A study of the final states K0n, Λπ0 and K0Δ0 in K−p interactions at 5 and 8 GeV/c☆
Abstract We present results on three reactions involving neutral final states which were studied in a magnet spark chamber system. These results are: (a) differential cross section with high statistics for K − p → K 0 n at 5 GeV /c (24 000 events) and at 8 GeV/ c (11 000 events) for t′ c ) 2 ; (b) differential cross section and polarization for K − p → Λπ 0 (backward peak) at 5 GeV/ c for u ′ c ) 2 ; and (c) differential cross section for K − p → K 0 Δ 0 (1232) at 5 GeV /c for t′ GeV /c) 2 . We compare our results with existing data and draw some phenomenological conclusions.
Carefully converged calculations are performed for the band gap of ZnO within many-body perturbation theory (G^0 W^0 approximation). The results obtained using four different well-established plasmon-pole models are compared with those of explicit calculations without such models (the contour-deformation approach). This comparison shows that, surprisingly, plasmon-pole models depending on the f-sum rule gives less precise results. In particular, it confirms that the band gap of ZnO is underestimated in the G^0 W^0 approach as compared to experiment, contrary to the recent claim of Shih et al.