Belle II

Belle II has been designed to make precise measurements of weak interaction parameters, study exotic hadrons, and search for new phenomena beyond the Standard Model of particle physics. In June 2022, SuperKEKB, the asymmetric energy accelerator that provides e+e− collisions inside Belle II, achieved a new luminosity world record of 4.7x1034cm−2s−1. From 2019-2022 Belle II accumulated a 400 fb-1 data sample (run 1). These data provide large samples of beauty and charm hadrons, as well as tau leptons. Unique searches for dark-matter related particles are also pursued.

Data taking has resumed in 2024 after a long shutdown period, during which both accelerator and detector have been improved. In December 2024, SuperKEKB achieved a new luminosity world record of 5.1x1034cm−2s−1, for a total data sample of 575 fb-1.

Events

Here for the complete list of events

Documents

Recent physics publications

  • Search for lepton-flavor-violating \(\tau^-\to \ell^- K^0_S\) decays at Belle and Belle II [2504.15745]
  • Measurement of the time-integrated \(CP\) asymmetry in \( D^0\to K^0_S K^0_S\) decays using opposite-side flavor tagging at Belle and Belle II [2504.15881]
  • Test of lepton flavor universality with measurements of \(R(D^+)\) and \( R(D^{*+})\) using semileptonic \( B\) tagging at the Belle II experiment [2504.11220]
  • Search for \( B^0\to K^{*0}\tau^+\tau^-\) decays at the Belle II experiment [2504.10042]
  • Measurements of the branching fractions of \(\Xi_c^+ \to \Sigma^+ K_S^0\), \( \Xi_c^+ \to \Xi^0 \pi^+\), and \( \Xi_c^+ \to \Xi^0 K^+\) decays at Belle and Belle II [2503.17643]
Here for the complete list of physics publications