TAVKHELIDZE

ALBERT NIKIFOROVICH

1930-2010

Academician of the Russian Academy of Sciences
Doctor of Physics and Mathematics
Professor

Albert Nikiforovich Tavkhelidze was born on December, 16, 1930 in Tbilisi, Georgian SSR, died on February, 27, 2010 in Moscow.

In 1948, after finishing High School No. 8 in Tbilisi, A.N. Tavkhelidze entered Tbilisi State University and graduated from it in 1953 specializing in Theoretical Physics.

In 1957 he completed postgraduate studies under the scientific supervision of Academician N.N. Bogoliubov at the V.A. Steklov Mathematical Institute of the USSR Academy of Sciences and received his PhD degree for the thesis "Photoproduction of pi-mesons on nucleons".

In 1956 A.N. Tavkhelidze was employed as researcher at the Joint Institute for Nuclear Research (JINR, Dubna). Later he was appointed as Head of the Department of Elementary Particle Theory and subsequently as Deputy Director of the Laboratory of Theoretical Physics (LTP, JINR). Together with Academicians N.N. Bogoliubov and A.A. Logunov he contributed to the formation of the research team of LTP.

In 1963 he received the degree of Doctor of Sciences for the thesis "Quasipotential approach in quantum field theory".

Since 1992 was a member of the JINR Scientific Council and a member of the Editorial Board of the Journal "Physics of Elementary Particles and Atomic Nuclei"

In 2000 he was awarded the title "Honorary Doctor of the Joint Institute for Nuclear Research".

In 2002 he received the N.N. Bogoliubov Prize.

From 1965 to 1970 he headed the Sector of Theoretical Physics at the Institute for High Energy Physics (IHEP) in Protvino.

In 1967-1971 he was Head of the Department of Elementary Particle Physics at the Institute for Theoretical Physics of the Academy of Sciences of the Ukraine, presently named after N.N. Bogoliubov (BITP of the National Academy of Sciences of the Ukraine, Kiev). The key role in the establishment of this Institute belonged to Academician N.N. Bogoliubov and A.N. Tavkhelidze.

In 1996 he received the N.N. Bogoliubov Prize of the National Academy of Sciences of the Ukraine.

In 2005 he was awarded the title "Honorary Doctor of the N.N.Bogolubov Institute for Theoretical Physics of the NAS of the Ukraine".

From 1967 to 1991 he was Deputy Editor-in-Chief of the journal of the USSR Academy of Sciences "Theoretical and Mathematical Physics", in its creation N.N. Bogoliubov and A.N. Tavkhelidze played the leading role.

A.N. Tavkhelidze was a founder and the first Director (1970-1986) of the Institute for Nuclear Research of the USSR Academy of Sciences (presently called Institution of the Russian Academy of Sciences (RAS) - the Institute for Nuclear Research of RAS (INR RAS, Moscow). He was Head of the Department of Theoretical Physics of this Institute till last his days.

The main fields of research of INR RAS include physics of elementary particles and of the atomic nucleus, neutrino astrophysics, and cosmology.

This Institute has basic nuclear physics facilities: the "Moscow Meson Factory" (in Troitsk), the Baksan Neutrino Observatory with a Gallium-germanium telescope as well as other low-background laboratories, a deep-water neutrino observatory at Lake Baikal, low-background laboratories with corresponding experimental devices in a salt mine (Ukraine), in mountains Gran Sasso and Monte Bianco (Italy).

The foundation of INR within the structure of the USSR Academy of Sciences was initiated by Academician M.A. Markov, who at that time was Academician-Secretary of the Academy's Nuclear Physics Section.

A.N. Tavkhelidze was a professor of the M.V. Lomonosov Moscow State University.

In 2008, by decision of the MSU Scientific Council, he took charge of the Chair "Elementary Particles and Cosmology", which was organized on his initiative at the University's Physics Faculty.

In 1967 he was elected Corresponding Member and in 1971 - Full Member of the Georgian Academy of Sciences.

In 1971, at the A. Razmadze Mathematical Institute of the Georgian Academy of Sciences, he opened a Theoretical Physics Department and headed it from 1971 till 2005.

In 1977-1994 A.N. Tavkhelidze was the Scientific Leader of the Institute of High Energy Physics (established on his initiative) of the I. Javakhishvili Tbilisi State University.

In 1994-2005 he was Director of this Institute.

From 1986 to 2005 he was President of the Georgian Academy of Sciences.

This period was marked by many historical events that led to serious political consequences: the disintegration of the USSR, the declaration by Georgia of its independence, the civil war and interethnic conflicts. Defending democratic reforms in the country, the Presidium of the Georgian Academy of Siences succeeded in adopting a number of Governmental Acts that guaranteed the Academy its national status and its autonomy. Regional sections of the Academy were set up. Within the Academy, transformations were implemented with regard to the democratic principles generally accepted in the scientific community.

It became possible for the Academy to establish direct scientific relations with world research centres. Initiated by the Presidium of the Georgian AS, Agreements were formalized at the governmental level concerning scientific and technical collaboration with the Joint Institute for Nuclear Research (JINR, Dubna) and the European Organization for Nuclear Research (CERN, Geneva).

In 2002 the President of Georgia signed laws, prepared by the Academy of Sciences and adopted by the Parliament of the country, that guarantee the structural integrity of the Georgian Academy of Sciences, its national status and self-government:
-the Law concerning the Georgian Academy of Sciences,
-the Law guaranteeing social security for scientific workers,
-the Law concerning the professional attestation of scientific and pedagogical personnel of higher qualification.

In 1986-2005 A.N. Tavkhelidze was professor of the I. Javakhishvili Tbilisi State University.

In 1986-2005 he was Editor-in-Chief of the journal "Communications of the Georgian AS" and Chairman of the Committee for State Prizes in Science and Technology under the President of Georgia.

In 1995-2005 he was organizer and Chairman of the Council for Informatization of the Georgian AS and Higher Education in Georgia. During this period the Academy of Sciences was computerized, received access to the Internet, and was provided with networking, computing and information resources.

In 1991-2005 he was Chairman of the Pugwash group in Georgia, Director of the Georgian Branch of the World Federation of Scientists.

In 1987-1990 he was Deputy of the Supreme Council of the Georgian SSR (11th convocation) and a member of the Presidium of the Supreme Council of the Georgian SSR.

In 1989 A.N. Tavkhelidze was elected People's Deputy of the USSR.

In 1984 he was elected Corresponding Member and in 1990 - Full Member (Academician) of the USSR Academy of Sciences (since 1991 - the Russian Academy of Sciences).

In 1967-1990 he was a member of a section of the Higher Attestation Commission, and in 1974-1990 he was a member of the Committee for Lenin and State Prizes under the USSR Council of Ministers.

A.N. Tavkhelidze was a foreign member of several Academies of Sciences.

In 1995-2005 he was Vice President of the International Association of Academies of Sciences (IААS). As recognition of his significant contributions to the strengthening of international scientific collaboration, in 1998 A.N. Tavkhelidze was awarded the Gold Medal "For promotion of the development of science", established by this organization.

A.N. Tavkhelidze was the organizer of a series of large-scale international conferences, seminars and schools for young scientists. As Deputy Chairman of the Organizing Committee, he actively participated in the organization of Rochester Conferences on High Energy Physics in Dubna (1964), Kiev (1970), and Tbilisi (1976).

He was the organizer of the International Conference "Quarks", which has been held regularly since 1980 with active support of the Directorate of INR RAS.

Academician A.N. Tavkhelidze was a recipient of the highest state awards of the USSR, the Russian Federation, and Georgia.

In 1973 he was awarded the USSR State Prize for the series of publications "Photoproduction of pi-mesons on nucleons".

In 1988 he was awarded the Lenin Prize for the series of publications "New quantum number - colour and establishment of dynamic regularities in the quark structure of elementary particles and atomic nuclei".

In 1998 he was awarded the State Prize of the Russian Federation "For creation of the Baksan neutrino observatory and research in the field of neutrino physics, elementary particle physics and cosmic rays".

In 2001 he was awarded the Prize of the Government of the Russian Federation "For the development, creation, and commissioning for scientific operation of the high-current linear proton accelerator of the Moscow Meson Factory".

In 1987, a discovery "The Matveev - Muradyan - Tavkhelidze quark counting rule" was registered in the USSR State Register.

In 2000 Pope John Paul II presented a commemorative token to A.N. Tavkhelidze for his active participation in the work of the World Federation of Scientists and on the occasion of the celebration of the 2000th anniversary of the Nativity of Christ.

A.N. Tavkhelidze was an Honorary Citizen of the cities of Tbilisi, Telavi, Bagdadi (Georgia), and Troitsk (Moscow Region).

His name was listed first in the Book of Honour of INR RAS.

THE MAIN LINES OF SCIENTIFIC ACTIVITY AND ORIGINAL WORKS

Dispersion relations and approximate equations in quantum field theory.

Within the framework of local quantum field theory, dispersion relations for the amplitudes of pion photoproduction on nucleons were established. Based on them, inhomogeneous singular equations in two-particle unitarity approximation were obtained. The kernel of these equations was the meson-nucleon scattering amplitude, while the inhomogeneous part represented the photoproduction amplitude in the one-nucleon approximation. Comparison of the predictions of these equations with experimental data provided the possibility of testing the validity of the underlying requirements of quantum field theory.

A. Logunov, A. Tavkhelidze. JETF, 1957, v. 32, 1393-1403.

A three-dimensional formulation of relativistic quantum field theory was been suggested. The quasipotential equations - the Logunov - Tavkhelidze equations - were been obtained for the scattering amplitude of interacting elementary particles as well as for the bound-state wave functions.

The Logunov - Tavkhelidze equations were successfully used for solving a wide variety of problems in quantum electrodynamics and strong interaction theory. The application of the quasipotential equations within quantum electrodynamics, based on the regular method for constructing a quasipotential, turned out to be quite efficient for calculating high-order corrections to the energy of bound states. In hadron physics, relying on the general principles of local quantum field theory such as relativistic invariance, unitarity, analyticity, and crossing symmetry, phenomenological local quasipotentials were suggested. The latter were used for studying the nature of the Regge behaviour of the two-particle scattering amplitude, the analytical properties of partial amplitudes in the complex plane of the angular momentum, the diffractive picture of small-angular scattering, and the exponential decrease in the differential cross section with the increase of the momentum transfer, and other phenomena. In QCD, quasipotential equations were applied to describe the spectra of quark bound states, to analyze the quark structure of hadrons and nuclei, and to study processes at high momentum transfers.

A. Logunov, A. Tavkhelidze. Nuovo Cim. 1963, v. 29, 380-399.

Finite-energy sum rules for meson-nucleon scattering amplitudes that establish the integral relations between the resonant part of the scattering amplitude and its Regge asymptote were obtained. The experimental test of the finite-energy sum rules actually revealed an important property of the global duality between Regge and resonant behaviours. The properties of global duality and its local realization (the Veneziano amplitude) have played a key part in the formulation of the string model of hadrons.

A. Logunov, L. Soloviev, A. Tavkhelidze. Phys. Lett. 1967, v. 24 B, 181-182.

The method of finite-energy sum rules was generalized to the case of quantum chromodynamics taking into account the inherent property of asymptotic freedom. The finite-energy sum rules, being a non-perturbative method, are widely applied in QCD.

N. Krasnikov, K. Chetyrkin, A. Tavkhelidze. Phys. Lett. 1978, v. 76 B, 83-84.

Fermion masses as a result of spontaneous symmetry breaking.

Following the N. Bogoliubov concept of spontaneous symmetry breaking, within the two-dimensional Schwinger - Thirring model, in which divergences are absent, an appearance of fermions masses due to spontaneous violation of γ₅ -invariance of theory was established.

B. Arbuzov, R. Faustov, A. Tavkhelidze. Docl. Acad. Nauk. 1961, v. 139, 345-347.

Using electroweak interactions as an example it was shown that the appearance of short-range forces carried by massive vector bosons may be totally due to the non-vanishing gauge-invariant vacuum average, scalar condensate <φ^χφ>=η, defining the order parameter theory, and is not related to spontaneous symmetry breaking of the isotopic symmetry.

V. Matveev, M. Shaposhnikov, A. Tavkhelidze. Theor. Mat. Phys. 1984, v. 59, 323-344.

The quantum number colour and coloured quarks

In 1965, N. Bogoliubov, B. Struminsky, and A. Tavkhelidze, independently of Y. Nambu and M. Han, put forward the hypothesis on a new quantum number characterizing quark states. This characteristic was subsequently termed "colour". In accordance with this hypothesis each quark of a given flavour may exist in three unitarily equivalent states corresponding to three conditional values of colour. The principle for the selection of physical states was formulated, according to which observable mesons and baryons are described by superposition of coloured quark states that satisfy the requirements of colourlessness and quantum statistics. It is important that the introduction of colour allowed the Pauli principle to be taken into account without coming into conflict with calculations of the dynamic electromagnetic characteristics of hadrons performed within SU(6) symmetry. The possibility of existence of coloured quarks with both fractional and integer electric charges was shown. In the latter case, colour symmetry is broken at least in electromagnetic interactions.

The new characteristic, "colour", formed the basis of the modern theory of strongly interacting elementary particles. Coloured quarks began to be considered as real fundamental constituents of hadron matter, and the quantum number "colour" as a charge responsible for strong interactions of quarks. As a result, this hypothesis led to the creation of quantum chromodynamics - the gauge theory of interactions of coloured quarks and gluons - and gave rise to numerous versions of the "Grand unification" theory.

Concerning the discovery of the quantum number «COLOUR»

N. Bogoliubov, B. Struminsky, A. Tavkhelidze. JINR Preprint D-1968, Dubna 1965.

A. Tavkhelidze. Proc. ICTP Seminar "High Energy Physics and Elementary Particles", (Trieste, 1965), Vienna 1965, 753-762, 763-779.

N. Bogoliubov, V.Matveev, Nguyen Van Hieu, D. Stoyanov, B. Struminsky, A.Tavkhelidze, V.Shelest. JINR Preprint P-2141, Dubna, 1965.

A relativistic model of hadrons composed of quasi-free coloured quarks

A relativistic composite model of hadrons was proposed in which baryons and mesons are considered as bound states of heavy quasi-free quarks moving in a certain self-consistent scalar potential. This potential prevents quarks from leaving hadrons, compensates their large masses and thus increases quark magnetic moments. The model exhibits the property of additivity of physical quantities, which is typical for nonrelativistic consideration. Baryons and mesons in the model are constructed in the framework of SU(6) symmetry by superposing all admissible states consistent with the requirements of quark statistics and condition of "colourlessness" of hadrons.

The dynamic quasi-free quark model made it possible to systematically describe both statically observed hadron characteristics (μ, g_V/g_A and others) and their form factors. It allowed one to explain weak leptonic decays of pseudoscalar π and K mesons, as well as electromagnetic decays of vector mesons ρ ⁰, ω ⁰ и φ ⁰ into electron-positron pairs via the annihilation of constituent quark-antiquark pairs.

Analysis of the widths of these decays points to the dependence of the effective scale of the bound system on the quantum numbers. For example:

In the case of the decay of π⁰ into two gamma-quanta, determined by the triangular anomaly, the annihilation model indicates the width of this decay being proportional to the number of different quark colours.

N.Bogolubov, B.Struminsky, A.Tavkhelidze. JINR Preprint D-1968, Dubna 1965.

N.Bogolubov, V.Matveev, Nguen Van Hieu, D.Stoianov B.Struminsky, A.Tavkhelidze, V.Shelest. JINR Preprint P-2141, Dubna 1965.

V.Matveev, B.Struminsky, A.Tavkhelidze. JINR Preprint P-2524, Dubna 1966.

A. Tavkhelidze. Proc. ICTP Seminar "High Energy Physics and Elementary Particles", (Trieste, 1965), Vienna, 1965, 753-762, 763-779.

A. Tavkhelidze. Proc. of the XIV Conf. on Particle Physics, Univ. of Brussels (Brussels, 1967), London, 1968, 145-154.

The quasi-free quark model and scaling laws at high energies

In 1969, based on the quasi-free quark model, an assumption was made that the scaling properties of interaction processes of electrons with nucleons revealed in experiments are common for all deep-inelastic lepton-hadron processes and can be derived in a model-independent way from the self-similarity principle.

According to the principle of self-similarity, the form factors and other characteristics of processes with high energies and large momentum transfers do not depend on any dimensional parameters, fixing the scale typical for lengths and momenta, and are homogeneous functions of relativistically invariant kinematic variables. The degree of homogeneity is determined by their physical dimension.

Application of the self-similarity principle made it possible for the first time to establish scaling laws, describing the mass spectrum of muon pairs, produced in proton collisions at high energies p + p → μ ⁺ + μ ^-+hadrons:

,

V.Matveev, R.Muradian, A.Tavkhelidze. JINR Preprint P2-4578, Dubna 1969.

V. Matveev, R. Muradyan, A. Tavkhelidze. Elementary Particles and Atomic Nuclei 1971, v. 2, 7-32.

Quark counting rules

In 1973, within the framework of the quasi-free quark model, based on the self-similarity principle, the so-called quark counting rules were established. These rules determine the asymptotics of form factors at large momentum transfers Q = and the character of the energy dependence of the differential cross section of an arbitrary binary reaction at large-angle scattering and high energies E = :

V. Matveev, R. Muradyan, A. Tavkhelidze. Lett. al Nuovo Cim. 1973, v. 7 , 719-723.

Scaling-invariant asymptotics in local quantum field theory

The scaling invariance observed experimentally in deep-inelastic, inclusive and binary reactions involving hadrons and leptons posed the question about the most general requirements to the field-theoretical model in which the scaling behaviour is possible. In view of this, the form factors of deep-inelastic scattering of electrons on nucleons, previously dealt with by Bjorken (1968), were examined. Within local quantum field theory it was demonstrated that the form factors W_1,2 are causal functions. Using the Yost - Lehman - Dyson representation for form factors, the sufficient conditions that provide for fulfilling the scaling properties of W_1,2 were formulated. In the quasi-free quark model these conditions are necessary as well, which provides for Bjorken scaling in local quantum field theory. An exact relation between the asymptotic properties of structure functions and the behavior of commutators of local currents in the vicinity of the light cone was established.

N. Bogoliubov, A. Tavkhelidze, V. Vladimirov. Theor. Mat. Phys. 1972, v. 12, 3-17.

N. Bogoliubov, A. Tavkhelidze, V. Vladimirov. Theor. Mat. Phys. 1972, v. 12 , 305-329.

Non-conservation of fermion and baryon numbers and the structure of the ground state in gauge theories

The problem of instability of normal baryon matter under the extreme conditions of ultra-high densities was resolved within the framework of the standard theory of electroweak interactions. It was shown that the complex structure of vacuum in gauge theories and the strong non-conservation of fermion quantum numbers is the key property that permits the conclusion to be drawn on the instability of ultra-dense baryon matter.

Of principle importance is the conclusion about possible existence in nature of processes of intense decay of normal matter, when contacting a droplet of ultra-dense fermion matter, with a powerful release of energy.

Within the framework of the "Grand unification" theory, a model of gauge interaction with superweak CP violation was proposed, permitting one to describe simultaneously both the effect of CP violation in rare K decays and the appearance of baryon asymmetry.

V. Matveev, V. Rubakov, M. Shaposhnikov, A. Tavkhelidze. Usp. Phys. Nauk 1988, v. 156, 253-295.

A. Ignatiev, N. Krasnikov, V. Kuzmin, A. Tavkhelidze. Phys. Lett. 1978, v.76 B, 436-438.

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