Radiative decays at LHCb

The radiative decay $\Lambda _{b}^{0}$ $\rightarrow$ $\Lambda ^{0}$ $\gamma$ is observed for the first time using a data sample of proton-proton collisions corresponding to an integrated luminosity of 1.7 fb$^{-1}$ collected by the LHCb experiment at a center-of-mass energy of 13 TeV. Its branching fraction is measured to be B($\Lambda _{b}^{0}$ $\rightarrow$ $\Lambda ^{0}$ $\gamma$) = (7.1 $\pm$ 1.5 $\pm$ 0.6 $\pm$ 0.7) 10$^{-6}$, where the quoted uncertainties are statistical, systematic and systematic from external inputs, respectively.A time-dependent analysis of the $B_{S}^{0} \rightarrow \phi \gamma$ decay rate is performed to determine the CP-violating observables $\mathit{S}\phi \gamma $ and $\mathit{C}\phi \gamma $, and the mixing-induced observable Adelta. The measurement is based on a sample of pp collision data recorded with the LHCb detector, corresponding to an integrated luminosity of 3 1/fb at center-of-mass energies of 7 and 8 TeV. The measured values are $\mathit{S}\phi \gamma $= 0.43 $\pm$ 0.30 $\pm$ 0.11, $\mathit{C}\phi \gamma $= 0.11 $\pm$ 0.29 $\pm$ 0.11, $\mathit{C}\phi \gamma $ = -0.67 $\pm$ 0.37 -0.41 $\pm$ 0.17, where the first uncertainty is statistical and the second systematic. The results are consistent with the Standard Model predictions.