Construction Proposals Take Aim at Top and Bottom Quarks

Cornell and Stanford are competing to build a B‐meson “factory,” and Fermilab wants to build a new injector ring for its Tevatron Collider. These are the two principal new construction initiatives proposed by the US highenergy‐physics community for completion by the middle of this decade. They are intended to address the two remaining “dangling participles” of the spectacularly successful standard model of the elementary particles: Understanding the violation of CP symmetry would seem to require a new source of B mesons much more profuse than the existing electronpositron rings; and determining the properties of the (still missing) top quark in adequate detail appears to necessitate an order of magnitude increase in the luminosity of the Tevatron proton‐antiproton collider.