Speaker
Description
The BeEST experiment searches for physics beyond the standard model (BSM) in the neutrino sector by measuring the recoiling daughter from the electron capture (EC) decay of 7Be. The 7Be is embedded in superconducting tunnel junction (STJ) sensors such that the low-energy (eV-scale) decay products are detected with sub-eV energy resolution. Modelling of low-energy backgrounds in the SiO2/Si substrate as well as phonon-mediated quasiparticle interactions in the STJs themselves is crucial to understanding potential physics beyond the Standard Model (BSM). In order to model these effects using the G4CMP toolkit, phonons transport across interfaces must be included. In this talk, recent development efforts to provide accurate phonon refraction across interfaces will be discussed as well as validation efforts. To ensure a low background environment for the BeEST, as well as other experiments utilizing low threshold detectors, the Colorado Underground Research Institute (CURIE) is a new shallow-underground laboratory located at the Edgar Experimental Mine. CURIE offers a testbed for the development of superconducting qubits and novel detector technologies, as well as for studying backgrounds relevant to rare-event searches, such as those for dark matter and neutrinoless double-beta decay. We welcome new collaborations and users for this facility.
The BeEST experiment is funded by the Gordon and Betty Moore Foundation (no. 10.37807/GBMF11571); the US Department of Energy, Office of Science, Office of Nuclear Physics, under award nos. DE-SC0021245 and SCW1758; the LLNL Laboratory Directed Research and Development program through grant nos. 19-FS-027 and 20-LW-006; the European Metrology Programme for Innovation and Research (EMPIR) project nos. 17FUN02 MetroMMC and 20FUN09 PrimA-LTD; the Natural Sciences and Engineering Research Council (NSERC) in Canada, and the FCT—Fundação para a Ciência e Tecnologia (Portugal)—through national funds in the framework of the project no. UID/04559/2020 (LIBPhys). TRIUMF receives federal funding through a contribution agreement with the National Research Council of Canada. This work was performed under the auspices of the US Department of Energy by LLNL under contract no. DE-AC52-07NA27344. F.P. is funded as part of the Open Call Initiative at Pacific Northwest National Laboratory and conducted under the Laboratory Directed Research and Development Program. Pacific Northwest National Laboratory is a multiprogram national laboratory operated by Battelle for the US Department of Energy.
