Pion-nucleon scattering in the KK-matrix approach

The $K$-matrix approach with effective Lagrangians is used to describe the $S$ and $P$ pion-nucleon partial-wave amplitudes in the energy range $E_{lab} \le 1$ GeV. It is demonstrated, that treating the resonance as $K$-matrix a pole gives the natural way to separate the resonance and non-resonance parts of the $\pi N$ amplitude. The model includes all the four-star $\pi N$ resonances, the non-resonance contributions are calculated from relevant Feynman graphs without any phenomenological form factors. Different contributions to the inelastic $\pi^-p \to \eta n$ amplitude are estimated

NeuLAND: The high-resolution neutron time-of-flight spectrometer for R3BR^{3}B at FAIR

NeuLAND (New Large-Area Neutron Detector) is the next-generation neutron detector for the R3B (Reactions with Relativistic Radioactive Beams) experiment at FAIR (Facility for Antiproton and Ion Research). NeuLAND detects neutrons with energies from 100 to 1000 MeV, featuring a high detection efficiency, a high spatial and time resolution, and a large multi-neutron reconstruction efficiency. This is achieved by a highly granular design of organic scintillators: 3000 individual submodules with a size of 5 7 5 7 250 cm3 are arranged in 30 double planes with 100 submodules each, providing an active area of 250 7 250 cm2 and a total depth of 3 m. The spatial resolution due to the granularity together with a time resolution of σt≤ 150 ps ensures high-resolution capabilities. In conjunction with calorimetric properties, a multi-neutron reconstruction efficiency of 50% to 70% for four-neutron events will be achieved, depending on both the emission scenario and the boundary conditions allowed for the reconstruction method. We present in this paper the final design of the detector as well as results from test measurements and simulations on which this design is based