  We propose a program at B-factories of inclusive, multi-track displaced
vertex searches, which are expected to be low background and give excellent
sensitivity to non-minimal hidden sectors. Multi-particle hidden sectors often
include long-lived particles (LLPs) which result from approximate symmetries,
and we classify the possible decays of GeV-scale LLPs in an effective field
theory framework. Considering several LLP production modes, including dark
photons and dark Higgs bosons, we study the sensitivity of LLP searches with
different number of displaced vertices per event and track requirements per
displaced vertex, showing that inclusive searches can have sensitivity to a
large range of hidden sector models that are otherwise unconstrained by current
or planned searches.
