Partial wave analysis of events in proton-proton reactions for energies between 1.9 and 3.5 GeV

• Applicant: Professorin Dr. Laura Fabbietti
• Subject Area: Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields ; Experimental Condensed Matter Physics
• Term: from 2014 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 258435442

The spectrum and the properties of nucleon resonances provide important insight into the non-perturbative sector of QCD. A proper way to investigate these nucleon resonances is to use a Partial-Wave-Analysis (PWA), where experimental data are decomposed into a sum of different partial wave amplitudes. For this purpose, mainly data on pion Nucleon elastic and inelastic reactions were considered in the past. Recently, it became also possible to study p+p reactions, where especially the production of open strangeness via the reaction p+p (to) p+ Lambda + K attracts a lot of interest. These reactions can indeed deliver new and complementary insight into the spectrum of N(star) resonances with a significant coupling to the Lambda Kaon decay channel. Furthermore, data on the p KLambda final state are extremely interesting in the context of strange exotic particles, like the predicted ppK.The study of the existence and the properties of such states in p+p reactions can contribute to an improved understanding of the low energy anti kaon nucleon dynamics below threshold. In herewith proposed project we intend to investigate various existing data on pKLambda production at different energies, and aim to fit all these data simultaneously with the Bonn-Gatchina PWA program. For this purpose, we will first apply the PWA to each data set separately, so that we get a first evaluation of which N(star) resonances contribute at which energy. Afterwards, we will combine all the data sets and fit them simultaneously. In this way we can extract the energy dependence for the different partial wave amplitudes. Finally, we also want to implement a ppK wave in the PWA framework, so that we can test how much room the data leave for the existence of such an exotic state.The results of the proposed analysis will contribute to an improved understanding of the N(star) resonance spectrum and it will also help to solve the puzzle about the existence or non-existence of kaonic-nuclear clusters, where the ppK is only the is only the simplest representation. The project shall be topic of a two and a half years Post Doc position.

• DFG Programme: Research Grants