Abstract Not Available.

Varied techniques have been employed for the production of nuclei in excited states. The techniques that are suitable vary with the nucleus to be studied and the nature of the particles which are emitted. Ordinarily, the desired excitation can be produced by bombarding the nucleus with light weight nuclear particles. If the incident particle is charged then it is necessary to have a more energetic particle than if the incident particle was uncharged, since it must penetrate the repulsive effects of the Coulomb field of the target nucleus. This effect can be eliminated by using neutrons to excite the nuclei, but if charged particles are used for the nuclear excitation then it is necessary to have some device to accelerate them to high kinetic energies. In the region of light weight target nuclei, a number of accelerators will suffice. The Van de Graaff and the Cockroft-Walton electrostatic accelerators have been satisfactorily used, whereas for heavier target nuclei various types of cyclotrons and linear accelerators have proved useful. In the past few years the development of Van de Graaff accelerators capable of achieving higher energies has led to the experimentation on medium Z nuclei. The Rice Institute 5.5 Mev Van de Graaff generator is suitable for such work and has been used in the experiments to be discussed here to study the excited states in some of the isotopes of iron, nickel, manganese, and copper.

The general theory for beta decay is developed in section 2 using a consistent normalization and phase convention for the lepton wave functions; these phases are not consistent in the literature. The resulting general expression is specialized in section 3 to the case of beta polarization; that is, the nucleus is assumed randomly oriented before and after the transition, and no information is available on the direction of motion of the neutrino. In section 4, the functions needed to calculate the polarization are expanded in powers of the nuclear radius, without using the low-Z approximation. Formulas for these combinations of the electron wave functions are given (for the spectrum) more generally than they have previously appeared; those needed for the polarization have not been given accurately before. In terms of these combinations, expressions for the spectrum and polarization terms of the transition probability are presented, through second forbidden transitions. Somewhat simplified expressions, but retaining more accuracy than the usual low-Z formulas, are also given for the allowed and first forbidden transitions. The results of a numerical evaluation of the spectrum and polarization are compared in section 5 with the low-Z approximate values. These approximate values for the polarization are found to be extremely good, even when the results for the spectrum differ by a factor of two! The expression for the polarization is a ratio of similar terms, and the higher coulomb corrections cancel nearly completely. The effect of the coulomb field on the forbiddenness expansion is considered in section 6, and the application of polarization measurements to tests of time reversal is discussed.

Abstract Not Available.

No description available.

After a brief introduction describing some of the physics and mechanics of scintillation detection, results of the development for the Central Trigger Barrel (CTB) for STAR and the Start Counter for CLAS are discussed. For the CTB development, 1 cm x 20 cm x 100 cm scintillators were studied with light guides of various geometries and materials attached to one end in order to optimize the uniformity and overall gain. The best results were obtained using a 61$\sp\circ$ OP-1 light guide attached to a BC 408 scintillator. An alternate approach using a wavelength shifter produces much lower pulse heights than the other method. The CEBAF scintillators are intended to enclose the target area in order to identify the beam bucket for a particular event with timing resolution of 350 ps or less. Single paddle and coupled-paddle approaches are discussed. The coupled-paddle approach meets the design goals.

We construct a quark-soliton model of the nucleon which interpolates between the MIT bag model of arbitrarily confined relativistic quarks and the Skyrme model in which the nucleon is a topological knot in the pion field. Confinement is achieved using the color dielectric model. The field equations are solved numerically for the so called hedgehog state for which the field equations reduce to radial ones. Nucleon observables are calculated by projecting the quark-soliton hedgehog ground state onto spin-isospin eigenstates, which are taken to be variationally best nucleon and nucleon isobar states.

The Exit Charge Detector (ECD) is used to determine the impact parameter of relativistic gold-gold interactions in BNL-AGS Experiment 896 by measuring the total charge of projectile-like particles in each collision. Results are presented from simulations which optimized the ECD's dimensions. The ECD was then constructed, and the hardware and the construction techniques used are described. Analyses of data from the operation of the ECD in heavy-ion collisions are discussed. These analyses indicated a significant amount of correlated noise in the experiment. A method to correct for this noise offline is discussed. Also, significant probabilities for the interaction of the beam with materials other than the target are investigated. Finally, plans to improve the detector for the coming Spring 1998 $\rm\sp{197}Au$ run are discussed.

The quark wave-functions of the lower-lying excited-state hyperons Λ(1405), Λ(1385), and Λ(1520) are not well understood. For example, the Λ(1405) may not be a regular three-quark state but K¯N molecule. Several competing models have been proposed, but none have been convincingly eliminated. Measuring radiative decays provides a means of discriminating between the models. The radiative branching ratios are predicted to be small (∼1%), but the radiative widths vary by factors of 2--10 from model to model. The existing experimental data is sparse and inconsistent; moreover, the radiative decay of the Sigma(1385) has never been observed before (except for one event). These lower-lying excited-state hyperons were produced in a tagged photon-beam experiment in the CLAS detector at TJNAF in the reaction gammap → K+Y* for photon energies from threshold to 2.4 GeV. The radiative branching ratio for the Sigma0(1385) relative to the Sigma0(1385) → Sigmapi0 channel was measured to be 0.021 +/- 0.008+0.004-0.007 corresponding to a partial width of 640 +/- 270+130-220 keV.

No description available.