The four-nucleon bound state and scattering below three-body breakup threshold are described based on the realistic coupledchannel potential CD Bonn + ∆ which allows the excitation of a single nucleon to a ∆ isobar. The Coulomb repulsion between protons is included. In the four-nucleon system the two-baryon coupled-channel potential yields effective two-, threeand fournucleon forces, mediated b...

Neutron-deuteron elastic scattering cross sections are calculated at different energies using modern nucleon-nucleon (NN) interactions and the Tucson-Melbourne three-nucleon force adjusted to the triton binding energy. Predictions based on NN forces only underestimate nucleon-deuteron data in the minima at higher energies starting around 60 MeV. Adding the three-nucleon forces fills up those mi...

Faddeev calculations have been performed for nucleon-deuteron photodisin-tegration of 3 He (3 H) and proton-deuteron radiative capture. The bulk of the results is based on the AV18 nucleon-nucleon force and the Urbana IX three-nucleon force together with explicit exchange currents or applying the Siegert approach. Three-nucleon force effects are predicted for both processes and supported by mos...

The nucleon axial coupling constant $g_A$ is calculated in the presence of an external uniform magnetic field using finite energy sum rules. correlation function proton, neutron and axial-vector currents both hadronic QCD sector. Once contribution form factor isolated, a double rule considered, i.e., usual contour integration for moments proton current. effects come mainly through in-medium cur...