A Method for Unambiguous Detection of a Hypothetical Bound Two-Neutron System

An experiment is proposed aiming at the unambiguous detection of mass A = 2 neutral particles via elastic scattering and neutron exchange reactions on protons in a plastic scintillating fibre detector. Di-neutrons would be produced in ordinary π ^? absorption at rest on ³He together with tagging protons. The basic advantages of the proposed process are the strict collinearity and opposite, and constant momenta of hypothetical di-neutrons and recoiling particles in the LAB reference frame. Moreover, the detection cross sections (² n + p → p + ² n; ² n + p → d + n) are calculable with three-nucleon codes based on ¹ a _nn dependent nn interactions.