Impact of the Velo 2 half misalignment on physical quantities

The impact of the misalignment of the Vertex Locator of the LHCb experiment on the physical quantities of the decay "$D^{*+} \rightarrow (D^{0}\rightarrow K^{-}\pi^{+}) \pi^{+} $" is studied in this note. Different misalignments of the 2 halves are applied to Monte Carlo data and the variations of the physical quantities with respect to the case without misalignment are evaluated. The results show the importance of the VELO 2 half alignment which can significantly affect the physics performance in the large misalignment case. A misalignment equal to the precision of the real-time alignment of the Vertex Locator is found to have a negligible effect on the studied physical quantities.