01-3-1135-2019

 
Fundamental Interactions of Fields and Particles

  

Theme leaders:

D.I. Kazakov O.V. Teryaev

Participating Countries and International organizations:
Belarus, Bulgaria, Canada, Chile, China, Croatia, Finland, France, Germany, Greece, Hungary, India, Iran, Italy, Poland, Portugal, Russia, Serbia, Slovakia, Spain, Sweden, United Kingdom, USA, Vietnam.

The problem under study and the main purpose of the reserch:
The main current problems of the modern theory of fundamental interactions are the development ofmethods of quantum field theory, their application to the description of elementary particle physics within the Standard Model and beyond, theoretical support for existing and planned experiments. Within the framework of the Standard Model, efforts will be focused on the developmentof multiloop computing methods and their applications to processes at the Large Hadron Collider, the development of new approaches to hadron physics, including heavy quark physics. In physics beyond the Standard Model, the search for Dark matter, manifestations of supersymmetry and other possible new physical phenomena are of particular interest. Theoretical support for the search for new physics in accelerator experiments will be combined with research and analysis of astrophysical data.

Developments in neutrino physics, including the field-theoretic description of neutrino oscillations and the processes of neutrino-nucleon interactions with nuclear matter, in particular in connection with the Baikal-GVD experiment, will remain under constant concern. Special attention will be paid to the theoretical support of the key elements of the JINR experimental program. By studying QCD methods, various approaches to the description of the structure of hadrons and quark-gluon matter under the specific conditions of the NICA complex will be developed and applied.

 

Projects in the theme:
	Name of the project	Project Leaders	Project code
1.	Quantum field theory and physics beyond the standard model	D.I. Kazakov A.V. Bednyakov	01-3-1135-1-2024/2028
2.	QCD and hadron structure	I.V. Anikin S.V. Mikhailov O.V. Teryaev	01-3-1135-2-2024/2028

3.

Phenomenology of strong interactions and precision physics

V.I. Korobov M.A. Ivanov

01-3-1135-3-2024/2028

4.	Theory of hadronic matter under extreme conditions	V.V. Braguta E.E. Kolomeitsev S.N. Nedelko	01-3-1135-4-2024/2028
5.	Theory of electroweak interactions and neutrino physics	A.B. Arbuzov V.A. Naumov	01-3-1135-5-2024/2028

 

Projects:
	Name of the project	Project Leaders
Laboratory    Responsible from laboratories
1.	Quantum Field Theory and physics beyond the Standard Model	D.I. Kazakov A.V. Bednyakov

BLTP	A.N. Baushev, A.T. Borlakov, Ch. R. Das, N.A. Gramotkov, V.A. Filippov, R.M. Iakhibbaev, A.V. Kotikov, G.A. Kozlov, A.I. Mukhaeva, A.V. Nesterenko, A.I. Onishchenko, M.V. Savina, O.P. Solovtsova, D.M. Tolkachev, D.A.Volkova

MLIT	S.V. Shmatov

VBLHEP

B.Yu. Alexakhin, B.G. Shaikhatdenov

 

Brief annotation and scientific rationale:
Quantum Field Theory (QFT) is a widely recognized "language" used to describe the properties of elementary particles and their interactions. It is well known that the triumph of the Standard Model (SM) of particle physics would have been impossible without comparing experimental data obtained from accelerators such as LEP (CERN), HERA (DESY), Tevatron (Fermilab), and LHC (CERN) with high-precision calculations performed using QFT methods. Many years have passed since the construction of the SM, and all these years scientists were searching for New Physics. The problem of dark matter in the Universe is an obvious argument for such searches. The main aim of the Project is to develop the quantum field formalism of gauge and supersymmetric theories, as well as to construct and study particle physics models beyond the Standard Model. In the context of the Project, it is planned to use existing experience and new ideas to investigate a wide range of problems related to high-precision calculations within and beyond perturbation theory as well as to the nature of possible New Physics. Special attention will also be paid to issues that arise at the intersection of particle physics, astrophysics, and cosmology.

Expected results upon completion of the project:
Improved estimate of the contribution from hadronic vacuum polarization to the anomalous magnetic moment of the muon.

Investigation of the shapes of higher twist contributions in deep inelastic scattering with the resummation of large threshold logarithms.

Calculation of two-loop diagrams that arise in non-relativistic QED using the effective mass method and investigation of the completeness of basis functions for elliptic polylogarithms.

Development of a new specialized computer package for the epsilon expansion of generalized hypergeometric functions with one or more variables, whose indices depend on the dimensional regularization parameter, as well as for the numerical calculation of the resulting functions.

Explicit analytical calculation of multi-point master integrals using differential equations.

Calculation of two-loop contributions to electron-muon scattering and quarkonia production.

Calculation of the double spectral density in the problem of sum rules for B-anti-B mixing, which is an important experimental quantity that imposes strict constraints on possible new physics.

Calculation of three-loop massive form factors and polarization operators in QCD.

Calculation of multi-loop amplitudes and form factors with a large number of kinematic invariants in theories with extended supersymmetry.

Derivation of systematic solutions to quantum spectral curve equations in the case of maximally supersymmetric Yang-Mills theory in four dimensions and ABJM theory in three dimensions, both in the weak and strong coupling limits.

Calculation of spectra, correlation functions, and amplitudes in a number of six-dimensional "fishnet" models.

Application of the large charge expansion method to gauge theories and analysis of the resulting implications in both particle physics and condensed matter theory.

Investigation of the scheme dependence of a previously proposed self-consistent subtraction procedure for non-renormalizable theories.

Calculation of effective potentials for a range of theories of modified gravity and their application to analyze various inflationary models.

Investigation of the theory and phenomenology of scalar and vector bosonic stars.

Detailed cosmological and astrophysical analysis of the properties of primary black holes and their connection to the dark matter problem and observable supermassive black holes.

Analysis of the prospects for experimental detection of additional Abelian gauge symmetries and an extended Higgs sector in a range of new physics models. Investigation of the so-called supersymmetric extensions of the Standard Model.

Physical analysis of LHC data aimed at detecting manifestations of the "dark sector" in events where either a Higgs boson or a Z boson is produced, accompanied by a significant fraction missing "transverse" energy (MET), presumably carried away by a messenger particle that ultimately decays into DM particles. The expected outcome is new anomalies in the experimental data (in the fortunate event – the discovery of New Physics), or, in the absence of such signals, new unique constraints on the model parameter space for the considered scenarios of dark matter and Higgs sector.

Development of new (using neural networks for global scanning) as well as optimization and improvement of existing software for modeling physical processes beyond the Standard Model.

Expected results of the project in the current year:
Detailed analysis of the properties of cosmological perturbations and their possible connection with the problem of rapid formation of supermassive black holes.

Theoretical study of the formation of galaxies and the velocity field of galaxies at the void center, comparison of the obtained results with observations.

Study of the diffuse supernova neutrino background (DSNB) within New Physics core-collapse models.

Phenomenological analysis of rare B-meson decays in New Physics 3-3-1 models with an extended gauge group.

Analysis of thermodynamics of scalar degrees of freedom in scalar boson stars within Higgs-like models with gravity.

Study of the hadronic vacuum polarization contributions to the muon anomalous magnetic moment at a new level of accuracy.

Derivation of an explicit form of electromagnetic corrections to the anomalous magnetic moments of leptons from diagrams with insertions of the polarization operator with five leptonic loops.

Multi-loop analysis of the asymptotically-safe quantum field model taking into account all possible scalar operators of dimension from two to four, investigation of the vacuum-stability constraint on model parameters.

Construction and study of large-charge expansion in a number of non-Abelian theories with global/local symmetries in strong and weak coupling regimes.

Calculation and analysis of the structure of multi-loop renormalization group equations for basis invariants of the scalar sector of a two higgs-doublet extension of the Standard Model.

Calculation of high-order corrections in a non-renormalizable model with 4 fermion interactions up to three-loop order. Derivation of recurrence relations and a generalized renormalization group equation. Numerical analysis of the latter and the study of the high-energy asymptotics of the solution.

Computation and study of the leading corrections to the effective potential in the Wess-Zumino model for the chiral potential of an arbitrary type.

Derivation and analysis of generalized renormalization group equations in scalar-tensor models of general type.

Analysis of the subtraction-scheme dependence of amplitudes and effective actions within non-renormalizable theories.

Development of a method for calculating universal anomalous dimensions of operators of various twists in the N=4 SYM and ABJM models using modular arithmetic.

Fitting of experimental data on deep inelastic scattering in schemes with effective resummation of large threshold logarithms.

Analysis of deep-inelastic-scattering sum rules in the framework of the analytical coupling at small values of the squared momentum transfer.

 

2.

QCD and hadron structure

I.V. Anikin S.V. Mikhailov O.V. Teryaev

BLTP	V.V. Bytiev, S.V. Goloskokov, R.V. Khakimov, N.V. Krasnikov, A.G. Oganesian, A.V. Pimikov, A.A. Pivovarov, G.Yu. Prokhorov, V.A. Saleev, A.A. Sazonov, O.V. Selyugin, D.A. Shohonov, A.Ya. Silenko, D. Strozik-Kotlorz, N.I. Volchanskiy, V.I. Zakharov, A.S. Zhevlakov

Brief annotation and scientific rationale:
Lacking a complete theoretical understanding of the color confinement, the only method of applying QCD is based on the factorization of the short-distance (perturbative) and long-distance (nonperturbative) dynamics. The conventional systematic way of dealing with the long-distance part is to parametrize it in terms of matrix elements of quark and gluonoperators between hadronic states generating GPDs, DAs, TMDs, etc. These matrix elements have to be either extracted from experiment or determined on the lattice. In many phenomenological applications they are usually modeled in terms of various nonperturbative methods or models.The main objective of the project is to develop comprehensive theoretical frameworks to study the multi-dimensional partonic content of hadrons by combining various approaches based on the factorization theorem and starting from the first principles of QCD.

For many years, theoretical and experimental studies of the nucleon structure have been restricted to a one-dimensional picture along a light-cone direction. Within this one dimensional picture, quark and gluon contents of the nucleus are described by the parton distribution functions (PDFs) which depend on the longitiudinal momentum of the parton inside the hadron.

Expected results upon completion of the project:
Analytic evaluation of 3-loop 2-point Feynman master-integrals with composite external vertices for arbitrary indices of propagators.

Calculation of α²_s(α_sβ₀)^n-1 and α³_sβ₁(α_sβ₀)^n-2 contributions in the nonsinglet ERBL evolution kernel and correlator of two vector composite quark currents in QCD.

Calculation of pion electromagnetic form factors in the framework of light-cone sum rules in the low and (or) moderate energy regime.

Revision of distribution amplitudes (leading twist) of (pseudo)scalar and (longitudinal and transverse) vector mesons within QCD sum rules taking into account new QCD corrections O(α²_s) obtained by us for all of their components.

Derivation and analysis of the full differential equation system for Feynman integrals with multiple parameters of masses and impulses.

Study of tau lepton decays and processes of electron-positron annihilation into mesons including the processes with three pseudoscalar mesons in the final state.

Investigation of the inner structure and nature of the meson interaction at low energies by using the Nambu–Jona-Lasinio model.

Study of the Drell-Yan hadronic structure function within the perturbative QCD in α²_s order of the coupling constant. Сheck of the Lam-Tung identity in α²_s order of the strong coupling constant.

Study of dark axion portal and obtaining bounds for the model in fixed target experiments. The analysis of new physics for NA64 experiment. Study of visible mode of axion or dark photon.

Study of the sum rules for hadron fragmentation functions in QCD with the use of the generalized truncated Mellin moments approach.

Investigation of analytical and numerical optimizations of perturbative series for observables using the renormalization group in QCD.

Study of anomalous transport phenomena in a relativistic quantum medium associated with the curvature of space-time.

Study of the influence of the hadron potential at large distances on the total cross sections, which determines the peculiarity of the scattering amplitude at small momentum transfer. Investigation of the energy dependence and crossing properties of the new anomalous terms of the elastic amplitude of proton-proton and proton-antiproton scattering at NICA energies.

Study of the new-found types of transverse momentum dependent parton distributions within the original frame that involves the newly-found additional contribution in the inverse Radon transforms.

Study of the phase diagram of the SU(2)-Higgs Electroweak theory. Study of Z(N) symmetry and thermodynamic properties of meta-stable states at very high temperature in the context of QCD and Electroweak theory.

The creation of a computational framework to analyze CMS Open Data.

Expected results of the project in the current year:
Study of tau lepton decays and processes of electron-positron annihilation with three mesons in the final state.

Analytical and numerical optimizations of perturbation series for observables using beta-expansion and renormalization group in QCD.

Calculation of the correlator of two vector composite quark currents and the nonsinglet ERBL evolution kernel of the orders α²_s(α_sβ₀)^n-1 and α³_sβ₁(α_sβ₀)^n-2 in QCD.

Analysis of polarization effects in the elastic e + p to e + p processes in the one-photon exchange approximation in the case when the spin quantization axes of the target proton at rest and the incident or scattered electron are parallel.

Study of heavy meson leptoproduction in the Generalized Parton Distributions approach.

Study of the charge sum rules for hadron fragmentation functions in QCD.

Study of inclusive hadron production in proton-proton and heavy-ion collisions at the NICA collider kinematics.

Analytical and numerical optimization of perturbative series for observables using the renormalization group in QCD. Applications to the DIS sum rules.

Analytic evaluation of 3-loop 2-point Feynman master-integrals with composite external vertices for arbitrary indices of propagators.

Development of a method to directly obtain higher orders of ε-expansion of multivariate hypergeometric functions which are important for QCD applications.

Evaluation (making use of resurgent-analysis methods) of currently unavailable nonperturbative contributions to the QCD Adler function of the subleading order in large-n_f expansion (n_f indicates the number of quark flavors).

Study of T-even hadronic structure functions of the Drell-Yan process.

Study of the axion and vector portal between the Standard Model and dark matter, implementation to fixed target experiments to obtain bounds for the model.

Study of dark matter from rare meson decays.

Сalculation of the electromagnetic pion form factor for moderate momentum transfers in the framework of the analytical perturbation theory of QCD and сomparison with the latest JLab experimental data.

Investigation of the possibility of existence of previously unknown phase transitions in relativistic fluid of elementary particles in the region of ultralow temperatures and extremely high accelerations and vorticities.

Analysis of manifestation of dark matter axions in their interaction with leptons proportional to the axion-photon coupling constant.

Investigation of the dissipative properties of the relativistic quantum medium in curved spaces with a horizon and search for dissipative transport coefficients for theories with different spins, and analysis of the connection with predictions based on string theory.

Derivation of the energy dependence of the contribution estimates of tenzor pomeron to spin-dependent amplitudes of nuclon-nuclon elastic scattering. Obtaining quantitative description of all available experimental data on differential cross sections and spin-correllation parameters in elastic NN-scattering from sqrt(s)= 5 GeV up to sqrt(s)= 14 TeV.

Study of the contribution of the effects induced by the effective one-loop action of Heisenberg-Euler QED and its generalization to QCD to the transport coefficients of transport effects (CME, CSE, CESE, CMW, CEW, CVE) in heavy ion collisions.

Study of particle production with orbital angular moments in strong interactions in heavy-ion collisions. Analysis of manifestation of dark matter axions in spin effects.

3.

Phenomenology of strong interactions and precision physics

V.I. Korobov M.A. Ivanov

BLTP	D. Aznabayev, G. Gurjav, A.N. Issadykov, D.I. Melikhov, Yu.S. Surovtsev, J. Tyulemissov, A. Tyulemissova

Brief annotation and scientific rationale:
The project is expected to develop low-energy effective field theories: non-relativistic quantum electrodynamics (NRQED) and covariant quark model of hadrons (Covariant Confined Quark Model, CCQM).

Expected results upon completion of the project:
Exploration of the possibilities of using the combined approach in NRQED, when part of the contributions to the energy of the bound system is considered in the framework of QED, as the total sum over all terms in the powers of the electron binding parameter v/c~Zα.

Introduction of new terms in the general NRQED scheme, which will make it possible to take into account the contributions of light scattering on light, nontrivial centipede diagrams for one- and two-loop self-energy diagrams, necessary for calculating corrections of the order mα⁷-mα⁸ and higher.

It is planned to study the spectra of pionic (π⁻−He+) and kaonic (K⁻−He+) helium atoms in order to refine the pion and kaon masses. The expected relative accuracy in mass measurements is ~10⁻⁸.

Within the framework of CCQM, investigate the possibility of violation of lepton universality in lepton decays of charmonium and bottomonium and their radial excitations.

Obtain bounds on the values of the Wilson coefficients of the Standard Model Effective Theory (SMEFT) operators responsible for the violation of lepton universality in the tauon sector.

Calculate the partial widths of strong and electromagnetic decays of vector D-mesons with an open charm.

Calculate matrix elements and widths of nonleptonic two-particle decays of charmed baryons without changing the charm.

Perform an analysis of strong decays of the charmonium-like state Y(4230) in order to study the nature of its structure.

Perform a theoretical analysis of lepton decays of the B-meson with four leptons in the final state.

 

Expected results of the project in the current year:
Obtaining the Wilson coefficients in the NRQED Lagrangian with the precision required to calculate corrections for bound states in quantum electrodynamics up to the order of mα⁸ inclusive.

Calculation of relativistic corrections of order mα⁶ for bound states of molecular hydrogen ions H₂⁺ and HD⁺ within the ab initio three-body formalism. At present, this term in the interaction Hamiltonian has been calculated only in the adiabatic approximation and has made the largest contribution to the theoretical error in the energies of rho-vibrational and spin transitions.

Analysis of leptonic decays of heavy quarkoniums within the framework of the covariant quark model based on a new approach to treat radial excitations.

Obtaining restrictions on the parameter characterizing the inverse moment of the amplitude of the B_s meson distribution using the available data for the form factors of weak transitions of the B_s meson to a photon and φ meson.

Calculation of the widths of single-photon radiative decays of S- and P-wave excitations of charmonium within the framework of the covariant quark model and study of the dependence of the results on the model parameters.

 

4.

Theory of hadronic matter under extreme conditions

V.V. Braguta E.E. Kolomeitsev S.N. Nedelko

BLTP	M. Bordag, M. Hasegawa, Y. Heo, Yu.B. Ivanov, A.S. Khvorostukhin, K.D. Montenegro, Nguyen Hoang Wu, A.V. Nikolsky, A.A. Roenko, A.M. Snigirev, D.A. Sychev, N.S. Tsegelnik, V.E. Voronin, D. Voskresensky

Brief annotation and scientific rationale:
Modern heavy ion accelerators make it possible to study the properties of strong interactions of elementary particles, which are described by quantum chromodynamics (QCD) under the influence of extreme external conditions. In particular, the quark-gluon matter that is created in such experiments is expected to have a temperature of several hundred MeV, the baryon chemical potential of about 100 MeV, external magnetic field eB ~ 1 GeV² and relativistic rotation with an angular velocity of ~ 10 MeV. Such conditions significantly change the properties of QCD. In the presented project, it is planned to study the properties of QCD at nonzero baryon density, high temperature, large external magnetic field and relativistic rotation using lattice simulation and other approaches.

Expected results upon completion of the project:
In the presented project, it is planned to study the properties of QCD at non-zero baryon density, non-zero temperature and non-zero magnetic field using lattice simulation with an imaginary chemical potential, dynamic u-, d-, and s- quarks and the physical mass of the pi-meson. To conduct such a study, a program written by our group will be used that implements advanced supercomputer technologies and algorithms.

It is expected that quark-gluon matter, which is produced in the process of collision of heavy ions, is not only highly heated and affected by a strong magnetic field but also has a non-zero angular velocity of rotation. Therefore, to interpret the results of heavy ion collision experiments, an important theoretical problem is the study of the properties of rotating quark-gluon matter. In the presented project, we are planning for the first time to study the properties of rotating quark-gluon matter in the framework of lattice simulation.

One of the aims of the project is to impose new constraints on the equation of state of the nuclear and hadronic matter under extreme conditions existing in heavy-ion collisions and the centers of compact stars. For this, the description of strongly interacting systems in and out of equilibrium will be developed. Such observables as the strange and charmed particle production, the directed and elliptic flows of particles, the global spin polarization of hyperons and their intercorrelations will be analyzed within transport and hydrodynamic approaches and compared with existing and future experimental data. Various sources of the spin polarization such as local vorticity of the medium, axial vortex effect, and electromagnetic field will be quantitatively compared and their role in the formation of the observable polarization signal will be clarified.

The possibility of the thermodynamic description of light nuclei and hypernuclei production in heavy-ion collisions within the hydrodynamic approach will be theoretically explored. Formulation of the equations of the viscous hydrodynamics with the internal spin and rotation degrees of freedom as an effective field theory will be achieved. Possible phase transformation in nonequilibrium and equilibrium nuclear matter under the influence of compression, heating, magnetic field, and rotation will be classified and studied. New constraints on the equation of state from the description of the neutron star masses, radii, and the neutron star cooling should be obtained.

Elementary hadronic scattering amplitudes and the corresponding differential cross sections are important ingredients of transport models. The multichannel description of the meson-baryon scattering within the generalized potential approach based on the chiral SU(3) Lagrangian with the parameters tuned to the lattice QCD data and available experimental data on the hadron scattering will be developed.

 

Expected results of the project in the current year:
Study of the mass-radius relationship for neutron and hybrid stars. Analysis of the equations of state both in the absence of hyperons and quarks and taking into account hyperonization and the possibility of the presence of a quark core. Comparison of the results with the results for the equations of state with sigma-scaled masses.

Study of charged pion condensation under the simultaneous action of rotation and magnetic field in the presence of electric and scalar potential wells and nuclear matter. Allowance for London moment and the Meissner effect. Carrying out analogies and study of differences with behavior of metallic superconductors.

Kaon interaction with other hadrons is noticeably weaker than the interaction of non-strange hadrons with each other. Therefore, one may expect that the kaon distribution in heavy-ion collisions gets frozen out earlier than those of non-strange hadrons. The impact of such early freezing on various observables will be studied.

As is well known, the chiral symmetry restoration results in modifications of kaons in dense baryonic matter. At the same time, the matter formed in relativistic heavy-ion collisions is not only (and not always) baryon dense but also consists of dense pion medium, the effect of which has not yet been studied. The effect of dense pion environment on the in-medium modifications of kaons in the relativistic heavy-ion collisions will be studied.

Gravitational form factors of hadrons are related to generalized parton distributions which are an important ingredient of the parton model. The parton model is applied to hard processes involving hadrons. On the other hand, the domain model of QCD vacuum describes low-energy physics of mesons. The latter will be applied to gravitational form factors, which will make it possible to find its connection with the parton model.

Various phenomenological relativistic generalizations of the Breit–Wigner formula are employed while analysing experimentally observed hadronic resonances. The line shape of light vector mesons is to be investigated in the domain model of QCD vacuum.

The relation between the observed alignment of spots in the X-ray films in cosmic ray emulsion experiments and the selection procedure of the highest-energy particles itself together with the transverse momentum conservation will be analyzed in the framework of the HYDJET++ model. The possible influence of transverse momentum conservation in every event in the statistical model approach will be taken into account in the form of missing transverse momentum.

The phenomenological analysis of Pb+Pb data for net-charge fluctuations at the LHC ene tgies will be made within the HYDJET++ model. It is expected that the modification of this model through the explicit inclusion of charge conservation in a statistical approach allows one to reproduce experimental data. 

In the framework of the lattice simulations, the properties of rotating QCD with dynamic fermions will be studied. In particular, spatially inhomogeneous phase transitions in rotating QCD will be considered.

5.

Theory of electroweak interactions and neutrino physics

A.B. Arbuzov V.A. Naumov

BLTP	A. Ahmedov, Yu.M. Bystritskii, M. Deka, A.D. Dolgov,  M.S. Dvornikov, S.B. Gerasimov, N.L. Haong, I.D. Kakorin, S.G. Kovalenko, K.S. Kuzmin, D.A. Kuznetsov, A.A. Nikitenko, N.N. Nikolaev, K. Nurlan, A.A. Osipov, V. Shmidt, M.K. Volkov, U.E.Voznaya, A.F. Zakharov, V.A. Zykunov
DLNP	D.S. Shkirmanov

Brief annotation and scientific rationale:
The Standard Model of particle physics is the most successful theory of fundamental interactions. Despite numerous experiments on its verification and a deep theoretical study of its properties, there are still many problems in this model that need to be solved. The presence of such problems leads us to believe that the Standard Model is only an effective theory, i.e., a low-energy approximation of a more fundamental physical theory. To search for new physical phenomena, it is necessary to have high-precision predictions obtained within the framework of the Standard Model. Within this project, it is planned to obtain such predictions for the conditions of existing and future experiments at colliders, including LHC, FCCee, CEPC, ILC. Calculations will be carried out in order to carry out precise verification of the Standard Model (SM) and search for the limits of applicability of the latter.

Expected results upon completion of the project:
Improvement of basic phenomenological models of electromagnetic nucleon forms-factors in the space-like and time-like domains of q² based on the global statistical analysis of elastic electron scattering data on hydrogen and deuterium. Implementation of the models in the form of software modules of the GENIE neutrino generator. Application of the results to calculations of the cross sections of neutrino-nucleon interactions in the models of the running axial mass (M_A^run) and SuSAM*.

Improvement of the superscaling model SuSAM* with a modified scaling function based on a global statistical analysis of quasielastic electron scattering data on various nuclear targets (from hydrogen to uranium). Model implementation in the GENIE generator. Predictions of the momentum distribution of nucleons in the nucleus within the superscaling approach.

Improvement of the RK model of resonance neutrinoproduction of pions with corrected contributions to the full amplitude based on the global statistical analysis of single pion production data in (anti)neutrino interactions with hydrogen and deuterium. Implementation of the model in the GENIE generator.

Development of a method for solving the quantum kinetic equations describing the transport of massive high-energy neutrinos in heterogeneous (astrophysical) media taking into account the neutrino mixing (including mixing with hypothetical sterile states) and their coherent and inelastic interactions with matter. Application of the theory to the calculation of the passage through the Sun of neutrinos generated by cosmic rays in the solar atmosphere (prediction of the flavor composition, energy and angular distributions). Evaluation of the corresponding background in the experiments on the detection of neutrinos generated by the annihilation of dark matter particles gravitationally bound in the Sun.

Study of the contribution of ultra-high energy neutrinos arising in a multidimensional modification of gravity and comparison of theoretical expectations with observations with the Baikal GVD and IceCube detectors.

Calculation of electroweak radiative corrections to electron-positron annihilation processes, which are planned to be studied at future colliders, including FCCee, CEPC and Super Charm-Tau Factory. Creation of computer programs that can be directly used to simulate and analyze data from experiments at these colliders.

Application of the method of parton distributions developed in QCD to describe electrodynamic corrections to processes studied in current and future experiments in the field of high energy physics.

Construction of high-precision theoretical predictions for Bhabha scattering processes at small and large angles used for luminosity monitoring at electron-positron colliders.

Analysis of semileptonic many-particle decay modes of tau leptons taking into account the excited states of mesons in intermediate states. Construction of a consistent scheme for describing such decays and creation of a computer program for simulating such processes.

Expected results of the project in the current year:
Precision calculation and systematization of the effects of radiative corrections in the forward-backward asymmetry of the dilepton production process in hadronic collisions in the CMS LHC experiment in the Run3/HL mode.

Study of spin asymmetry in the processes of production of pseudoscalar mesons in proton-proton collisions under the conditions of the STAR experiment.

Calculation of the bremsstrahlung and pair production cross sections at low energies under the conditions that will be used to obtain a polarized positron beam.

Description of tau lepton decays and processes of meson production in colliding electron-positron beams in the energy range up to 2 GeV within the framework of the U(3)xU(3) Nambu-Jona-Lasinio model.

High-precision calculation of the light quark masses by fitting the squares of the masses of π⁺, K⁺, and K⁰ mesons to their analytical expressions obtained in the NNLO approximation of 1/Nc expansion.

Study of the impact of NNLO corrections to the Wess-Zumino-Witten anomaly, due to the explicit violation of chiral SU(3)xSU(3) symmetry on the widths of two-photon decays of pions and eta mesons.

Analytical calculations and numerical analysis of higher-order radiative corrections to the processes of electron-positron annihilation and muon-electron scattering under the conditions of modern and future experiments.

Calculation of the contribution of the Casimir energy of the Standard Model fields to the energy density of the Universe within the conformal cosmological model.

Study of scattering of ultrarelativistic neutrinos by a black hole surrounded by a magnetized accretion disk.

Investigation of the problem of non-Abelian gauge symmetry breaking for the solution of the Yang-Mills equation in an expanding space with a negative scalar curvature parameter.

Calculations of baryon and lepton asymmetry of the Universe in the process of capturing heavy neutrinos by primary black holes.

Estimation of the ultrahigh energy neutrino flux in the process of cosmic-ray generation during decay or annihilation of superheavy dark matter particles.

Possible birth of relic neutrinos by photons in the transformation of gravitons into photons in cosmic magnetic fields.

Resonant evolution of transitions between active and sterile neutrinos.

Optimization of the MC model of resonant single pion neutrinoproduction on nucleons and implementation of the model in the GENIE neutrino generator.

Optimization of the running axial mass model for description of quasielastic neutrino scattering on nuclei.

Obtaining constraints on the parameters of alternative theories of gravitation from observations of trajectories of bright stars in the neighborhood of the Galactic Center.

Study of gravitational lensing for the dark matter model of the Galactic Center.

Study of shadows in the neighborhood of the Galactic Center.

Collaboration

Country or International Organization	City	Institute or laboratory
Belarus	Gomel	GSTU
		GSU
	Minsk	INP BSU
		IP NASB
		JIPNR-Sosny NASB
Bulgaria	Sofia	INRNE BAS
Canada	Corner Brook	MUN
Chile	Arica	UTA
	Santiago	UNAB CTEPP
China	Beijing	IHEP CAS
	Guangzhou	SYSU
	Haikou	HNU
	Lanzhou	IMP CAS
Croatia	Zagreb	RBI
Finland	Helsinki	HIP
France	Paris	ENS
		UPMC
	Saclay	IRFU
Germany	Dusseldorf	HHU
	Hamburg	Univ.
	Karlsruhe	KIT
	Regensburg	UR
	Tubingen	Univ.
	Zeuthen	DESY
Greece	Rethymno	UoC
Hungary	Budapest	ELTE
India	Ettimadai	Amrita
	Kolkata	IACS
	Sunabeda	CUO
Iran	Tehran	IPM
		Univ.
Italy	Naples	INFN
	Pisa	INFN
Poland	Katowice	US
	Krakow	INP PAS
	Otwock (Swierk)	NCBJ
Portugal	Coimbra	UC
Russia	Chernogolovka	LITP RAS
	Dubna	Dubna State Univ.
	Irkutsk	ISDCT SB RAS
		ISU
	Moscow	ITEP
		SINP MSU
	Moscow, Troitsk	INR RAS
	Novosibirsk	BINP SB RAS
		NSU
	Protvino	IHEP
	Vladivostok	FEFU
Serbia	Belgrade	AOB
		INS "VINCA"
Slovakia	Bratislava	CU
		IP SAS
Spain	Granada	UGR
Sweden	Stockholm	KTH
United Kingdom	Liverpool	Univ.
	London	Imperial College
USA	Wako, TX	BU
Vietnam	Hanoi	IOP VAST
	Ho Chi Minh City	VNUHCM