[en] It is shown that chiral symmetry is responsible for large cancellations in the two-pion exchange nucleon-nucleon interaction, which are similar to those occurring in free pion-nucleon scattering. (author)

[en] Four of the six parameters defining the two-loop ππ scattering amplitude have been determined using Roy dispersion relations. Combining this information with the Standard _χPT expressions, the threshold parameters, low-energy phases and the O(p⁴) constants l₁^r, l₂^r are obtained. The result reproduces the correct D-waves but it is incompatible with existing Standard _χPT analyses of K₁₄ form factors beyond one loop. (author)

[en] One of the main characteristics of the high-energy hadronic or nuclear collisions is the existence of large event-by-event fluctuations, manifested in several observed quantities. The effects of fluctuations in the initial conditions, by using the Interacting Gluon Model, modified by the inclusion also of the impact-parameter fluctuation is investigated. Some observables which follow directly from this model, such as the inelasticity and leading-particle distributions as well as the energy-dependence of the average inelasticity, exhibit a good agreement with all the existing data. The rapidity and pseudo-rapidity distributions calculated by applying the one-dimensional hydrodynamical model with fluctuating mass and momentum show a considerable deviation from those computed with the average initial conditions, using the same mechanism. To account for the semi-inclusive distributions and the forward-backward correlation, it is necessary to take into account also the multiplicity fluctuation, for fireballs of fixed masses. This has been done within the longitudinal phase-space model, with the energy and momentum distributions of the fireballs given by the IGM. (author)

[en] Starting from the past experimental results on multiplicity distributions in intervals of rapidity and of their analysis in terms of the superposition of events of soft and semi-hard type (see the talk of A. Giovannini) three possible scenarios for hh collisions in the TeV energy region are discussed. (author)

[en] The production properties of jets in W events have been measured using √s = 1.8 TeV pp collisions at the Fermilab Tevatron Collider. Experimental results from several CDF and D0 analyses are compared to leading-order and next-to-leading-order QCD predictions

[en] Comparison of interaction portion with leading neutral pions production at the (3-50) TeV and 60 GeV initial energies under interaction with large energy transfer at same sample of neutral component K_π⁰>0.6 is carried out. Integral energy spectrum for leading neutral pions is reached from interactions with iron atom nuclei which is comparing with analogous spectrum from interaction with carbon nuclei. Confrontation of cosmic hadrons interaction characteristics with both iron and carbon atoms nuclei testify about absence of changes according to transition from light nuclei to more heavy one

[en] The CDF and D0 experiments have measured bb production in pp interactions at √s = 1800 GeV and 630 GeV (the energy at which the previous measurement was performed by the UAl experiment). The Tevatron measurements are used to evaluate, for the first time, the center-of-mass energy and rapidity dependence of b-quark production cross section measured with the same detectors. Preliminary results from these measurements are presented and compared with the next-to-leading order QCD predictions

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[en] We have made a precise measurement of the inclusive jet cross section at √s=1800 GeV. The result is based on an integrated luminosity of 92 pb^-1 collected at the Fermilab Tevatron anti pp Collider with the D0 detector. The measurement is reported as a function of jet transverse energy (60 GeV ≤ E_T ≤ 500 GeV ), and in the pseudo- rapidity intervals |η| ≤ 0.5 and 0.1 ≤ |η| ≤ 0.7. A preliminary measurement of the pseudorapidity dependence of inclusive jet production ( |η| ≤ 1.5 ) is also discussed. The results are in good agreement with predictions from next-to-leading order (NLO) quantum chromodynamics (QCD). D0 has also determined the ratio of jet cross sections at √s=630 GeV and √s=1800 GeV ( |η| ≤ 0.5). This preliminary measurement differs from NLO QCD predictions