Symmetry is one of the most powerful concepts in modern physics and it underlies many fundamental laws, such as the conservation of energy and momentum. However, there is a very obvious lack of symmetry all around us: why is the universe made of matter rather than antimatter? The big bang is thought to have created equal amounts of matter and antimatter but, to the best of our knowledge, all the antimatter has disappeared, along with most of the matter. How can this be explained?
The answer is not yet known, but the clues lie in understanding the symmetry, or the lack of it, between the basic interactions of matter and antimatter.
In the May issue of Physics World, Helen Quinn and JoAnne Hewett from the Stanford Linear Accelerator Center describe the search for antisymmetry in particle physics.