Speaker
Description
Strange and charm baryons provide unique laboratories for strong interactions in the confinement domain, the interplay of strong and weak interactions in baryon decays, and searches for physics beyond the Standard Model. Modern electron-positron collider experiments such as BESIII at BEPC-II in China and Belle II at SuperKEKB in Japan produce baryons in abundance. Their versatile, high-acceptance detector systems can reconstruct complex baryon decays, including charged, neutral and long-lived particles.
BESIII, optimised in the tau-charm region, is a clean source of spin-polarised and entangled strange hyperon-antihyperon pairs. This unique feature has enabled pioneering measurements of hyperon form factors and, exploiting the world-record sample of 10 billion J/Psi vector charmonium mesons, high-precision tests of charge conjugation and parity (CP) conservation. Furthermore, the well-constrained kinematics of the produced hyperons and antihyperons makes them an effective “beam” for secondary hyperon-nucleon and antihyperon-nucleon scattering measurements. Finally, the extended energy range of the BEPC-II has opened the avenue for studies of the lightest single-charm baryon.
The new-generation B-factory Belle II has collected a world-leading sample of Upsilon(4S) bottomonium decays. Belle II is a versatile source of baryons where the production primarily occurs through quark fragmentation and B meson decays. By virtue of its high collision energy, Belle II gives access to the charm-baryon and charm-strange baryon excitation spectra. The multi-purpose detector can detect multi-body and multi-sequential decays which has enabled CP tests in charm-baryon decays at world-leading precision, and the most precise measurement of single-charm baryon lifetime.
In this talk, I will discuss the potential of baryon physics at electron-positron colliders and present recent highlights from the BESIII and Belle II experiments.