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Charmed hadron spectroscopy is a quickly progressing field that has enjoyed a growing interest in recent years from both theorist and experimentalists. Open-charmed hadrons consist of a heavy quark bound to a light quark (, , quarks). These particles are in particular spin-parity states making for a very interesting quantum mechanical system allowing the study of the QCD potential holding them together. Decays of type offer a rich environment to study charmed spectroscopy thanks to their abundance and low background. Using collision data at 7, 8, and 13 TeV center-of-mass energies corresponding to an integrated luminosity of collected with the LHCb detector at CERN's Large Hadron Collider, this thesis presents the most accurate measurement to-date of four branching fraction ratios of modes. These are measured to be \begin{equation*} \begin{split} \frac{\mathcal{B} (B^+ \rightarrow D^{+}D^-K^+)}{\mathcal{B} (B^+ \rightarrow \overline{D}^{0}D^0K^+)} &= 0.590 \pm 0.017 (\mathrm{stat}) \pm 0.008 (\mathrm{syst}) \pm 0.013 (\mathcal{B}(D)) , \[10pt] \frac{\mathcal{B} (B^+ \rightarrow D^{-}D^+K^+)}{\mathcal{B} (B^+ \rightarrow \overline{D}^{0}D^0K^+)} &= 0.524 \pm 0.015 (\mathrm{stat}) \pm 0.007 (\mathrm{syst}) \pm 0.012 (\mathcal{B}(D)) , \[10pt] \frac{\mathcal{B} (B^0 \rightarrow D^{-}D^0K^+)}{\mathcal{B} (B^0 \rightarrow D^{-}D^0K^+} &= 1.767 \pm 0.028 (\mathrm{stat}) \pm 0.018 (\mathrm{syst}) \pm 0.036 (\mathcal{B}(D)) , \[10pt] \frac{\mathcal{B} (B^+ \rightarrow D^{+}D^-K^+)}{\mathcal{B} (B^+ \rightarrow D^{-}D^+K^+)} &= 1.098 \pm 0.040 (\mathrm{stat}) \pm 0.017 (\mathrm{syst}), \end{split} \end{equation} where the first uncertainty is statistical, the second systematic, and the third is due to the uncertainties on the meson decay branching fractions measured by other experiments. Furthermore, this thesis shows the Dalitz plots of the final states for these decay modes using data samples an order of magnitude larger than samples collected by other experiments. These measurements are an important step towards a full amplitude analysis of decays.
In addition, this thesis summarizes the installation and studies of the BCAM system used to monitor the position of the Inner Tracker detector of LHCb.
Olivier Schneider, Aurelio Bay, Yi Zhang, Yi Wang, Guido Haefeli, Frédéric Blanc, Tatsuya Nakada, François Fleuret, Elena Graverini, Renato Quagliani, Federico Betti, Sebastian Schulte, Veronica Sølund Kirsebom, Jian Wang, Mingkui Wang, Zhirui Xu, Zheng Wang, Lei Zhang, Christoph Frei, Jessica Prisciandaro, Mark Tobin, Minh Tâm Tran, Niko Neufeld, Matthew Needham, Marc-Olivier Bettler, Michel De Cian, Greig Alan Cowan, Maurizio Martinelli, Vladislav Balagura, Liang Sun, Pietro Marino, Luca Pescatore, Mirco Dorigo, Xiaoxue Han, Liupan An, Federico Leo Redi, Chitsanu Khurewathanakul, Plamen Hristov Hopchev, Thibaud Humair, Maxime Schubiger, Hang Yin, Guido Andreassi, Violaine Bellée, Maria Vieites Diaz, Olivier Göran Girard, Axel Kuonen, Preema Rennee Pais, Pavol Stefko, Tara Nanut, Maria Elena Stramaglia, Tommaso Colombo, Vladimir Macko, Guillaume Max Pietrzyk, Evgenii Shmanin, Dipanwita Dutta, Yiming Li, Hans Dijkstra, Gerhard Raven, Peter Clarke, Frédéric Teubert, Victor Coco, Adam Davis, Paolo Durante, Yu Zheng, Anton Petrov, Maxim Borisyak, Chunhui Chen, Zhipeng Tang
Olivier Schneider, Aurelio Bay, Yi Zhang, Yi Wang, Guido Haefeli, Frédéric Blanc, Tatsuya Nakada, François Fleuret, Elena Graverini, Renato Quagliani, Federico Betti, Sebastian Schulte, Veronica Sølund Kirsebom, Jian Wang, Mingkui Wang, Zhirui Xu, Zheng Wang, Lei Zhang, Ho Ling Li, Christoph Frei, Mark Tobin, Minh Tâm Tran, Niko Neufeld, Matthew Needham, Marc-Olivier Bettler, Michel De Cian, Greig Alan Cowan, Maurizio Martinelli, Vladislav Balagura, Liang Sun, Pietro Marino, Luca Pescatore, Mirco Dorigo, Xiaoxue Han, Liupan An, Federico Leo Redi, Chitsanu Khurewathanakul, Plamen Hristov Hopchev, Thibaud Humair, Maxime Schubiger, Hang Yin, Guido Andreassi, Violaine Bellée, Olivier Göran Girard, Axel Kuonen, Preema Rennee Pais, Pavol Stefko, Tara Nanut, Maria Elena Stramaglia, Yao Zhou, Tommaso Colombo, Vladimir Macko, Guillaume Max Pietrzyk, Evgenii Shmanin, Simone Meloni, Xiaoqing Zhou, Surapat Ek-In, Dipanwita Dutta, Yiming Li, Hans Dijkstra, Gerhard Raven, Peter Clarke, Frédéric Teubert, Victor Coco, Adam Davis, Paolo Durante, Yu Zheng, Anton Petrov, Maxim Borisyak, Chunhui Chen, Zhipeng Tang, Katharina Müller, Xuan Li, Alexey Boldyrev, Almagul Kondybayeva, Hossein Afsharnia