J. T. O’Brien

Low-multipolarity magnetic transitions inSi30,S32, andS34studied by 180° electron scattering

Low-multipolarity magnetic transitions of [sup 30]Si, [sup 32]S, and [sup 34]S were studied by 180[degree] inelastic electron scattering at low momentum transfers ([ital q][similar to]0.3--0.5 fm[sup [minus]1]). These measurements, made in the excitation energy region from 9 to 14 MeV, revealed several previous unreported levels. These are the first low-[ital q] results obtained by electron scattering for [sup 30]Si and [sup 34]S. Multipolarities and transition strengths for all the observed transitions were determined in a model-independent analysis. A large fragmentation of [ital M]1 strength is observed in the 4[ital N]+2 nuclei [sup 30]Si and [sup 34]S, while more strength is concentrated into fewer transitions in the self-conjugate nucleus [sup 32]S. The experimental [ital M]1 strength distributions are compared with configuration-mixing shell-model calculations. The sums of the transition strengths are in good agreement with recent shell-model calculations using an effective [ital M]1 operator.

Absorption in flight of positive pions in carbon

We describe an experiment to measure the absorption in flight of π+ mesons in carbon for pion energies between 80 and 140 MeV. The measurement is important for discriminating between competing theoretical predictions for the energy dependence of the absorption cross section in this region.