Main Image
Volume 377 - 18th International Conference on B-Physics at Frontier Machines (Beauty2019) - Rare decays
Radiative decays at LHCb
P. Krokovny
Full text: pdf
Pre-published on: 2020 February 10
Published on:
The radiative decay Lambda_b -> Lambda gamma is observed for the first time using a data sample of proton-proton collisions corresponding to an integrated luminosity of 1.7 1/fb collected by the LHCb experiment at a center-of-mass energy of 13 TeV. Its branching fraction is measured to be B(Lambda_b -> Lambda gamma) = (7.1 +- 1.5 +- 0.6 +- 0.7) 10^{-6}, where the quoted uncertainties are statistical, systematic and systematic from external inputs, respectively.

A time-dependent analysis of the Bs -> phi gamma decay rate is performed to determine the CP-violating observables S and C, 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 S= 0.43 +- 0.30 +- 0.11, C= 0.11 +- 0.29 +- 0.11, Adelta = -0.67 +0.37 -0.41 +- 0.17, where the first uncertainty is statistical and the second systematic. The results are consistent with the Standard Model predictions.
Open Access
Creative Commons LicenseCopyright owned by the author(s) under the term of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.