Ruprecht Karls Universität Heidelberg



Finite resonance widths in particle decays

BeschreibungThe ALICE experiment at CERN's Large Hadron Collider (LHC) studies the quark-gluon plasma (QGP), a state of matter at extremely high temperatures made up of deconfined quarks and gluons, which is created in relativistic heavy ion collisions. The fascinating properties of this new state of matter are inferred from the measured long-lived particle spectra, for which the correct modelling of particle decays is very important. Thanks to uncertainty principle the short lived resonances have a spread of rest-mass values known as a resonance width. Taking into account the resonance widths in particle decays may help explaining certain anomalies in experimental data [1] and underpredicted low momentum particle spectra [2].

We are looking for a bachelor student with an interest in nuclear and particle physics, strong analytic skills and some experience in numerical programming.

The project aims to implement the effects of finite resonance widths in the recently developed technique of fast resonance decays [3]. It is envisaged that the thesis would consist of the analytic write-up and a numerical implementation in C++. The student would work in close collaboration with Dr. Aleksas Mazeliauskas (ITP) and under the guidance of Prof. Klaus Reygers (PI).

1. "The thermal proton yield anomaly in Pb-Pb collisions at the LHC and its resolution", Anton Andronic, Peter Braun-Munzinger, Bengt Friman, Pok Man Lo, Krzysztof Redlich, and Johanna Stachel, arXiv:1808.03102
2. "Effects of ρ-meson width on pion distributions in heavy-ion collisions" Pasi Huovinen, Pok Man Lo, Michał Marczenko, Kenji Morita, Krzysztof Redlich, Chihiro Sasaki, Phys.Lett. B769 (2017) 509-512
3. "Fast resonance decays in nuclear collisions", Aleksas Mazeliauskas, Stefan Floerchinger, Eduardo Grossi, Derek Teaney, arXiv:1809.11049, Eur. Phys. J. C (2019) 79: 284.
4. Background reading: Review of Particle Physics, M. Tanabashi et al. (Particle Data Group), Phys. Rev. D 98, 030001 Section 47. Kinematics Section 48. Resonances

Please contact:

Dr. Aleksas Mazeliauskas, ITP (


Prof. Klaus Reygers, PI (
KontaktKlaus Reygers, Aleksas Mazeliauskas
Veröffentlicht am2019-04-03
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