Philip R. Page

RELATIVISTIC SYMMETRY SUPPRESSES QUARK SPIN-ORBIT SPLITTING

Experimental data indicate small spin-orbit splittings in hadrons. For heavy-light mesons we identify a relativistic symmetry that suppresses these splittings. We suggest an experimental test in electron-positron annihilation. Furthermore, we argue that the dynamics necessary for this symmetry are possible in QCD.

Gluonic charmonium resonances at BaBar and BELLE

Abstract We confront predictions for hybrid charmonium and other gluonic excitations in the charm region with recently observed structures in the mass range above 3 GeV. The Y ( 4260 ) , if resonant, is found to agree with expectations for hybrid charmonium. The possibility that other gluonic excitations may be influencing the data in this region is discussed.

The D∗0D̄0 threshold resonance

Tests are discussed to distinguish c cbar, hybrid charmonium and molecular interpretations of the narrow Belle resonance at 3872 MeV.

Interpretation of the Θ+ as an isotensor pentaquark with weakly decaying partners

The {Theta}{sup +}(1540), recently observed at LEPS, DIANA and CLAS, is hypothesized to be an isotensor resonance. This implies the existence of a multiplet where the {Theta}{sup ++}, {Theta}{sup +} and {Theta}{sup 0} have isospin-violating strong decays, and the {Theta}{sup +++} and {Theta}{sup -} have weak decays and so are long-lived. Production mechanisms for these states are discussed. The J{sup P} assignment of the {Theta} is most likely 1/2{sup -} or 3/2{sup -} or 5/2{sup -}.

Strong Decays of Strange Quarkonia

In this paper we evaluate strong decay amplitudes and partial widths of strange mesons (strangeonia and kaonia) in the 3P0 decay model. We give numerical results for all energetically allowed open-flavor two-body decay modes of all nsbar and ssbar strange mesons in the 1S, 2S, 3S, 1P, 2P, 1D and 1F multiplets, comprising strong decays of a total of 43 resonances into 525 two-body modes, with 891 numerically evaluated amplitudes. This set of resonances includes all strange qqbar states with allowed strong decays expected in the quark model up to ca. 2.2 GeV. We use standard nonrelativistic quark model SHO wavefunctions to evaluate these amplitudes, and quote numerical results for all amplitudes present in each decay mode. We also discuss the status of the associated experimental candidates, and note which states and decay modes would be especially interesting for future experimental study at hadronic, e+e- and photoproduction facilities. These results should also be useful in distinguishing conventional quark model mesons from exotica such as glueballs and hybrids through their strong decays.

Hybrid meson decay phenomenology

The phenomenology of a newly formulated model of hybrid meson decay is developed. The decay mechanism is based on the heavy quark expansion of QCD and the strong coupling flux tube picture of nonperturbative glue. A comprehensive list of partial decay widths of a wide variety of light, s{bar s}, c{bar c}, and b{bar b} hybrid mesons is presented. Results which appear approximately universal are highlighted along with those which distinguish different hybrid decay models. Finally, we examine several interesting hybrid candidates in detail. {copyright} {ital 1999} {ital The American Physical Society}

Hybrid and conventional baryons in the flux-tube model

Conventional and hybrid light quark baryons are constructed in the non-relativistic flux-tube model of Isgur and Paton, which is motivated by lattice QCD. The motion of the flux tube with the three quark positions fixed, except for center of mass corrections, is discussed. It is shown that the problem can be reduced to the independent motion of the junction and the strings connecting the junction to the quarks. The important role played by quark-exchange symmetry in constraining the flavor structure of (hybrid) baryons is emphasized. The flavor, quark spin S, total spin J, and parity P of the seven low-lying hybrid baryons are found to be N2(1/2)+, N2(3/2)+, Delta4(1/2)+, Delta4(3/2)+, and Delta4(5/2)+, where the notation is flavor[2S+1](J)P, and the N2(1/2)+ and N2(3/2)+ states are doublets. The motion of the three quarks in an adiabatic potential derived from the flux-tube dynamics is considered. A mass of 1870 +/- 100 MeV for the lightest nucleon hybrids is found by employing a variational method.

Do ψ(4040), ψ(4160) signal hybrid charmonium?

Abstract We suggest that ψ(4040) and ψ(4160) are strong mixtures of ground state hybrid charmonium at ∼ 4.1 GeV and the ψ(3S) of conventional charmonium. The Γe+e−, masses and total widths of the ψ(4040) and ψ(4160) are in accord with this hypothesis. Their hadronic decays are predicted to be dominated by the ψ(3S) component and hence are correlated. In particular we find a spin counting relation Γ(4160 → D s D s ∗ ) ∼ 4Γ(4040 → D s D s ) due to their common ψ(3S) component. For D and D ∗ production, using ψ(4040) branching ratios as input, we predict that the decay pattern of the ψ(4160) will be very different from that of the ψ(4040). These predictions may be tested in historical data from SPEAR, BES or at future Tau-Charm Factories.

The D*0 D0bar threshold resonance

Tests are discussed to distinguish c cbar, hybrid charmonium and molecular interpretations of the narrow Belle resonance at 3872 MeV.

Constructing hybrid baryons with flux tubes

Hybrid baryon states are described in quark potential models as having explicit excitation of the gluon degrees of freedom. Such states are described in a model motivated by the strong coupling limit of Hamiltonian lattice gauge theory, where three flux tubes meeting at a junction play the role of the glue. The adiabatic approximation for the quark motion is used, and the flux tubes and junction are modeled by beads which are attracted to each other and the quarks by a linear potential, and vibrate in various string modes. Quantum numbers and estimates of the energies of the lightest hybrid baryons are provided. (c) 1999 The American Physical Society.