Science

The physics of the B quark are in their most exciting and interesting times with BaBar's and BELLE's recent observation of CP violation that will lead perhaps to its total understanding. CP violation results from the very small differences between the behaviour of matter and antimatter.

A high luminosity B-factory at the Stanford Linear Accelerator Center is enabling us to pursue an aggressive program studying and understanding the origin of CP violation. The beams are ~ 3 and 9 GeV positrons and electrons, at currents of 1 and 2 Amps! We are talking Gigawatt's here! At the BaBar Experiment at the PEP-II storage ring in Stanford, California we are investigating the phenomena of CP violation by examining a huge (now almost two hundred million) number of B meson decays.

We hope to further our understanding of the origin of the matter-antimatter asymmetry of the universe, which is very closely related CP violation. Most consistent Big-Bang theories predict equal parts of matter and antimatter in our universe.

However, no experimental evidence exists for huge pockets of antimatter, rather than matter, and hence a big question in particle physics today is "where has all the anti-matter gone?"

We have a bit of a lead: in rare decays of neutral kaons, we have seen evidence for a tiny amount CP violation... that is, decays in which there is a matter-antimatter asymmetry.

But it is hard (seemingly impossible!) to use this tiny violation of CP symmetry and incorporate it into a consistent theory to explain the vast matter-antimatter asymmetry of our universe within the Standard Model.

Such an asymmetry may potentially be accommodated within the Standard Model via quark couplings specified in the CKM matrix. So at SLAC, we are making and reconstructing tens of millions of B mesons per year, and are making progress in gaining some insight into and understanding of the phenomenon of CP violation.

While we are studying all these B decays there are many other types of physics we can investigate; after all, we have the worlds largest supply of B mesons, and charmed particles as well. We can study rare decays, investigate interactions of the quarks, search for new particles, measure lifetimes of short-lived particles, and study QED and QCD, among other things. There is no shortage of interesting thesis topics.