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The three-nucleon system is the simplest, non-trivial testing ground which allows one to probe quantitatively modern nucleon-nucleon interaction models. The rigorous technique of solving the Faddeev equations for the three-nucleon system allows one to test the influence of additional dynamical ingredients, referred to as three-nucleon forces, as well as the Coulomb interaction and relativistic effects. A large set of high precision, exclusive cross-section data for the 1H(d,pp)n breakup reaction at 130 MeV was obtained at KVI, Groningen. This allowed us to establish for the first time clear evidence for three-nucleon force contributions to the cross sections of the breakup process and to confirm recent predictions of a sizable influence of the Coulomb force in this reaction. [ABSTRACT FROM AUTHOR]

High precision vector Ax,Ay and tensor Axx,Axy,Ayy analyzing powers for the 1H(dvector ,pp)n breakup reaction were measured at 130 MeV beam energy with the detection system covering a large part of the phase space. Results are compared with rigorous theoretical calculations based on realistic nucleon-nucleon potentials, also with a so-called three-nucleon force included, as well as on chiral perturbation theory. Theoretical predictions generally describe the data quite well, but in some regions discrepancies have been observed, which indicate incompleteness of the present-day treatment of three nucleon dynamics. [ABSTRACT FROM AUTHOR]

The importance of the isospin symmetry breaking in extracting various particle physics parameters is discussed. In particular the measurement of isospin symmetry breaking in the reaction pd→3Hπ+/3Heπ0 is presented. The energy dependence of the measured cross sections ratio indicate isospin symmetry breaking effects. Within a simple model based on π0-η meson mixing the mixing angle of these mesons is extracted. [ABSTRACT FROM AUTHOR]

A new facility for particle physics with polarized cold neutrons has been taken into operation at the spallation source SINQ at PSI. After extraction of the first beam, its intensity and polarization have been measured as a function of the neutron wavelength. The beam characteristics are among the best in the world for studies of neutron decay. An experimental area was constructed with infrastructure support for convenient experimentation. The physics program will focus on detailed investigations of the free neutron decay process, in particular fundamental symmetries of the weak interaction. The first approved experiment is a novel search for time reversal violation. [ABSTRACT FROM AUTHOR]

A non-zero value of the R-correlation coefficient due to the e - polarization component, perpendicular to the plane spanned by the spin of the decaying neutron and the electron momentum, would signal a violation of time reversal symmetry and thus physics beyond the Standard Model. The value of the N-correlation coefficient, given by the transverse e - polarization component within that plane, is expected to be finite. The measurement of N serves as an important systematic check of the apparatus for the R-measurement. The first phase of data taking has been completed. Preliminary results from a limited data sample show no deviations from the Standard Model predictions. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Comparison of the cross sections measured over a large part of the phase space of the deuteron-proton breakup at 130 MeV with the results of rigorous, Faddeev-like calculations is presented. Global analysis, including nearly 1200 data points, reveals a better agreement for theoretical predictions which include three-nucleon force (3NF) model over the results obtained with only nucleon-nucleon realistic potentials. A possible way to probe details of the 3NF models via studying “non-standard” projections of the multi-dimensional phase space is envisaged. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

A new facility for particle physics has been installed at the spallation source SINQ. An experimental area has been constructed for a series of experiments fed by a high intensity, polarized cold neutron beam. The physics program for this new facility will focus on free neutron decay studies addressing mainly the questions of fundamental symmetries (time reversal and parity) in the weak interactions. [ABSTRACT FROM AUTHOR]

Vector and tensor analyzing powers of the 1H(dvector ,pp)n breakup process have been measured at the beam energy of 130 MeV. The forthcoming results will be compared with predictions based on various 2N and 3N forces models in quest for a correct structure of the 3NF. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]