Friday, April 04, 2008

More CP Violation

On the heels of the KEK report that I mentioned earlier, here comes the analysis of the data from the Tevatron at Fermilab that point to the same conclusion.

The amount of CP violation observed in experiments (and enshrined in the standard model), however, is far too little to explain why matter should have prevailed in its ancient war with antimatter. To get a clean look at CP symmetry, DZero and its sibling detector, CDF, focus on the BS, which consists of a bottom quark and a strange antiquark. (Quarks are components of protons and neutrons.) Working independently, the two detectors both found an extra dose of CP violation beyond what the standard model predicts.

Neither result on its own was very convincing, so a team of Italian researchers combined the data, similar to the way medical researchers cull information from independent clinical trials, to look for rare side effects. Together, the data make it 99.7 percent likely that the discrepancy is real, not due to chance, says physicist Luca Silvestrini of the National Institute for Nuclear Physics in Rome, who took part in the study submitted to Physical Review Letters.

Looks like both the CDF and D0 got similar things, which is always good.



H.Wolfe said...


I was at a seminar (slides are here and the speaker made it pretty clear that niether CDF nor D0 were endorsing the UTfit combination, since the UTfit group mixed results from slightly different measurements. They are working on a combined fit internally now, but the real answer will come when the full Tevatron luminosity is in. It's quite possible that one or both experiments could then see or exclude the effect individually.

ZapperZ said...

Ah, thank you very much for the clarification and that link.