Measurement of $CP$ violation in two-body charged charmless decays of $B$ mesons at LHCb.

Perazzini S., Fazzini D.
  Martedì 12/09   09:00 - 13:00   Aula A208   I - Fisica nucleare e subnucleare
$CP$ violation observables in charmless charged two-body $B$ decays may provide important informations in the discovery of New Physics. Thanks to the characteristics of the LHCb detector and the large beauty production cross-section, unprecedented samples of such decays are now available. We will present the final measurements of direct and mixing-induced $CP$ violation in $B_{d}\rightarrow \pi^{+} \pi^{-}$ and $B_{s}\rightarrow K^{+} K^{-}$ decays, updated to the full Run I data-sample of 3 $fb^{-1}$. The new measurements improve considerably the previous LHCb results and in $B_{d}\rightarrow \pi^{+}\pi^{-}$ have a precision comparable with the $B$ factories. The achievement of these significant results has been possible exploiting the larger data-sample and the new algorithms for tagging the flavour of the $B-mesons$ at production.