Convenient location of a near-threshold proton-emitting resonance in $^{11}$B

Abstract

The presence of cluster-like narrow resonances in the vicinity of reaction/decay thresholds is a ubiquitous phenomenon with profound consequences. We argue that the continuum coupling, present in the open quantum system description of the atomic nucleus, can profoundly impact the nature of near-threshold states. In this Letter, we discuss the structure of the recently observed near-threshold resonance in $^{11}$B, whose very existence explains the puzzling beta-delayed proton emission of the neutron-rich $^{11}$Be.