Strong interest in feeble interactions

The First Feebly Interacting Particles (FIPs) Workshop took place from 31 August to 4 September at CERN. The FIPs concept encapsulates the paradigm that the new physics includes very feebly interacting particles, complementary to the strongly interacting sector at the TeV (or beyond) scale, typically searched for at LHC. Structured around the four “portals” that may link SM particles and fields to a rich dark sector – axions, dark photons, dark scalars and heavy neutral leptons – the workshop highlighted the synergies and complementarities among a great variety of experimental facilities, and called for close collaboration across different physics communities.