Resolution of the solar neutrino anomaly

The solar neutrino anomaly, measurements discrepant from predictions of the Standard Solar Model, has existed for over 30 years. Multiple experiments measuring fluxes from several reactions in the hydrogen fusion chain have added to the puzzle. Each of the several elements of the enigma are resolved by recognition of measurements establishing that most of the sun's fusion must occur near the surface rather than the core

Onset of rotational damping in superdeformed nuclei

We discuss damping of the collective rotational motion in A\sim 150 superdeformed nuclei by means of a shell model combining the cranked Nilsson mean-filed and the surface-delta two-body residual force. It is shown that, because of the shell structure associated with the superdeformed mean-field, onset energy of the rotational damping becomes E_x \sim 2-3 MeV above yrast line, which is much higher than in normal deformed nuclei. The mechanism of the shell structure effect is investigated through detailed analysis of level densities in superdeformed nuclei. It is predicted the onset of damping varies in different supedeformed nuclei along with variation in the single-particle structure at the Fermi surface

Comparison of 4d and 3d lattice results for the electroweak phase transition

We compare 4d lattice results for the finite temperature phase transition in the SU(2)+Higgs model with 3d lattice results for the phase transition in the corresponding dimensionally reduced effective theory. While the large errorbars and the lack of a relation of the 4d lattice gauge coupling to continuum physics prevent rigorous conclusions, the results are nevertheless compatible. This provides a direct non-perturbative check of dimensional reduction in the present context

Nucleon spin structure from the instanton vacuum

We discuss the evaluation of the nucleon isoscalar axial coupling, g_A^{(0)}, in the instanton vacuum, using the 1/N_c expansion. This approach allows a fully consistent treatment of the U(1)_A anomaly. We compute the nucleon matrix element of the topological charge density, \langle N | F\widetilde{F} | N \rangle, and show that it reduces to the matrix element of the divergence of the isoscalar axial quark current. Our arguments show that the usual evaluation of g_A^{(0)} in the chiral quark soliton model is consistent with the U(1)_A anomaly in leading order of 1/N_c. Such calculations give g_A^{(0)} = 0.36, which is in agreement with the recent estimate by Ellis and Karliner

The late emission of thermonuclear supernovae

The subject of late-time emission of Type Ia supernovae and its implications for the understanding of the explosions of C+O WDs is reviewed

The stochastic gravity-wave background: sources and detection

A world-wide effort is now underway to build gravitational wave detectors based on highly-sensitive laser interferometers. These include projects in the United States, France and Italy, Germany and Britain, Japan, Austraulia, and other countries. When data from detectors at different sites is properly combined, it will permit highly-sensitive searches for a stochastic background of relic gravitational radiation. These lectures (from the Les Houches School in October 1995) review the current status of this program, and discuss the methods by which data from different detectors can be used to make measurements of, or place limits on, a stochastic background. We discuss the current observational limits on a stochastic background, and the potential sensitivity that will be achieved by optimal use of the detectors currently under construction. We examine in detail several potential sources of a stochastic background of gravitational radiation, arising from processes occuring in the early universe, and demonstrate how the detection of such radiation could provide a glimpse of the very early universe, approximately 10^{-22} seconds after the big bang

Top quark polarization in polarized e+e- annihilation near threshold

Top quark polarization in e^+e^- annihilation into t\bar t is calculated for linearly polarized beams. The Green function formalism is applied to this reaction near threshold. The Lippmann--Schwinger equations for the S-wave and P-wave Green functions are solved numerically for the QCD chromostatic potential given by the two-loop formula for large momentum transfer and Richardson's ansatz for intermediate and small momenta. S-P--wave interference contributes to all components of the top quark polarization vector. Rescattering of the decay products is considered. The mean values \langle n \ell \rangle of the charged lepton four-momentum projections on appropriately chosen directions n in semileptonic top decays are proposed as experimentally observable quantities sensitive to top quark polarization. The results for \langle n \ell \rangle are obtained including S-P--wave interference and rescattering of the decay products. It is demonstrated that for the longitudinally polarized electron beam a highly polarized sample of top quarks can be produced

Renormalization of the topological charge in Yang-Mills theory

The conditions leading to a nontrivial renormalization of the topological charge in four--dimensional Yang--Mills theory are discussed. It is shown that if the topological term is regarded as the limit of a certain nontopological interaction, quantum effects due to the gauge bosons lead to a finite multiplicative renormalization of the theta--parameter while fermions give rise to an additional shift of theta. A truncated form of an exact renormalization group equation is used to study the scale dependence of the theta--parameter. Possible implications for the strong CP--problem of QCD are discussed

Sonoluminescence and the Heimlich effect

The phenomenon of sonoluminescence (SL), originally observed some sixty years ago, has recently become the focus of renewed interest, particularly with the discovery that one can trap a single bubble and induce it to exhibit SL stably over a large number of acoustical cycles. In this work we shall adopt a version of the provocative suggestion put forward by Schwinger: the mechanism responsible for the radiation in SL is a dynamic version of the Casimir effect. It has been known since Casimir's original work in 1948 that the zero-point energy of quantum fields can be modified by the presence of boundaries, and that these modifications generate observable effects. For example, in Casimir's original work, the quantum fluctuations of the electromagnetic field in the presence of a pair of uncharged, parallel, perfectly conducting plates were shown to give rise to an attractive force between the plates

Spectroscopy of Lyman break galaxies in the Hubble deep field

We report on the initial results of a spectroscopic investigation of galaxies in the Hubble Deep Field which exhibit spectral discontinuities between the F450W and F300W passbands, indicative of the presence of the Lyman continuum break in the redshift range 2.4 3 galaxies we have previously identified in other fields, characterized by very compact cores (some with multiple components) with half--light radii of 0.2-0.3 arcseconds, often surrounded by more diffuse and asymmetric ``halos''. A few of the brighter HDF Lyman break galaxies, however, have particularly unusual morphologies