[en] Recent results of lattice Monte-Carlo calculations in QCD are used to estimate the value of Λsub(anti MS). Special attention is paid to the role played by the light quarks in the construction of the continuum limit of lattice approximations in QCD. The resulting value of Λsub(anti MS) turns out to be strongly dependent on n sub(f), the number of light quarks taken into account

[en] The problem of defining quark distribution functions in higher orders of perturbative QCD is reviewed. A formalism is constructed, which allows simple transformation from one such definition (factorization scheme) into another. This formalism leads to a new way of parametrising the nonperturbative properties of hadrons, which in contrast to the conventional way, employing quark distribution functions at some referential Q₀ is unique

[en] The results are commented upon of three scientists of the Nuclear Research Institute of the Academy of Sciences in Moscow, concerning the special method of analytical handling of Feynman diagrams, and integrations in multi-parameter spaces. Some surprising results of solving the equation of quark-gluon interaction within quantum chromodynamics discussed. The respective mathematical series is divergent and powerful computers are needed to achieve further advance in the solution of the problem. (M.D.). 4 figs., 2 refs

[en] Current theoretical framework for the calculation of heavy quark production in γγ collisions is reviewed. The importance of including direct photon contributions up to the order α²α²_s and of proper choice of renormalization and factorization scales in the evaluation of σ(γγ → QQ) is emphasized. (author)

No abstract available

[en] According to today's knowledge based on the history of the given period, quarks and leptons are the basic particles of matter. Gauge theories describe their interactions. Accelerators being built or designed will be used for testing the results of the theories. They include the 3000 GeV proton accelerator in Serpukhovo, the antiproton-proton 540 GeV storage rings at CERN near Geneva, the colliding proton-proton 800 GeV rings at Brookhaven National Laboratory in the USA, the electron-positron 260 GeV colliding beams at CERN, and the electron(35 GeV)-proton(800GeV) storage rings at DESY near Hamburg in the FRG. (Ha)

[en] We reformulate perturbation expansions in renormalized quantum field theories in a way that allows straightforward handling of situations when in the conventional approach (i.e. in fixed renormalization scheme) these expansions are divergent. In our approach the results of perturbation calculations of physical quantities appear in the form of (under certain circumstances) convergent expansions in powers of a free parameter χ, characterising the procedure involved. This inherent ambiguity of perturbative calculations is conjectures to be an expression of the underlaying ambiguity in the separation of the full theory into its perturbative and nonperturbative parts. The close connection of our results with the Borel summation technique is demonstrated and their relation to conventional perturbation expansions in fixed renormalization scheme is clarified

[en] Decay of the proton has not yet been observed. This fact is quantitatively described using the so-called baryon number. Proton decay could be observed by detecting its decay products. The most difficult part of the operation is to distinguish the resulting particles from the background particles of cosmic radiation. All experiments are therefore being made in gold or salt mines or in tunnels running through high mountains. Interest in measuring proton stability has been aroused by recently presented grand unified theories according to which the proton life is 10sup(29+-2) years. (E.S.)

[en] The concept of local parton hadron duality and its local version is discussed within the framework of HERWIG and JETSET event generators. The aim is to answer the basic question of QCD phenomenology and, namely, what is the relation between the properties of experimentally observed hadrons and the assumed underlying parton dynamics. e⁺e^- annihilations in LEP 2 energy range are considered as these interactions provide theoretically the cleanest condition for the discussion of this concept. (R.P.) 3 refs.; 3 figs

[en] Interactions of virtual photons are analyzed in terms of their parton distribution functions. It is shown that the concept of parton distribution functions is phenomenologically very useful even for highly virtual photons involved in hard collisions. The role of longitudinal photons for proper interpretation of the data on jet cross section in the region of moderate photon virtualities accessible at HERA is explored