Ted Barnes

Q anti-Q G Hermaphrodite Mesons in the MIT Bag Model

Abstract We suggest that hybrid (q q g) mesons could exist with rather light masses. The spectrum of the ground state nonets, J PC = (0, 1, 2) −+ ; 1 −− is calculated in the MIT bag model including O(α s ) energy shifts. We discuss hadronic transitions among these states, consider their possible production at LEAR and SPEAR and indicate some interesting decay signatures.

Hyperfine splittings of bag model gluonia

Order α s contributions to the energy shifts in gluonia are studied in the MIT bag model. The naive result that M (0 −+ ) > M (0 ++ ) is preserved for α s ≲ 3, although M (0 −+ ) M (2 ++ ) results for α s ≳ 0.54. The 0 −+ and 2 ++ can thus be identified with ι(1440) and θ (1640) for reasonable values of α s and bag size, in which case the 0 ++ mass is predicted to be ∼ 1.0 GeV.

A light exotic qq̄g hermaphrodite meson

Abstract We suggest that qqg mesons mat exist as low as 1 GeV in mass. The exotic J PC =1 −+ multiplet will have distinctive decay modes and perhaps be relatively stable. The bag model spectrum of the lowest lying qqg multiplet including hyperfine splittings is computed analogously to Jaffes qqqq bag model multiplets. Relevance to light meson phenomenology is discussed.

Where are hermaphrodite baryons

Abstract The ground state spectrum of QQG and QQQG hadrons is studied in the MIT bag model including O( α S ) QCD forces. If there are no O -+ (QQG) states below 1.3 GeV then only P 11 and P 13 Q 3 G states can occur below 2 GeV, I= 3 2 being repelled to high masses, Possibilities of establishing hermaphrodite states are discussed.

Bound state effects in ϒ→ζ(8.3)+γ

Abstract We have calculated the rates for ϒ(1S,2S) → scalar or pseudoscalar +γ, including upsilon wavefunction effects. For a scalar we find that bound state effects reduce B (25)/ B (1S) by 20–30%. For a pseudoscalar these effects enhance B (2S)/ B (1S) by 5%.

The spin-independent quarkonium effective hamiltonian due to a scalar confining potential☆

Abstract The O( ν 2 / c 2 ) quarkonium hyperfine hamiltonian due to scalar confinement has been disputed in the literature, due to ambiguities in the Bethe-Salpeter derivation. In this paper we give a general procedure for directly reducing Feynman diagrams to equivalent potentials; application to scalar exchange gives the scalar contribution to the hyperfine hamiltonian, which we compare with previous results.

Photoproduction of hermaphrodite baryons

Abstract We show that photoexcitation of the lightest hermaphrodite baryons is strongly suppressed from proton targets but allowed from neutrons, a result that is reminiscent of a quark model selection rule due to Moorhouse. This is consistent with suggestions that the P 11 (1710) is the lightest q 3 G baryon and eliminates the possibility that the Roper resonance is dominantly an hermaphrodite state. Magnetic moments do not constrain the possibility of considerable mixing of q 3 G into the nucleon and deltas Fock space wavefunctions.

The MIT bag can accommodate the θ(1640) and (1440) as glueballs

Abstract QCD perturbation effects at O(αs) are studied for gluonia in the MIT bag. If αs > 0.54 then the 2++ is heavier than the O in line with the θ(1640) and (1440) states. The observed splitting and absolute magnitudes are consistent with a bag radius 1 fm. A scalar glueball is predicted at 1 GeV and may mix with S∗ (980).

Numerical solution of field theories using random walks

Abstract We show how random walks in function space can be employed to evaluate field theoretic vacuum expectation values numerically. Specific applications which we study are the two-point function, mass gap, magnetization 〈π〉 and classical solutions. This technique offers the promise of faster calculations using less computer memory than current methods.

A numerical study of the bound state spectrum of : γ(Φ6−Φ4)2: In lattice Hamiltonian field theory

Abstract We confirm the existence of a bound state in the model : γ(Φ 6 −Φ 4 ) 2 + 1 2 m 0 2 Φ 2 2 : of Glimm, Jaffe and Spencer. Our lattice result for the binding energy at small γ / m 2 is in reasonable agreement with the perturbative formula of Dimock and Eckmann. The spectrum at large coupling depends crucially on the choice of normal-ordering mass.