BaBar Physics
The RAL group has made a strong contribution to the physics analysis on BaBar, working mainly on charmless decays but also performing a wide range of analyses from tau to charmonium physics. Below is a list of analysis topics which the RAL group has published papers on:
- Charmless B decays
- Charmed B decays
- Charmonium B decays
- Tau decays
A list of BaBar publications performed by the RAL group is available.
Charmless B Decays
The RAL groups main contribution to the BaBar experiments analysis effort has been through rare charmless decays. Charmless B decays are events that proceed without a charm quark appearing in the decay chain and are important as a possible source of CP violation. They also have a very low probability of occuring (ie. one in every million B decays is expected to be charmless), therefore any unconsidered physics contributions will enhance the decay probability. The RAL group has measured many charmless B decay probabililties, in many cases observing specific decays for the first time. Below is a table of the charmless decays studied by the RAL group.
| Analysis |
First Observation |
World's best measurement |
| B+ -> K+K+K- |
No |
Yes |
| B+ -> K+pi+pi- |
No |
Yes |
| B+ -> pi+pi+pi- |
No |
Yes |
| B+ -> K*+K+K- |
Yes |
Yes |
| B+ -> K*+pi+pi- |
Yes |
Yes |
| B+ -> K*+pi+K- |
No |
Yes |
| B+ -> K*+K+pi- |
No |
Yes |
| B+ -> K*+K*0 |
No |
Yes |
| B0 -> K*0K+K- |
Yes |
Yes |
| B0 -> K*0pi+pi- |
Yes |
Yes |
| B0 -> K*0pi+K- |
Yes |
Yes |
| B0 -> K*0K+pi- |
No |
Yes |
| B0 -> K*+pi- |
No |
Yes |
| B0 -> K*0K*0bar |
Yes |
Yes |
| B0 -> K*+K*- |
No |
Yes |
Charmed B decays
We have performed branching fraction measurments of charm decays B0 -> D+pi- and B+ -> D0barpi+. These high statistic decays have been used to determine systematic uncertainties and calibrate analyses with similar topologies.
Charmonium B decays
The RAL group has performed analyses on factorisation suppressed decays B-> chi_c0 K*. We have observed this decay at a rate higher than predicted by theory. This implies unconsidered contributions in our theoretical models. $$>
Tau decays
The BaBar experiment produces millions of B meson pairs and so is consequently called a "B factory". However millions of tau pairs are also produced. The tau particle essentially has all the properties of an electron but is roughly 3000 times heavier and therefore unstable. With so many tau decays we have been able to provide limits on lepton flavour violation.
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