Large Hadron Collider (LHC), with an energy seven times greater than the energy of the Tevatron, is now under construction. The LHC holds the promise of being a superb instrument of discovery, and there is every expectation that it will uncover important new phenomena. Maintenance of a forefront U.S. program in elementary-particle physics requires direct involvement in construction and utilization of this unique facility. The U.S. high-energy physics community is poised to play a leading role in both the construction of the LHC and its use in uncovering the physics of electroweak symmetry breaking. Although this physics is something completely new, strong theoretical arguments say that it must show up at the LHC.
The field of high-energy physics must now start to look beyond the horizon of the current program. As advised in Chapter 7, in order to explore the physics issues that are expected to remain open after the LHC, new accelerators and colliders will be needed. Given the long time scales for the design and construction of such facilities, it is essential to begin the planning process now. The ever-increasing size and cost of these facilities will require full international participation in all stages of their design, construction, and operation.
Maintenance of a leadership position in elementary-particle physics beyond the LHC era requires developing accelerator technologies to push the energy frontier ever higher, and it involves helping to build international consensus both on what technologies should be chosen for the next collider and on where the collider should be sited. Although the committee believes that it is highly desirable to have a forefront facility located within the United States, it is crucial that we maintain a technological base sufficient to allow full U.S. participation in all aspects of the design, construction, and operation of any such facility, independent of its ultimate location.
Over the past two decades, to address the important physics questions, very large experimental facilities have become the major instruments of the field. Accordingly, there have been changes in the way the field operates, particularly with respect to university groups. U.S. universities are recognized worldwide as being at the forefront of graduate education, and universities are the center of the process to educate future physicists. University groups, comprising approximately three-quarters of the experimental particle physics community, have always played a critical role in high-energy physics research. To understand how the challenging environment has affected university groups, the National Science Foundation (NSF) and the Department of Energy (DOE) have recently undertaken a comprehensive study of the situation. The committee applauds both agencies for taking this initiative.
In parallel with participation in large forefront facilities, it is essential to maintain an ability to support well-targeted areas of investigation, not necessarily at the energy frontier or accelerator-based. Much of our knowledge of the field comes from experiments of great precision or great sensitivity at lower energies that take advantage of new detector or accelerator technologies. Within