학술논문
Search for a neutron dark decay in $^6$He
Document Type
Working Paper
Author
Joubioux, M. Le; Savajols, H.; Mittig, W.; Fléchard, X.; Hayen, L.; Penionzhkevich, Yu. E.; Ackermann, D.; Borcea, C.; Caceres, L.; Delahaye, P.; Didierjean, F.; Franchoo, S.; Grillet, A.; Jacquot, B.; Lebois, M.; Ledoux, X.; Lecesne, N.; Liénard, E.; Lukyanov, S.; Naviliat-Cuncic, O.; Piot, J.; Singh, A.; Smirnov, V.; Stodel, C.; Testov, D.; Thomas, J. C.; Verney, D.
Source
Subject
Language
Abstract
Neutron dark decays have been suggested as a solution to the discrepancy between bottle and beam experiments, providing a dark matter candidate that can be searched for in halo nuclei. The free neutron in the final state following the decay of $^6$He into $^4$He $+$ $n$ + $\chi$ provides an exceptionally clean detection signature when combined with a high efficiency neutron detector. Using a high-intensity $^6$He$^+$ beam at GANIL, a search for a coincident neutron signal resulted in an upper limit on a dark decay branching ratio of Br$_\chi \leq 4.0\times10^{-10}$ (95\% C.L.). Using the dark neutron decay model proposed originally by Fornal and Grinstein, we translate this into an upper bound on a dark neutron branching ratio of $\mathcal{O}(10^{-5})$, improving over global constraints by one to several orders of magnitude depending on $m_\chi$.