Collisions of electrons and positrons were observed for the first time In the SuperKEKB collider (Japan). The Belle II detector that was installed where the collision took place registered the event. Scientists from Novosibirsk State University and the Institute of Nuclear Physics SB RAS took part in the development and creation of one of the key systems in the Belle II detector, a 40-ton electromagnetic calorimeter based on cesium iodide crystals.
The Belle II experiment began in the KEK High Energy Accelerator Research Organization Laboratory (Tsukuba, Japan). New particles were produced by the annihilation of electrons and positrons, specifically B meson pairs and its antiparticles. The production of other hadrons was also observed.
The Belle II detector is one of the key systems for the SuperKEKB collider. It was designed and built by an international team that includes more than 750 researchers from 25 countries. The capabilities of Belle II are a big improvement over those of the previous Belle detector. In particular, its performance increased significantly. The calorimeter allows Belle II to register and measure the energy of photons with great efficiency and high accuracy and, consequently, to restore neutral pions.
Several laboratories associated with the NSU Physics Department participated in the modernization of the Belle II detector colorimeter that led to the successful work of the SuperKEKB collider.
Aleksander Kuzmin, Head of the Laboratory for Researching Physics of B- and D-Mesons Physics, Doctor of Physical and Mathematical Sciences, and Lead Researcher at the GI Budker Institute of Nuclear Physics, is coordinator of the Belle II detector calorimeter group and one of the developers of the data collection system.
Aleksander Kuzmin described their work,
The electronics of the Belle II detector calorimeter were improved significantly for the new experiment. It now allows the reconstruction of high-energy photons for more than 30 thousand events of electron-positron collisions per second. In addition, the information from the calorimeter allows you to quickly, within a millionth of a second, determine whether the event is useful and send a signal for it to be registered in all the detector systems.
Over the next ten years, the scientists will accumulate data on the birth of 50 billion pairs of B-mesons and their antiparticles. This is 50 times more than was obtained in the previous Belle experiment.