Neutrinos from Stored Muons nuSTORM: Expression of Interest

The $ u$STORM facility has been designed to deliver beams of $ u_e$ and $ u_mu$ from the decay of a stored $mu^pm$ beam with a central momentum of 3.8 GeV/c and a momentum spread of 10%. The facility is unique in that it will: serve the future long- and short-baseline neutrino-oscillation programmes by providing definitive measurements of $ u_e N$ and $ u_mu N$ scattering cross sections with percent-level precision; allow searches for sterile neutrinos of exquisite sensitivity to be carried out; and constitute the essential first step in the incremental development of muon accelerators as a powerful new technique for particle physics. Of the world's proton-accelerator laboratories, only CERN and FNAL have the infrastructure required to mount $ u$STORM. In view of the fact that no siting decision has yet been taken, the purpose of this Expression of Interest (EoI) is to request the resources required to: investigate in detail how $ u$STORM could be implemented at CERN; and develop options for decisive European contributions to the $ u$STORM facility and experimental programme wherever the facility is sited. The EoI defines a two-year programme culminating in the delivery of a Technical Design Report.