التفاصيل البيبلوغرافية
| العنوان: |
Measurement of the branching fraction, longitudinal polarization fraction, and charge-parity violating asymmetry in $B^+\rightarrow\rho^+\rho^0$ decays at Belle |
| المؤلفون: |
GANIEV, ELDAR |
| المساهمون: |
Ganiev, Eldar, TONELLI, DIEGO |
| بيانات النشر: |
Università degli Studi di Trieste |
| سنة النشر: |
2021 |
| المجموعة: |
Università degli studi di Trieste: ArTS (Archivio della ricerca di Trieste) |
| مصطلحات موضوعية: |
Particle physic, Standard model, CP violation, Belle, KEKB, Settore FIS/04 - Fisica Nucleare e Subnucleare |
| الوصف: |
This is an experimental particle physics thesis aimed at measurements of properties of $B^+\rightarrow\rho^+\rho^0$ decays for the determination of the quark-mixing matrix angle \newline \mbox{$\alpha/\phi_2=\text{arg}(-(V_{td}V^*_{tb})/(V_{ud}V^*_{ub}))$}, a fundamental parameter of quark dynamics. The analysis uses the full data set of electron-positron ($e^+e^-$) collisions produced by the energy-asymmetric KEKB collider at the $\Upsilon(4S)$ resonance collected by the Belle experiment and corresponding to 772 million pairs of bottom-antibottom mesons. Belle is an hermetic magnetic spectrometer surrounded by particle-identification detectors, calorimeters, and muon detectors designed to reconstruct the decay products of 10.58 GeV $e^+e^-$ collisions. The analysis is entirely developed using simulated and control-data samples. Only when all procedures are established the analysis is applied to the signal candidates in data. The principal challenge is to overcome the initial $10^{-6}$ signal-to-background ratio with a selection sufficiently discriminating to isolate an abundant, low-background signal without introducing intractable correlations in the multidimensional fit that determines the parameters of interest. Data are enriched in $B^+\rightarrow\rho^+\rho^0$ events by a multivariate statistical-learning selection that suppresses the most prominent source of background. A multidimensional fit of sample composition then identifies statistically the signal. Special care is devoted to keep the impact of systematic uncertainties under control. A total of approximately 1000 $B^+\rightarrow\rho^+\rho^0$ decays are reconstructed. The fit results, combined with acceptance and efficiency corrections determined from simulation, allow for determining the $B^+\to\rho^+\rho^0$ branching fraction, \begin{center} $\mathcal{B}(B^+\rightarrow\rho^+\rho^0)~=~[\text{xx}]^{+1.20}_{-1.19}~(\textrm{stat})\pm 1.46~(\textrm{syst})$, \end{center} the fraction of longitudinally polarized $B^+\rightarrow\rho^+\rho^0$ decays, ... |
| نوع الوثيقة: |
doctoral or postdoctoral thesis |
| اللغة: |
English |
| العلاقة: |
http://hdl.handle.net/11368/2995661Test |
| الإتاحة: |
http://hdl.handle.net/11368/2995661Test |
| حقوق: |
info:eu-repo/semantics/openAccess |
| رقم الانضمام: |
edsbas.E13E7317 |
| قاعدة البيانات: |
BASE |
