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More than 130 physicists gathered at the KEK Tsukuba Campus from October 6 to 10 for the Belle II Physics Week 2025. The event brought together theorists from the wider physics community and experimentalists from the Belle II collaboration, as well as participants from other major experiments including LHCb, BESIII, and NA62.

Now in its eighth year, Physics Week has become an annual highlight for the Belle II community. The 2025 meeting was organized in collaboration with the KEK Theory Center, and sponsored by the Toshiko Yuasa Lab (TYL), the Kobayashi-Maskawa Institute, and the US–Japan Science and Technology Cooperation Program in High Energy Physics.

 

 

Each Physics Week focuses on a specific topic to encourage dialogue between theorists and experimentalists. This year’s theme, “Rare decays of beauty and charm hadrons with missing energy,” explored one of the most promising areas for uncovering new physics in high-energy scale or probing new light particles in dark sectors.

The program was structured with “school” sessions in the mornings and “workshop” sessions in the afternoons, fostering active discussion and exchange of ideas among participants. In addition, the week featured a poster session, a tour of the Belle II detector, panel discussions, Q&A sessions with theorists, and a hands-on tutorial on a commonly used analysis tool.

Through these activities, Belle II Physics Week 2025 provided an engaging environment for collaboration and learning, strengthening connections within the community and between theory and experiment.