On 20 February the Belle II detector at SuperKEKB in Japan recorded its first e+e– collisions since summer 2022, when the facility entered a scheduled long shutdown. During the shutdown, a new vertex detector incorporating a fully implemented pixel detector, together with an improved beam pipe at the collision point, was installed to better handle the expected increases in luminosity and backgrounds originating from the beams. Furthermore, the radiation shielding around the detector was enhanced, and other measures to improve the data-collection performance were implemented.
Belle II, for which first collisions were recorded in the fully instrumented detector in March 2019, aims to uncover new phenomena through precise analysis of the properties of B mesons and other particles produced by the SuperKEKB accelerator. Its long-term goal is to accumulate a dataset 50 times larger than that of the former Belle experiment.
