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Measurement of matter-antimatter differences in beauty baryon decays

Abstract : 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. Using data from the LHCb experiment at the Large Hadron Collider, a search is made for CP-violating asymmetries in the decay angle distributions of Λ0b 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 Λ0b 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.
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Contributor : Claudine Bombar <>
Submitted on : Monday, October 3, 2016 - 2:01:59 PM
Last modification on : Thursday, February 25, 2021 - 10:58:35 AM

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R. Aaij, L. Beaucourt, M. Chefdeville, D. Decamp, N. Déléage, et al.. Measurement of matter-antimatter differences in beauty baryon decays. Nature Physics, Nature Publishing Group, 2017, 13, pp.391-396. ⟨10.1038/nphys4021⟩. ⟨in2p3-01375686⟩



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