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We discuss the interplay between higher orders of the perturbative QCD expansion and higher-twist contributions in the analysis of recent Jefferson Lab data on the lowest moments of spin-dependent proton and neutron structure functions Γ1p,n(Q2) and Bjorken sum rule function Γ1p-n(Q2) at 0.05
The generalized Gerasimov-Drell-Hearn sum rule is known to be very sensitive to QCD radiative and power corrections. We improve the previously developed QCD-inspired model for the Q2 dependence of the Gerasimov-Drell-Hearn sum rule. We take into account higher order radiative and higher-twist power corrections extracted from precise Jefferson Lab data on the lowest moment of the spin-dependent pro
The amplitudes of the central exclusive production of χc mesons are calculated using different unintegrated gluon distribution functions (UGDFs). The procedure of generalisation of UGDF for non-forward case by saturation of positivity constraints is suggested. We compare exclusive production of all charmonium states χc(0+), χc(1+) and χc(2 +) including branching fraction for radiative J/ψ+γ decay
Near-threshold production of boson pairs is considered within the framework of the model of unstable particles with smeared mass. We describe the principal aspects of the model and consider the strategy of calculations including the radiative corrections. The results of calculations are in good agreement with LEP II data and Monte-Carlo simulations. Suggested approach significantly simplifies calc
We consider exclusive double diffractive production of scalar χc(0+), axial-vector χc(1+) and tensor χc(2+) charmonia in proton-(anti)proton collisions at different energies. The corresponding amplitudes for these processes are derived within the kt -factorisation approach and the corresponding cross section is calculated with different unintegrated gluon distribution functions (UGDFs) known from
Near-threshold production of charged boson pairs is considered within the framework of the model of unstable particles with smeared mass. The results of calculations are in good agreement with LEP II data and Monte Carlo simulations. Suggested approach significantly simplifies calculations with respect to standard perturbative one.
We discuss exclusive elastic double diffractive axial-vector χc (1+) meson production in proton-antiproton collisions at the Tevatron. The amplitude for the process is derived within the kt-factorization approach with unintegrated gluon distribution functions (UGDFs). We show that the famous Landau-Yang theorem is not applicable in the case of off-shell gluons. Differential cross sections for diff
The split SUSY scenario with light Higgsino states is treated as an application to the dark matter problem. We have considered the structure of the neutralinonucleon interaction and calculated cross-section of the neutralinonucleon scattering. The decay properties of the lightest chargino and next lightest neutralino are analyzed in details.
Anomalous dimensions of high-twist Wilson operators in generic gauge theories occupy a band of width growing logarithmically with their conformal spin. We perform a systematic study of its fine structure in the autonomous SL (2) subsector of the dilatation operator of planar N = 4 super-Yang-Mills theory which is believed to be integrable to all orders in 't Hooft coupling. We resort in our study
We calculate several differential distributions for exclusive double-diffractive χc(0++) production in the proton-antiproton collisions at the Tevatron and in proton-proton collisions at RHIC and LHC. We use unintegrated gluon distributions (UGDFs) within the kt-factorization approach. The g*g*→χc(0++) transition vertex is calculated as a function of gluon virtualities via the standard perturbativ
The reasonableness of the use of perturbative QCD notions in the region close to the scale of hadronization, i.e., below 1GeV is under study. First, the interplay between higher orders of pQCD expansion and higher-twist contributions in the analysis of recent Jefferson Lab (JLab) data on the generalized Bjorken sum rule function Γ1p-n(Q2) at 0.1
We analyze a connection between the neutralino mass sign, parity and structure of the neutralino-boson interaction. Correct calculation of spin-dependent and spin-independent contributions to neutralino-nuclear scattering should consider this connection. A convenient diagonalization procedure, based on the exponential parametrization of unitary matrix, is suggested.
Near-threshold production of neutral boson pairs is considered within the framework of the model of unstable particles with smeared mass. The results of calculations are in good agreement with LEP II data and Monte Carlo simulations. Suggested approach significantly simplifies calculations with respect to standard perturbative one.
We discuss double-diffractive (double-elastic) production of the η′-meson in the pp→pη′p reaction within the formalism of unintegrated gluon distribution functions (UGDF). We estimate also the contribution of γ*γ*→η′ fusion. The distributions in the Feynman xF (or rapidity), transferred four-momenta squared between initial and final protons (t1,t2) and azimuthal angle difference between outgoing p
The amplitude for scalar Higgs boson production in the fusion of two off-shell gluons is calculated including finite (not infinite) masses of quarks in the triangle loop. In comparison to the effective Lagrangian approach, we have found a new term in the amplitude. The matrix element found can be used in the k⊥-factorization approach to the Higgs boson production. The results are compared with the
Anomalous triangle graphs for the divergence of the axial-vector current are studied using the dispersive approach generalized for the case of higher orders of perturbation theory. The validity of this procedure is proved up to the two-loop level. By direct calculation in the framework of dispersive approach we have obtained that the two-loop axial-vector-vector (AVV) amplitude is equal to zero. A
