Optimization of the signal selection of exclusively reconstructed decays of B0 and B/s mesons at CDF-II
- Univ. of Karlsruhe (Germany)
The work presented in this thesis is mainly focused on the application in a Δms measurement. Chapter 1 starts with a general theoretical introduction on the unitarity triangle with a focus on the impact of a Δms measurement. Chapter 2 then describes the experimental setup, consisting of the Tevatron collider and the CDF II detector, that was used to collect the data. In chapter 3 the concept of parameter estimation using binned and unbinned maximum likelihood fits is laid out. In addition an introduction to the NeuroBayes{reg_sign} neural network package is given. Chapter 4 outlines the analysis steps walking the path from the trigger level selection to fully reconstructed B mesons candidates. In chapter 5 the concepts and formulas that form the ingredients to an unbinned maximum likelihood fit of Δms (Δmd) from a sample of reconstructed B mesons are discussed. Chapter 6 then introduces the novel method of using neural networks to achieve an improved signal selection. First the method is developed, tested and validated using the decay B0 → Dπ, D → Kππ and then applied to the kinematically very similar decay Bs → Dsπ, Ds→ Φπ, Φ → KK. Chapter 7 uses events selected by the neural network selection as input to an unbinned maximum likelihood fit and extracts the B0 lifetime and Δmd. In addition, an amplitude scan and an unbinned maximum likelihood fit of Δms is performed, applying the neural network selection developed for the decay channel Bs → Dsπ, Ds → Φπ, Φ → KK. Finally chapter 8 summarizes and gives an outlook.
- Research Organization:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-07CH11359
- OSTI ID:
- 907804
- Report Number(s):
- FERMILAB-THESIS-2006-41; TRN: US0703320
- Country of Publication:
- United States
- Language:
- English
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