Effect of nuclear interactions of neutral kaons on CP asymmetry measurements

We examine the effect of the difference in nuclear interactions of ${K}^0$ and $\bar{K}^0$ mesons on the measurement of CP asymmetry for experiments at $e^+e^-$ colliders - charm and $B$-meson factories. We find that this effect on CP asymmetry can be as large as 0.3%, and therefore sufficiently significant in interpreting measurements of CP asymmetry when neutral kaons are present in the final state.Comment: accepted to PR

Hadron widths in mixed-phase matter

We derive classically an expression for a hadron width in a two-phase region of hadron gas and quark-gluon plasma (QGP). The presence of QGP gives hadrons larger widths than they would have in a pure hadron gas. We find that the $\phi$ width observed in a central Au+Au collision at $\sqrt{s}=200$ GeV/nucleon is a few MeV greater than the width in a pure hadron gas. The part of observed hadron widths due to QGP is approximately proportional to $(dN/dy)^{-1/3}$.Comment: 8 pages, latex, no figures, KSUCNR-002-9

Far Ultraviolet Observations of the Dwarf Nova VW Hyi in Quiescence

We present a 904-1183 A spectrum of the dwarf nova VW Hydri taken with the Far Ultraviolet Spectroscopic Explorer during quiescence, eleven days after a normal outburst, when the underlying white dwarf accreter is clearly exposed in the far ultraviolet. However, model fitting show that a uniform temperature white dwarf does not reproduce the overall spectrum, especially at the shortest wavelengths. A better approximation to the spectrum is obtained with a model consisting of a white dwarf and a rapidly rotating ``accretion belt''. The white dwarf component accounts for 83% of the total flux, has a temperature of 23,000K, a v sin i = 400 km/s, and a low carbon abundance. The best-fit accretion belt component accounts for 17% of the total flux, has a temperature of about 48,000-50,000K, and a rotation rate Vrot sin i around 3,000-4,000 km/s. The requirement of two components in the modeling of the spectrum of VW Hyi in quiescence helps to resolve some of the differences in interpretation of ultraviolet spectra of VW Hyi in quiescence. However, the physical existence of a second component (and its exact nature) in VW Hyi itself is still relatively uncertain, given the lack of better models for spectra of the inner disk in a quiescent dwarf nova.Comment: 6 figures, 10 printed page in the journal, to appear in APJ, 1 Sept. 2004 issue, vol. 61

The atmospheric effects of stratospheric aircraft: A current consensus

In the early 1970's, a fleet of supersonic aircraft flying in the lower stratosphere was proposed. A large fleet was never built for economic, political, and environmental reasons. Technological improvements may make it economically feasible to develop supersonic aircraft for current markets. Some key results of earlier scientific programs designed to assess the impact of aircraft emissions on stratospheric ozone are reviewed, and factors that must be considered to assess the environmental impact of aircraft exhaust are discussed. These include the amount of nitrogen oxides injected in the stratosphere, horizontal transport, and stratosphere/troposphere assessment models are presented. Areas in which improvements in scientific understanding and model representation must be made to reduce the uncertainty in model calculations are identified