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Theory of Fundamental Interactions

• Investigation of the arbitrariness in divergence subtraction procedure in supersymmetric theories in higher dimensions and calculation of the leading counter-terms in all orders of perturbation theory.
  
  Theoretical support of search for new physics at the LHC based on experimental data from ATLAS and CMS.
  
  Theoretical study of supersymmetric models of Dark matter and analysis of experimental data on direct and indirect Dark matter search.
  
  Investigation of the effects due to radiative corrections in Drell-Yan processes after increasing LHC luminosity and beam energy.
  
  Studies of parton densities in nuclei.
  
  Investigation of high-energy asymptotics of the structure functions F2 and FL and their heavy quark parts.
  
  Development of the method that would enable one to account for the effects due to continuation of the perturbative QCD results into the timelike domain, at an arbitrary order of perturbation theory.
  
  Calculation of high-order corrections to renormalization-group functions and theoretical analysis of their influence on predictions in particle physics and in studies of critical phenomena.
  
  Analysis of ambiguities in high-order calculations of different renormalization-group functions in QFT models with chiral interactions.
  
  Theoretical study of rare higgs-boson decays predicted in some New Physics models. Development of twistor and ambitwistor description of multiloop form factors of local and Wilson line operators in theories with extended supersymmetry. Study and development of twistor description for loop reggeon amplitudes.
  
  Studies of the dark matter problem in the framework of the Standard Model and beyond it, including its supersymmetric generalizations. Building of Minimal Consistent Dark Matter models. Development of the strategy of comparing/mapping of their parameters for results of searches.
  
  
• Calculation of quark-gluon subprocess contribution to exclusive Drell-Yan process amplitude, estimate of its observability at CMS, COMPASS and NICA.
  
  Investigation of relations between meson distribution amplitudes and gluonic poles in twist 3 correlators and their manifestations for matching of various kinematical regimes of pion-nucleon Drell-Yan process.
  
  Investigations of connection between mechanisms of hyperon polarization in hadronic and heavy-ion collisions and duality between field-theoretical and hydrodynamical descriptions of spin effects.
  
  Generalization of QCD low-energy theorems for gluonic anomaly accounting for effects of mixing and contributions of heavy quarkonia and gluonia.
  
  Common analysis of azimuthal asymmetries in SIDIS in perturbative and non-perturbative QCD.
  
  Lattice calculations of heavy quarkonia polarizabilities and investigation of their relations with charmed pentaquark spectroscopy.
  
  Development of methods of extrapolation of parton distributions to low-x domain using the truncated moments and their applications to fragmentation functions.
  
  
• Study of semileptonic B-meson decay with tau-lepton in the final state and the subsequent leptonic and semihadronic tau-decays.
  
  Investigation of new observables in the Standard Model as well as in different new-physics scenarios.
  
  Study of spectra of light atoms and molecules in higher orders of the fine structure constant for determination of the improved values of the fundamental physical constants and resolution of the proton charge radius problem.
  
  Calculation of the hadronic light-by-light contributions to the muon anomalous magnetic moment in the leading and next-to-leading orders in the 1/N_c parameter.
  
  Study of the properties of the f1, a1, K1 axial-vector mesons in ground and radially excited states, their strong and electromagnetic hadron decays and production in e+e- colliding beams and tau-lepton decays.
  
  Calculation of masses and decay constants of exotic glueballs within QCD sum rules. Study of the glueball dynamics by strong coupling expansion of the SU(3) Yang-Mills Hamiltonian in the flux-tube gauge. Study of the multiquark hadrons and existence of the extraneous dibaryons.
  
  Calculation of the contributions of light mesons to the hyperfine structure of muonic hydrogen.
  
  Calculations of two loop contributions for Moeller scattering and Drell-Yan process within the Standard Model, radiative corrections evaluation to the process of antiproton-proton annihilation into a lepton pair and a pair of mesons for the PANDA facility.
  
  Studies pertaining to the QCD vacuum and QCD phase diagram (also in the presence of a strong magnetic field): the role of strangeness and multiquark interactions in the characteristics of the low lying meson nonets, in the freeze-out region of relativistic heavy-ion experiments, in the position of the critical end point, and in the regime of dense matter relevant for compact stars.
  
  Studies of the high-density equations of state and mass-radius observations for compact stars and multi-polytrope approach to a strong first-order phase transition that produces high-mass twin stars as an observable signature of it.
  
  
• Participation (continuation) in the tmfT Collaboration (finite temperature with twisted mass fermions in lattice QCD) aimed at description of the quark-gluon thermodynamics including strange and charmed quarks and consideration of new observables indicating the crossover. Study of the gluon spectral function at finite temperature (longitudinal and transversal). Completion of the work on the EoS via trace anomaly. Study of the temperature dependence of the topological susceptibility and obtaining of more detailed results on topological structure supporting evidence for dyons. For N_f=2 with imaginary chemical potential µ extending gluon and ghost propagator from imaginary to real µ. Finite µ for SU(2) QCD: study of the phase diagram. Study of anomalous transport phenomena in QGP, calculation of the bulk viscosity, properties of QCD with nonzero chiral chemical potential.
  
  Study of the role of viscosity effects at the hydrodynamic stage of the system evolution for the multiplicity of created particles (mainly pions) and the transverse momentum spectra using the Israel-Stewart second-order equations. Rapidity distributions as well as transverse momentum spectra of identified hadrons (including strange particles) produced in the NICA energy range.
  
  The hadronic part of the EoS at finite temperatures will be constructed including the first two SU(3) multiplets in baryon (octet of spin 1/2 and decuplet of spin 3/2 particle) and meson (octet of pseudoscalar meson and nonet of vector mesons) sectors.
  
  Construction of a new class of hybrid EoS with first-order phase transition fulfilling constraints from nuclear physics and compact star observations. Providing of EoS tables with and without phase transition for HIC simulation.
  
  Performing of analytical calculations for the ultrarelativistic transverse momentum distributions for the Tsallis-3 and Renyi statistics.
  
  Evaluation of correlation functions for an ensemble of domain wall networks representing nonperturbative QCD vacuum by employing methods of analytical and numerical multidimensional integration.
  
  Calculation of the one-loop effective potential for arbitrary Abelian gluon fields in finite volume for various boundary conditions. Investigation of the stabilization of the domain size due to the quark lowest modes. Study of the role of strong electromagnetic fields as trigger of deconfinement transition.
  
  Investigation of the anisotropic stage of the QGP evolution and the dependence of the approach to thermal equilibrium on the breaking of scale invariance based on analytic black brane solutions with non-conformal asymptotics for the 5-dimesional gravity with a dilaton corresponding to a dual description of QGP.
  
  Investigation of the critical behavior of a system consisting of scalar and fermion fields: relations between the scalar and fermion condensates and the masses of the particles in this system for the case of zero temperature.
  
  
• A detailed statistical analysis of available acclerator data on exlusive (anti)neutrino-nucleus interactions at low and intermediate energies will be performed aiming at the extration of the electroweak axial-vector current parameters. The results will be claimed in the current and future oscillation experiments with accelerator and atmospheric experiments (NOvA, DUNE, Super- and Hyper-Kamiokande, etc.).
  
  The cross sections of processes involving neutrinos are expressed through the neutrino mixing matrix. It will be shown that the probabilities of all processes can be represented in an equivalent way explicitly in terms of the neutrino mass matrix. The existence of such representations allows fitting of the mass matrix of neutrinos directly from the experimental data.
  
  Starting from the variational energy principle, the equations of hydrostatic equilibrium of stars will be derived without assuming the local electroneutrality of matter. We will find the first and second unconditional variational derivatives of the interaction energy, as well as the conditional variational derivatives along the constraint surface "fixed total charge of the star". The effect of deviations from the local electroneutrality on neutrino spectra in supernovae will be calculated. The stability criteria of the solutions, associated with the positive definiteness of the second variations, will be studied.
  
  The process of double beta decay of the nucleus with the capture of one of the beta-electrons on the outer electron shell of the atom will be studied. This problem is of interest in connection with the experiment of the NEMO 3 and SuperNEMO collaboration. The possibility that one or both electrons emitted from the nucleus in neutrinoless double beta decay might undergo an inelastic collision with the bound electrons in the atomic shell and either shift them to a higher energy level (excitation) or eject them from the atom (ionization) will also be studied.
  
  In a number of generalizations of the Standard Model, the existence of a neutrino condensate is predicted. This scenario will be analyzed from the point of view of the effect produced by the condensate on the probability of neutrinoless double beta decay of nuclei.
  
  The R-parity breaking SUSY mechanisms of the neutrinoless double beta decay will be revised following the current SUSY phenomenology. The importance of the one and two pion exchange in this process will be discussed. The corresponding nuclear matrix elements will be calculated within the QRPA with isospin symmetry restoration.
  
  The electron neutrino mass can be determined by the upper end of the deexcitation (bolometer) spectrum of ¹⁶³Dy after electron capture in ¹⁶³Ho. All deexcitation spectra (X rays, Auger electron and the recoil of Holmium) end at the Q value minus the neutrino mass. Recently, the theoretical spectra were calculated by including also the second hole in the atomic excitations of dysprosium. The impact of the internal bremsstrahlung electron capture process on the end of deexcitation spectra will be studied.
  
  The uncertainties in the calculated reactor antineutrino spectrum will be evaluated. For that purpose, the improved theoretical description of the first forbidden beta decays will be obtained by considering the exact Dirac wave functions of the electron with finite nuclear size and electron screening taken into account.
  
  Within a field-theoretical approach with wave packets, the off-shell regime of neutrino oscillations will be investigated; the regime works at super-short distances between the source and detector.
  
  

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