guest ::
| Home > Publications database > Suppression of Light $q\bar{q}$ Backgrounds with Multivariate Techniques in the Measurement of Radiative B-Meson Decays |
| Home > Publications database > Suppression of Light $q\bar{q}$ Backgrounds with Multivariate Techniques in the Measurement of Radiative B-Meson Decays |
| Bachelor Thesis | PUBDB-2024-06300 |
; ;
2024
Hamburg
Abstract: The Standard Model of particle physics has been highly successful in describing fundamental particles and their interactions, but potential extensions are needed to address itslimitations. Precise measurements of rare decays, such as the radiative B → Xsγ decay, provide an opportunity to test Beyond Standard Model (BSM) theories, due to them being suppressed by the Standard Model. This thesis focuses on the suppression of lightquark-antiquark ($q\bar{q}$) continuum backgrounds, a dominant source of noise in the analysis of the B → $X_sγ$ decay, using multivariate classification techniques to improve the signal to -background ratio. Furthermore, an attempt is made to suppress $B\bar{B}$-backgrounds. In particular, Boosted Decision Trees (BDTs) are trained to differentiate the rare B → $X_sγ$ signal from continuum and $B\bar{B}$-backgrounds. Specifically, two approaches are employed: multi-class classifiers and the consecutive application of binary classifiers. The data analyzed were collected by the Belle II detector from $e^+e^−$ -collisions at the SuperKEKB collider in Japan. The work presented in this thesis includes the selection and analysis of discriminating variables, the development and training of BDTs, and the evaluation of their performance. The trained models demonstrate promising results in suppressing background noise, especially continuum events. The analysis provides valuable insights into the variable importance and limitations of the single approaches, as well as the potential for future refinement.
|
The record appears in these collections: |
PDF
PDF (PDFA)