Since the post series on Particles and Interactions became a bit longer than I wanted, I thought I would break it up. Let’s start with a recap of modern physics that will you will need to understand the structure of matter.
Quantum Mechanics (QM) is the physics of small things. How do they behave and how do they interact with each other? Conspicuously absent from this framework of QM is why. Why small things do what they do is a question QM leaves alone. And, if you are to make any headway into this subject, your best bet is to curb your urge to ask why. Nature is what she is. Our job is to understand the rules by which she plays the game of reality, and do our best to make use of those rules to our advantage in experiments and technologies. Ours is not to reason why. Really.
In all our scientific endeavors, we use similar high-level techniques to understand and study things. The most common technique is reductionism. It is based on the belief that the behavior, properties and structure of large and complex objects can be understood in terms of their simpler constituents. In other words, we try to understand the whole (the universe, for instance) in terms of smaller, reduced constituents (such as particles).
Recently, I gave a talk on particles and interactions to my daughter’s classmates who were planning on a trip to DESY, Germany and wanted to have an idea of what it was all about. As my first talk of this kind, I was a bit nervous because I didn’t know what level, and background, I should peg the talk at. I didn’t want to make it too basic, which I thought would be a waste of time. Nor did I want to make it too technical, which also would make it useless in a different way.