Baryon resonances can be considered excited states of nucleons (protons and neutrons), and they play an important role in relativistic collisions of nucleons with each other or with other particles. Their properties are still not thoroughly understood, therefore their study is an interesting topic of present-day experimental and theoretical research.
The aim of the present PhD project is to develop an effective Lagrangian model of baryon resonances including their strong and electromagnetic interactions, and apply the model to various reactions. In particular, we plan to study pion-proton and proton-proton collisions at the energies of ongoing experiments by the HADES collaboration (GSI, Darmstadt, Germany). The development of the model will be based on our previous work described in the publications [1]-[3] below.
[1] Zétényi M, Nitt D, Buballa M, Galatyuk T: Role of baryon resonances in the pi(-)p -> ne(+)e(-) reaction within an effective-Lagrangian model, PHYSICAL REVIEW C 104 (2021) 015201.
[2] Speranza E, Zétényi M, Friman B: Polarization and dilepton anisotropy in pion-nucleon collisions, PHYSICS LETTERS B 764 (2017) 282-288.
[3] Zétényi M, Wolf Gy: Dilepton production in pion-nucleon collisions in an effective field theory approach, PHYSICAL REVIEW C 86 (2012) 065209.
The applicant should be familiar with the basics of quantum field theory, including perturbation theory. Practical experience in calculating cross sections and decay rates at lowest order is necessary. A good understanding of space-time symmetries, the representation theory of rotation-, Lorentz- and Poincare groups is desirable. Experience in using a computer algebra system like Mathematica is welcome. The knowledge of a general purpose programming language suitable for demanding numerical computations (preferably c++), or at least the willingness to learn one is essential.