Formation of bound dineutrons in the ${}^{175}Lu (n, {}^2n) {}^{174g}Lu$ nuclear reaction and its cross section

Abstract

The dineutron as a bound chargeless nucleus of two identical nucleons has been attracting attention for many decades. In addition to the study of the formation of a bound dineutron in the outgoing channel of some specific nuclear reactions, cross section estimates have been gaining interest as research target. We used a traditional neutron activation technique to irradiate Lu samples followed by measurements of the induced activity with HPGe spectrometer in order to detect gamma-peaks of the ${}^{175}Lu (n, 2n)^{174g}Lu$ reaction product when this reaction channel is not open for incident neutron energies. Based on two measurements of the instrumental gamma ray spectra of Lu samples we reliably identified the presence of the ${}^{174g}Lu$ isotope in the outgoing channel of the ${}^{175}Lu(n, {}^2n)^{174g}Lu$ nuclear reaction. Also, the cross section for this nuclear reaction was obtained and to be equal $33.5 \pm 5.9$ mb. For the first time, the dineutron as a nuclear reaction product was indirectly detected via statistically significant observation of the induced activity of ${}^{174g}Lu$ with corresponding cross-section estimate.