Measurement of the time dependent CP Asymmetry of $B \to K^* \gamma$ decays in the Belle II experiment

Sumitted to PubDB: 2023-02-01

Category: Phd Thesis, Visibility: Public

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Authors	Jerome Baudot, Tristan Fillinger
Date	Jan. 1, 2022
Belle II Number	BELLE2-PTHESIS-2023-002
Abstract	The Standard Model of particle physics, which describes the fundamental particles and their interactions, is the most successful theory in the history of science. For decades it has been tested by numerous scientific collaborations with great success. However, the theory remains incomplete. In order to find evidence of physics beyond the Standard Model, the experiments are upgraded to gather more and more data with higher accuracy. This thesis presents the proposition of a new vertex detector for the Belle~II experiment, along with its software implementation. With Belle, this thesis presents a new time-dependent measurement of the $CP$ violation with $B^0 \to K^{0}_{S} \pi^+ \pi^- \gamma$, which can improve the constrains on some Standard Model parameters. With Belle II, the rediscovery of $B^0 \to K^{0}_{S} \pi^+ \pi^- \gamma$ and the branching fraction measurement of $B^0 \to K^{0}_{S} \pi^0 \gamma$ with around 190 fb$^{-1}$ is described. The result of ${\cal B}\left(B^0 \to K^{0}_{S} \pi^0 \gamma\right) = \left(7.28 \pm 1.75\mathrm{(stat) \pm 1.03\mathrm{(syst) \right) \times 10^{-6}$ is compatible with the predictions.
Conference	Strasbourg