MURMUR: a new low-noise experiment for the search of neutron-hidden neutron transitions in the context of braneworld scenarios

Coraline Stasser, Guy Terwagne, Jacob Lamblin, Olivier Méplan, Guillaume Pignol, Bernard Coupé, Silva Kalcheva, Steven Van Dyck, Michaël Sarrazin

Research outputpeer-review


{MURMUR is a new passing-through-walls neutron experiment installed near the BR2 nuclear reactor at the Belgian Nuclear Research Center (SCK⋅CEN, Mol, Belgium) and designed to search neutron interbrane transitions in the context of braneworld scenarios. In such scenarios, our visible Universe could be a 3-brane embedded in a multidimensional space-time, called the bulk, which could contain some other invisible adjacent 3-branes. Theoretical works have shown that the existence of hidden braneworlds can be experimentally tested thanks to neutron exchanges between braneworlds. A neutron n in our visible brane can be converted into a hidden neutron n′ -- propagating in a hidden braneworld -- when scattered by a nucleus with a cross section σ(n→n′)∼σE(n→n)×p, where σE is the usual elastic cross-section and p the neutron swapping probability. Hidden neutrons could thus be generated in the moderator of the BR2 nuclear reactor where a high neutron flux undergoes many elastic scatterings. This hidden neutron flux could be free to travel out of the biological shielding of the reactor up to a matrix made of lead, acting as an antenna, which makes possible to regenerate hidden neutrons into visible ones thanks to reverse swapping. These regenerated neutrons can be detected thanks to a neutron detector placed inside the lead block. The MURMUR experimental setup is described, as well as the included upgrades compared to the first experiment of this kind carried out at the ILL (Grenoble, France) in 2015. The first results of MURMUR are introduced and discussed, and some upcoming improvements of the experimental setup are introduced.
Original languageEnglish
Title of host publication40th International Conference on High Energy physics
Subtitle of host publicationParallel: Operation, Performance and Upgrade of Present Detectors
PublisherSissa Medialab
Number of pages6
StatePublished - 15 Apr 2021
Event2020 - ICHEP - 40th International Conference on High Energy physics - Online
Duration: 28 Jul 20206 Aug 2020


Conference2020 - ICHEP - 40th International Conference on High Energy physics

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