The 21 cm emission line from neutral hydrogen represents a promising observational probe of cosmological evolution. In particular, measuring the highly redshifted 21 cm emission from the Epoch of Reionization (EoR) will illuminate a crucial and currently poorly understood period in cosmological history. The EoR denotes the period when radiation from early galaxies and black holes ionized the intergalactic medium.
An exciting scientific frontier is the 3-dimensional exploration of nucleon (and nuclear) structure: nuclear femtography. The study of Generalized Parton Distributions (GPDs) captures the images of the transverse position distributions of fast moving quarks. Therefore, they provide richer information about the nucleon structure than the well known form factors and parton distribution functions. GPDs are accessible via exclusive reactions, where all particles in the final state are identified.
The thermodynamic properties of the ionized baryons in galaxies, groups, and clusters encode the effects of the assembly history and feedback processes that shape galaxy and cluster formation. These properties can be studied through the imprints that the scattering of cosmic microwave background (CMB) photons off the free-electron gas in galaxies and clusters leave on high resolution CMB maps: the thermal and kinematic Sunyaev-Zel’dovich effects.
Direct searches for dark matter which targeted SUSY-motivated areas of parameter space employed well-studied nucleon interactions at keV to MeV energy scales to predict typical DM-nucleon interaction distributions. Much lighter DM, probed by a new generation of experiments sensitive to eV-scale energy deposits, however, rely instead on condensed matter effects to extract larger recoil energies from the DM than would be suggested by the simple elastic kinematics of heavier DM.
The HUNTER experiment (Heavy Unseen Neutrinos from Total Energy-momentum Reconstruction) is a search for sterile neutrinos with masses in the 20-300 keV range. The experiment uses a combination of AMO, nuclear and particle physics techniques to do kinematically complete missing mass reconstruction of neutrinos from 131-Cs electron capture decays. A magneto-optically trap (MOT) of 131-Cs atoms provides a pure sample of ~10^8 radioactive atoms suspended in EUHV with no inert material present.