Stefano Perazzini: Observation of time-dependent CP violation in Bs decays
https://zoom.us/j/304578256
Flavour physics in the quark sector has been an incredible tool for discovery over several decades, since the first observation of the breaking of the charge-parity (CP) symmetry in kaon decays dating back to the 1960s. CP violation (CPV) is modelled in the Standard Model (SM) of particle physics by the Cabibbo-Kobayashi-Maskawa (CKM) mechanism. The current experimental determination of the amount of CPV in the SM is not able to explain the imbalance between the amount of matter and anti-matter in the Universe. More precise measurements are fundamental to further constrain the parameters of the CKM mechanism, hopefully finding discrepancies hinting for new sources of CPV not accounted for in the SM. In the last years, the LHCb experiment had access to unprecedented statistics of beauty and charm particles, thanks to the very large production cross section of b and c quarks in p-p collisions at Large Hadron Collider (LHC) and to the design of the detector, optimised to collect and study the decays of particles with heavy quarks. Exploiting the collected data, LHCb performed precision measurements of CPV, leading to first observations of this phenomenon in several decays of beauty and charm particles. The results allowed physicists to test the Cabibbo-Kobayashi-Maskawa mechanism to very high precision setting new constraints on the presence of physics beyond the SM. In this seminar we will present the first observation of time-dependent CPV in the decays of the Bs meson, performed by LHCb. Particular attention will be put on the importance of this measurement in the quest to discover physics beyond the SM and on the experimental techniques used.
Connections will begin at 12:30 with the seminar beginning at 13:00. Password for Zoom is NielsBohr.