High-energy physics is entering a new era in which decisive experiments should yield deeper understanding of the basic building blocks of matter, their interactions, and their relation to the cosmos. As the Large Hadron Collider (LHC) nears completion at CERN, the worldwide particle-physics community argues that another large accelerator facility is needed. The community’s consensus is that this new facility should be a 30-km-long pair of linear accelerators that will fire electrons and positrons at each other at collision energies up to about 1 TeV. This article discusses what’s being done to realize that linear collider and what we can expect it to accomplish.
Experimental results and theoretical developments over the past 40 years have already provided a coherent theory of particle physics that has been verified with great precision. This so-called standard model ascribes three of the fundamental interactions to the exchange of force-mediating spin-1 particles, the so-called gauge...
