Why does the Universe contain matter? According to the Standard Model, the leading theory of particle physics, matter and antimatter should have been created in nearly equal amounts after the Big Bang. Yet the observable Universe consists almost entirely of matter. The small differences between matter and antimatter described by the Standard Model cannot fully account for this imbalance.
Wouter Hulsbergen, Professor by Special Appointment in Flavour Physics at the LHC at VU Amsterdam and researcher at Nikhef, is a co-applicant on a newly awarded grant through the Swiss National Science Foundation (Schweizerischer Nationalfonds). The grant will support a collaboration between EPFL and the local LHCb group at Nikhef and VU Amsterdam. The project will search for signs of physics beyond the Standard Model through precise measurements of neutral B-mesons. These particles display quantum behaviour that makes it possible to study extremely small differences between matter and antimatter, known as CP violation.
The researchers will use the full Run 3 dataset from the LHCb experiment at CERN. They will combine measurements of several B-meson decays to determine a key quantity in the Standard Model, the CKM angle β. The goal is to improve the precision of this measurement by a factor of two to three. Such measurements can reveal effects of new particles or interactions, including particles that are too heavy to be produced directly at the Large Hadron Collider. Comparing several decay processes is essential at this level of precision, as subtle effects must be understood and controlled.
The grant will fund one PhD candidate and one postdoctoral researcher for the local LHCb group. The PhD candidate is expected to spend one year at EPFL or CERN, further strengthening the collaboration between the Swiss and Dutch teams. The research will also contribute to the calibration and understanding of LHCb’s new scintillating-fibre tracking detector. Better characterisation of the detector improves the reliability of simulations and measurements, benefiting this project as well as other LHCb searches for new physics