RESUMO
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+χ provides an exceptionally clean detection signature when combined with a high efficiency neutron detector. Using a high-intensity ^{6}He^{+} beam at Grand Accélérateur National d'Ions Lourds, a search for a coincident neutron signal resulted in an upper limit on a dark decay branching ratio of Br_{χ}≤4.0×10^{-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 O(10^{-5}), improving over global constraints by one to several orders of magnitude depending on m_{χ}.
RESUMO
Healthcare monitoring is a general concern for patients requiring a continuous medical assistance and treatment. In order to increase mobility of such patients, a huge effort is pursued worldwide for the development of wearable monitoring systems able to measure vital physiological parameters such as respiratory movements, cardiac activity, pulse oximetry, temperature of the body [1]. Technical or smart textiles that incorporate different sensors play a growing role in these developments as they are well suited for wearability and can ensure comfort to the user [2, 3]. While most developments up to now have been focused on the use of electrical sensors, the aim of OFSETH [4] is to take advantage of pure optical sensing technologies for extending the capabilities of medical technical textiles for wearable health monitoring. OFSETH expects to achieve a breakthrough in healthcare monitoring applications where standard (non-optical) monitoring techniques show significant limits such as for the monitoring of anesthetized patients under Medical Resonance Imaging (MRI).