SENTINEL Consortium

Physics beyond the Standard Model via neutrino kinematics

The Superconducting and Engineered Nanomechanical Techniques for Investigating Neutrinos at Low Kinematics (SENTINEL) Consortium brings together groups at Colorado School of Mines, Yale University, Lawrence Berkeley National Laboratory, and Lawrence Livermore National Laboratory to develop and deploy tabletop quantum‑sensor experiments that probe physics beyond the Standard Model (BSM) through precision measurements of neutrino kinematics.

Precision measurements of decay kinematics—especially electron‑capture and beta decays—are sensitive to subtle deviations from Standard Model expectations. SENTINEL exploits quantum‑limited sensors to resolve recoil and spectral signatures that constrain heavy (sterile) neutrinos, exotic weak currents, and other BSM scenarios, while advancing techniques for direct neutrino‑mass measurements.

Key Technologies

Superconducting Tunnel Junction Detectors

Superconducting tunnel junction (STJ) detectors are cryogenic Josephson junctions formed by two superconducting electrodes separated by a thin insulating barrier. Absorption of ionizing radiation or low‑energy quanta breaks Cooper pairs and produces quasiparticles. As these quasiparticles tunnel across the barrier, they generate a transient charge/current pulse that is read out with low‑noise electronics.

STJs combine high intrinsic energy resolution with a high per‑pixel count‑rate capability and are applied to precision electron‑capture spectroscopy (for example, in the BeEST effort) to search for heavy neutral leptons and other BSM signatures.

Levitated Nanoparticles

Levitated optomechanics trap small particles in an ultra‑high vacuum using optical fields, suppressing thermal noise to approach the quantum measurement limit. With particle sizes ranging roughly from sub‑micron to tens of microns, these systems achieve extreme sensitivity to tiny forces and acceleration, making them powerful sensors for recoil and impulse detection relevant to neutrino kinematics and new‑interaction searches.

Groups and Institutions