way to study hybrids
rigorously is via excited adiabatic potentials. Hybrids can be modelled by both
the bag and flux-tube models. The low-lying hybrid baryon is N 1/2^+ with a
mass of 1.5-1.8 GeV. Hybrid baryons can be produced in the glue-rich processes
of diffractive gamma N and pi N production, Psi decays and p pbar annihilation.Comment: Invited plenary talk presented at the ``9th International Conference
on the Structure of Baryons'' (BARYONS 2002), 3-8 March, Newport News, VA,
USA. 12 pages, 7 encapsulated postscript figures, LaTe
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