Student Projects and Thesis

List of topics for theses (bachelor, master, doctoral):

  • B-physics at the ATLAS experiment with the following potential topics:
    • Links to SIS: bachelor/diploma, doctoral
    • Specific work to be adjusted to the current status of analyses at ATLAS:
      • Analysis of decay Bs → J/ψφ (measurement of CP-violation)
      • Analysis of decay Bd → K*μμ (search for New Physics effects)
      • Event selection and background suppression in the decays above
      • Evaluation of systematic uncertainties in the analyses above
      • Studies of trigger in the analyses above
      • Studies of mass-(time)-angular fit model in the decays above

Projects topics include:

  • Physics of elementary particles (b-hadrons) at the ATLAS experiment, including work with real data and simulations
    • The student will be introduced to the ATLAS experiment at CERN and to the basic principles of reconstruction of decays of hadrons containing b-quarks (b-hadrons). The analyses of production and decays of these particles allow to test predictions of the Standard Model of elementary particles and search for deviations caused by New Physics (new particles). These measurements form an alternative to the direct searches for new particles, with the advantage of possible sensitivity to heavy particles not directly accessible at the accelerator. The student will choose a specific topic, including background suppression, detector resolution, systematic uncertainties, statistical methods etc. (see topics below).
  • Tests and developments of analysis and statistics tools (mainly focused on B-physics)
  • Learn C++ (ROOT), Latex, possibly Python and work in Linux OS within the projects

List of student projects, see also IPNP SFG page, study department and SIS (obsolete !):

  • Optimization of the selection of b-hadron decays in the ATLAS experiment
    • An important step in analyzing a specific b-hadron decay is the suppression of possible backgrounds. These can come either from other specific b-hadron decays, or as a pure random combinatorics of several decays or processes. The aim of the project is to write macros for background suppression, based on tuned selections (cuts) of kinematical and other properties of the analyzed b-decay, possibly also trying advanced multivariate techniques.
  • Evaluation of the performance of reconstruction of b-hadron decays at the ATLAS experiment
    • Knowledge of the precision of reconstruction of b-hadron decays at the experiment is a key to successful analysis. The aim of the project is study of the detector precision in several kinematic variables of b-hadron, and finding a functional form to describe them. The work is done on simulations, but can be also enhanced to try basic comparisons with real data.
  • Fast simulations of the b-hadron events in the future ATLAS Upgrade experiment (using Delphes package)
    • Proper simulations of processes in the large experiments as ATLAS are usually slow and very CPU demanding. Delphes is a piece of SW trying to provide fast simulations, based on the approximate parametrization of the detector performance. The aim of the project is to study the Delphes SW and try to use it to compare the “full” proper simulation, using simulated data of b-hadron decays at the ATLAS Experiment.
  • Toy Monte-Carlo studies of the b-hadron analyses with the ATLAS experiment
    • Analysis of b-hadrons at the ATLAS experiment usually includes complicated multidimensional fits, typically of b-hadron decay angles, mass and decay time. The aim of this project is to study the precision and biases in these fits, using so-called toy Monte-Carlo data: i.e. data generated from the fit-functions themselves.
  • Implementation of b-hadron decay angular distributions in RooFit package
    • Analysis of b-hadrons at the ATLAS experiment usually includes complicated multidimensional fits, typically of b-hadron decay angles, mass and decay time. Some of these fit-functions need are not available with the used fit-SW RooFit. The aim of the project is to implement the most common fit-function in the RooFit SW, namely for b-hadron mass distribution or decay angles.
  • Study of b-hadron event generators (Pythia, EvtGen)
    • Analyses of b-hadron decays required studying via simulations. There are several SW packages allowing fast generator-level simulations (i.e. not simulating specific experiment) to learn about possible background processes or to study the effects of kinematic selections. The aim of the project is to study some of those effects.
  • Study of data-fit tools
    • The particle physics experiments rely upon complicated statistical methods, as for example data fits with predefined functions. There is a number of SW tools to perform these operations. The aim of the project is to compare the performance and features of some of the most common tools (ROOT, R-language, python numpy, …). The tests will be using data from b-hadron decays at the ATLAS experiment.
  • ROOT-based online analysis of gamma spectra
    • Practical courses of nuclear physics at IPNP MFF UK often include analyses of measured gamma spectra – finding peaks and their properties like position, the width or the signal yield. The aim of the project is to develop such an analysis using ROOT SW.
  • Test functional decomposition to search for new particles in ATLAS B-physics data
    • Search for new particles is often based on a search for peaks in invariant mass or other spectra. There are number of techniques revealing such peaks and determining their statistical significance. A new method called functional decomposition has been developed recently. The aim of the project is to document and test the methods on typical b-hadron spectroscopy analysis.