2016/09/30 by I Bediaga, LHCb collaboration, R. Aaij +782 · 2 citations
Physics and Astronomy · #Antimatter #Baryon #Baryon number #CP violation #Hadron #High-Energy Particle Collisions Research #Large Hadron Collider #Lepton #Meson #Nuclear physics #Parity (physics) #Particle decay #Particle physics #Particle physics theoretical and experimental studies #Physics #Physics beyond the Standard Model #Quantum Chromodynamics and Particle Interactions #Standard Model (mathematical formulation) #hep-ex
paper · pdf · doi:10.1038/nphys4021
published as Nature Physics 13, 391-396 (2017) · All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-030.html
openalex created_date 2016/09/30 · openalex publication_date 2017/01/30 · arxiv created 2017/10/27 · arxiv updated 2017/10/30 · openalex updated_date 2026/08/06
Differences in the behaviour of matter and antimatter have been observed in K and B meson decays, but not yet in any baryon decay. Such differences are associated with the non-invariance of fundamental interactions under the combined charge-conjugation and parity transformations, known as CP violation. Here, using data from the LHCb experiment at the Large Hadron Collider, we search for CP-violating asymmetries in the decay angle distributions of Λb0 baryons decaying to pπ−π+π− and pπ−K+K− final states. These four-body hadronic decays are a promising place to search for sources of CP violation both within and beyond the standard model of particle physics. We find evidence for CP violation in Λb0 to pπ−π+π− decays with a statistical significance corresponding to 3.3 standard deviations including systematic uncertainties. This represents the first evidence for CP violation in the baryon sector. CP violation has deep implications for particle physics and cosmology. Previously observed only in meson decays, signs of CP violation have now been spotted in baryon decays by analysing the proton–proton collision data from the LHCb detector.