The LHCb collaboration has published today in Nature Physics the first evidence for the violation of the CP symmetry in baryon decays with statistical significance of 3.3 standard deviations (σ). CP violation has been observed in K and B meson decays, but not yet in any baryon decay. If the measurement is confirmed with a statistical significance of 5σ using a larger data sample, it will be the first time that an asymmetry in the decay rate of baryon and an anti-baryon is observed. In the quark model of particle physics mesons are composed of a quark and antiquark pair while baryons (anti-baryons) are composed of three quarks (anti-quarks).
See LHCb Public Web Page at: http://lhcb-public.web.cern.ch/lhcb-public/