  The 2020 Update of the European Strategy for Particle Physics (ESPP) (see
https://cds.cern.ch/record/2720129 ) recommended that muon beam R\&D should be
considered a high-priority future initiative and that a programme of
experimentation be developed to determine the neutrino cross-sections required
to extract the most physics from the DUNE and Hyper-K long-baseline
experiments. The ENUBET and nuSTORM collaborations have begun to work within
and alongside the CERN Physics Beyond Colliders study group and the
international Muon Collider collaboration to carry out a joint, five-year R\&D
programme to deliver a detailed plan for the implementation of an
infrastructure in which:
  (1) ENUBET and nuSTORM deliver the neutrino cross-section measurement
programme identified in the ESPP and allow sensitive searches for physics
beyond the Standard Model to be carried out; and in which \ (2) A 6D muon
ionisation cooling experiment is delivered as part of the technology
development programme defined by the international Muon Collider collaboration.
  This document summarises the status of development of the nuSTORM and 6D
cooling experiments and identifies opportunities for collaboration in the
development of the initiative outlined above.
