Antimatter

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Antimatter

A cloud chamber photograph of the first observed positron, 2 August 1932

In modern physics, antimatter is defined as matter composed of the antiparticles (or "partners") of the corresponding particles in "ordinary" matter, and can be thought of as matter with reversed charges and parity, or going backward in time (see CPT symmetry). Antimatter occurs in natural processes like cosmic ray collisions and some types of radioactive decay. Antiparticles can also be generated at particle accelerators, but only a tiny fraction of these have successfully been bound together in experiments to form antiatoms. Total artificial production has been only a few nanograms.^[1] No macroscopic amount of antimatter has ever been assembled due to the extreme cost and difficulty of production and handling. Nonetheless, antimatter is an essential component of widely available applications related to beta decay, such as positron emission tomography, radiation therapy,^[2] and industrial imaging.

In theory, a particle and its antiparticle (for example, a proton and an antiproton) have the same mass, but opposite electric charge, and other differences in quantum numbers.

A collision between any particle and its anti-particle partner leads to their mutual annihilation, giving rise to different proportions of intense photons (gamma rays), neutrinos, and sometimes less-massive particle–antiparticle pairs. The majority of the total energy of annihilation emerges in the form of ionizing radiation. If surrounding matter is present, the energy content of this radiation will be absorbed and converted into other forms of energy, such as heat or light. The amount of energy released is usually proportional to the total mass of the collided matter and antimatter, in accordance with the mass–energy equivalence equation, E=mc².

Antiparticles bind with each other to form antimatter, just as ordinary particles bind to form normal matter. For example, a positron (the antiparticle of the electron) and an antiproton (the antiparticle of the proton) can form an antihydrogen atom. The nuclei of antihelium have been artificially produced, albeit with difficulty, and are the most complex anti-nuclei so far observed. Physical principles indicate that complex antimatter atomic nuclei are possible, as well as anti-atoms corresponding to the known chemical elements.

There is strong evidence that the observable universe is composed almost entirely of ordinary matter, as opposed to an equal mixture of matter and antimatter. This asymmetry of matter and antimatter in the visible universe is one of the great unsolved problems in physics. The process by which this inequality between matter and antimatter particles is hypothesised to have occurred is called baryogenesis.

Definitions

Antimatter particles carry the same charge as matter particles, but of opposite sign. That is, an antiproton is negatively charged and an antielectron (positron) is positively charged. Neutrons do not carry a net charge, but their constituent quarks do. Protons and neutrons have a baryon number of +1, while antiprotons and antineutrons have a baryon number of –1. Similarly, electrons have a lepton number of +1, while that of positrons is –1. When a particle and its corresponding antiparticle collide, they are both converted into energy.

The French term for "made of or pertaining to antimatter", contraterrene, led to the initialism "C.T." and the science fiction term seetee, as used in such novels as Seetee Ship.

History

Conceptual

The idea of negative matter appears in past theories of matter that have now been abandoned. Using the once popular vortex theory of gravity, the possibility of matter with negative gravity was discussed by William Hicks in the 1880s. Between the 1880s and the 1890s, Karl Pearson proposed the existence of "squirts" and sinks of the flow of aether. The squirts represented normal matter and the sinks represented negative matter. Pearson's theory required a fourth dimension for the aether to flow from and into.

The term antimatter was first used by Arthur Schuster in two rather whimsical letters to Nature in 1898, in which he coined the term. He hypothesized antiatoms, as well as whole antimatter solar systems, and discussed the possibility of matter and antimatter annihilating each other. Schuster's ideas were not a serious theoretical proposal, merely speculation, and like the previous ideas, differed from the modern concept of antimatter in that it possessed negative gravity.

The modern theory of antimatter began in 1928, with a paper by Paul Dirac. Dirac realised that his relativistic version of the Schrödinger wave equation for electrons predicted the possibility of antielectrons. Although Dirac had laid the groundwork for the existence of these "antielectrons" he initially failed to pick up on the implications contained within his own equation. He freely gave the credit for that insight to J. Robert Oppenheimer, whose seminal paper "On the Theory of Electrons and Protons" (Feb 14th 1930) drew on Dirac's equation and argued for the existence of a positively charged electron (a positron), which as a counterpart to the electron should have the same mass as the electron itself. This meant that it could not be, as Dirac had in fact suggested, a proton. Dirac further postulated the existence of antimatter in a 1931 paper which referred to the positron as an "anti-electron". These were discovered by Carl D. Anderson in 1932 and named positrons from "positive electron". Although Dirac did not himself use the term antimatter, its use follows on naturally enough from antielectrons, antiprotons, etc.

The Feynman–Stueckelberg interpretation states that antiparticles obey the same equations of motion as regular particles but with charge, parity and time inverted. This allows analysis of antiparticles using Feynman diagrams with time reversed.

Particle discoveries

After Carl Anderson's discovery of the positron in 1932, it was 22 years before the next antimatter particle was found. In 1955 Chamberlain, Segrè, Wiegand, Ypsilantis publish their the discovery of the antiproton and in 1956 Cork, Lambertson, Piccioni, Wenzel discovered the antineutron. Both teams used the Bevatron in Berkeley, California.

Antigalaxies

The discovery of antimatter led to both scientific and science fiction speculations on astronomical antimatter bodies: antiplanets, antistars, and antigalaxies. Leon Lederman at Columbia University even speculated anti-planets might harbor intelligent life. The antigalaxy idea was also used to explain the baryon asymmetry problem: the particle physics of the Big Bang model cannot explain why our universe has more matter than antimatter. Maurice Goldhaber suggested that our universe consists of matter rather than antimatter because the one universe of each type split at the beginning of time. By the 1970s the asymmetry problem was accepted as unexplained and the possibility of antigalaxies largely abandoned.

Notation

One way to denote an antiparticle is by adding a bar over the particle's symbol. For example, the proton and antiproton are denoted as p and p, respectively. The same rule applies if one were to address a particle by its constituent components. A proton is made up of u u d quarks, so an antiproton must therefore be formed from u u d antiquarks. Another convention is to distinguish particles by positive and negative electric charge. Thus, the electron and positron are denoted simply as e⁻
and e⁺
respectively. To prevent confusion, however, the two conventions are never mixed.

Properties

There is no difference in the gravitational behavior of matter and antimatter. In other words, antimatter falls down when dropped, not up. This was confirmed with the thin, very cold gas of thousands of antihydrogen atoms that were confined in a vertical shaft surrounded by superconducting electromagnetic coils. These can create a magnetic bottle to keep the antimatter from coming into contact with matter and annihilating. The researchers then gradually weakened the magnetic fields and detected the antiatoms using two sensors as they escaped and annihilated. Most of the anti-atoms came out of the bottom opening, and only one-quarter out of the top.

There are compelling theoretical reasons to believe that, aside from the fact that antiparticles have different signs on all charges (such as electric and baryon charges), matter and antimatter have exactly the same properties. This means a particle and its corresponding antiparticle must have identical masses and decay lifetimes (if unstable). It also implies that, for example, a star made up of antimatter (an "antistar") will shine just like an ordinary star. This idea was tested experimentally in 2016 by the ALPHA experiment, which measured the transition between the two lowest energy states of antihydrogen. The results, which are identical to that of hydrogen, confirmed the validity of quantum mechanics for antimatter.

Origin and asymmetry

See also: Baryogenesis

Most things observable from the Earth seem to be made of matter rather than antimatter. If antimatter-dominated regions of space existed, the gamma rays produced in annihilation reactions along the boundary between matter and antimatter regions would be detectable.

Antiparticles are created everywhere in the universe where high-energy particle collisions take place. High-energy cosmic rays striking Earth's atmosphere (or any other matter in the Solar System) produce minute quantities of antiparticles in the resulting particle jets, which are immediately annihilated by contact with nearby matter. They may similarly be produced in regions like the center of the Milky Way and other galaxies, where very energetic celestial events occur (principally the interaction of relativistic jets with the interstellar medium). The presence of the resulting antimatter is detectable by the two gamma rays produced every time positrons annihilate with nearby matter. The frequency and wavelength of the gamma rays indicate that each carries 511 keV of energy (that is, the rest mass of an electron multiplied by c²).

Observations by the European Space Agency's INTEGRAL satellite may explain the origin of a giant antimatter cloud surrounding the Galactic Center. The observations show that the cloud is asymmetrical and matches the pattern of X-ray binaries (binary star systems containing black holes or neutron stars), mostly on one side of the Galactic Center. While the mechanism is not fully understood, it is likely to involve the production of electron–positron pairs, as ordinary matter gains kinetic energy while falling into a stellar remnant.

Antimatter may exist in relatively large amounts in far-away galaxies due to cosmic inflation in the primordial time of the universe. Antimatter galaxies, if they exist, are expected to have the same chemistry and absorption and emission spectra as normal-matter galaxies, and their astronomical objects would be observationally identical, making them difficult to distinguish. NASA is trying to determine if such galaxies exist by looking for X-ray and gamma ray signatures of annihilation events in colliding superclusters.

In October 2017, scientists working on the BASE experiment at CERN reported a measurement of the antiproton magnetic moment to a precision of 1.5 parts per billion. It is consistent with the most precise measurement of the proton magnetic moment (also made by BASE in 2014), which supports the hypothesis of CPT symmetry. This measurement represents the first time that a property of antimatter is known more precisely than the equivalent property in matter.

Antimatter quantum interferometry has been first demonstrated in 2018 in the Positron Laboratory (L-NESS) of Rafael Ferragut in Como (Italy), by a group led by Marco Giammarchi.

Natural production

Main article: Positron emission

Positrons are produced naturally in β⁺ decays of naturally occurring radioactive isotopes (for example, potassium-40) and in interactions of gamma quanta (emitted by radioactive nuclei) with matter. Antineutrinos are another kind of antiparticle created by natural radioactivity (β⁻ decay). Many different kinds of antiparticles are also produced by (and contained in) cosmic rays. In January 2011, research by the American Astronomical Society discovered antimatter (positrons) originating above thunderstorm clouds; positrons are produced in terrestrial gamma ray flashes created by electrons accelerated by strong electric fields in the clouds. Antiprotons have also been found to exist in the Van Allen Belts around the Earth by the PAMELA module, and similar antiproton belts may exist around Jupiter, Saturn, Neptune, and Uranus.

Antiparticles are also produced in any environment with a sufficiently high temperature (mean particle energy greater than the pair production threshold). It is hypothesized that during the period of baryogenesis, when the universe was extremely hot and dense, matter and antimatter were continually produced and annihilated. The presence of remaining matter, and absence of detectable remaining antimatter, is called baryon asymmetry. The exact mechanism that produced this asymmetry during baryogenesis remains an unsolved problem. One of the necessary conditions for this asymmetry is the violation of CP symmetry, which has been experimentally observed in the weak interaction.

Recent observations indicate black holes and neutron stars produce vast amounts of positron-electron plasma via the jets.

Observation in cosmic rays

Main article: Cosmic ray

Satellite experiments have found evidence of positrons and a few antiprotons in primary cosmic rays, amounting to less than 1% of the particles in primary cosmic rays. This antimatter cannot all have been created in the Big Bang, but is instead attributed to have been produced by cyclic processes at high energies. For instance, electron-positron pairs may be formed in pulsars, as a magnetized neutron star rotation cycle shears electron-positron pairs from the star surface. Therein the antimatter forms a wind that crashes upon the ejecta of the progenitor supernovae. This weathering takes place as "the cold, magnetized relativistic wind launched by the star hits the non-relativistically expanding ejecta, a shock wave system forms in the impact: the outer one propagates in the ejecta, while a reverse shock propagates back towards the star." The former ejection of matter in the outer shock wave and the latter production of antimatter in the reverse shock wave are steps in a space weather cycle.

Preliminary results from the presently operating Alpha Magnetic Spectrometer (AMS-02) on board the International Space Station show that positrons in the cosmic rays arrive with no directionality, and with energies that range from 10 GeV to 250 GeV. In September, 2014, new results with almost twice as much data were presented in a talk at CERN and published in Physical Review Letters. A new measurement of positron fraction up to 500 GeV was reported, showing that positron fraction peaks at a maximum of about 16% of total electron+positron events, around an energy of 275 ± 32 GeV. At higher energies, up to 500 GeV, the ratio of positrons to electrons begins to fall again. The absolute flux of positrons also begins to fall before 500 GeV, but peaks at energies far higher than electron energies, which peak about 10 GeV. These results on interpretation have been suggested to be due to positron production in annihilation events of massive dark matter particles.

Cosmic ray antiprotons also have a much higher energy than their normal-matter counterparts (protons). They arrive at Earth with a characteristic energy maximum of 2 GeV, indicating their production in a fundamentally different process from cosmic ray protons, which on average have only one-sixth of the energy.

There is an ongoing search for larger antimatter nuclei, such as antihelium nuclei (that is, anti-alpha particles), in cosmic rays. The detection of natural antihelium could imply the existence of large antimatter structures such as an antistar. A prototype of the AMS-02 designated AMS-01, was flown into space aboard the Space Shuttle Discovery on STS-91 in June 1998. By not detecting any antihelium at all, the AMS-01 established an upper limit of 1.1×10⁻⁶ for the antihelium to helium flux ratio. AMS-02 revealed in December 2016 that it had discovered a few signals consistent with antihelium nuclei amidst several billion helium nuclei. The result remains to be verified, and as of 2017, the team is trying to rule out contamination.

Artificial production

Positrons

Main article: Positron

Positrons were reported in November 2008 to have been generated by Lawrence Livermore National Laboratory in large numbers. A laser drove electrons through a gold target's nuclei, which caused the incoming electrons to emit energy quanta that decayed into both matter and antimatter. Positrons were detected at a higher rate and in greater density than ever previously detected in a laboratory. Previous experiments made smaller quantities of positrons using lasers and paper-thin targets; newer simulations showed that short bursts of ultra-intense lasers and millimeter-thick gold are a far more effective source.

In 2023, the production of the first electron-positron beam-plasma was reported by a collaboration led by researchers at University of Oxford working with the High-Radiation to Materials (HRMT) facility at CERN. The beam demonstrated the highest positron yield achieved so far in a laboratory setting. The experiment employed the 440 GeV proton beam, with ${\displaystyle 3\times {10}^{11}}$ protons, from the Super Proton Synchrotron, and irradiated a particle converter composed of carbon and tantalum. This yielded a total ${\displaystyle 1.5\times {10}^{13}}$ electron-positron pairs via a particle shower process. The produced pair beams have a volume that fills multiple Debye spheres and are thus able to sustain collective plasma oscillations.

Antiprotons, antineutrons, and antinuclei

Main articles: Antiproton and Antineutron

The existence of the antiproton was experimentally confirmed in 1955 by University of California, Berkeley physicists Emilio Segrè and Owen Chamberlain, for which they were awarded the 1959 Nobel Prize in Physics. An antiproton consists of two up antiquarks and one down antiquark (uud). The properties of the antiproton that have been measured all match the corresponding properties of the proton, with the exception of the antiproton having opposite electric charge and magnetic moment from the proton. Shortly afterwards, in 1956, the antineutron was discovered in proton–proton collisions at the Bevatron (Lawrence Berkeley National Laboratory) by Bruce Cork and colleagues.

In addition to antibaryons, anti-nuclei consisting of multiple bound antiprotons and antineutrons have been created. These are typically produced at energies far too high to form antimatter atoms (with bound positrons in place of electrons). In 1965, a group of researchers led by Antonino Zichichi reported production of nuclei of antideuterium at the Proton Synchrotron at CERN. At roughly the same time, observations of antideuterium nuclei were reported by a group of American physicists at the Alternating Gradient Synchrotron at Brookhaven National Laboratory.

Antihydrogen atoms

Main article: Antihydrogen

Antimatter facilities

Low Energy Antiproton Ring (1982–1996)
Antiproton Accumulator	Antiproton production
Antiproton Collector	Decelerated and stored antiprotons
Antimatter Factory (2000–present)
Antiproton Decelerator (AD)	Decelerates antiprotons
Extra Low Energy Antiproton ring (ELENA)	Decelerates antiprotons received from AD

In 1995, CERN announced that it had successfully brought into existence nine hot antihydrogen atoms by implementing the SLAC/Fermilab concept during the PS210 experiment. The experiment was performed using the Low Energy Antiproton Ring (LEAR), and was led by Walter Oelert and Mario Macri. Fermilab soon confirmed the CERN findings by producing approximately 100 antihydrogen atoms at their facilities. The antihydrogen atoms created during PS210 and subsequent experiments (at both CERN and Fermilab) were extremely energetic and were not well suited to study. To resolve this hurdle, and to gain a better understanding of antihydrogen, two collaborations were formed in the late 1990s, namely, ATHENA and ATRAP.

In 1999, CERN activated the Antiproton Decelerator, a device capable of decelerating antiprotons from 3.5 GeV to 5.3 MeV – still too "hot" to produce study-effective antihydrogen, but a huge leap forward. In late 2002 the ATHENA project announced that they had created the world's first "cold" antihydrogen. The ATRAP project released similar results very shortly thereafter. The antiprotons used in these experiments were cooled by decelerating them with the Antiproton Decelerator, passing them through a thin sheet of foil, and finally capturing them in a Penning–Malmberg trap. The overall cooling process is workable, but highly inefficient; approximately 25 million antiprotons leave the Antiproton Decelerator and roughly 25,000 make it to the Penning–Malmberg trap, which is about ⁠1/1000⁠ or 0.1% of the original amount.

The antiprotons are still hot when initially trapped. To cool them further, they are mixed into an electron plasma. The electrons in this plasma cool via cyclotron radiation, and then sympathetically cool the antiprotons via Coulomb collisions. Eventually, the electrons are removed by the application of short-duration electric fields, leaving the antiprotons with energies less than 100 meV. While the antiprotons are being cooled in the first trap, a small cloud of positrons is captured from radioactive sodium in a Surko-style positron accumulator. This cloud is then recaptured in a second trap near the antiprotons. Manipulations of the trap electrodes then tip the antiprotons into the positron plasma, where some combine with antiprotons to form antihydrogen. This neutral antihydrogen is unaffected by the electric and magnetic fields used to trap the charged positrons and antiprotons, and within a few microseconds the antihydrogen hits the trap walls, where it annihilates. Some hundreds of millions of antihydrogen atoms have been made in this fashion.

In 2005, ATHENA disbanded and some of the former members (along with others) formed the ALPHA Collaboration, which is also based at CERN. The ultimate goal of this endeavour is to test CPT symmetry through comparison of the atomic spectra of hydrogen and antihydrogen (see hydrogen spectral series).

Most of the sought-after high-precision tests of the properties of antihydrogen could only be performed if the antihydrogen were trapped, that is, held in place for a relatively long time. While antihydrogen atoms are electrically neutral, the spins of their component particles produce a magnetic moment. These magnetic moments can interact with an inhomogeneous magnetic field; some of the antihydrogen atoms can be attracted to a magnetic minimum. Such a minimum can be created by a combination of mirror and multipole fields. Antihydrogen can be trapped in such a magnetic minimum (minimum-B) trap; in November 2010, the ALPHA collaboration announced that they had so trapped 38 antihydrogen atoms for about a sixth of a second.  This was the first time that neutral antimatter had been trapped.

On 26 April 2011, ALPHA announced that they had trapped 309 antihydrogen atoms, some for as long as 1,000 seconds (about 17 minutes). This was longer than neutral antimatter had ever been trapped before. ALPHA has used these trapped atoms to initiate research into the spectral properties of antihydrogen.

In 2016, a new antiproton decelerator and cooler called ELENA (extra low energy antiproton decelerator) was built. It takes the antiprotons from the antiproton decelerator and cools them to 90 keV, which is "cold" enough to study. This machine works by using high energy and accelerating the particles within the chamber. More than one hundred antiprotons can be captured per second, a huge improvement, but it would still take several thousand years to make a nanogram of antimatter.

The biggest limiting factor in the large-scale production of antimatter is the availability of antiprotons. Recent data released by CERN states that, when fully operational, their facilities are capable of producing ten million antiprotons per minute. Assuming a 100% conversion of antiprotons to antihydrogen, it would take 100 billion years to produce 1 gram or 1 mole of antihydrogen (approximately 6.02×10²³ atoms of antihydrogen). However, CERN only produces 1% of the antimatter Fermilab does, and neither are designed to produce antimatter. According to Gerald Jackson, using technology already in use today we are capable of producing and capturing 20 grams of antimatter particles per year at a yearly cost of 670 million dollars per facility.

Antihelium

Antihelium-3 nuclei (³
He, i.e. two antiprotons and one antineutron) were first observed in the 1970s in proton–nucleus collision experiments at the Institute for High Energy Physics by Y. Prockoshkin's group (Protvino near Moscow, USSR) and later created in nucleus–nucleus collision experiments. Nucleus–nucleus collisions produce antinuclei through the coalescence of antiprotons and antineutrons created in these reactions. In 2011, the STAR detector reported the observation of artificially created antihelium-4 nuclei (anti-alpha particles) (⁴
He) from such collisions.

The Alpha Magnetic Spectrometer on the International Space Station has, as of 2021, recorded eight events that seem to indicate the detection of antihelium-3.

Preservation

Antimatter cannot be stored in a container made of ordinary matter because antimatter reacts with any matter it touches, annihilating itself and an equal amount of the container. Antimatter in the form of charged particles can be contained by a combination of electric and magnetic fields, in a device called a Penning trap. This device cannot, however, contain antimatter that consists of uncharged particles, for which atomic traps are used. In particular, such a trap may use the dipole moment (electric or magnetic) of the trapped particles. At high vacuum, the matter or antimatter particles can be trapped and cooled with slightly off-resonant laser radiation using a magneto-optical trap or magnetic trap. Small particles can also be suspended with optical tweezers, using a highly focused laser beam. The record for storing antiparticles is currently held by the TRAP experiment at CERN: antiprotons were kept in a Penning trap for 405 days. CERN scientists have demonstrated the transportation of 92 antiprotons for a distance of about five miles using BASE-STEP, a 1,000 kg (2,200 lb) truck-mounted cryogenic Penning trap apparatus, paving the way for practical shipments of antimatter to other institutions for study.

Cost

Scientists claim that antimatter is the costliest material to make. In 2006, Gerald Smith estimated $250 million could produce 10 milligrams of positrons (equivalent to $25 billion per gram); in 1999, NASA gave a figure of $62.5 trillion per gram of antihydrogen. This is because production is difficult (only very few antiprotons are produced in reactions in particle accelerators) and because there is higher demand for other uses of particle accelerators. According to CERN, it has cost a few hundred million Swiss francs to produce about 1 billionth of a gram (the amount used so far for particle/antiparticle collisions). In comparison, to produce the first atomic weapon, the cost of the Manhattan Project was estimated at $23 billion with inflation during 2007.

Several studies funded by NASA Innovative Advanced Concepts are exploring whether it might be possible to use magnetic scoops to collect the antimatter that occurs naturally in the Van Allen belt of the Earth, and ultimately the belts of gas giants like Jupiter, ideally at a lower cost per gram.

Uses

Medical

A PET/CT system

Matter–antimatter reactions have practical applications in medical imaging, such as positron emission tomography (PET). In positive beta decay, a nuclide loses surplus positive charge by emitting a positron (in the same event, a proton becomes a neutron, and a neutrino is also emitted). Nuclides with surplus positive charge are easily made in a cyclotron and are widely generated for medical use. Antiprotons have also been shown within laboratory experiments to have the potential to treat certain cancers, in a similar method currently used for ion (proton) therapy.

Fuel

Isolated and stored antimatter could be used as a fuel for interplanetary or interstellar travel as part of an antimatter-catalyzed nuclear pulse propulsion or another antimatter rocket. Since the energy density of antimatter is higher than that of conventional fuels, an antimatter-fueled spacecraft would have a higher thrust-to-weight ratio than a conventional spacecraft.

If matter–antimatter collisions resulted only in photon emission, the entire rest mass of the particles would be converted to kinetic energy. The energy per unit mass (9×10¹⁶ J/kg) is about 10 orders of magnitude greater than chemical energies, and about 3 orders of magnitude greater than the nuclear potential energy that can be liberated, today, using nuclear fission (about 200 MeV per fission reaction or 8×10¹³ J/kg), and about 2 orders of magnitude greater than the best possible results expected from fusion (about 6.3×10¹⁴ J/kg for the proton–proton chain). The reaction of 1 kg of antimatter with 1 kg of matter would produce 1.8×10¹⁷ J (180 petajoules) of energy (by the mass–energy equivalence formula, E=mc²), or the rough equivalent of 43 megatons of TNT – slightly less than the yield of the 27,000 kg Tsar Bomba, the largest thermonuclear weapon ever detonated.

Not all of that energy can be utilized by any realistic propulsion technology because of the nature of the annihilation products. While electron–positron reactions result in gamma ray photons, these are difficult to direct and use for thrust. In reactions between protons and antiprotons, their energy is converted largely into relativistic neutral and charged pions. The neutral pions decay almost immediately (with a lifetime of 85 attoseconds) into high-energy photons, but the charged pions decay more slowly (with a lifetime of 26 nanoseconds) and can be deflected magnetically to produce thrust.

Charged pions ultimately decay into a combination of neutrinos (carrying about 22% of the energy of the charged pions) and unstable charged muons (carrying about 78% of the charged pion energy), with the muons then decaying into a combination of electrons, positrons and neutrinos (cf. muon decay; the neutrinos from this decay carry about 2/3 of the energy of the muons, meaning that from the original charged pions, the total fraction of their energy converted to neutrinos by one route or another would be about 0.22 + (2/3)⋅0.78 = 0.74).

Weapons

Main article: Antimatter weapon

Antimatter has been considered as a trigger mechanism for nuclear weapons. A major obstacle is the difficulty of producing antimatter in large enough quantities, and there is no evidence that it will ever be feasible. Nonetheless, the U.S. Air Force funded studies of the physics of antimatter in the Cold War, and began considering its possible use in weapons, not just as a trigger, but as the explosive itself.

Annihilation

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Annihilation

A Feynman diagram showing the mutual annihilation of a bound state electron positron pair into two photons. This bound state is more commonly known as positronium.

In particle physics, annihilation is the process that occurs when a subatomic particle collides with its respective antiparticle to produce other particles, such as an electron colliding with a positron to produce two photons. The total energy and momentum of the initial pair are conserved in the process and distributed among a set of other particles in the final state. Antiparticles have exactly opposite additive quantum numbers from particles, so the sums of all quantum numbers of such an original pair are zero. Hence, any set of particles may be produced whose total quantum numbers are also zero as long as conservation of energy, conservation of momentum, and conservation of spin are obeyed.

During a low-energy annihilation, photon production is favored, since these particles have no mass. High-energy particle colliders produce annihilations where a wide variety of exotic heavy particles are created.

The word "annihilation" takes its use informally for the interaction of two particles that are not mutual antiparticles – not charge conjugate. Some quantum numbers may then not sum to zero in the initial state, but conserve with the same totals in the final state. An example is the "annihilation" of a high-energy electron antineutrino with an electron to produce a W⁻ boson.

If the annihilating particles are composite, such as mesons or baryons, then multiple different particles are typically produced in the final state.

The inverse of annihilation is pair production, the process in which a high-energy photon converts its energy into mass.

History

Paul Dirac introduced annihilation in 1931. His paper was named "On the Annihilation of Electrons and Protons" because he had not yet realized the positive charge (negative energy) states were anti-electrons. Annihilation was used to verify the existence of the antiproton in 1956.

Production of a single boson

If the initial two particles are elementary (not composite), then they may combine to produce only a single elementary boson, such as a photon (γ), gluon (g), Z, or a Higgs boson (H⁰
). If the total energy in the center-of-momentum frame is equal to the rest mass of a real boson (which is impossible for a massless boson such as the γ), then that created particle will continue to exist until it decays according to its lifetime. Otherwise, the process is understood as the initial creation of a boson that is virtual, which immediately converts into a real particle + antiparticle pair. This is called an s-channel process. An example is the annihilation of an electron with a positron to produce a virtual photon, which converts into a muon and anti-muon. If the energy is large enough, a Z could replace the photon.

Examples

Electron–positron annihilation

Electron/positron annihilation at various energies

Main article: Electron–positron annihilation

e⁻
 + e⁺
 → γ + γ

When a low-energy electron annihilates a low-energy positron (antielectron) the most probable result is the creation of two or more photons, since the only other final-state Standard Model particles that electrons and positrons carry enough mass–energy to produce are neutrinos, which are approximately 10,000 times less likely to produce, and the creation of only one photon is impossible by momentum conservation—a single photon would carry nonzero momentum in any frame, including the center-of-momentum frame where the total momentum vanishes. Both the annihilating electron and positron particles have a rest energy of about 0.501 million electron-volts (MeV). If their kinetic energies are relatively negligible, this total rest energy appears as the photon energy of the photons produced. Each of the photons then has an energy of about 0.511 MeV. Momentum and energy are both conserved, with 1.012 MeV of photon energy (accounting for the rest energy of the particles) moving in opposite directions (accounting for the total zero momentum of the system).

If one or both charged particles carry a larger amount of kinetic energy, various other particles can be produced. Furthermore, the annihilation (or decay) of an electron–positron pair into a single photon can occur in the presence of a third charged particle, to which the excess momentum can be transferred by a virtual photon from the electron or positron. The inverse process, pair production by a single real photon, is also possible in the electromagnetic field of a third particle.

Proton–antiproton annihilation

When a proton encounters its antiparticle (and more generally, if any species of baryon encounters the corresponding antibaryon), the reaction is not as simple as electron–positron annihilation. Unlike an electron, a proton is a composite particle consisting of three "valence quarks" and an indeterminate number of "sea quarks" bound by gluons. Thus, when a proton encounters an antiproton, one of its quarks, usually a constituent valence quark, may annihilate with an antiquark (which more rarely could be a sea quark) to produce a gluon, after which the gluon together with the remaining quarks, antiquarks, and gluons will undergo a complex process of rearrangement (called hadronization or fragmentation) into a number of mesons (mostly pions and kaons), which will share the total energy and momentum. The newly created mesons are unstable, and unless they encounter and interact with some other material, they will decay in a series of reactions that ultimately produce only photons, electrons, positrons, and neutrinos. This type of reaction will occur between any baryon (particle consisting of three quarks) and any antibaryon consisting of three antiquarks, one of which corresponds to a quark in the baryon. (This reaction is unlikely if at least one among the baryon and anti-baryon is exotic enough that they share no constituent quark flavors.) Antiprotons can and do annihilate with neutrons, and likewise antineutrons can annihilate with protons, as discussed below.

Reactions in which proton–antiproton annihilation produces as many as 9 mesons have been observed, while production of 13 mesons is theoretically possible. The generated mesons leave the site of the annihilation at moderate fractions of the speed of light and decay with whatever lifetime is appropriate for their type of meson.

Similar reactions will occur when an antinucleon annihilates within a more complex atomic nucleus, save that the resulting mesons, being strongly interacting, have a significant probability of being absorbed by one of the remaining "spectator" nucleons rather than escaping. Since the absorbed energy can be as much as ~2 GeV, it can in principle exceed the binding energy of even the heaviest nuclei. Thus, when an antiproton annihilates inside a heavy nucleus such as uranium or plutonium, partial or complete disruption of the nucleus can occur, releasing large numbers of fast neutrons. Such reactions open the possibility for triggering a significant number of secondary fission reactions in a subcritical mass and may potentially be useful for spacecraft propulsion.

Higgs production

In collisions of two nucleons at very high energies, sea quarks and gluons tend to dominate the interaction rate, so neither nucleon need be an anti-particle for annihilation of a quark pair or "fusion" of two gluons to occur. Examples of such processes contribute to the production of the long-sought Higgs boson. The Higgs is directly produced very weakly by annihilation of light (valence) quarks, but heavy t or b sea or produced quarks are available. In 2012, the CERN laboratory in Geneva announced the discovery of the Higgs in the debris from proton–proton collisions at the Large Hadron Collider (LHC). The strongest Higgs yield is from fusion of two gluons (via annihilation of a heavy quark pair), while two quarks or antiquarks produce more easily identified events through radiation of a Higgs by a produced virtual vector boson or annihilation of two such vector bosons.

Succession, continuity and legacy of the USSR

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Succession,_continuity_and_legacy_of_the_USSR

The Soviet Union, officially the Union of Soviet Socialist Republics (USSR), was a transcontinental country that spanned much of Eurasia from 1922 to 1991. It was a founding member of the United Nations in 1945, as well as a permanent member of the United Nations Security Council. Following the dissolution of the USSR in 1991, its seat at the United Nations was transferred to the Russian Federation, which is its continuator state.

Background

The Treaty on the Formation of the Union of Soviet Socialist Republics officially created the USSR. The Treaty was approved on 30 December 1922 by a conference of delegations from the Russian SFSR, the Transcaucasian SFSR, the Ukrainian SSR and the Byelorussian SSR. The Treaty and the Declaration were confirmed by the First All-Union Congress of Soviets and signed by heads of delegations – Mikhail Kalinin, Mikhail Tskhakaya, and Grigory Petrovsky, Alexander Chervyakov respectively on December 30, 1922. The treaty provided flexibility to admit new members. Therefore, by 1940 the Soviet Union grew from the founding four (or six, depending on whether 1922 or 1940 definitions are applied) republics to 15 republics.

Transition period and cessation of the existence of the Soviet Union

Main article: Transition period and cessation of the existence of the Soviet Union

In the Soviet Union, the transition period was declared by adoption the Law of the USSR "On the bodies of state power and administration of the Union of Soviet Socialist Republics in the transition period" which was signed into law on 5 September 1991. It was assumed that the Soviet Union would come out of the transition period with a new name of the Union when all the treaties are signed, ratified, come into force and the new parliament assembled. However, this did not happen.

As the Kommersant newspaper wrote on 7 October 1991, a series of conflicts occurred in the RSFSR government during preparations for the signing of the Treaty on the Economic Community. In his speech to members of the Russian parliament, RSFSR State Secretary Gennady Burbulis declared Russia's special role as the legal successor to the Soviet Union. Accordingly, the ways of drafting agreements with the republics should be determined by the Russian leadership. Instead of the planned order, he suggested signing a political agreement first, followed by an economic one. The newspaper suggested that Burbulis' goal was to persuade Yeltsin not to sign the agreement as it stands at the time. Yegor Gaidar, Alexander Shokhin and Konstantin Kagalovsky were named as the developers of the statement made by Burbulis. In the same time, a group of "isolationist patriots" consisting of Mikhail Maley, Nikolai Fedorov, Alexander Shokhin, Igor Lazarev and Mikhail Poltoranin criticized Ivan Silaev and Yevgeny Saburov for wanting to preserve the Soviet Union.

On 18 October 1991, in the St. George Hall of the Grand Kremlin Palace, Mikhail Gorbachev and the leaders of eight Union republics (excluding Ukraine, Moldova, Georgia and Azerbaijan) signed the Treaty on the Economic Community as planned. Ukraine and Moldova said they would sign at a later date. This economic agreement was then to be supplemented by a similar political agreement. On 14 November in Novo-Ogaryovo, Mikhail Gorbachev and the heads of the seven union republics pre-agreed to sign a treaty on the creation of a political union called the Union of Sovereign States, which would have no constitution but would remain a subject of international law as the Soviet Union had been. The Treaty would complement the previous economic treaty and was scheduled to be signed in December.

Because of the referendum results and the actions of the Verkhovna Rada, Leonid Kravchuk refused on 7 December to sign such a political agreement that did not take Ukraine's status into account. Boris Yeltsin said that if Ukraine would not sign, then Russia would not sign either, although at this moment, besides Russia, six republics still wanted to sign the new Union treaty. The Belovezha Accords were signed on 8 December, where it was Burbulis who authored the phrase “The Union of Soviet Socialist Republics as a subject of international law and geopolitical reality ceases to exist.” The agreement declared the dissolution of the USSR by its remaining founder states (denunciation of the Treaty on the Creation of the USSR) and established the Commonwealth of Independent States (CIS). On 10 December, the accord was ratified by the Ukrainian and Belarusian parliaments. On 12 December, the agreement was ratified by the Russian Parliament, therefore the Russian SFSR renounced the Treaty on the Creation of the USSR and de facto declared Russia's independence from the USSR.

On 26 December 1991, the USSR was self-dissolved by the Council of the Republics of the Supreme Soviet of the Soviet Union, the upper house of the Supreme Soviet of the Soviet Union (the lower house, the Soviet of the Union, was without a quorum).

General agreements

On 14 February 1992, the heads of state instructed the foreign ministers of the Commonwealth participating states to prepare a document on the legal succession of treaties, all property, state archives, debts and assets of the former Union of Soviet Socialist Republics.

On 20 March 1992, the CIS Council of Heads of State signed the Decision on the succession of state property, debts and assets of the former USSR.

On 15 May 1992, the CIS Council of Heads of State signed a Protocol Decision on the activities of the Commission on Succession to Treaties, of mutual interest, state property, state archives, debts and assets of the former Union of Soviet Socialist Republics.

On 6 July 1992 the CIS Council of Heads of State signed a Memorandum of Understanding on the issue of succession to treaties of the former Union of Soviet Socialist Republics that are of mutual interest. According to the text.

• Almost all multilateral international treaties of the former Union of Soviet Socialist Republics are of common interest to the Commonwealth participating States. However, these treaties do not require any joint decisions or actions of the participating States of the Commonwealth. The question of participation in these treaties is decided in accordance with the principles and norms of international law by each Commonwealth participant state on its own.
• There are a number of bilateral international treaties of the former Union of Soviet Socialist Republics that affect the interests of two or more (but not all) Commonwealth participant states. These treaties require decisions or actions by those Commonwealth participating States to which the treaties apply.
• A number of bilateral treaties affect the interests of all Commonwealth participating States. These include, for example, treaties on borders and their regime. Such treaties are required by international law to remain in force, and participation is limited to those Commonwealth participating States that share a contiguous border with non-Commonwealth countries.
• If any questions arise concerning succession to treaties of the former Union of Soviet Socialist Republics, consultations will be held between the States concerned.

International relations, treaties and organizations

The Declaration of the Twelve (Belgium, Denmark, France, Germany, Greece, Ireland, Italy, Luxembourg, Portugal, Spain, the Netherlands and the United Kingdom) on the future status of Russia and other former Soviet Republics was published on 23 December 1991, according to which "The European Community and its Member States have noted with satisfaction the decision of the participants at the Alma Ata meeting on 21 December 1991 to establish a Commonwealth of Independent States. They note that the international rights and obligations of the former USSR, including those arising from the Charter of the United Nations, will continue to be exercised by Russia. They note with satisfaction the acceptance by the Russian Government of these commitments and responsibilities and will continue to deal with Russia on this basis, taking into account the change in its constitutional status."

On 4 September 1991, U.S. Secretary of State James Baker articulated five basic principles that would guide U.S. policy toward the emerging republics: self-determination consistent with democratic principles, recognition of existing borders, support for democracy and rule of law, preservation of human rights and rights of national minorities, and respect for international law and obligations. The basic message was clear—if the new republics could follow these principles, they could expect cooperation and assistance from the United States. Self-determination is a cardinal principle in modern international law but no right to secession is recognized under international law.

The "Guidelines on the Recognition of New States in Eastern Europe and the Soviet Union", adopted by Ministers of the EC (Belgium, Denmark, France, Germany, Greece, Ireland, Italy, Luxembourg, Portugal, Spain, the Netherlands and the United Kingdom) on 16 December 1991. According to a scientific paper: "EC Guidelines on the Recognition of New States in Eastern Europe and the Soviet Union approved in December 1991 constituted a remarkable innovation in European policy-making."

On 21 December 1991, the Council of Heads of State decided that the member states of the Commonwealth, referring to Article 12 of the Agreement on the Establishment of the Commonwealth of Independent States, based on the intention of each state to fulfill obligations under the UN Charter and participate in the work of this organization as full members, taking into account that the original members of the UN were the Republic of Belarus, the USSR and Ukraine, expressing satisfaction that the Republic of Belarus and Ukraine continue to participate in the UN as sovereign independent states, decided that "the Commonwealth States support Russia in continuing the membership of the USSR in the UN, including permanent membership in the Security Council, and other international organizations." The document entered into force for 11 countries on December 21. On 23 December 1991 this appears in print in the New York Times: "Member states of the commonwealth support Russia in taking over the U.S.S.R. membership in the U.N., including permanent membership in the Security Council and other international organizations."

The Declaration of the Twelve on the future status of Russia and other former Soviet Republics was published on 23 December 1991, according to which "The European Community and its Member States have noted with satisfaction the decision of the participants at the Alma Ata meeting on 21 December 1991 to establish a Commonwealth of Independent States. They note that the international rights and obligations of the former USSR, including those arising from the Charter of the United Nations, will continue to be exercised by Russia. They note with satisfaction the acceptance by the Russian Government of these commitments and responsibilities and will continue to deal with Russia on this basis, taking into account the change in its constitutional status. They are prepared to recognise the other Republics constituting the Community as soon as they receive assurances from those Republics that they are prepared to fulfil the requirements set out in the "Guidelines on the Recognition of New States in Eastern Europe and the Soviet Union", adopted by Ministers on 16 December 1991. They expect, in particular, that those Republics will give them assurances that they will fulfil their international obligations arising from treaties and agreements concluded by the Soviet Union, including the ratification and implementation of the CFE Treaty by the Republics to which it applies, and that they will establish a single control over nuclear weapons and their non-proliferation."

Thus, the 12 countries (Belgium, Denmark, France, Germany, Greece, Ireland, Italy, Luxembourg, Portugal, Spain, the Netherlands and the United Kingdom) do not need to recognize Russia's independence from the Soviet Union and establish new relations with Russia as a new state, because relations have already been established with the Soviet Union, of which Russia has become the continuator in international relations. Recognition of the independence of other 11 countries (Armenia, Azerbaijan, Belarus, Georgia, Kazakhstan, Kyrgyzstan, Moldova, Tajikistan, Turkmenistan, Ukraine, Uzbekistan) occurs on the condition that they assume the obligations under the treaties signed by the Soviet Union, including respect for the provisions of the Charter of the United Nations and the commitments subscribed to in the Final Act of Helsinki and in the Charter of Paris, guarantees for the rights of ethnic and national groups and minorities, respect for the inviolability of all frontiers and acceptance of all relevant commitments with regard to disarmament and nuclear non-proliferation as well as to security and regional stability.

Marko Milanovic, Professor of Public International Law at the University of Reading School of Law noted in 2009: "The best example of continuation and separation is the Soviet Union, which continued its existence as the Russian Federation, along a number of new successor states. (Note that a continuator state is often misleadingly termed as the successor state, even though there may be a number of actual successor states alongside the continuator.) A continuator state like Russia by definition remains a party to all treaties of its predecessor, because for all intents and purposes it is the predecessor. Thus, for example, Russia continued the Soviet Union’s UN membership and its permanent seat on the Security Council."

UN membership

On 23 December Russia officially received the USSR's seat on the UN Security Council. The international community recognized it as continuator state to the Soviet Union.

On 24 December, Yeltsin sent a Letter to the Secretary-General of the United Nations from the President of the Russian Federation with the following content:

I have the honour to inform you that the membership of the Union of Soviet Socialist Republics in the United Nations, including the Security Council and all other organs and organizations of the United Nations system, is being continued by the Russian Federation (RSFSR) with the support of the countries of the Commonwealth of Independent States. In this connection, I request that the name "the Russian Federation" should be used in the United Nations in place of the name "the Union of Soviet Socialist Republics". The Russian Federation maintains full responsibility for all the rights and obligations of the USSR under the Charter of the United Nations, including the financial obligations. I request you to consider this letter as confirmation of the credentials to represent the Russian Federation in the United Nations organs for all the persons currently holding the credentials of representatives of the USSR to the United Nations.

The Gudok newspaper notes that Yeltsin's letter was sent by the secretary-general to all UN members with a note that this appeal is of a notification nature, stating reality, and does not require formal approval by the UN. All permanent members of the UN Security Council and other leading countries agreed with this approach. By a note of 3 January 1992, the Russian Foreign Ministry appealed to the heads of diplomatic missions in Moscow with a proposal to consider consular and diplomatic missions of the USSR in foreign countries as representatives of Russia. By a note of 13 January 1992, the heads of foreign diplomatic missions were notified that the Russian Federation continued to exercise the rights and fulfil the obligations arising from international treaties concluded by the USSR, with a request to consider Russia as a party to all existing international treaties instead of the USSR.

The UN website lists Russia as a member of the United Nations as follows: "The Union of Soviet Socialist Republics was an original Member of the United Nations from 24 October 1945. In a letter dated 24 December 1991, Boris Yeltsin, the President of the Russian Federation, informed the Secretary-General that the membership of the Soviet Union in the Security Council and all other United Nations organs was being continued by the Russian Federation with the support of the 11 member countries of the Commonwealth of Independent States."

In an interview with Nezavisimaya Gazeta on 1 April 1992, Foreign Minister Andrei Kozyrev explained the situation: “Many people think that Russia became the legal successor of the USSR automatically, but this is far from being the case. We faced a very difficult political and diplomatic task. Russia is not a legal successor, but a continuing state of the USSR. The successor states are in fact all the former republics of the Soviet Union, but it is Russia that is the continuator.”

More than 30 years later on 10 January 2025 Kozyrev reconfirmed that Russia is the continuator of the USSR, and all 12 countries are the successors of the USSR.

There was no automaticity. It was an open question. The solution was suggested to us by Western countries, especially by the British, who had a huge experience in solving inheritance issues, they had an empire. The British dug somewhere in their archives and proposed a variant of a successor state. There is a monstrous confusion even among historians who write about it and political analysts. It is simply an unwillingness to understand. So, all of them are legal successors. All Union republics. The three Baltic republics refused to be successors. All the others, Georgia, Armenia, Kazakhstan were legal successors and now remain legal successors. In relation to foreign debt, it was a deal. With respect to the UN Security Council, an international conference of all successors under international law had to be convened to resolve the issues. Therefore, a continuator was invented. A continuator is one of the inheritors, one of the legal successors, whom everybody recognises, but it doesn't require ratification. It is simply a declaration that it is recognised as a continuing state of the legal function that is written in the UN Charter for the USSR and now for Russia. It was a manoeuvre. The republics agreed. The other 4 permanent members of the UNSC agreed. If someone disagreed, raised their hand and said ‘Where is the Soviet Union? Yesterday the Soviet Union was sitting here, and now someone under the sign of the Russian Federation. What is this?', it would have failed. There was a unique moment when the decision could have been challenged easily. But now it is an irrevocable decision and it is impossible to challenge it.

In an interview with the UN Radio, Ambassador Yuli Vorontsov described:

Our cooperation with the leading Western countries and, first of all, with the United States has worked out well. American lawyers gave us a very good legal option, which made the disputes about what belongs to the Russian Federation and what does not belong to it pointless. They suggested that our application to change the name of the country should say, as we said at the time, that the Russian Federation was the continuator of the Soviet Union. That word “ continuator” helped out a lot. A continuator means that Russia continues to have a seat on the Security Council. The other countries, the former Soviet republics, were newly independent states. They could not be continuators. The Secretary General was given a message from President Yeltsin. This message said that we, the Russian Federation, being the continuator of the Soviet Union in the United Nations, notify you that the name of the country will now be different - the Russian Federation. In fact, the whole process outwardly looked like a simple change of the sign at the table of delegations in the General Assembly and the Security Council. Instead of the nameplate 'Soviet Union' the name 'Russian Federation' appeared.

After that, in the official documents of the organization “USSR” was changed to “Russia”. For example, at the meeting of the Security Council on 23 December 1991, Vorontsov was listed as the representative of the Soviet Union, and already on 31 December as the representative of the Russian Federation. On 31 January 1992, John Major, chairman of the Security Council and British Prime Minister, said to Yeltsin personally, who was attending a Security Council meeting: “Mr, President, thank you, I know the Council would wish me to welcome Russia as a permanent member of our Council. You are very welcome indeed.”

Yeltsin in 1993 signed a decree "In order to legally secure the state property of the Russian Federation abroad and in connection with the signing of the Agreement on the distribution of all property of the former USSR abroad of 6 July 1992, I hereby decree: The Russian Federation, as a continuing state of the Union of the SSR, assumes all rights to the immovable and movable property of the former USSR located abroad, as well as the fulfilment of all obligations related to the use of this property."

According to the letter of the Ministry of Justice of the Russian Federation dated 16 January 2012 N 07-1407:

From the point of view of international law, the geopolitical transformations of 1991 did not lead to the disappearance of the USSR as a subject of international law. Despite the changes in territory, length of borders, size of population, etc., the state called ‘USSR’ did not cease to exist, but continued its international legal personality under the name of ‘Russian Federation’. The term ‘continuity’ is used in international law to denote this kind of phenomenon. A State continuing under a new name to fulfil international rights and obligations in respect of the relevant territory, population, property, etc., is called a ‘continuing State’. In terms of its legal consequences, the situation of continuation is fundamentally different from that of succession. Whereas in the case of succession, international rights and obligations are transferred by an expression of will from one State (‘predecessor State’) to another (‘successor State’), that is, from one subject of international law to another, in the case of continuation, their exercise is automatically continued by the same State, a subject of international law, but with a different name.

The approval of a State as a continuing or successor State depends not only on its own will, but also on the recognition of the relevant status by the international community. The status of the Russian Federation as a continuation State of the USSR has been officially or quietly recognised by the international community as a whole and by virtually all States individually. The statement of Russian continuity is contained, for example, in the Russian-German statement of 21 November 1991, the joint declaration of the Russian Federation and the United Kingdom of 1992, and the official statements of the governments of Belgium and Sweden. In the joint statement of 23 December 1991, the EC Member States acknowledged that ‘the international rights and obligations of the former USSR, including rights and obligations under the UN Charter, will continue to be exercised by Russia’. The EC Member States welcomed the Russian Government's agreement to assume such obligations and responsibilities and declared that as such they would continue their friendly relations with our country, taking into account the change in its constitutional status.

Russia's status as a continuation state of the USSR is stated in many international treaties concluded by our country after 1991, including agreements on the inventory of the treaty and legal framework between Russia and foreign states (for example, intergovernmental protocols with Romania, Macedonia, Cyprus, Croatia, the Czech Republic, Slovakia, Denmark, Greece, Hungary). The Treaty between the Russian Federation and the Kingdom of Belgium on Consent and Cooperation of 8 December 1993, the Treaty between Russia and France of 7 February 1992, the Agreement between the Government of the Russian Federation and the Government of the Federal Republic of Germany on Cultural Cooperation of 16 December 1992, the Agreement between the Government of the Russian Federation and the European Space Agency on the Establishment of the Permanent Mission of the Agency in the Russian Federation of 10 April 1995, and others. The recognition of the status of a continuing state of the USSR was also reflected in Russia's continuation of the Soviet Union's membership in international organisations.

Nuclear weapons

The US Secretary of State James Baker at the time stated that no one but Russia could control Soviet nuclear weapons, in particular, making a statement on 10 December 1991 at Princeton University.

On December 21, 1991, the Republic of Belarus, the Republic of Kazakhstan, the Russian Federation (RSFSR) and Ukraine signed the Agreement on Joint Measures Regarding Nuclear Weapons, according to which "until the complete elimination of nuclear weapons in the territories of the Republic of Belarus and Ukraine, the decision on the need to use them shall be taken in agreement with the heads of state participating in the Agreement by the President of the RSFSR", "the Republic of Belarus and Ukraine undertake to accede to the 1968 Treaty on the Non-Proliferation of Nuclear Weapons as non-nuclear states and to conclude an appropriate safeguards agreement with the IAEA", "by July 1, 1992, the Republic of Belarus, the Republic of Kazakhstan and Ukraine will ensure the removal of tactical nuclear weapons" and "the Governments of the Republic of Belarus, the Republic of Kazakhstan, the Russian Federation (RSFSR) and Ukraine undertake to submit the START Treaty for ratification to the Supreme Councils of their states". Belarus, Russia and Kazakhstan have ratified the agreement, but since Ukraine has not ratified it, it has not entered into force.

On December 25, M.S. Gorbachev announced his resignation as President of the USSR and handed over the "nuclear briefcase" to the President of the RSFSR B.N. Yeltsin.

On December 30, 1991, 11 countries signed the Agreement between the participant states of the Commonwealth of Independent States on Strategic Forces, according to which "the member states of the Commonwealth recognize the need for a unified command of the Strategic Forces and the maintenance of unified control over nuclear weapons", "For the period until their complete destruction, nuclear weapons deployed on the territory of Ukraine are under the control of the unified command of the Strategic Forces with the aim of not using them and dismantling them by the end of 1994, including tactical nuclear weapons - by July 1, 1992", "The process of destroying nuclear weapons deployed on the territory of the Republic of Belarus and Ukraine is carried out with the participation of the Republic of Belarus, the Russian Federation and Ukraine under the joint control of the Commonwealth states". The document entered into force for 11 countries on December 30.

Debts and assets

On 4 December 1991, 12 republics (except the Baltic states) signed an agreement on joint liability for repaying the USSR's debt to external creditors, according to which Russia's share was 61% of the Soviet debt. In order to leave the agreement on joint liability in the past, Russia proposed a "zero option".

After the dissolution of the USSR on 26 December 1991, all former Soviet Union property was automatically transferred to Russian ownership. On 2 April 1992, Russia declared itself the sole legal successor to all debts of the former USSR and pledged to repay them in full, while receiving rights to all financial and material assets of the USSR. The remaining former Soviet republics could start with a "clean slate". In this case, they would have neither debts nor assets.

On 30 December 1991, 11 countries signed the Agreement of the Heads of State of the Commonwealth of Independent States on the property of the former USSR abroad, according to which "the member states of the Commonwealth mutually recognize that each of them has the right to an appropriate fixed fair share in the property of the former USSR abroad and will facilitate the implementation of this right." The document entered into force for 11 countries on December 30.

On 13 March 1992, the CIS Council of Heads of Government signed the Charter of the Interstate Council for Supervision of Debt Servicing and Use of Assets of the Union of Soviet Socialist Republics.

On 13 March 1992, the CIS Council of Heads of Government signed the Agreement on Amendments to the Agreement on Succession in respect of External State Debt and Assets of the Union of Soviet Socialist Republics of December 4, 1991.

On 6 July 1992, 11 countries signed the Agreement on the distribution of all property of the former USSR abroad, according to which "the termination of the existence of the USSR as a state-subject of international law dictates the need for the earliest possible settlement of a set of issues related to the property of the former USSR abroad between the successor states represented by the Republic of Azerbaijan, the Republic of Armenia, the Republic of Belarus, the Republic of Kazakhstan, the Republic of Kyrgyzstan, the Republic of Moldova, the Russian Federation, the Republic of Tajikistan, Turkmenistan, the Republic of Uzbekistan and Ukraine." Movable and immovable property of the former USSR outside its territory and investments located abroad are subject to division and shall pass to the Parties in accordance with the following scale of fixed shares in the assets of the former USSR based on a single aggregate indicator. The share (in percent) is as follows:

• Republic of Azerbaijan 1.64
• Republic of Armenia 0.86
• Republic of Belarus 4.13
• Republic of Kazakhstan 3.86
• Republic of Kyrgyzstan 0.95
• Republic of Moldova 1.29
• Russian Federation 61.34
• Republic of Tajikistan 0.82
• Turkmenistan 0.70
• Republic of Uzbekistan 3.27
• Ukraine 16.37
• TOTAL 95.23 (because "The combined share of Georgia, Latvia, Lithuania and Estonia, amounting to 4.77 percent, is not covered by this Agreement)

The document entered into force for 11 countries on 6 July 1992.

As the Kommersant newspaper wrote in 2006, "The statement of a group of creditor countries made during negotiations between representatives of the governments of these countries and a delegation of the Russian Federation in Paris on 2 April 1993 noted that the issue of the distribution of responsibility for the payment of the debt of the former USSR to foreign creditors should be resolved through the conclusion of bilateral agreements between the Russian Federation and other successor states of the former Union. As a result, the debt and assets of the USSR were transferred to Russia." On 9 December 1994, Ukraine and the Russian Federation concluded the Treaty on the Settlement of Issues of Succession to the External State Debts and Assets of the former USSR (the so-called ‘Zero Option’ Treaty). According to this treaty, Ukraine transfers to the Russian Federation the obligations to pay Ukraine's share in the external debt of the former USSR (Article 3), and the Russian Federation accepts Ukraine's share in the assets of the former USSR (Article 4) as of 1 December 1991. At the same time, the Treaty on the “zero option” has not been ratified by the Verkhovna Rada yet, i.e. it has no legal force.

Ukraine is the only former Soviet republic that has not ratified the zero-option treaty as of 2024.

As a result of the Russian government's announcement on 2 April 1993 that it would assume all obligations of the former Soviet republics to repay the USSR's foreign debt in return for their renunciation of their shares in the USSR's foreign assets, Russia received the entire external debt of 96.6 billion USD. This amount included loans from other countries and commercial obligations to members of the London Club of creditors, holders of VEB bonds and domestic government foreign currency loan bonds (OVGVZ). In 2017, the Russian Ministry of Finance announced that it had paid off the entire debt of the USSR and the last country to receive the money was Bosnia and Herzegovina. In 2022, the Russian embassy in the UK estimated that Russia paid out 110 billion dollars on its own.

In 2014, Ukrainian Prime Minister Arseniy Yatsenyuk raised the issue, to which the Russian Foreign Ministry responded at the time that Moscow reserves the right to insist that Ukraine immediately compensate $20 billion if Kiev returns to the “zero option” problem. In 2020, 2021 and 2022, Vladimir Putin reminded that Ukraine has still not ratified and acted on the signed document and continues to demand some of the assets of the former Soviet Union.

In the summer of 2022, Ukraine demanded the return of “at least a third of what is abroad (of the Soviet Union)”, including some facilities in the United Kingdom that Ukraine believes “were illegally registered to the Russian Federation”. The speaker of the State Duma, Vyacheslav Volodin, responded that Kiev should have taken on one third of the USSR debts before making such claims.

Internal debt

On 13 March 1992, the CIS Council of Heads of Government signed the Agreement on Principles and Mechanism of Servicing the Internal Debt of the Former USSR.

On March 13, 1992 the CIS Council of Heads of Governments signed an Appeal of the Heads of Governments of the participant states of the Commonwealth of Independent States and the Republic of Georgia in connection with the adoption of the Agreement on Principles and Mechanism of Servicing the Internal Debt of the Former USSR.

Domestic property and organizations

On 14 February 1992, the Heads of State instructed the heads of government and national (central) banks of the Commonwealth participating states to prepare within two weeks an interstate agreement on the division of assets and liabilities of the former State Bank of the USSR.

On 20 March 1992, the CIS Council of Heads of State signed an Agreement on the division of assets and liabilities of the former State Bank of the USSR between the central banks of the participant states of the Commonwealth of Independent States.

On 6 July 1992 the CIS Council of Heads of State signed the Agreement on Succession to the State Archives of the former Union of Soviet Socialist Republics.

On 9 October 1992, the CIS Council of Heads of State signed the Agreement on Mutual Recognition of Rights and Regulation of Property Relations.

Legacy of the Russian Empire

In 1996, Paris and Moscow signed an accord for Russia to partly repay czarist bonds. In 2010, Advokatskaya Gazeta, the newspaper of the Federal Chamber of Lawyers of the Russian Federation, reported that "In France, lawsuits were also filed against the Russian government, demanding repayment of the loan (in full). However, the court (in France) refused to recognize the Russian Federation as a guarantor for the issuance of the tsarist loans. According to the court's position, the actions of the Russian Empire are covered by diplomatic immunity, which the Russian Federation inherited as the legal successor of the Russian Empire and which neutralizes lawsuits directed against the Russian Federation."