000004440 001__ 4440
000004440 005__ 20240729131144.0
000004440 037__ $$aBELLE2-CONF-PROC-2024-015
000004440 041__ $$aeng
000004440 100__ $$aMichele Mantovano
000004440 245__ $$aMeasurements of lepton-flavour universality in semileptonic B decays at Belle and Belle II
000004440 260__ $$a$$c2024-07-21
000004440 300__ $$a8
000004440 520__ $$aThe Belle and Belle II experiments have collected a $1.1$\,ab$^{-1}$ sample of $e^{+}e^{-} \rightarrow B\bar B$ collisions at the $\Upsilon(4S)$ resonance. These data, with low particle multiplicity, constrained initial state kinematics and excellent lepton identification, are an ideal environment to study lepton-flavour universality in semileptonic decays of the $B$ meson. We present measurements of branching-fraction ratios that test the universality of $\tau$ and light leptons, using both exclusive and inclusive $B$ semileptonic decays. We also report measurements of angular observables that probe universality between electrons and muons.
000004440 6531_ $$alepton-flavour universality 
000004440 6531_ $$asemileptonic B decays
000004440 6531_ $$aangular asymmetries
000004440 8560_ $$fmichele.mantovano@ts.infn.it
000004440 8564_ $$uhttps://docs.belle2.org/record/4440/files/BELLE2-CONF-PROC-2024-015.pdf