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 study of flavour-changing neutral currents (FCNC) gives access toimportant tests of the Standard Model (SM) and allows to search for hints ofbeyond the SM phenomena. We present here the study of the very rare decays$B^0\rightarrow \mu^+\mu^-$ and $B_s^0\rightarrow \mu^+\mu^-$ using datacorresponding to an integrated luminosity of 25 fb$^{-1}$ of $7$~TeV and$8$~TeV proton-proton collisions collected with the ATLAS detector during theLHC Run 1. For $B^0$, an upper limit on the branching fraction is set atBR$(B^0 \rightarrow \mu^+\mu^-) < 4.2\times 10^{-10}$ at 95\% confidence level.For $B^0_s$, the branching fraction BR$(B^0_s \rightarrow\mu^+\mu^-)=(0.9^{+1.1}_{-0.8})\times 10^{-9}$ is measured. The results areconsistent with the SM expectation with a p-value of 4.8\%, corresponding to2.0 standard deviations. Another study sensitive to possible new physicscontributions in $b \rightarrow s\ell\ell$ decays is the angular analysis ofthe decay $B^0 \rightarrow K^*\mu^+\mu^-$. Here we present the results obtainedusing proton-proton collisions at $\sqrt{s}=8$~TeV from LHC data collected withthe ATLAS detector. The study is based on 20.3 fb$^{-1}$ of integratedluminosity collected during 2012. Measurements of the $K^*$ longitudinalpolarisation fraction and a set of angular parameters obtained for this decayare presented. The results are compared to a variety of theoretical predictionsand found to be compatible with them.

Study of $b \to s\ell\ell$ decays at ATLAS