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This work presents an investigation of elastic proton-proton scattering using data collected with the recently upgraded HADES detector using beams of protons with kinetic energies of T = 4.53 GeV and T = 1.60 GeV that were incident upon a liquid hydrogen target. This is the first measurement emerging from the upgraded detector setup, including a Forward Detector with straw-tube tracking planes designed for the PANDA experiment. The well-constrained two-body kinematic relations of elastic scattering have been exploited to study the detector alignment, the beam alignment, and to provide the final measurement of the beam energy. In addition, the recorded luminosity of the experiment has been determined by normalizing the HADES data in a range of the squared four-momentum transfer t that overlaps with measurements by previous experiments worldwide. Furthermore, the differential cross sections have been determined over a large range of t from which the slope parameter B is extracted, yielding B = (8.98 ± 0.30) (GeV/c) −2 and(7.3 ± 0.1) (GeV/c) −2 at T = 4.53 GeV and 1.60 GeV, respectively. This contribution to the world database on elastic proton-proton scattering provides input to theoretical modeling and serves as a reference for luminosity determinations by future experiments in the same energy range.

Hyperons and their electromagnetic decays have become one of the major objects of interest of the HADES experiment, providing access to the inner structure those hadrons at the femtometer scale. With a recently collected data sample of reactions produced by a 4.5GeV proton beam impinging on a liquid hydrogen target, a new avenue of such studies has opened up. Several steps are necessary in data pre-processing, such as quality assurance, calibration and normalization, before any data analysis can be performed. A "standard" reaction, namely elastic pp scattering, has been proven to be a versatile tool that can be applied to tackle those. A feasibility study for a planned measurement of the "unknown" Dalitz decay of the Σ⁰ hyperon, produced in pp→pK+Σ⁰ reactions, is performed. This would be the first measurement of an electromagnetic Dalitz decay of a hyperon. Two complementary analysis strategies are developed for this purpose. Preliminary simulation studies show that a pioneering measurement of the Σ⁰→Λe⁺e⁻ decay is feasible.