Tobias Huber

Contact

Universität Siegen
Fakultät IV / Department Physik
Theoretische Physik 1
Walter-Flex-Straße 3
57072 Siegen, Germany
Office: ENC B-115
Phone: +49 271 740-3711
Fax: +49 271 740-3804
Mail: huber@physik.uni-siegen.de


Research Projects and Collaborations

Our current understanding of Nature at its smallest length-scales is incorporated in the so-called Standard Model (SM) of particle physics, a quantum field theory that contains the entire set of known elementary particles, as well as the interactions between them (except gravity). The Lagrangian density of the SM obeys a non-abelian, local gauge symmetry which gets spontaneously broken via the so-called Higgs-mechanism. Two important consequences of the latter are the creation of particle masses, and flavour transitions in the charged-current weak interactions.

Despite the fact that the SM describes elementary particle processes such as scatterings and decays extremely well, there is consensus that most likely it is not the ultimate theory of Nature. Two prominent shortcomings of the SM are the lack of a Dark Matter candidate and the fact that the amount of CP violation needed for creating the observed Baryon asymmetry of the Universe is too small. One therefore expects new effects (new particles and/or interactions) at yet unexplored scales, so-called „Physics beyond the SM“, or „New Physics“.

There are essentially two approaches to search for New Physics: „Direct“ searches via the on-shell production of new particles at colliders, and „indirect“ searches via virtual effects in low-energy processes. In both approaches, precision in theoretical predictions and in experimental measurements is an indispensable ingredient for testing the SM, and for the quest of finding effects beyond it. My main research topics therefore are in Quark Flavour Physics, in particular the physics of particles containing the bottom quark, Effective Field Theories, and Multi-loop computations.

Inclusive rare and radiative decays of BB mesons

  • Study of the radiative Flavour-Changing Neutral Current (FCNC) decays B→XsγB \to X_s \gamma and B→XdγB \to X_d \gamma.
  • Study of the semileptonic FCNC decay B→Xsℓ+ℓ−B \to X_s \ell^+ \ell^-.
  • Study of charged-current semileptonic decays and extraction of elements of the CKM matrix.

This research is performed in the CRC P3H in project C1a in close collaboration with other groups in Siegen and Karlsruhe.

Exclusive non-leptonic decays

  • Study of two-body non-leptonic decays of BB mesons and Λb\Lambda_b baryons into heavy-light and charmless final states.
  • Study of three-body non-leptonic decays of BB mesons and Λb\Lambda_b baryons.

This research is performed in the CRC P3H in project C2b in close collaboration with other groups in Siegen.

Multi-loop computations

  • Developments of algorithms for loop-integral reduction.
  • Study of basic ingredients for collider processes at the multi-loop level in QCD.
  • Study of higher orders in supersymmetric gauge theories such as 𝒩=4\mathcal{N}=4 SYM.

This research is performed in collaboration with the department of Mathematics in Siegen and within the Cluster of Excellence CmF in collaboration with groups in Bonn.

Third-party Funding

Cluster of Excellence „Color-Meets-Flavor“ (since 2026)
Joint Teaching, Research and Outreach Activities between Bonn-Dortmund-Siegen-Jülich
DFG Collaborative Research Center TRR 257
„Particle Physics Phenomenology after the Higgs Discovery“ (since 2020)
Project C1a: „Inclusive semi-leptonic, rare and radiative decays of B mesons“ (with Thomas Mannel and Matthias Steinhauser)
Project C2b: „Exclusive non-leptonic and rare b-quark decays“ (with Thorsten Feldmann)
DFG Research Unit FOR 1873
„Quark Flavour Physics and Effective Field Theories“ (2013-2019)
Project 5: „QCD and Effective Theories for Nonleptonic Decays“ (2013-2016)
„Higher Order Corrections to Nonleptonic and Rare Decays“ (2016-2019)

Group Members

  • Gilberto Tetlalmatzi-Xolocotzi (PostDoc)
  • Sandra Kvedaraitė (PostDoc)
  • Jakob Müller (PhD student)
  • Sherzad Amin (Master student)
  • Fynn-Lukas Dienst (Master student)

Publications

Citation Summary (inspirehep.net)

Selected publications:

Outreach

I enthusiastically participate in the program Rent-a-Prof of the School of Science and Technology.

Lehre/Teaching

Meine Lehrtätigkeit umfasst den gesamten Kurskanon in theoretischer Physik:

Mathematische Ergänzungen
TP1: Mathematische Methoden der Theoretischen Physik
TP2: Theoretische Mechanik
TP3: Klassische Feldtheorie
TP4: Quantenmechanik
TP5: Statistische Physik

In addition I offer compulsory and elective courses for Bachelor- and Master students, partially in English, for example:

Theoretical particle physics 1 and 2 (quantum field theory and the Standard Model)
Computational techniques for loop diagrams
Computer algebra in Theoretical Physics
Effective field theory

My teaching performance received as recognition the Young Teacher Award (Nachwuchslehrpreis) of the School of Science and Technology in 2017!

CV

  • since 2023: apl Professor at University of Siegen (Germany)
  • since 2017: Staff Member at Uni Siegen (Germany)
  • 2017: Habilitation in Physics at Uni Siegen (Germany)
  • 2009 – 2017: Junior Staff Member at Uni Siegen (Germany)
  • 2006 – 2009: Postdoc at RWTH Aachen University (Germany)
  • 2003 – 2006: PhD Student, Uni Zürich (Switzerland)