Energy and angular dependence of double differential cross sections d 2 σ/dΩdE was measured for reactions induced by 2.5 GeV protons on Au target with isotopic identification of light products (H, He, Li, Be, and B) and with elemental identification of heavier intermediate mass fragments (C, N, O, F, Ne, Na, Mg, and Al). It was found that two different reaction mechanisms give comparable contributions to the cross sections. The intranuclear cascade of nucleon-nucleon collisions followed by evaporation from an equilibrated residuum describes low energy part of the energy distributions whereas another reaction mechanism is responsible for high energy part of the spectra of composite particles. Phenomenological model description of the differential cross sections by isotropic emission from two moving sources led to a very good description of all measured data. Values of the extracted parameters of the emitting sources are compatible with the hypothesis claiming that the high energy particles emerge from pre-equilibrium processes consisting in a breakup of the target into three groups of nucleons; small, fast and hot fireball of ∼ 8 nucleons, and two larger, excited prefragments, which emits the light charged particles and intermediate mass fragments. The smaller of them contains ∼ 20 nucleons and moves with velocity larger than the CM velocity of the proton projectile and the target. The heavier prefragment behaves similarly as the heavy residuum of the intranuclear cascade of nucleon-nucleon collisions.

The final analysis of the experiment determining both components of the transverse polarization of electrons (σT1, σT2) emitted in the β decay of polarized, free neutrons is presented. The T-odd, P-odd correlation coefficient quantifying σT2, perpendicular to the neutron polarization and electron momentum, was found to be R= 0.004 ± 0.012 ± 0.005. This value is consistent with time-reversal invariance and significantly improves both the earlier result and limits the relative strength of the imaginary scalar couplings in the weak interaction. The value obtained for the correlation coefficient associated with σT1, N= 0.067 ± 0.011 ± 0.004, agrees with the standard model expectation, providing an important sensitivity test of the experimental setup. The present result sets constraints on the imaginary part of scalar and tensor couplings in weak interactions. Implications for parameters of the leptoquark exchange model and the minimal supersymmetric model with R-parity violation are discussed

The energy and angular dependence of double differential cross sections d 2 σ/dΩdE were measured for p, d, t, 3,4 He, 6,7 Li, 7,9 Be, and 10,11 B produced in collisions of 0.175 GeV protons with Ni target. The analysis of measured differential cross sections allowed to extract total production cross sections for ejectiles listed above. The shape of the spectra and angular distributions indicate the presence of other nonequilibrium processes besides the emission of nucleons from the intranuclear cascade, and besides the evaporation of various particles from remnants of intranuclear cascade. These nonequilibrium processes consist of coalescence of nucleons into light charged particles during the intranuclear cascade, of the fireball emission which contributes to the cross sections of protons and deuterons, and of the break-up of the target nucleus which leads to the emission of intermediate mass fragments. All such processes were found earlier at beam energies 1.2, 1.9, and 2.5 GeV for Ni as well as for Au targets, however, significant differences in properties of these processes at high and low beam energy are observed in the present study.

The transverse polarization of electrons emitted in the beta decay of polarized 8Li nuclei has been measured. For the time-reversal violating triple correlation parameter we find R=(0.9+/-2.2)x10(-3). This result is in agreement with the standard model and yields improved constraints on exotic tensor contributions to the weak interaction. Combined with other experimental results and using a model for the coupling constants, a new limit for the mass of a possible scalar leptoquark, m(LQ)>560 GeV/c(2) (90% C.L.), is obtained.