The Science Program at the Spallation Neutron Source's Fundamental Neutron Physics Beamline

The Fundamental Neutron Physics Beamline (FNPB) at Oak Ridge National Lab’s Spallation Neutron Source (SNS) supports an ongoing program of precision neutron experiments exploring the fundamental symmetries of nature, with two parallel beamlines: one with the full spectrum of cold neutrons from the SNS and the other with 8.9 A neutrons selected by a crystal monochromator. A program of experiments exploring parity violation in hadronic interactions was recently completed. The Nab experiment, which measures the neutrino-electron correlation (a) and Fierz interference term (b) in non-polarized neutron decay has recently started acquiring commissioning data and will soon transition to production data acquisition. The process of determining the future use of the facility after the completion of the Nab experiment is now underway. An open call for Expressions of Interest for use of the two beamlines included in the facility was recently concluded by Oak Ridge management. The potential scope of the future science program will be reviewed.