Thesis BELLE2-MTHESIS-2023-013

CP violation in B decays at Belle II

Mehraj Chhetri ; Dr Jim Libby

Indian Institute of Technology Madras Chennai

Abstract: The $CP$ violation in the standard model can be observed through the decay of $B$ meson and a parameter which gives a measure of $CP$ violation is the angle $\phi_3$ of the unitarity triangle. Precisely measuring $\phi_3$ is an essential test for the standard model, and such measurements can be made using tree-level decays that are unaffected by new physics. The optimal approach for obtaining highly precise measurements of $\phi_3$ involves the use of the $B\rightarrow DK$ decay channel, which currently offers the most sensitive method for performing these measurements. This dissertation explores the possibility of measurement of angle $\phi_3$ using model-independent Dalitz plot analysis of $B^{\pm} \rightarrow D\:(K_L^0\:\pi^+\pi^-)\:K^{\pm}$ where $D$ can either be $D^0$ or $\Bar{D}^0$. The decay channel is reconstructed using kinematic constraint. The signal is then extracted by employing a fast-boosted decision tree technique to suppress the continuum background. However, the present study concludes that the precision measurement of $\phi_3$ cannot be achieved using this mode due to the weak signal strength, which imposes limitations on the statistical accuracy. The analysis is performed on a simulated data sample generated at the $\Upsilon(4S)$ center of mass energy of $e^- e^+$ collision at Bele II, with an integrated luminosity corresponding to $200\:\mathrm{fb}^{-1}$.

Note: Presented on 15 05 2023
Note: MSc

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 Record created 2023-05-23, last modified 2023-05-23

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