Physical Society Colloquium

Do Matter-Antimatter Asymmetries Matter?

Aaron Roodman

SLAC/Stanford University

Why is the universe made of just matter particles with almost no antimatter? Why are there three generations of quarks and leptons, with complicated weak-interactions across those generations? These perplexing questions lack any compelling explanation within the Standard Model of particle physics, and new experimental discoveries will likely be needed to answer them. New matter-antimatter asymmetries, beyond those expected in the Standard Model, would shed light on both questions. The Babar experiment at the Stanford Linear Accelerator Center has observed matter-antimatter asymmetries in decays of the B-meson, and is now hunting for additional asymmetries in certain rare and interesting B-meson decays. In this colloquium, I will describe how we detect matter-antimatter asymmetries, why different decays may have different asymmetries, and the implications of our measurements towards answering some of the puzzles in particle physics.