Friday, June 15, 2007

D0 discovers "cascade b"

If someone is interested in dirty corners of heavy quark physics, she may want to know that D0-brains at the Tevatron have discovered the "cascade b" particle whose mass is 5.77 GeV, dominated by the bottom-quark.

It is the first baryon that contains quarks of all three generations, namely "dsb". Note that all of them are lower quarks, making the net charge "-1". While the evidence so far has been largely indirect (from LEP), D0-brains have found it as a 5.5 sigma bump via its decay

$\Xi_b^- \to J/ \psi + \Xi^-.$

In other words, the probability that it is background equals 0.033 ppm. Yes, the left hand side is the new particle. See
Space Daily
In the preprint, there is a funny typo in the list of authors. Can you find it?

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