Many models of dark matter and hidden sectors predict new particles with masses below the electroweak scale. Low-energy electron-positron colliders such as BABAR are ideally suited to discover these hidden-sector particles. We present several recent BABAR searches for low-mass hidden-sector particles, including new searches for prompt and long-lived leptonically decaying hidden scalars...
The constituents of dark matter are still unknown, and the viable possibilities span a very large mass range. Specific scenarios for the origin of dark matter sharpen the focus on a narrower range of masses: the natural scenario where dark matter originates from thermal contact with familiar matter in the early Universe requires the DM mass to lie within about an MeV to 100 TeV. Considerable...
The FASER, ForwArd Search ExpeRiment is an experiment under construction at the Large Hadron Collider at CERN, Switzerland. It’s aim is to be operational at the next run of the LHC from 2021 and search for new light and weakly-interacting particles. At high-energy colliders, they may be produced at low transverse momentum and highly collimated in the very forward direction of the collision...
The Belle II experiment at the SuperKEKB energy-asymmetric $e^+ e^-$ collider is a substantial upgrade of the B factory facility at the Japanese KEK laboratory. The design luminosity of the machine is $8\times 10^{35}$ cm$^{-2}$s$^{-1}$ and the Belle II experiment aims to record 50 ab$^{-1}$ of data, a factor of 50 more than its predecessor. During 2018, the machine has completed a...
Massive photon-like particles are predicted in many extensions of the Standard Model as possible portals toward a hidden sector where Dark Matter is secluded [1]. They are vector bosons mediating the interaction between ordinary and dark matter and can be produced in different processes through a feeble mixing to the photon. The PADME experiment [2], conducted at Laboratori Nazionali di...
The Heavy Photon Search (HPS) experiment searches for electro-produced dark photons using an electron beam provided by the CEBAF accelerator at the Thomas Jefferson National Accelerator Facility. A search for e+e- resonances in the invariant mass distribution has sensitivity to dark photons with larger coupling, while the additional requirement of a displaced vertex to identify long-lived dark...
