Related papers: The Belle II Physics Book

A small component of dark matter (DM) that is strongly interacting with the standard model sector is consistent with various experimental observations. Despite the small abundance, strongly-interacting DM can lead to pronounced signals in…

The Belle~II Collaboration presents four new analyses: The measurement of $V_{ub}$ from $B \to \pi e \nu_e$ decays with a fit to the differential $q^2$ spectrum, the determination of $V_{cb}$ using a fit to the differential $w$ distribution…

Radiative and electroweak penguin mediated decays of $B$ mesons are a great probe for physics beyond the Standard Model of particle physics. Furthermore, recently anomalies on exclusive $b \rightarrow s \ell^{+} \ell^{-}$ processes, which…

The possibility of a dark sector weakly coupling to Standard Model (SM) particles through new light mediators is explored at the Belle II experiment. We present here results from three different searches, for a long-lived (pseudo)scalar…

We report measurements of the $\bar{B}^0 \to D^{*+} \ell^{-} \bar{\nu}_l$ and $B^- \to D^{0} \ell^{-} \bar{\nu}_l$ processes using 34.6 fb$^{-1}$ of collision events recorded by the Belle II experiment at the SuperKEKB asymmetric-energy…

We present a measurement of time-dependent rate asymmetries in $B^0\to \phi K^0_S$ decays to search for non-standard-model physics in $b\to q \overline{q}s$ transitions. The data sample is collected with the Belle II detector at the…

The Belle~II experiment is designed to search for physics beyond the Standard Model by investigating rare decays at the SuperKEKB \(e^{+}e^{-}\) collider. Owing to the significant beam background at high luminosity, the data acquisition…

High precision flavor physics measurements are an essential complement to the direct searches for new physics at the LHC. Such measurements can be performed at an upgraded KEKB accelerator. The status of the SuperKEKB collider and Belle II…

High precision flavor physics measurements are an essential complement to the direct searches for new physics at the LHC. Such measurements will be performed using the upgraded Belle II detector and upgraded KEKB accelerator. The status of…

We measure the branching fractions for the decays $\bar{B}^0 \to D^{*+} e^{-} \bar{\nu}_e$ and $\bar{B}^0 \to D^{*+} \mu^{-} \bar{\nu}_\mu$ using $8.70 \pm 0.09~{\rm fb}^{-1}$ of data collected by the Belle II experiment at the SuperKEKB…

We describe the present status of the computing system in the Belle experiment at the KEKB $e^+e^-$ asymmetric-energy collider. So far, we have logged more than 160 fb$^{-1}$ of data, corresponding to the world's largest data sample of 170M…

The Belle and Belle II experiments have collected an 1.6 ab$^{-1}$ sample of $e^+e^-$ collision data at center-of-mass energies near the $\Upsilon(nS)$ resonances. In particular, the Belle II experiment collected a 19.2 fb$^{-1}$ sample of…

The measurement of two-particle angular correlation functions in high-multiplicity $e^+e^-$ collisions at $\sqrt{s}=10.52$ GeV is reported. In this study, the $89.5~{\text{fb}}^{-1}$ of hadronic $e^+e^-$ annihilation data collected by the…

We present a first measurement of the $\bar{B^{0}} \rightarrow D^{*+} \ell^{-} \nu_{\ell}$ branching fraction using fully reconstructed $B$ meson decays employing the Full Event Interpretation algorithm. Collision events corresponding to an…

The Belle II Collaboration reported the first measurement on ${\rm Br}(B^+\rightarrow K^+\nu\bar{\nu})$, which lies 2.7$\sigma$ away from the Standard Model expectation. This result may be manifestation of new physics beyond the Standard…

A search for the flavor-changing neutral-current decay $B^{+}\to K^{+}\nu\bar{\nu}$ is performed at the Belle II experiment at the SuperKEKB asymmetric energy electron-positron collider. The results are based on a data sample corresponding…

We report a measurement of the branching fraction of $B \to K^{\ast}(892)\ell^+\ell^-$ decays, where $\ell^+\ell^- = \mu^+\mu^-$ or $e^+e^-$, using electron-positron collisions recorded at an energy at or near the $\Upsilon(4S)$ mass and…

Light pseudoscalars interacting pre-dominantly with Standard Model gauge bosons (so-called axion-like particles or ALPs) occur frequently in extensions of the Standard Model. In this work we review and update existing constraints on ALPs in…

This contribution illustrates a new search for the flavor-changing neutral-current decay ${B^+ \to K^+ \nu \bar \nu}$ performed by the Belle II experiment at the SuperKEKB asymmetric-energy electron-positron collider. In this study, a…

The Belle II experiment at the Super B factory SuperKEKB, an asymmetric $e^+e^-$ collider located in Tsukuba, Japan, is tailored to perform precision B physics measurements. The centre of mass energy of the collisions is equal to the rest…