122963493
Neutron-Capture Cross Sections of the Stable Lead Isotopes
Neutron-capture yields for several samples of separated lead isotopes were obtained at the Oak Ridge electron linear accelerator, in the neutron energy range above 2.5 keV. These were analyzed for resonance-capture areas and parameters. The data are included in a new evaluation of lead cross-section data.
124123364
Comments on the Doorway State in Pb 206
The neutron capture cross section of $^{206}\mathrm{Pb}(n, \ensuremath{\gamma})$ has been measured with high resolution at the Oak Ridge electron linear accelerator. The capture results show that the reported ${s}_{\frac{1}{2}}$ doorway in $^{206}\mathrm{Pb}$ is not observed in the photon channel.
121426208
Vacuum Energy in Gauged Extended Supergravity
Abstract The one loop vacuum energy in gauged extended supergravity is calculated in anti de Sitter space using zeta function regularisation. It vanishes for N ⩾ 5. The energy zeta function has no poles for N ⩾ 3.
39584401
Cosmic strings confront COBE
We investigate large-angle anisotropies in the cosmic microwave radiation background which are induced by cosmic strings. We numerically evolve a string network from a redshift Z-100 to the present day and we use this data to generate a full-sky temperature map using sophisticated Green's function methods. Based on a limited number of realizations, we have compared the results of our simulations with the observations of the COBS-DMR experiment, demonstrating broad consistency. We have obtained a preliminary normalization for the string mass-per-unit-length μ in the cosmic string scenario.
59928909
Observational Limit on Gravitational Waves from Binary Neutron Stars in the Galaxy
Using optimal matched filtering, we search 25 hours of data from the LIGO 40-m prototype laser interferometric gravitational-wave detector for gravitational-wave chirps emitted by coalescing binary systems within our Galaxy. This is the first test of this filtering technique on real interferometric data. An upper limit on the rate R of neutron star binary inspirals in our Galaxy is obtained: with 90% confidence, R<0.5h-1. Similar experiments with LIGO interferometers will provide constraints on the population of tight binary neutron star systems in the Universe.
121348159
Measurement of the Crab spectrum with Milagro
Through use of new algorithms for estimating γ-ray and cosmic ray primary energies of events in Milagro we determine the energy spectra of gamma rays from the Crab nebula and spectra of Milagro background triggers have been determined in the energy range 1 to 100 TeV. The measured spectra are compared with those measured by ACT techniques and direct measurements of cosmic ray spectra.
123517774
THE GRAVITON PROPAGATOR IN HOMOGENEOUS AND ISOTROPIC SPACETIMES
We find the propagator for gravitons in spacetimes with homogeneous and isotropic flat (k =0) spatial sections. The method also appfies to the k = +1 and k = -1 cases. The vacuum state is assumed to be homogeneous and isotropic in the same way as the spacetime. In the four most interesting physical cases, which are de Sitter space, the radiation and dust dominated models, and flat space, we obtain the graviton propagator in closed form for the adiabatic vacuum state.