Wn Cottingham

The Static Baryon Baryon Potential in the Skyrme Model

Abstract Methods for deriving a static baryon-baryon (nucleon-nucleon as well as nucleon-delta and transition) potential from the Skyrme model are briefly reported. Some results obtained with these methods are also presented and discussed.

Nuclear binding and the skyrme model

Abstract A serious shortcoming of the Skyrme model is that it appears to predict for the NN interaction no attraction at medium range. We show that the symmetric quartic term, in powers of derivatives of the meson fields, not considered in the original Skyrme model, provides attractive NN forces. We argue that incorporation of vector mesons, especially the ω meson, along with this new quartic term into the Skyrme model can lead to a realistic description of the NN interaction.

A quark-antiquark potential from a superconducting model of confinement

Abstract The Landau-Ginzburg phenomenological theory of superconductivity is used as a model of flux confinement. A monopole pair of sources is included to simulate a quark-antiquark system. The interaction energy is found in the static approximation appropriate for heavy quark systems, and equated with the interquark potential. This potential is compared with other suggested phenomenological potentials and succeeds in reproducing heavy quark spectra.

Soliton stars at finite temperature

Abstract We investigate the properties of soliton stars in the Lee-Wick model when a temperature dependence is introduced into this model. It is found that at some critical temperature Tc ∼ 100−200 MeV, a first order phase transition occurs leading to the formation of soliton stars with some characteristics similar to those considered by Lee and Pang but with much smaller mass and size. When they cool to their cold configuration their mass ∼ 10−6 M⊙.

Single-Δ production contribution to proton-proton inelasticity parameters

Abstract We present here a meson exchange calculation of the nucleon-nucleon peripheral partial wave inelasticity parameters below 1 GeV lab kinetic energy. These theoretical estimates if used as constraints in future NN phase-shift analyses should reduce the ambiguities in the inelastic region.

Can quark models explain electroproduction of the L = 1 supermultiplet?

Abstract A review of the application of quark models to photo- and electroproduction of the [70, 1-] nucleon resonances is presented. Also since there is no dynamically complete theory of the quarks in hadrons, we decompose a wide class of algebra-preserving quark models for electroproduction into three elements: the electromagnetic current, the quark wavefunctions, and the hadronic boost prescription. All quark models have made choices, often implicit, for these three ingredients although they are not independent in a complete theory. In focussing attention on these ingredients, we highlight the wide range of choices which may be made in empirical quark model applications. Several resulting models are examined and compared with both the proton magnetic form factor and the electroproduction data; some of these models compare more favourably with the data than others. In particular we find that popular models using free quark spinors cannot simultaneously fit the photoproduction data and the behaviour of the reduced matrix elements in the electroproduction region. However, with spinors derived from a Dirac equation with a potential all the elements present in the data may be reproduced.

Electroproduction in the quark model

Abstract The resonance excitation amplitudes of the Devenish and Lyth analysis of electroproduction are fitted within the context of the symmetric quark model. The form-factors for the L = 1 and 2 multiplets, both transverse and longitudinal, are obtained.

The fall of the sphaleron

Abstract Baryon number violation in the electroweak standard model proceeds over and around the sphaleron barrier connecting vacua of different Chern-Simons number. The sphaleron is a static, but metastable state which has two basic modes of decay, one producing predominantly leptons and baryons, the other, antileptons and antibaryons. This paper makes a careful examination of this phenomenon.

Tensor meson production in photon-photon collisions

Recent work on the electromagnetic properties of tensor mesons is extended to their production in e+e- collisions via the two-photon process. It is shown how the model proposed can be tested experimentally.

The multichannel Blankenbecler-Sugar equation in low-energy kaon-nucleon scattering

The multichannel Blankenbecler-Sugar (1966) equation is solved for the J=1/2 partial waves in kaon-nucleon scattering. Particular attention is paid to the isospin-zero state so that only the K*N and KN channels are included. Reggeised particle exchanges are used as the driving potentials. The authors examine the possibility of a Z0* resonance and its generalisation in SU(3) symmetry.