Study of $B_c^+ \to J/\psi D_s^+$ and $B_c^+ \to J/\psi D_s^{*+}$ decays with the ATLAS detector

The results of the measurement of the $B_c^+ \to J/\psi D_s^+$ and $B_c^+ \to J/\psi D_s^{*+}$ decay properties with the ATLAS experiment are presented. The analysis uses $pp$ collision data collected by ATLAS at $\sqrt{s} = 7$ and $8$~TeV. The ratios of the branching fractions of the two decays and that of a reference mode $B_c^+ \to J/\psi \pi^+$ are measured. The transverse polarisation fraction in the $B_c^+ \to J/\psi D_s^{*+}$ decay is determined. The results are found to be in agreement with the earlier LHCb measurement. Available theoretical predictions for the measured properties are generally consistent with the data.