English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The Belle II experiment at the SuperKEKB energy-asymmetric $e^+ e^-$ collideris a substantial upgrade of the B factory facility at the Japanese KEKlaboratory. The design luminosity of the machine is $8\times 10^{35}$cm$^{-2}$s$^{-1}$ and the Belle II experiment aims to record 50 ab$^{-1}$ ofdata, a factor of 50 more than its predecessor. From February to July 2018, themachine has completed a commissioning run, achieved a peak luminosity of$5.5\times 10^{33}$ cm$^{-2}$s$^{-1}$, and Belle II has recorded a data sampleof about 0.5 fb$^{-1}$. Main operation of SuperKEKB has started in March 2019.We use this dataset to characterize the performance of the detector regardingthe tracking of charged particles, the reconstruction of known resonances, andthe capability of identifying displaced decay vertices. To assess the B Physicscapabilities of the experiment, one of the first benchmarks consists in themeasurement of the lifetime of B mesons and of the $B^0-\bar B^0$ mixingfrequency. We present the first results, based on samples of B mesons thatdecay to hadronic and semileptonic final states.

B lifetime and $B^0-\bar B^0$ mixing results from early Belle II data