Dominance of High-Spin Two-Particle, One-Hole Transitions in (p, π−) Reactions

Abstract

Measurements of broad-range momentum spectra for (p,^") reactions on a number of target nuclei with 13 ^A ^ 92 have revealed a striking and systematic selectivity for one or a few low-lying discrete states in the residual nuclei. It is proposed that the dominant transitions lead to high-spin, stretched (or nearly stretched) two-particle, one-hole states, as favored by a two-nucleon pion production mechanism.

C12,13(pKorkmaz1, Bland2, Jacobs3 et al. 1987Phys. Rev. Lett.Self Cite23050View full textAdd to dashboardCite

“…In contrast, all (p,n~) transitions are effected by quite restricted TNM paths (pn-+ ppn~ on a target neutron from an orbital specific to the initialand 2p-lh final-state configurations), yielding a relative population of states dominated by momentum-matching considerations. 3 The resulting implication that mirror states populated strongly in both reactions correspond to high-spin 2p-lh transitions facilitates spectroscopic applications (e.g., a 5 ~ assignment to the strong states near E x = 15 MeV in 14 0 and 14 C) to be discussed in a future in-depth report on these data. We concentrate below on results for continuum regions of the l3 C(p,x ± ) spectra, and for the discrete transition to the strong, sharp, previously unknown state at is* =23.2 MeV in 14 C. The 12 C(/?poi,7r + ) data, acquired to complement results for the latter transition, show ( Fig.…”

“…The relative strengths of different states also differ appreciably between the two reactions, but in ways generally consistent with TNM expectations. 3 For example, low-spin states with relatively poor momentum matching are populated more strongly in FIG. 1.…”