G. J. Stephenson

SYSTEMATIC THEORETICAL SEARCH FOR DIBARYONS IN A RELATIVISTIC MODEL

A relativistic quark potential model is used to do a systematic search for quasi-stable dibaryon states in the u, d and s three-flavor world. Flavor symmetry breaking and channel coupling effects are included and an adiabatic method and fractional parentage expansion technique are used in the calculations. The relativistic model predicts dibaryon candidates completely consistent with the nonrelativistic model.

MSW-Like Enhancements Without Matter

We study the effects of a scalar field, coupled only to neutrinos, on oscillations among weak interaction current eigenstates. The effect of a real scalar field appears as effective masses for the neutrino mass eigenstates, the same for as for ν. Under some conditions, this can lead to a vanishing of δ m2, which maximizes mixing independently of the vacuum mixing angles, as in the MSW effect. We discuss some examples and show that it is possible to resolve an apparent discrepancy in spectra required by r-process nucleosynthesis in the mantles of supernovae and by solar neutrino solutions.

The Thomas rotation

We review why the Thomas rotation is a crucial facet of special relativity, that is just as fundamental, and just as “unintuitive” and “paradoxical,” as such traditional effects as length contraction, time dilation, and the ambiguity of simultaneity. We show how this phenomenon can be quite naturally introduced and investigated in the context of a typical introductory course on special relativity, in a way that is appropriate for, and completely accessible to, undergraduate students. We also demonstrate, in a more advanced section aimed at the graduate student studying the Dirac equation and relativistic quantum field theory, that careful consideration of the Thomas rotation will become vital as modern experiments in particle physics continue to move from unpolarized to polarized cross sections.

No Λ oscillations

Abstract We examine a recently published calculation which predicts an oscillatory behaviour for the decay of Λs produced together with a neutral kaon, and proposes a new expression for the wavelength of kaon strangeness oscillations. We modify the calculation by imposing the requirement that the interference of the K L and K S components of the kaon wave function occurs at a specific space-time point. With this requirement, the unusual results predicted vanish, and the conventional results are recovered.We examine a recently published calculation which predicts an oscillatory behaviour for the decay of Lambdas produced together with a neutral kaon, and proposes a new expression for the wavelength of kaon strangeness oscillations. We modify the calculation by imposing the requirement that the interference of the K_L and K_S components of the kaon wave function occurs at a specific space-time point. With this requirement, the unusual results predicted vanish, and the conventional results are recovered.

Oscillations of recoil particles against mixed states

Some consequences of the oscillations of neutral kaons and neutrinos are discussed, in particular, the possibility of oscillations of particles recoiling against kaons or neutrinos from the production process. We show that there are no stationary oscillations of these recoil particles in any order, and that the apparent long-wavelength oscillations, which might appear to result when an earlier treatment of ours was taken to higher order, are spurious. We show that the recoil particles may show a travelling interference pattern. It may be possible to observe this pattern for

Multichannel oscillations and relations between LSND, KARMEN, and MiniBooNE, with and without CP violation

\Lambda

The wavelength of neutrino and neutral kaon oscillations

s produced in a reaction, but there seems to be little hope of observing this for the case of neutrinos from muon decay.

INTERACTIONS OF A NEUTRINO WITH AN EXTREMELY LIGHT SCALAR

We show by examples that multichannel mixing can affect both the parameters extracted from neutrino oscillation experiments, and more general conclusions derived by fitting the experimental data under the assumption that only two channels are involved in the mixing. Implications for MiniBooNE are noted and an example based on maximal CP violation displays profound implications for the two data sets ({nu}{sub {mu}} and {nu}{sub {mu}}) of that experiment.

A possible connection between massive fermions and dark energy

Neutral kaons, and probably also neutrinos, exhibit oscillations between flavor eigenstates, as a result of being produced in a superposition of mass eigenstates. Several recent papers have addressed the question of the energies and momenta of the components of these states, and their effect on the coherence of the states and on the wavelength of the oscillations. We point out that the mass eigenstates need have neither equal momentum nor equal energy, but can nevertheless be coherent, and that a correct treatment of the kinematics recovers the usual result for the wavelength of the flavor oscillations.

IMPLICATIONS OF QUARK–LEPTON SYMMETRY FOR NEUTRINO MASSES AND OSCILLATIONS

Abstract An extremely light scalar weakly interacting with light neutrinos has interesting consequences in stellar evolution, neutrino oscillations and laboratory neutrino mass measurements. In this paper we construct realistic gauge models for such scalar-neutrino interactions.