Measurement of time-dependent $CP$ violation in $B^0_s \to D^\mp_s K^\pm$ decays with LHCb

In $B^0_s \to D^\mp_s K^\pm$ decays $CP$ violation in the interference between direct decay and decay after mixing results in a time-dependent asymmetry of the decay rates. From a measurement of this asymmetry five $CP$ observables can be determined, which are themselves sensitive to the CKM angle $\gamma$. In order to probe the unitarity of the CKM matrix it is crucial to improve on the precision of $\gamma$, as it is the least well known CKM angle. The presented analysis uses the full Run I dataset of $3 \text{fb}^{−1}$ of $pp$ collisions that was collected at centre-of-mass energies of 7 and 8 TeV with the LHCb detector.