2,039 research outputs found
Hybrid meson properties in Lattice QCD and Flux Tube Models
Flux tube model predictions for hybrid meson decays are beginning to be
confronted by Lattice QCD. We compare the two approaches for the -wave decay
of the exotic , and find excellent agreement. Results suggest that in
Strong QCD, \qq~ creation occurs with S=1.Comment: 6 pages, 1 figure, v2: discussion of parameters and lattice
uncertainties adde
Scalar Glueball-qqbar Mixing above 1 GeV and implications for Lattice QCD
Lattice QCD predictions have motivated several recent studies of the mixing
between the predicted JPC = 0++ glueball and a qqbar nonet in the 1.3 to 1.7
GeV region. We show that results from apparently different approaches have some
common features, explain why this is so and abstract general conclusions. We
place particular emphasis on the flavour dependent constraints imposed by
decays of the f0(1370), f0(1500) and f0(1700) to all pairs of pseudoscalar
mesons. From these results we identify a systematic correlation between
glueball mass, mixing, and flavour symmetry breaking and conclude that the
glueball may be rather lighter than some quenched lattice QCD computations have
suggested. We identify experimental tests that can determine the dynamics of a
glueball in this mass region and discuss quantitatively the feasibility of
decoding glueball-qqbar mixing.Comment: 33 pages, Latex, 4 Figure
Symmetry breaking and quark-hadron duality in structure functions
We identify conditions under which a summation over nucleon resonances can
yield, via quark-hadron duality, parton model results for electromagnetic and
neutrino structure functions at large x. While a summation over the lowest even
and odd parity multiplets is sufficient to achieve duality in the symmetric
quark model, a suppression of transitions to specific final states is required
for more realistic cases incorporating SU(6) breaking. We outline several
scenarios consistent with duality, discuss their implications for the high Q^2
behavior of transition form factors, and illustrate how they can expose the
patterns in the flavor-spin dependence of inter-quark forces.Comment: 30 pages, 9 figures, to appear in Phys. Rev.
Hadron Spectroscopy (theory): Diquarks, Tetraquarks, Pentaquarks and no quarks
States beyond those expected in the simple constituent quark model are now
emerging. I focus on the scalar glueball and its mixing with states in the
nonet, and also on correlations in Strong QCD that may form diquarks
and seed states. Some models of the pentaquark candidate
are critically discussed.Comment: Plenary talk at ICHEP0
Hybrid meson production by electromagnetic and weak interactions in a flux-tube simulation of lattice QCD
We calculate rates for hybrid meson production by electromagnetic and weak
interactions in the flux-tube model. Applications include photo and
electroproduction at Jefferson Laboratory and HERA, and the production of light
strange and charmed hybrids in the weak decays of heavy flavours.
Photoproduction of some light hybrids is predicted to be prominent in charge
exchange reactions, and accessible in . Production of light or charmed hybrids in and decays may be
feasible with high statistics. Photoproduction of the axial hybrid meson is
predicted to be large courtesy of exchange, and its strange counterpart
is predicted in with . Production
rates for exotic hybrid candidates are given special
attention. Selection rules that can help to distinguish between hybrid and
conventional states with the same are noted.Comment: uses psfrag; One reference correcte
Electroweak production of hybrid mesons in a Flux-Tube simulation of Lattice QCD
We make the first calculation of the electroweak couplings of hybrid mesons
to conventional mesons appropriate to photoproduction and to the decays of
or mesons. amplitudes are found to be large and may contribute in
charge exchange allowing production of (amongst others)
the charged exotic hybrid off exchange. Axial hybrid meson
photoproduction is predicted to be large courtesy of exchange, and its
strange hybrid counterpart is predicted in with . Higher multipoles, and some implications for hybrid charmonium
are briefly discussed.Comment: 4 page
Central production of mesons: Exotic states versus Pomeron structure
We demonstrate that the azimuthal dependence of central meson production in
hadronic collisions, when suitably binned, provides unambiguous tests of
whether the Pomeron couples like a conserved vector-current to protons. We
discuss the possibility of discriminating between q-qbar and glueball
production in such processes. Our predictions apply also to meson production in
tagged two-photon events at electron--positron colliders and to vector-meson
production in ep collisions at HERA.Comment: 15 pages, latex, no figur
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