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\noindent {\bf Preface}  \vspace{\baselineskip} 

This work has been carried out by the LHCb collaboration, which is an international
collaboration of more than 1400 scientists and engineers from 86 institutes in 19 countries. This implies the usage of common software to analyze the data collected by the LHCb experiment. Both the collection of the data and the development of common software used to analyze the data stems from the effort of many current and former collaboration members. No part of this work would have been possible without the numerous contributions of the other (ex-)members of the collaboration.

This analysis is a significant advance towards the first angular analysis of the \BuToKstmm  decay with the \Kstar decaying into $\Kp\piz$ at the \lhcb. The challenging reconstruction of the \piz resulted in unforeseen challenges leading to large statistical uncertainties. 
All aspects of the analysis have been carefully studied and fully implemented in pseudoexperiments. Those are then used to extract the expected sensitivity to New Physics contributing to the angular parameters. With the current dataset, no sufficient impact on the knowledge of this  parameters could be reached.
However, this study still provides an important insight into the \BuToKstKppizmm decay, presents solutions to many unexpected complications, and will serve as a basis for future analyses performed using the anticipated \runIII dataset.

This analysis has been carried out with the supervision of post-doctoral researchers at the Heidelberg University and at the \'{E}cole Polytechnique F\'{e}d\'{e}rale de Lausanne. The author is responsible for the implementation of the selection software and the modifications to the \fcncfitter. The validation of this implementation has been done in close collaboration with another PhD student. 

Moreover, as the collaboration task, the author worked on the development of the software tool \TrackCalib. \TrackCalib provides the means to correct for the track reconstruction efficiency in any \lhcb analysis. The author is also responsible for the validation and modifications of the corresponding tracking efficiency trigger and stripping lines, providing the collaboration with the best possible tracking efficiency estimation. This has been done in collaboration with a post-doctoral researcher at the Heidelberg University.
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