Measurement of charmed baryon-antibaryon asymmetry at LHCb

Project title: Measurement of charmed baryon-antibaryon asymmetry at LHCb
Main applicant: Andrzej Kupsc, Division of Nuclear Physics
Fellow applicant: Patrik Adlarson and Lars Eklund, Division of Nuclear Physics
Grant amount: 3 440 000 SEK for the period 2022-2025

The purpose of this project is to understand how matter differs from antimatter, using as a tool the combined charge conjugation (C) and parity flip (P) symmetry. Novel analysis methods will be implemented to test CP symmetry in decays of charmed baryons measured by the LHCb experiment at CERN. Multidimensional fits to angular distributions of sequential two-body decays are used to extract and compare decay parameters for baryons and their antibaryons. The PI has developed these methods and implemented them together with a co-applicant for strange-baryon studies at the BESIII experiment. Together with a PhD student they will extend and apply these methods to the LHCb charmed-baryon data. The second co-applicant will bring in his expertise as a long-time member of LHCb. The initial task to develop the analysis methods is based on already collected data, but includes also the preparation of a new trigger algorithm needed before the next LHCb run in 2022. The further tasks will provide highly sensitive CP-violation tests using T-odd observables (first-ever test for charmed baryons) and Cabibbo suppressed decay modes. The minimal outcome of the project will be three peer-reviewed papers. But the observation of CP violation in charmed-baryon decays, maybe even beyond the standard model prediction, would be ground-breaking.