Nikolay Volchanskiy

We obtain QCD radiative corrections to distribution amplitudes of π and ρ mesons within QCD sum rules. To this end, we calculate correlators of two different composite vertices at order O ( α s 2 β 0 ) , where β ₀ is the first coefficient in the expansion of QCD ϒ-function.

The problems of simple elementary weakly interacting massive particles (WIMPs) appeal to extend the physical basis for nonbaryonic dark matter. Such extension involves more sophisticated dark matter candidates from physics beyond the Standard Model (BSM) of elementary particles. We discuss several models of dark matter, predicting new colored, hyper-colored or techni-colored particles and their accelerator and non-accelerator probes. The nontrivial properties of the proposed dark matter candidates can shed new light on the dark matter physics. They provide interesting solutions for the puzzles of direct and indirect dark matter search.

The problems of simple elementary weakly interacting massive particles (WIMPs) appeal to extend the physical basis for nonbaryonic dark matter. Such extension involves more sophisticated dark matter candidates from physics beyond the Standard Model (BSM) of elementary particles. We discuss several models of dark matter, predicting new colored, hyper-colored or techni-colored particles and their accelerator and non-accelerator probes. The nontrivial properties of the proposed dark matter candidates can shed new light on the dark matter physics. They provide interesting solutions for the puzzles of direct and indirect dark matter search.

We consider the most general two-loop massless correlator I(n ₁ , n ₂ , n ₃ , n ₄ , n ₅; x, y; D) of two composite vertices with the Bjorken fractions x and y for arbitrary indices {n _i } and space-time dimension D; this correlator is represented by a “kite” diagram. The correlator I({n _i }; x, y; D) is the generating function for any scalar Feynman integrals related to this kind of diagrams. We calculate I({n _i }; x, y; D) and its Mellin moments in a direct way by evaluating hypergeometric integrals in the α representation. The result for I({n _i }; x, y; D) is given in terms of a double hypergeometric series — the Kampé de Férriet function. In some particular but still quite general cases it reduces to a sum of generalized hypergeometric functions ₃ F ₂. The Mellin moments can be expressed through generalized Lauricella functions, which reduce to the Kampé de Férriet functions in several physically interesting situations. A number of Feynman integrals involved and relations for them are obtained.

We study possibilities to extend the Standard Model (SM) by three flavors of vectorlike heavy quarks in pseudoreal representation of symplectic hypercolor gauge group. This extension of SM predicts a rich spectra of heavy composite hypermesons and hyperbaryons (all of them carry integer spins) including fourteen pseudo-Nambu--Goldstone states emerging in dynamical breaking of the global symmetry group of the H-quarks, SU(6), to its Sp(6) subgroup. The properties of the lightest states depend strongly on the choice of heavy-quark hypercharges. Our focus is placed on the variants of the model with partially composite Higgs boson, i.e. the experimentally observed boson is comprised of the elementary SM Higgs and a mixture of H-hadrons.