Bachelorarbeiten zur Datenanalyse
| Thema: | Search for long-live axionlike particles deaying 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 tau 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. Currently, work on this is ongoing for the case of a promptly-decaying ALP. However, it is expected that searching for a long-lived ALP would be able to produce significantly better cross section upper limits. In this project, you will study the production of a long-lived tauphilic ALP a in the process ee→γa(→ττ). A key goal will be to determine the expected level of background and to analyse the dominant processes that compose this background. This project will also focus on determining appropriate signal selection strategies for the displaced ALP vertex, and methods to help with signal-background discrimination. This leads to the outcome of this project which will be the first-ever expected cross section limits for such an ALP within this mass range. |
| Sie lernen kennen: | BSM B meson physics, python programming, statistical data analysis |
| Referent: | Prof. Dr. Torben Ferber (he/him) |
| Ansprechpartner: | Dr. Priyanka Cheema (she/her) |
| Letzte Änderung: | 01.08.2026 |
| Thema: | Event classification in B- → μ- μ- π+ decay at Belle II |
| Zusammenfassung: | The lepton number violating process B- → μ- μ- π+ is forbidden in the Standard Model. However, if neutrinos are their own antiparticles, processes that involve lepton-number violation can proceed via the production of on-shell Majorana neutrinos. The aim of this thesis is to optimize the selection criteria for the B- → μ- μ- π+ decay at Belle II using ML-based tools to suppress background processes. |
| Sie lernen kennen: | BSM B meson physics, python programming, statistical data analysis |
| Referent: | Prof. Dr. Torben Ferber (he/him) |
| Ansprechpartner: | Dr. Pablo Goldenzweig (he/him) |
| Letzte Änderung: | 23.07.2026 |
| 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 → K τ+ τ- 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: | 23.07.2026 |