Fundamental Physics at the Intensity Frontier.

摘要

Particle physics aims to understand the universe around us. The Standard Model of particle physics describes the basic structure of matter and forces, to the extent we have been able to probe thus far. However, it leaves some big questions unanswered. Some are within the Standard Model itself, such as why there are so many different masses. In other cases, the Standard Model simply fails to explain some phenomena, such as the observed matter-antimatter asymmetry in the universe, the existence of dark matter and dark energy, and the mechanism that reconciles gravity with quantum mechanics. These gaps lead us to conclude that the universe must contain new and unexplored elements of Nature. Most of particle and nuclear physics is directed towards discovering and understanding these new laws of physics. These questions are best pursued with a variety of approaches, rather than with a single experiment or technique. Particle physics uses three basic approaches, often characterized as exploration along the cosmic, energy, intensity frontiers. Each employs different tools and techniques, but they ultimately address the same fundamental questions. This allows a multi-pronged approach where attacking questions from different angles furthers knowledge and provides deeper answers, so that the whole is more than a sum of the parts. A coherent picture or underlying theoretical model can more easily emerge, to be proven correct or not.