Planning the Future of U.S. Particle Physics (Snowmass 2013) Chapter 1- Summary. Conference: i mn Contributed to Community Summer Study 2013: Snowmass on the Mississippi (CSS 2013), 29 Jul - 6 Aug 2013. CONF-NUMBER = C13-07-29.2.

摘要

The 2013 Community Summer Study, known as “Snowmass,” brought together nearly 700 physicists to identify the critical research directions for the United States particle physics program. Commissioned by the American Physical Society, this meeting was the culmination of intense work over the past year by more than 1000 physicists that defined the most important questions for this field and identified the most promising opportunities to address them. This Snowmass study report is a key resource for setting priorities in particle physics. Particle physicists seek to understand the structure of the universe. We address two main questions: What are the most elementary constituents of nature, and what are the forces that cause them to interact? These questions are fundamental, and the desire to explore them is a defining characteristic of the human spirit. At the same time, finding the answers has practical value: It helps drive technical innovation in instrumentation, computing, and accelerators, and leads to the development of a skilled technical workforce. The development of new technologies, from industrial techniques, to medical imaging, high-performance computing, and beyond, has continually improved the quality of human life. The discovery of the Higgs boson in 2012 was a remarkable achievement made possible by decades of worldwide collaboration. The existence of the Higgs boson was predicted in the 1960s. By last year it was the sole missing piece of the theory we call the Standard Model. This theory provides a coherent picture of the strong, weak, and electromagnetic interactions, with the latter two unified in an “electroweak” theory. The Standard Model contains quarks, leptons, force carriers, and now the Higgs boson. However, the Standard Model still leaves significant questions unanswered. What is the nature of the Higgs boson? What can we learn from discovering that neutrinos have mass? Can the known forces be further unified? The particles of the Standard Model make up only 5% of the universe — what is the other 95%? Why is the universe almost all matter and no antimatter?