[en] A boundary condition expressing strong absorption, supplemented by a phenomenological isospin-dependent potential are applied to the calculation of total, elastic and charge-exchange cross-sections for proton-antiproton interactions at low momenta. The radius of the absorptive region and the effective coupling constant are the sole parameters; the model is surprisingly rewarding with respect to its simplicity. (author)

No abstract available

No abstract available

[en] We review the definition of pierce numbers, which are a generalization of the concept of thrust. These quantities provide a useful way to characterize the jet structure of high energy events. Geometrical and topological problems encountered in calculating the pierce numbers of an event are discussed. The degree of hierarchy in the jet structure influences both the calculational problems and the physics results. We have previously developed, and used in a number of simulation studies, a computer program which calculates approximate values of the pierce numbers. We describe here a modification of this program which is slower in operation but more accurate. Values of thrust, as obtained using these programs, are compared with the exact value and with other approximations. The influence of the approximations on the invariant masses of jet combinations is also examined. (orig.)

[en] We propose to study the reaction e⁺e^-→J/psi+X for energies just above the charmonium region and calculate the production rates for various exclusive channels. J/psi+(ππ), eta', l(1,440) are expected as dominant final states. (orig.)

[en] Experimental limits are obtained on any non-electromagnetic long range pion nucleon interaction, from accurate π⁺p scattering data and from pionic atom energy levels. Such an interaction is effectively ruled out in the region rapprox. <=100 fm unless its potential falls off faster than r^-4. (orig.)

[en] The possibility that quarks and leptons are composite objects is discussed. The rishon model is studied in detail as an explicit example. (orig.)

[en] The differential cross section of proton and pion emission is reported for the reaction 12.6 GeV/c K^- + Ta → p,π^+- (THETA 1ab>=120⁰) + X, together with the results of 28.5 GeV/c p+Ta interactions. It is shown that the cross section of backward particle emission increases up to at least 28.5 GeV/c. (author)

[en] We extend our systematic study of the properties of hadron jets produced in antineutrino-nucleon charged current interactions to those observables which characterize the distribution of particles perpendicular to the jet axis. These antineutrino-induced jets are found to have properties similar to those of the jets observed in e⁺e^- annihilation at comparable c.m. energies. No deviations from the simple quark-parton model predictions are found. (orig.)

[en] This chapter contains the results of some of the fundamental problems encountered in reactor calculations. The first part is devoted to the theory of approximate methods solving boundary value problem for the stationary neutron transport equation. It collects mainly the results of research carried at the Computing Center CYFRONET of the Institute of Nuclear Research at Swierk, Poland by M. Borysiewicz, T. Kulikowska, R. Stankiewicz, and G. Spiga from the University of Bologna. The second part is devoted to investigating the neutron scattering kernel in thermalization and solving down problems