Observation of a cusp-like structure in the ${\hat{I}}^{3}p\to K^{+}\hat{I}{\pounds }^0$ cross section at forward angles and low momentum transfer

Abstract

The ${\hat{I}}^{3}p\to K^{+}\hat{I}{\pounds }^0$ differential cross section at extremely forward angles was measured at the BGOOD experiment. A three-quarter drop in strength over a narrow range in energy and a strong dependence on the polar angle of the $K^{+}$ in the centre-of-mass of the reaction is observed at a centre-of-mass energy of 1900\,MeV. Residing close to multiple open and hidden strangeness thresholds, the structure appears consistent with meson-baryon threshold effects which may contribute to the reaction mechanism.

9 pages (including a 2 page appendix of tabulated data), 10 figures