Twenty years of ${\Theta }^{+}$

Abstract

Twenty years ago, in 2003, two experimental groups, LEPS and DIANA, announced the discovery of a light, narrow, exotic baryon with mass within the range of 1540 MeV, which was later dubbed as ${\Theta }^{+}$. In this talk we recall the history of this discovery and its theoretical foundations. We also discuss possible future experiments that could determine the existence of ${\Theta }^{+}$.

Comments: 22 pages, 3 figuras, contribution to Corfu Summer Institute 2023 "School and Workshops on Elementary Particle Physics and Gravity" (CORFU2023)