Bachelorarbeiten zur Datenanalyse
| Thema: | Dynamic reweighting of B-meson branching ratios at Belle II |
| Zusammenfassung: | In experiments such as Belle II, we rely on large Monte Carlo simulations to model background processes. Producing these simulations takes months on distributed computing systems, so they cannot be regenerated frequently. At the same time, our knowledge of how particles decay improves over time as new measurements are made. Existing simulations that use this information do not automatically reflect these improvements and therefore become outdated. This leads to a mismatch between the decay information used in existing simulations and current experimental knowledge. In this project, you will develop a software framework that compares the decay information stored in simulated events with up to date decay information. Based on this comparison, the framework will apply corrections or reweightings to the outdated simulation output without rerunning the full simulation again. Using the rare decay B->Ktautau as a primary use case, you will study the impact of these updates on signal sensitive physics observables. In such rare decay channels, even small mismodeling of dominant background branching fractions can fake a new physics signal or hide a real effect. |
| Sie lernen kennen: | python programming, information parsing, databases, template fitting, rare decay analysis |
| Referent: | Prof. Dr. Torben Ferber (he/him) |
| Ansprechpartner: | Lennard Damer (he/him) |
| Letzte Änderung: | 30.01.2026 |
| Thema: | Searching axion-like-particle decaying into tau leptons at Belle II |
| Zusammenfassung: | Axion-like-particles (ALPs) are well-motivated extensions of the Standard Model that could explain dark matter and other anomalies. Belle II provides an excellent opportunity to search for ALPs, in particular ALPs that dominantly couple to τ leptons, so-called tauphilic ALPs. Within the mass range Belle II is capable of exploring, the parameter space for such tauphilic ALPs is largely unexplored. In this project, you will study the production of a tauphilic ALP a in the process ee→γa(→ττ). A key difficulty in this search is determining the optimal strategy for the τ lepton reconstruction. The τ lepton can decay either into an electron or muon (and neutrinos) or into hadrons, and furthermore, some hadronic decays include multiple pi0 mesons that are challenging to reconstruct. Choosing between these groups, or deciding to combine them, has direct impacts on the signal efficiency and background rejection, both of which strongly determine the sensitivity of this search. Therefore, the focus of this project will be on exploring these different τ reconstruction strategies and using data analysis techniques to determine which strategy maximises the search sensitivity. |
| Sie lernen kennen: | python programming, data analysis, BSM searches |
| Referent: | Prof. Dr. Torben Ferber (he/him) |
| Ansprechpartner: | Dr. Priyanka Cheema (she/her) |
| Letzte Änderung: | 30.01.2026 |