[en] It is shown that the rates of the decays Υ(1 ³D₁)→ηΥ(1S) and Υ(1 ³D₂)→ηΥ(1S) should be comparable to and likely exceed that of the recently discussed in the literature two-pion transition Υ(1D)→ππΥ(1S). The reason for this behavior is that the discussed η transitions are enhanced by the contribution of the anomaly in the flavor singlet axial current in QCD

[en] Theoretical estimates of the radiative and annihilative decays of the 1¹D₂ charmonium level are discussed within the framework of the nonrelativistic potential model of charmonium. It is argued that the state CHI(3.45) possibly seen in PSI' radiative decay cannot be identified with the 1¹D₂ charmonium level

[en] Theoretical investigation of γ resonance production in the e⁺e^- annihilation is presented. For this purpose vacuum polarization by vector (electromagnetic) current of b quarks is considered. The calculation of the amplitude of the process leads to the sum rules for γ resonance production. The L-transform of the vacuum polarization amplitudes is discussed. It is shown that agreement of theoretical prediction with experimental data is fulfilled for the b quark mass m=4.65+-0.05 GeV. It is evident for reality of gluon exchange at short distances

[en] The precise knowledge of the onset of the cross section σ(e⁺e^-→τ⁺τ^-) at the threshold is necessary for improving the accuracy of determination of the τ mass from the threshold measurements. The QED radiative corrections of relative order α and α², additional to the well-known Coulomb factor, are considered in the threshold region. The correction terms of order α² are calculated, which contain coefficients enhanced by large parameters. As a result it is argued that the known O(α) corrections provide the accuracy of the description of the cross section close to 10^-4, rather than 10^-3 as claimed in the recent literature. Also analytical expressions are provided for some limiting cases of the corrections, previously calculated numerically

[en] Mass splittings and e⁺e^- widths of heavy quarkonium states are considered. The properties of the quarkonium levels are determined dominantly by the Coulomb-like short-distance gluon exchange. Deviations from the ''Coulomb'' behaviour can be considered as corrections. The corrections discussed are due to interaction of heavy quarks with nonperturbative fluctuations of gluonic field in the true vacuum of QCD. Expressions for corrections to mass splittings of 2S and 1S levels are obtained as well as for 2S-1P splitting and for e⁺e^- widths of 1³S₁ and 2³S₁ states. The results obtained suggest a very natural interpolation of the e⁺e^- widths between the mass region of applicability of the approach and the data on γ resonances. With this interpolation numerical estimates of the widths for arbitrary quark mass above Msub(b) are given incorporating the Z boson contribution

[en] Decay rate of a false vacuum in (1+1) dimensions is considered in a situation when there are zero or soft fermionic or bosonic modes which are localized on the soliton that converts the false vacuum into a lower one. It is shown that up to exponentially small corrections the decay rate is contributed independently by soliton states, corresponding to different values of the occupation numbers of the soft modes. The contribution of each of the soliton states is given by the formula derived in an earlier work

[en] The phenomenological analysis of b anti b quarkonium states is presented. Certain matrix elements of the nonrelativistic imaginary time propagator, contributed by S and P waves are calculated for a heavy quarkonium. Effects of interaction of the quarkonium with nonperturbative fluctuations of the gluonic field in the physical vacuum of QCD are taken into account as well as those due to the short-distance Coulomb like gluon exchange. The results for the S wave are found to be in agreement with the data on γ and γ' resonances. It is shown that the γ(9.46) mass is definitely below are bare quark threshold: 2msub(b)-Msub(γ)=130+-50 MeV. Mass of the 1P level is calculated: Msub(1P)-Msub(γ)=370+-30 MeV

[en] Nonperturbative large scale fluctuation of gluonic field which are present in the exact vacuum of QCD result in modification of interaction between quarks in quarkonium. Such effects are considered for heavy quarks in cases when the size of the quarkonium system is much smaller than that of the dominating gluonic fluctuations. The Green function of relative motion in heavy quarkonium is calculated for energy below threshold with the account of leading nonperturbative effects. It is shown that once nonperturbative gluonic degrees of freedom are taken into consideration they can never be absorbed into a sort of interaction potential between quarks

[en] It is shown that the ultrarelativistic growth of bubbles of new phase in the course of false vacuum decay gives rise to effective fading of residual oscillations of fields around the stable values in the new phase. The damping rate corresponds to constant total energy of the oscillations inside the bubble. It is argued that as a possible consequence of this behavior under certain assumption about phase transition in QCD the amplitude of the coherent invisible axion wave can be at present much less than it is usually estimated. As a result the upper bound for the axion constant can be relaxed from f_a < or approx. 10¹² GeV up to f_a < or approx. 3x10¹⁶ GeV

[en] By means of the effective action method the rate of quantum decay of false vacuum in (1+1) dimensions is expressed in the form of a universal closed formula+ whose validity does not rely on suemiclassical expansion