Using data collected in proton–proton collisions at the LHC at a centre-of-mass energy of 7 TeV LHCb has observed a fascinating feature of quantum mechanics. The strange beauty particle (matter) B0s composed of a beauty antiquark (b) bound with a strange quark s turns into its antimatter partner composed of a b quark and an s antiquark (s) about 3 million million times per second (3*1012). The B0s particles have been identified through their decay into strange charm Ds particles (composed of a charm quark c bound with a strange s antiquark) and one or three πs. Of course, LHCb observes B0s particles and antiparticles only during their short lifetime in which they travel about 1 cm in the LHCb detector.

The plot shows the observation of these oscillations when all data have been folded into one oscillation period. The variable Amix is proportional to the difference between the number of events in which the produced matter(antimatter) B0s particle had the same identity during its decay, and the number of events in which it had not, as a function of its lifetime.

click in the image to get it in higher resolution

The B0s oscillations were observed for the first time by the Fermilab experiments CDF and D0 in 2006, see Press Release article. The oscillation parameters measured by the LHCb Collaboration show agreement with those measured at Fermilab.

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