Optimization of the signal selection of exclusively reconstructed decays of B0 and B/s mesons at CDF-II

Doerr, Christian

doi:10.2172/907804

Title: Optimization of the signal selection of exclusively reconstructed decays of B0 and B/s mesons at CDF-II

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Abstract

The work presented in this thesis is mainly focused on the application in a Δm_s measurement. Chapter 1 starts with a general theoretical introduction on the unitarity triangle with a focus on the impact of a Δm_s 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 Δm_s (Δm_d) 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 B_s → D_sπ, D_s→ Φπ, Φ → KK. Chapter 7 uses events selected by the neuralmore »« less

Authors:

Doerr, Christian ^[1]

Univ. of Karlsruhe (Germany)

Publication Date:: Fri Jun 23 00:00:00 EDT 2006

Research Org.:: Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

Sponsoring Org.:: USDOE

OSTI Identifier:: 907804

Report Number(s):: FERMILAB-THESIS-2006-41
TRN: US0703320

DOE Contract Number:: AC02-07CH11359

Resource Type:: Thesis/Dissertation

Country of Publication:: United States

Language:: English

Subject:: 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS, 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; AMPLITUDES; B MESONS; DECAY; FERMILAB COLLIDER DETECTOR; FERMILAB TEVATRON; LIFETIME; MAXIMUM-LIKELIHOOD FIT; MESONS; NEURAL NETWORKS; OPTIMIZATION; UNITARITY; Experiment-HEP; Instrumentation

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                    Doerr, Christian. Optimization of the signal selection of exclusively reconstructed decays of B0 and B/s mesons at CDF-II.  United States: N. p., 2006. 
        Web.  doi:10.2172/907804.

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                    Doerr, Christian. Optimization of the signal selection of exclusively reconstructed decays of B0 and B/s mesons at CDF-II.  United States.  https://doi.org/10.2172/907804

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                    Doerr, Christian. 2006.  
        "Optimization of the signal selection of exclusively reconstructed decays of B0 and B/s mesons at CDF-II".  United States.  https://doi.org/10.2172/907804.  https://www.osti.gov/servlets/purl/907804.

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@article{osti_907804,

  title        = {Optimization of the signal selection of exclusively reconstructed decays of B0 and B/s mesons at CDF-II},

  author       = {Doerr, Christian},

  abstractNote = {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.},

  doi          = {10.2172/907804},

  url          = {https://www.osti.gov/biblio/907804},
  journal      = {},
number       = ,

  volume       = ,

  place        = {United States},

  year         = {Fri Jun 23 00:00:00 EDT 2006},

  month        = {Fri Jun 23 00:00:00 EDT 2006}

}

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