The CDF experiment at the Tevatron claims to have observed a long-sought rare process — the decay of a particle called the B_s meson to a muon and anti-muon — and the observed rate is at least 1.5 times and perhaps as much as 6 times what was expected in the Standard Model. Very interesting, but very early days yet. I have a preliminary post here — to be updated when I fully understand the result.