| Thema: | Recoil-assisted vertexing of displaced diphoton decays of axion-like particles at Belle II |
| Zusammenfassung: |
Belle II can search for axion-like particles (ALPs) that couple to photons and are produced in e+e- → γ a. For ALP masses below a few hundred MeV and small couplings, the decay a → γγ happens at macroscopic distances from the interaction point. This intermediate-lifetime region lies between prompt three-photon searches and searches for invisible final states.
Reconstructing a displaced vertex from photons is difficult because photons leave no tracks, however the recoil photon and the known initial state define the ALP flight line.
A single daughter photon that converts in the vertex detector then locates the decay vertex.
The goal of this MSc thesis is to test the method with full Belle II simulation. The steps include the reconstruction of photon conversions in the vertex detectors, the determination of conversion vertex and direction resolution, the implementation of the recoil-assisted vertex reconstruction, studies of prompt and reducible backgrounds including beam background, and an estimate of the expected sensitivity .
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| Sie lernen kennen: | BSM dark sector physics, photon reconstruction, python programming, statistical data analysis |
| Referent: | Prof. Dr. Torben Ferber (he/him) |
| Ansprechpartner: | Dr. Giacomo De Pietro (he/him) |
| Letzte Änderung: | 30.09.2026 |
| Thema: | Search for the charged lepton flavor violating B+ → K*+ τ+ ℓ- decay at Belle II |
| Zusammenfassung: |
The observation of charged lepton flavor violating B meson decays would constitute clear evidence for physics beyond the Standard Model. One such decay,
B+ → K*+ τ+ ℓ-, has recently been studied in the Belle II ETP group. As evidenced by this thesis, the analysis is at an advanced stage. The goal of this MSc thesis is to complete the analysis. The remaining steps include data/MC comparison studies, a comprehensive demonstration of fit stability, the final fit to data (including discovery or limit setting), and the evaluation of all systematic uncertainties.
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| 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: | 30.09.2026 |
| Thema: | Search for Beyond the Standard Model (BSM) Higgs Bosons |
| Zusammenfassung: |
We perform a search for additional Higgs bosons in the next-to-minimal supersymmetric standard model (NMSSM). In the signal process, a standard model (SM) Higgs boson (H) and a BSM Higgs boson Y are produced in the decay of a heavy particle X (X → YH).
We are performing this search in a final state, where one of the Higgs bosons decays into two τ-leptons and the other one into two bottom quarks.
With your thesis, you can contribute to the ongoing research based on the LHC Run-2 and Run-3 data, recorded with the CMS Detector in the years 2016--2025.
During your thesis, you can work on particular aspects of the analysis, a few example are:
- Include the boosted kinematic regime, where the Higgs bosons have high transverse momentum and the identification of decays into τ-leptons and b-quarks pose a challenge
- Improve the kinematic reconstruction of the Higgs boson decays into τ-leptons and b-quarks using neural networks
- Systematically study improvements in the parametric neural network-based event categorization
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| Sie lernen kennen: | BSM Higgs physics, data analysis, python programming, C++ programming, machine learning |
| Referent: | Prof. Markus Klute,
Priv. Doz. Dr. Roger Wolf |
| Ansprechpartner: | Dr. Nikita Shadskiy,
Moritz Molch |
| Letzte Änderung: | 20.08.2026 |
| Thema: | Differential (STXS) cross section measurement of single Higgs boson production |
| Zusammenfassung: |
A differential measurement of single Higgs boson production in the ττ lepton final state based on the Simplified Template Cross Section (STXS) scheme provides a partitioning of the Higgs boson phase space that minimizes theoretical uncertainties.
The resulting measurements allow for precise comparisons between experimental results and Standard Model (SM) predictions while being sensitive to potential deviations from the SM arising from new physics effects.
Working on this topic, you can contribute to the analyses performed using LHC Run-2 data and extend them to the new Run-3 data-taking periods.
You will gain hands-on experience with particle physics precision measurements, including state-of-the-art background estimation techniques, a sophisticated treatment of systematic uncertainties, and the practical use of machine learning techniques.
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| Sie lernen kennen: | Higgs physics, data analysis, python programming, C++ programming, machine learning |
| Referent: | Prof. Markus Klute,
Priv. Doz. Dr. Roger Wolf |
| Ansprechpartner: | Artur Monsch,
Sofia Giappichini |
| Letzte Änderung: | 20.08.2026 |
| Thema: | Development of the τ-embedding in real CMS data |
| Zusammenfassung: |
The τ-embedding method is an approach to estimate the background, e.g., of Z → ττ events for H → ττ analyses at CMS, from data.
The method has been invented by KIT students in 2011. Since then it has been continuously supported and developed.
As a student working on this topic, you will get deep insights to the software framework used to record, reconstruct, and analyze the enormous amount of data collected by the CMS experiment.
You will learn about the whole data processing chain of one of the largest experiments world-wide, from the taken data through the reconstruction up to visualizing the data.
As the CMS software framework (CMSSW) itself is written in C++ and python, basic knowledge of writing code with these languages is required.
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| Sie lernen kennen: | data processing, data analysis, python programming, C++ programming, Monte Carlo simulation |
| Referent: | Priv. Doz. Dr. Roger Wolf,
Prof. Günter Quast |
| Ansprechpartner: | Christian Winter |
| Letzte Änderung: | 20.08.2026 |
| Thema: | Measurement of the WH charge asymmetry |
| Zusammenfassung: |
The production of a Higgs boson in association with a W boson is sensitive to the coupling of the Higgs boson to light quarks.
Anomalous couplings may influence the abundance of positive over negative W bosons, in addition to the asymmetry implied by the structure functions of the proton.
We are analyzing CMS data to target such measurements, focusing on the Higgs boson decay to W boson pairs.
The analysis is set up and under review in CMS.
We plan to conclude it, and then to combine it with the same analysis targeting the Higgs boson decay to a pair of tau leptons, also developed at KIT.
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| Sie lernen kennen: | Higgs physics, statistical analysis, data analysis, Python programming, C++ programming, ROOT |
| Referent: | Prof. Markus Klute,
Priv. Doz. Dr. Roger Wolf |
| Ansprechpartner: | Dr. Nicolò Trevisani |
| Letzte Änderung: | 20.08.2026 |
| Thema: | Di-tau mass reconstruction at FCC-ee with Machine Learning methods |
| Zusammenfassung: |
Precise tau lepton reconstruction is challenging due to the presence of neutrinos in the final state and hadronic signatures that mimic quark decays.
Traditional reconstruction methods are usually unable to fully reconstruct the mass of the mother particle because of that.
The project aims to develop and apply machine learning techniques to improve the di-tau mass reconstruction, and in turn the separation of the different sources, leveraging the precision tracking and calorimetry capabilities of the FCC-ee detector, where clean and high-rate events from electron-positron collisions will provide unprecedented opportunities for many studies.
Primarily, this project will focus on H→ττ signatures, where the aim is to separate the signal from background coming from Z and W bosons.
Possible extensions can include searches for additional Higgs bosons in the next-to-minimal supersymmetric standard model (NMSSM).
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| Sie lernen kennen: | Higgs physics, tau lepton physics, data analysis, Python programming, ROOT, Future Colliders |
| Referent: | Prof. Dr. Markus Klute,
Priv. Doz. Dr. Roger Wolf |
| Ansprechpartner: | Sofia Giappichini |
| Letzte Änderung: | 09.06.2026 |
| Thema: | Cross-section measurement of H→ττ at FCC-ee at √s=125 GeV |
| Zusammenfassung: |
This project focuses on measuring the cross-section of Higgs boson decays to tau lepton pairs at the FCC-ee operating at a center-of-mass energy of √s = 125 GeV, corresponding to the Higgs mass resonance in the scope of an upscaled FCC project.
The H→ττ channel provides an important probe of the Higgs coupling to fermions and serves as a crucial test of the Standard Model.
The student will develop analysis techniques to identify tau pairs, reconstruct the Higgs mass using advanced methods, and extract the signal cross-section.
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| Sie lernen kennen: | Higgs physics, tau lepton physics, data analysis, Python programming, ROOT, Future Colliders |
| Referent: | Prof. Dr. Markus Klute,
Priv. Doz. Dr. Roger Wolf |
| Ansprechpartner: | Sofia Giappichini |
| Letzte Änderung: | 09.06.2026 |
| Thema: | Search for Heavy Neutral Leptons at FCC-ee at √s=125 and 240 GeV |
| Zusammenfassung: |
Heavy Neutral Leptons (HNLs) are hypothetical particles that could explain several open questions in particle physics, including neutrino masses, the matter-antimatter asymmetry in the universe, and dark matter.
The FCC-ee offers a unique opportunity to search for HNLs through their production in Higgs boson decays and electroweak processes at center-of-mass energies of √s=125 GeV and 240 GeV.
This project will focus on developing search strategies for HNLs in various decay channels, identifying characteristic signatures such as displaced vertices or missing energy, and setting limits on HNL masses and mixing parameters.
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| Sie lernen kennen: | BSM physics, Higgs physics, data analysis, Python programming, ROOT, Monte Carlo simulation, Future Colliders |
| Referent: | Prof. Dr. Markus Klute,
Priv. Doz. Dr. Roger Wolf |
| Ansprechpartner: | Sofia Giappichini |
| Letzte Änderung: | 09.06.2026 |
| Thema: | Search for Heavy Neutral Leptons at FCC-ee at √s=90 GeV decaying into a pair of tau leptons |
| Zusammenfassung: |
Heavy Neutral Leptons (HNLs) are hypothetical particles that could explain several open questions in particle physics, including neutrino masses, the matter-antimatter asymmetry in the universe, and dark matter.
The FCC-ee offers a unique opportunity to search for HNLs through their associated production wiht a SM neutrino at √s=91 GeV, taking advantage of the unprecented luminosity envisioned at this stage.
This project will focus on developing search strategies for HNLs in the leptonic decay channels, in particular decaying into two taus, identifying characteristic signatures such as displaced vertices or missing energy, and setting limits on HNL masses and mixing parameters.
This is an extension of the search conducted in our group in the electron and muon channels with a realistic HNl model which includes two HNLs.
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| Sie lernen kennen: | BSM physics, Higgs physics, data analysis, Python programming, ROOT, Monte Carlo simulation, Future Colliders |
| Referent: | Prof. Dr. Markus Klute,
Priv. Doz. Dr. Roger Wolf |
| Ansprechpartner: | Sofia Giappichini |
| Letzte Änderung: | 09.06.2026 |
