η-nuclei in the SCAN experiment

η-mesic nucleus or the quasibound nuclear state of an η-meson in a nucleus is caused by the strong-interaction force alone. The project SCAN2 is aimed at searching and studying the η-meson nuclei production. The experiment is based on two-arms spectrometer using internal target at the Nuclotron. The setup was designed to study products from η-meson nucleus decay in the reaction d + 12C → (A)η + X → π + p + (A – 2) at deuteron energies from 0:5 to 2:5 GeV/nucl. The energy spectrum of secondary protons has been measured. The dependence of the yields of protons and pions on the beam energy has been obtained. This dependence can show us the minimum energy for the S 11 resonance formation. The first prototype of the neutron detector, which will be used in a new modified experimental setup SCAN3 for recording of neutrons from η-nucleus decays in the πn and pn channels, has been tested. The time-offlight method to obtain the neutron spectrum was used. The time resolution and efficiency of the neutron detector have been obtained.

Role of repulsive interactions in the interplay with missing strange resonances

The standard implementation of the HRG model has been shown to be unable to describe all the available data on QCD matter. Here we show the balance of repulsive and attractive hadronic interactions on QCD thermodynamics through observables both calculated by lattice simulations and measured in experiment. Attractive interactions are mediated by resonance formation, which are here implemented through extra states predicted by the Quark Model, while repulsive interactions are modelled by means of Excluded Volume (EV) effects. Informations on flavour dependent effective sizes are extracted. It is found that EV effects are present in lattice QCD thermodynamics, and are essential for a comprehensive description of higher order fluctuations of conserved charges.