Probing dark forces and light hidden sectors at low-energye+e−colliders

A dark sector—a new non-Abelian gauge group Higgsed or confined near the GeV scale—can be spectacularly probed in low-energy $e^{+}{e}^{-}$ collisions. A low-mass dark sector can explain the annual modulation signal reported by DAMA/LIBRA and the PAMELA, ATIC, and INTEGRAL observations by generating small mass splittings and new interactions for weak-scale dark matter. Some of these observations may be the first signs of a low-mass dark sector that collider searches can definitively confirm. Production and decay of $\mathcal{O}(\mathrm{GeV})$-mass dark states is mediated by a Higgsed Abelian gauge boson that mixes kinetically with hypercharge. Existing data from BABAR, BELLE, CLEO-c, and KLOE may contain thousands of striking dark-sector events with a high multiplicity of leptons that reconstruct mass resonances and possibly displaced vertices. We discuss the production and decay phenomenology of Higgsed and confined dark sectors and propose $e^{+}{e}^{-}$ collider search strategies. We also use the DAMA/LIBRA signal to estimate the production cross sections and decay lifetimes for dark-sector states.