Experimental Study of Heavy Flavor and CP Violation with the LHCb Experiment at the CERN LHC Collider

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A major focus of experimental particle physics research is on the search for physics beyond the Standard Model. Flavor physics plays a key role in this endeavor via precision measurements of flavor processes sensitive to quantum loop effects, which complement direct searches at the highest energy accelerators. The physics reach of the LHCb experiment at the CERN LHC collider includes precision measurements of rare decays and matter-antimatter asymmetry in the charm quark and the bottom quark systems. At the current level of precision, these measurements impose severe constraints on the energy scale and the structure of new physics models. However, areas of deviations from the Standard Model are emerging, including signs of lepton non-universality in radiative and semi-leptonic B decays, which are highly sensitive to the presence of new scalar particles. The precision of future measurements in some key areas is expected to reach the required sensitivity to clarify these anomalies or further strengthen the deviations from the Standard Model predictions. These results could, in conjunction with studies at high energies, point the way to the structure of the physics beyond the Standard Model. This project involves a Maryland experimental particle physics group study of heavy flavor and CP violation with the LHCb experiment. It includes the development and construction of off-detector electronics for the upstream tracker for the LHCb detector upgrade and the installation and commissioning of the tracker, as well as major participation in the physics analysis of recorded and future LHCb data. The physics analysis effort is focused on measurements related to two current anomalies in the decays of B mesons: hints of departure from Lepton Flavor Universality in semileptonic B decays and the longstanding “Kaon pion” puzzle, where the measured CP asymmetries in the family of B to Kaon plus pion decays deviate from expectations. These anomalies, if confirmed, could be due to the imprints of new physics on flavor processes. Several data analysis techniques will be developed and used, including the use of machine learning. The findings of new sources of CP violation beyond the SM will have a profound impact on the understanding of the origin of baryon-antibaryon asymmetry and the field of cosmology. The studies of flavor processes will also yield precision information on the decay properties of the bottom and charmed hadrons, serving as a powerful testing ground for the predictions of lattice QCD calculations. The group’s detector upgrade effort provides excellent opportunities for training undergraduate students in experimental and engineering techniques. The group works closely with an outreach program run by the physics and astronomy departments at the University of Maryland, the GRAD-MAP, which is aimed at providing research and training opportunities for undergraduates from underrepresented groups in the Maryland and Washington area community colleges. The group plans to expand this effort to data analysis with the LHCb data by introducing students to advanced data handling and analysis techniques, such as machine learning.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.