M.R. Braunstein

Evidence for Δ− components in nuclei

Abstract Ratios of double-differential cross sections for incident 500-MeV pions are presented for ( π + , π + p) and ( π + , π − p) reactions on 12,13 C, 90 Zr, and 208 Pb. A comparison with intra-nuclear cascade-model calculations suggest that the outgoing pion spectra show a feature consistent with quasi-free scattering from the Δ − component of the nuclear ground state wave function.

A CCD Image Archive Of Comet C/1995 O1 (Hale-Bopp): Dust Expansion Velocities

An optical archive of comet Hale-Bopp was obtained over 28 nights from June 1996 to May 1997 covering a range of heliocentric distances of r = 4.12 − 0.91. The CCD images were obtained with the 0.8-m University of Washington Manastash Ridge Observatory and the 0.25-m Pennsylvania State University at Eriemobile observatory. The reduced images clearly document the evolution of features of the coma, which were dominated by radial jetsfrom r = 4.1 − 2.3 AU, curved fan-shaped jets from r = 1.2 − 1.0 AU, and arcs or shells for 0.9 < r < 1.0 AU. We present the images and derive an average dust expansion velocity of Vdust = 0.67 ± 0.07 km s−1 from measurements of the arc features. The images in thearchive will be made available to other researchers for further study.

Quasifree pion single charge exchange at 500 MeV

Abstract Pion single charge exchange at 500 MeV has been used to observe inclusive quasifree scattering on carbon and zirconium. Fitted differential cross sections for carbon agree with a Pauli-blocked Fermi-gas model, but shifts of the QF peak positions relative to free scattering show a softening effect.