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@MASTERSTHESIS{Sulimann:615859,
author = {Sulimann, Sen},
othercontributors = {Tackmann, Kerstin and Moreira de Carvalho, Ana Luisa},
title = {{S}uppression of {L}ight $q\bar{q}$ {B}ackgrounds with
{M}ultivariate {T}echniques in the {M}easurement of
{R}adiative {B}-{M}eson {D}ecays},
school = {University of Hamburg},
type = {Bachelorarbeit},
address = {Hamburg},
reportid = {PUBDB-2024-06300},
pages = {66},
year = {2024},
note = {Bachelorarbeit, University of Hamburg, 2024},
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.},
cin = {BELLE},
cid = {I:(DE-H253)BELLE-20210408},
pnm = {611 - Fundamental Particles and Forces (POF4-611)},
pid = {G:(DE-HGF)POF4-611},
experiment = {EXP:(DE-H253)BELLE-20150101},
typ = {PUB:(DE-HGF)2},
url = {https://bib-pubdb1.desy.de/record/615859},
}