Differential cross sections of 2 H(d,d)d elastic scattering and proton transfer 2 H(d, 3 He)n reactions at 160 MeV beam energy have been obtained. They have been normalized relative to the existing cross-section data for the 2 H(d,d)d elastic scattering at 180 and 130 MeV, benefitting from the negligible energy dependence of this observable at certain range of the four momentum transfer. The experiment was performed at KVI in Groningen, the Netherlands using the BINA detector. The elastic scattering data are compared to theoretical predictions based on the lowest-order term in the Neumann series expansion for four-nucleon transition operators. The calculations underpredict the data. The data presented in this paper can be used to validate the future theoretical findings.

The HADES collaboration uses the e+e− production as a probe of the resonance matter produced in collisions at incident energies of 1-3.5 GeV/nucleon at GSI. Elementary reactions provide useful references for these studies and give information on resonance Dalitz decays (R→Ne+e−). Such processes are sensitive to the structure of time-like electromagnetic baryon transitions in a kinematic range where (off-shell) vector mesons play a crucial role. Results obtained in proton-proton reactions and in a commissioning pion-beam experiment are reported and prospects for future pion beam experiments and for first hyperon Dalitz decay measurements are described. The connection with the investigations of medium effects to be continued with HADES in the next years at SIS18 and SIS100 is also discussed.

A rich set of differential cross section of the three-body 2 H(d,dp)n breakup reaction at 160 MeV deuteron beam energy has been measured over a large range of the available phase space. The experiment was performed at KVI in Groningen, the Netherlands, using the BINA detector. The cross-section data for the breakup reaction have been normalized to the simultaneously measured 2 H(d,d) 2 H elastic scattering cross section. The breakup cross sections obtained for 147 kinematically complete configurations near the quasifree scattering kinematics are compared to the recent approximate calculations for the three-cluster breakup in deuteron-deuteron collisions. The cross sections for 294 kinematic configurations of the quasi-free scattering regime, for which no theoretical calculations exist, are also presented. Besides the three-body breakup, semiinclusive energy distributions for the four-body 2 H(d, pp)nn breakup are reported. This article belongs to the Topical Collection "Ludwig Faddeev Memorial Issue".

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A set of differential cross section of the three-body 2 H(d, d p)n breakup reaction at 160-MeV deuteron beam energy is presented for 147 configurations covering a wide kinematical region around quasifree scattering. The experiment was performed at KVI in Groningen, the Netherlands, using the BINA detector. The cross-section data have been normalized to the 2 H(d, d ) 2 H elastic-scattering cross section. The data are compared to the results of recent single-scattering approximation (SSA) calculations for three-cluster breakup in deuteron-deuteron collisions. This comparison shows that SSA provides the correct order of magnitude of the cross sections. The studied energy is probably too low to meet the SSA assumptions which prevents better accuracy of the description.