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. 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.

Events

Here is the complete list of events

Recent Publications
  • Search for lepton flavor-violating decay modes \( B^0\to K^0_S\tau^\mp\ell^\pm\) (\(\ell=\mu,e\)) with hadronic \(B\)-tagging at Belle and Belle II [2412.16470]
  • Measurement of the branching fraction, polarization, and time-dependent \(CP\) asymmetry in \(B^0\to \rho^+\rho^-\) decays and a constraint on the CKM angle \(\phi_2\) [2412.19624]
  • Measurement of the branching fraction and \(CP\)-violating asymmetry of the decay \(B^0\to\pi^0\pi^0\) using 387 million bottom-antibottom meson pairs in Belle II data [2412.14260]
  • Observation of the decay \(B^0 \to J/\psi\omega\) at Belle II [2412.12338]
  • Observations of the singly Cabibbo-suppressed decays \(\Xi_c^{+} \to pK_{S}^{0}\), \(\Xi_c^+ \to \Lambda \pi^+\),and \(\Xi_c^+ \to \Sigma^{0} \pi^+\) at Belle and Belle II [2412.10677]

Click here for the complete list of publications