Parity violation in 2s–1d nuclei using the (p, α) reaction

In order to extend our knowledge of the weak spreading width to the nuclear mass 30 region, parity-violation measurements have begun at the Triangle Universities Nuclear Laboratory using the 31P(p,α0)28Si reaction. Longitudinally polarized protons are scattered from 31P nuclei at several MeV, and a large solid angle silicon-strip detector detects the alpha particles at backward angles. By rapidly reversing the spin direction of the protons, we measure the helicity dependence of the alpha yield. A discussion of the working system and preliminary results are given.