000004510 001__ 4510
000004510 005__ 20240924021108.0
000004510 037__ $$aBELLE2-CONF-PROC-2024-020
000004510 041__ $$aeng
000004510 100__ $$aMeihong Liu
000004510 245__ $$aMeasurements of electroweak penguin and lepton-flavour violating $B$ decays to final states with missing energy at Belle and Belle II
000004510 260__ $$a$$c2024-09-11
000004510 300__ $$a6
000004510 520__ $$aElectroweak penguin and lepton-flavour violating $B$ decays are key focuses of the Belle II physics program. These processes are particularly challenging due to the presence of neutrinos in the final states, resulting in `missing energy' in the rare $b\to s$ transitions. Using electron-positron collision data collected at the $\Upsilon(4S)$ resonance, we present the first evidence for $B^+\to K^+\nu\bar{\nu}$ and the most stringent upper limit on $B^0\to K^{*0}\tau^+\tau^-$. Additionally, combining Belle and Belle II data, we report the first results on $B^0\to K^{0}_S\tau^\pm\ell^\mp$ ($\ell=e,\mu$).
000004510 8560_ $$fliumh19@fudan.edu.cn
000004510 8564_ $$uhttps://docs.belle2.org/record/4510/files/BELLE2-CONF-PROC-2024-020.pdf