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A set of differential cross-section data of the 1 H(d, pp)n breakup reaction at 130 MeV deuteron beam energy has been measured in the domain of very forward polar angles with the use of the Germanium Wall detector at the Forschungszentrum Jülich. The data obtained for over 1000 kinematical points (112 geometries) are compared with the theoretical predictions based on various models of the three-nucleon (3N) dynamics. They comprise: the realistic nucleon-nucleon potentials alone or combined with the three-nucleon force (3NF), the coupled-channel calculations with the explicit treatment of the Δ-isobar excitation and finally, the potentials derived from chiral perturbation theory. In the part of the phase space studied, the Coulomb interaction between protons has a strong impact on the differential cross section of the breakup reaction. The strongest Coulomb effects are found in regions where the relative energy of the two protons is the smallest. In these regions the

Set of vector analyzing power data of the dp elastic scattering and 1 H ( d,pp)n breakup reactions at 130-MeV deuteron beam energy has been measured in the domain of very forward polar angles. The results are compared with theoretical predictions originating from various approaches: realistic nucleon-nucleon (NN) potentials and the NN potentials combined with a three-nucleon force (3NF) model and with predictions based on the ChPT framework. In case of the breakup process, none of the theoretical calculations reveal sensitivity to any of the dynamical effects such as 3NF or Coulomb interaction and they describe the experimental data equally well. For the elastic scattering, the Coulomb correction appears not negligible at very small θ c.m.d . The effect seems to be confirmed by the data. Few-nucleon systems are microscopic laboratories most suited for detailed study of the nucleon-nucleon (NN) interaction dynamics and the nuclear forces. Among them, the system composed of three nucleons (3N) is the simplest nontrivial environment where NN force models can be tested. Properties of 3N systems at medium energies are mainly determined by pairwise NN interaction. There are, however, reasons to assume the existence of additional dynamical effects like three-nucleon force (3NF) related to the presence of the third nucleon, or the Coulomb interaction, very significant in the domain of small polar angles of the emitted protons. Both effects are modeled within different theoretical formalisms.The realistic two-nucleon (2N) forces can be combined with the recent version of the 2π -exchange Tucson-Melbourne (TM) 3NF [1] or in the case of AV18 NN force with the Urbana IX 3NF [2]. Alternatively, 3NF can be generated by an explicit treatment of the isobar excitation within the coupled channel (CC) method [3]. For the 3N system, creation of a -containing state yields an effective 3NF but also two-barion dispersion. These two effects usually compete, and therefore * izabela.ciepal@uj.edu.pl the net effects of including the isobar in the potential are smaller than for approaches with the phenomenological 3NF's. When the chiral perturbation theory (ChPT) is used at the next-to-next-to-leading order (NNLO), the 3N contributions arise naturally, fully consistently with the NN force terms [4].The long-range electromagnetic component of the NN interaction was successfully implemented in CC formalism [5,6] as well as in the calculations [7] based on the AV18 NN potential combined with the Urbana IX 3NF.Besides the binding energies of the light nuclei, the importance of the 3NF was experimentally confirmed on the basis of the data originating from the nucleon-deuteron elastic scattering process [8][9][10][11][12][13][14][15][16][17]. In general, inclusion of the 3NF component improves the description of the cross-sectional data. However, quite significant discrepancies between the theoretical models and polarization observables are still present. Exploration of the nucleon-deuteron breakup can be considered as a natural next step in the...

We report on a high-statistics measurement of the most basic double-pionic fusion reaction np → dπ 0 π 0 over the energy region of the d * (2380) resonance by use of a polarized deuteron beam and observing the double fusion reaction in the quasifree scattering mode. The measurements were performed with the WASA detector setup at COSY. The data reveal substantial analyzing powers and confirm conclusions about the d * resonance obtained from unpolarized measurements. We also confirm the previous unpolarized data obtained under complementary kinematic conditions.