Recent Results in Bottomonium

Great strides have been made in the understanding of bound states of the bottom quark, b, and its antiquark, [Formula: see text], since the discovery of the first Ψ resonances in 1977. These bound states, known as bottomonium, have a rich spectrum whose masses and transition amplitudes shed valuable light on the strong interactions. We review some recent developments in bottomonium physics, including the discovery of the spin-singlet states [Formula: see text] and [Formula: see text], the first D-wave states, one or more candidates for spin-triplet [Formula: see text] excitations, and above-threshold states with strong transitions to states below threshold. We also present information about transitions, production, and signatures of new physics.