$pp\to pK\Lambda$ and $pp\to n\Lambda K^+π^+$ analyses at HADES at 4.5 GeV

by Óscar Marcos Pérez Cytron (GSI/RUB)

Tuesday Jul 14, 2026, 3:00 PM → 3:45 PM Europe/Zurich

NB2/158 (RUB)

Zoom link: 

https://cern.zoom.us/j/65752554157?pwd=y8GU4dSmhAZQLrzg4nlNXu196VofcN.1

Abstract:

This talk presents the initial analysis of exclusive associated-strangeness production in proton–proton collisions at 4.5 GeV, 
focusing on the $pp\to pK\Lambda$ and $pp\to n\Lambda K^+π^+$ channels recorded by the HADES experiment. 
We present the current status of the reconstruction and event-selection strategy for these channels developed in parallel.

 

The $pp\to pK\Lambda$ channel analysis targets the recoil $\Lambda$ polarization via partial wave analysis model constraints, 
and differential cross sections sensitive to intermediate nucleon resonances $N^*(1440)–N^*(1710)$. This channel also serves 
as a benchmark for our ability to reconstruct secondary particles and resonances ahead of the upcoming pion-beam campaign.

 

The core physics of the $pp\to n\Lambda K^+π^+$ channel targets the $K^+π^+$ subsystem, which forms a pure I=3/2 state free 
of conventional resonances, isolating the non-resonant, repulsive $Kπ$ interaction. Extracting the S-wave phase shift and 
scattering length would provide a benchmark for SU(3) chiral perturbation theory and Lattice QCD, superseding ~50-year-old 
direct scattering measurements. Additionally, the $\Lambda n$ final-state interaction offers input for the hyperon–nucleon potential, 
relevant to the neutron star equation of state and the hyperon puzzle.