Experimental Flavor Physics

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Bachelor Thesis Topics

Image: Particle2

Sensitivity to the rare decay B -> e nu

Purely leptonic decays of B mesons are rare processes because of low coupling between b and u quarks and helicity suppression. The latter is in particular reducing the branching ratio of B -> e nu decays so that an observation at Belle II would be a clear sign of new physics. A search for this decay should be set up and the sensitivity estimated.

Optimization of particle identification

For many analyses it is essential to know the type of a detected particle. Several detector components provide information that can be used to distinguish electrons, muons, pions, kaons, protons and deuterons. At Belle II this information is encoded in likelihoods for the different particle types. A method to optimally combine the measurements of the different detectors using prior probabilities should be developed and compared with alternative methods, e.g. based on machine learning techniques.

Measurement of anti-deuteron production

The understanding of fluxes of cosmic anti-matter is important for example to estimate backgrounds of dark matter annihilation signals. The particle identification capabilities of Belle II will allow to measure the production of anti-deuteron in e+e- collisions. A measurement technique to determine the anti-deuteron production cross-sections should be developed.

Sensitivity to tau neutrino mass at Belle II

Neutrino oscillations and cosmological arguments provide tight constraints on the neutrino masses, but direct limits on the tau neutrino mass are still at the order of several MeV. The known kinematics of tau lepton pairs produced at Belle II allows to derive a constraint on the tau neutrino mass by measuring the energy of the detectable final state particles in hadronic tau decays. The sensitivity of such a measurement should be studied.

Averaging of measurements

The same physical quantities are often measured by different experiments or with different methods. To optimally exploit the measurements they are combined. The averaging procedure has to take into account the correlations between the measurements. A survey of existing tools should be done and the results applied to the tools of the Heavy Flavor Averaging Group for B to charm decays.

Development of services for future particle detectors

Highly granular calorimeters are important for the accurate reconstruction of events at future collider experiments. The high number of cells in such a calorimeter requires compact power supplies with many individually controllable channels. There are various opportunities to contribute to the design, construction, and characterization of power supply prototypes.


A structured program is offered for the bachelor theses in the summer semester.