The Belle II experiment has collected a 424 fb$^{-1}$ sample of $e^+e^-$ collisions produced by the asymmetric SuperKEKB collider. Ninety percent of the sample is at the $\Upsilon(4S)$ resonance, which decays to $B$-meson pairs. The predecessor experiment, Belle, collected nearly 1$~$ab$^{-1}$ of data from 1999-2010, three-quarters of which was at the $\Upsilon(4S)$. From these $\Upsilon(4S)$...
In this talk I review recent perturbative and non-perturbative developments in Heavy Quark Effective Theory (HQET).
In light of the recent branching fraction measurement of $B^{+}\to K^{+}\nu\bar{\nu}$-decay and its deviation from the SM expectation, we analyze the prospect of an axion-like particle (ALP) as the cause of such a departure. We assume a long-lived ALP with a mass of the order of a pion that predominantly decays to two photons. We assess the scenario where the ALP decay length is several meters...
Rare kaon decays are among the most sensitive probes of both heavy and light new physics beyond the Standard Model description thanks to high precision of the Standard Model predictions, availability of very large datasets, and the relatively simple decay topologies. The NA62 experiment at CERN is a multi-purpose high-intensity kaon decay experiment, and carries out a broad rare-decay and...