Measurement of time-dependent $\mathcal{CP}$ violation in charmless B decays at LHCb

In the following we present the measurements of time-dependent $\mathcal{CP}$ violation in charmless B meson decays performed by LHCb analyzing the $p-p$ collision data collected at a center-of-mass energy of 7 TeV during the 2010 and 2011 LHC runs. In particular we will focus on the analysis of charmless two-body B decays where the direct and mixing-induced CP asymmetry terms of the $B^{0}\to\pi^{+}\pi^{-}$ and $B_{s}^{0}\to K^{+}K^{-}$ decays have been measured using 0.69 fb$^{-1}$ of data collected during 2011. The measurement of the branching ratio of the $B_{s}^{0}\to K^{*0}\bar{K}^{*0}$ decay, using 35 pb$^{-1}$ collected during 2010, is also reported. In the end we show the relative branching ratios of all the decay modes of $B_{(s)}^{0}\to K_S h^{+}h^{\prime -}$ decays (where $h^{(\prime)}=\pi,K$), measured analyzing 1 fb$^{-1}$ of data collected during 20 11.